Temporary anti-toppling supporting method for pier body inclination caused by landslide

Abstract

The invention relates to a temporary anti-toppling supporting method for pier body inclination caused by landslide, and relates to the technical field of construction. Comprising the steps of slope toe wall construction, toe wall foundation lofting, retaining wall foundation excavation, cushion layer pouring, formwork installation, concrete pouring and formwork removal and maintenance. The temporary anchoring system construction comprises the steps of anchor cable hole site lofting, drilling, anchor cable mounting, steel strand anchoring section grouting construction, pier column carrying pole beam construction position foundation leveling, temporary anchoring structure construction platform erecting, pier column carrying pole beam mounting, anchor backing plate and anchor head mounting, PE sleeve mounting, anchor cable mounting and tensioning; constructing a temporary anti-toppling device pile foundation: pre-burying a steel casing, placing a drilling machine in place and drilling, mounting a reinforcement cage and a sounding pipe, mounting a guide pipe, pouring micro-expansion concrete, and pre-burying a column foundation bolt; installing and constructing a temporary anti-dumping device steel support; installing a pile top anchoring steel plate, a steel pipe stand column, installing and welding an inclined strut, and pouring concrete in the stand column. The inclined pier body can be supported and stabilized.

Description

Technical Field

[0001] The invention relates to the technical field of project construction, and in particular to a temporary anti-dumping support method for a pier body that is tilted due to a landslide. Background Art

[0002] A landslide on one side of the overpass caused a large amount of mountain earth to impact the pier along the sliding surface, causing the pier to tilt and causing the upper part of the pier top to be dislocated from the original support. The offset was 1.3 meters according to the test report. The specific fracture position of the lower part of the pier column is currently unknown, and temporary on-site support is required. After the on-site temporary support construction is completed, the earthwork will be cleared for the second time, and then the design survey will confirm the specific protection measures. Due to the large amount of soil engineering caused by the landslide, the on-site earthwork and the overall bridge support are divided into two units for construction. Due to the complex structure of the mountain soil and the sliding belt soil, especially the soil will lose its original hardness after being washed by rainwater, there are many dangerous factors in construction on rainy days, and the construction is difficult. In addition, the construction area is under the existing bridge, with limited working clearance, making it difficult to select drilling and hoisting equipment, and customized modified equipment is required for drilling construction; there are stones mixed in the soil layer below the drilling location, which makes it easy for the hole to collapse when the pile foundation is drilled, and there are many isolated rocks when the earth is backfilled, which greatly interferes with the pile foundation drilling; the anti-dumping device and pier anchor are located at a high position and are heavy, so they need to be hoisted by a crane. At the same time, they are installed by humans riding on a aerial platform. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a temporary anti-dumping support method for the tilting of the pier body caused by a landslide. The method can enhance the stability of the slope and protect the pier body of the overpass from the influence of the landslide through the construction of the slope footing wall. The temporary anchoring system is constructed by setting anchor cables for lateral anchoring to generate reverse pulling force on the pier body, so that during the second clearing process, the interference with the pier body and the displacement deformation caused by the second tilting can be reduced. The soil engineering of the on-site construction platform can be stabilized through the pile foundation construction of the temporary anti-dumping device and the installation construction of the steel support of the temporary anti-dumping device, and then the tilted pier body can be supported and stabilized, thereby ensuring the sustainability of the slope under complex geological conditions and difficult construction conditions, and ensuring the construction speed and quality.

[0004] To achieve the above object, the present invention provides a temporary anti-dumping support method for a pier body that is tilted due to a landslide, comprising the following steps:

[0005] Step S1, construction of slope retaining wall: firstly, the retaining wall foundation is laid out, then the retaining wall foundation is excavated, then the cushion layer is poured, then the formwork is installed and fixed, and finally the concrete is poured and the formwork is removed for maintenance;

[0006] Step S2, construction of temporary anchoring system: firstly, stake out the anchor hole, then drill the hole, then install the anchor cable, then perform grouting construction of the anchoring section of the strand, then level the foundation of the pier column shoulder beam construction position, then set up a temporary anchoring structure construction platform, then install the pier column shoulder beam, then install the anchor pad and anchor head, then install the PE casing, and finally install the anchor cable and tension;

[0007] Step S3, temporary anti-dumping device pile foundation construction: first pre-embed the steel casing, then put the drilling rig in place and drill holes, then install the steel cage and the acoustic detection pipe, then install the conduit, then pour the micro-expansion concrete, and finally pre-embed the column foot bolts;

[0008] Step S4, installation and construction of steel support for temporary anti-dumping device: first install the anchor steel plate on the pile top, then install and weld the steel pipe columns and diagonal braces, and then pour concrete in the columns.

[0009] Furthermore, in step S1, after pouring the cushion layer, the method for installing and fixing the formwork is as follows:

[0010] After the foundation pit is excavated, the participating parties conduct a hidden inspection of the pit bottom. After confirmation, the on-site construction personnel calculate the volume of C25 cushion concrete and carry out cushion concrete. Since the base is a slope, the slump of concrete cannot be too large, and the concrete thickness is controlled at 10cm. The cushion size is controlled to exceed the footing wall by 10cm.

[0011] After the cushion concrete is poured and the cushion strength reaches 1.5MPa, the construction personnel are arranged to process the slope toe wall formwork. The formwork uses 1200*2400*16tmm bamboo plywood. Behind the bamboo plywood, 4*7.5cm wooden horizontal ribs are set with a spacing of 20cm. Double φ48 steel pipe vertical ribs are used on the outside of the horizontal ribs with a spacing of 60cm. Square wood is used for temporary support on the inside of the formwork, and the vertical ribs on both sides are fixed with φ16 butterfly buckles. After the formwork is installed and self-inspected and qualified, the supervisor is contacted in time to report the reinforced formwork. After the inspection is passed, the concrete is poured. When pouring concrete, the material must be symmetrically layered, and the layer thickness must not exceed 30cm, and it must be vibrated densely with a vibrating rod.

[0012] Furthermore, in step S2, the method steps for grouting construction of the anchoring section of the steel strand are as follows:

[0013] A1. Calculate the amount of materials to be used according to the depth of the rock hole on site, and prepare grouting materials, grouting equipment, grouting mixer, and reclaimed water on site according to the designed mix ratio;

[0014] A2. Start stirring: After pouring the grouting material into the mixer, add a certain proportion of water according to the mix ratio requirements, stir for 3 minutes, and check the consistency of the grouting material to see if it meets the working consistency requirements of the grouting machine;

[0015] A3. Grouting: After the grouting pipe is led out from the grouting machine, it is connected to the grouting of the anchor cable and grouting begins. The grouting pressure is The specific grouting pressure needs to be determined according to the on-site grouting conditions to control the grouting material pressure. During the grouting process, a dedicated person needs to be arranged to detect the grouting material level at the anchor hole. When the liquid level visually reaches the hole mouth, the grouting pressure should be reduced in time to allow the liquid level to slowly rise to the hole mouth and stop grouting.

[0016] A4. Grouting: Follow the same grouting method as above to complete the grouting of the remaining two bundles of anchor cables; then check the anchor cable holes that have been grouted. If the liquid level drops, install the grouting pipe on the grouting pipe and start grouting. When the liquid level reaches the hole mouth, wait for 5 minutes. If the liquid level does not drop any more, the grouting operation is completed.

[0017] Furthermore, in step S2, the method of installing the anchor cable and tensioning is as follows:

[0018] After the anchor structure on the pier side is welded, use nylon belt to tie the free end of the anchor cable firmly, pass one end through the anchor end, install the anchor on the steel strand, adjust the crane lifting point, manually pull each steel strand to a semi-tensioned state, and place the clip in time. After the clip is stressed, place the clip on the remaining 5 steel strands in the same way as above, so that the clip is in working condition;

[0019] After the grouting of the anchor cable is completed and the design strength of the grouting material reaches the tensioning requirement, the steel strand tensioning construction can be carried out;

[0020] Before tensioning the anchor cable, the tensioning equipment needs to be calibrated: During the calibration, the jack, oil pipe, bed force gauge and high-pressure oil pump are connected, and the test is repeated three times on the press machine using the jack's active force output method. The average value is taken and the curve of the jack's force (KN) and the pressure (MPa) indicated by the pressure gauge is drawn as the basis for tensioning the anchor cable;

[0021] The tensioning is divided into two times. During the first tensioning, the tensioning stress of each bundle is 6KN, that is, when the tensioning stress of each strand is 1KN, the state of the anchor cable is observed. After holding the load for 10 minutes, if the anchor cable is in a normal state, the second tensioning is started. The second tensioning reaches 101% of the design load. At this time, observe whether the anchor cable is in a taut state, and then increase the tensioning stress of each strand to 3.37KN, that is, the locking load of the anchor cable is reached; according to the same method, the remaining two bundles of anchor cables are tensioned until all three bundles of anchor cables are tensioned.

[0022] Furthermore, in step S3, the method for pre-embedding the steel casing is as follows:

[0023] The first section of the steel casing is drilled with a rotary drill and then placed in the casing + mechanical pressure method. First, use a rotary drill to drill at the pile position with a 1.9m barrel drill. When drilling to the location where there is a collapsed hole or a solitary rock on the hole wall, backfill with C20 concrete. After the pouring height exceeds the defect position by 2 meters, stop pouring to make the concrete compact and reinforce the hole wall at the location where the collapsed hole or solitary rock exists. When the concrete solidifies, continue drilling with a 1.6m drill bit. If there is no more collapsed hole when drilling into the medium-weathered rock layer, install a steel casing with a diameter of φ1800mm and continue drilling into the rock layer.

[0024] When installing the steel casing, a 16t truck crane is used to lift it into place, and after adjusting the verticality, the casing is pressed down by an excavator. The casing lowering length is controlled according to the height of the reinforced hole wall concrete. The initial length of the casing is 3-5 meters below the wellhead. If the bottom of the casing reaches the reinforced position, the steel casing will continue to be lowered. The specific lowering length needs to be determined according to the on-site hole collapse situation;

[0025] If the height of the casing that leaks out of the ground is too high, when drilling into the medium weathered rock formation, the drill bit will not be affected by the height of the casing when entering the hole, so the construction drilling can be carried out directly; if the casing exceeds the height of the ground when the drill bit enters the hole, it will affect the drill bit. Use an oxygen-acetylene cutter on site to cut off the protruding part, and then continue drilling into the medium weathered rock formation;

[0026] After drilling the holes, the steel casing of each pile is raised to reach the design height. After the steel casing is welded, the steel cage is installed and concrete is poured.

[0027] Furthermore, in step S3, the method of positioning the drilling machine and drilling a hole is as follows:

[0028] Before the drilling rig is in place, the base of the drilling rig should be leveled and kept stable without displacement and subsidence. Ensure that the drilling rig does not move or sink during the drilling construction process; the hole position should be accurate, so that the initial hole wall is vertical, round and solid. The hole construction should be carried out with light pressure and slow progress. During the drilling process, in order to prevent the occurrence of hole expansion and hole shrinkage accidents, the rotation speed and drilling speed should be slowed down. After the drill bit completely passes through the backfill soil layer, continue drilling at a normal drilling speed;

[0029] First, use a φ1900mm diameter barrel drill bit to drill, which is convenient for installing casing during normal drilling in the original soil layer and reinforcing the hole wall when the hole wall is uncontrollable. During the drilling process, check the hole diameter and verticality frequently. When the hole depth reaches the position of the medium-weathered rock layer, use a φ1600mm diameter drill bit to continue drilling. In response to the geological conditions and record the changes in the soil layer, retain the slag sample and put it in the slag sample box. Generally, take it every two to three meters, and then take it once when there is a geological change; and record the observation data regularly and by designated personnel; use different drilling speeds and drilling pressures for different soil layers;

[0030] When drilling in soil layers prone to hole collapse, timely retain image data and ask the design, supervision and owner to confirm the soil layer; if hole collapse occurs or there are many holes around the hole wall, withdraw the drilling rig in time and backfill the area with C20 concrete to allow the concrete to penetrate into the holes around the piles, which will have a dense and reinforced effect on the hole wall. After the concrete solidifies, continue drilling the hole. During the drilling process, reduce the drilling speed and drill slowly and evenly;

[0031] When pouring concrete in a collapsed hole or a large area of ​​holes around the pile, the concrete pouring height should be controlled to be more than 2 meters above the collapsed hole or the hole wall with holes around it. The concrete is squeezed into the collapsed hole or the pile foundation hole wall with holes around it by using its own weight pressure to form a relatively dense and stable hole wall, providing favorable construction conditions for subsequent drilling construction;

[0032] When drilling piles that have been backfilled with concrete, use a drill bit with a diameter of φ1600 for drilling. If there is a collapse or isolated rock geology, use the same method as above, reinforce the hole wall, and continue to use a drill bit with a diameter of φ1600 for drilling until the designed hole depth is reached;

[0033] During construction, check the wear and tear of the drill bit and the connection parts. If the tooth head is worn, repair it in time.

[0034] During the drilling operation, observe the changes in the ground where the main machine is located. If sinking is found, the machine should be stopped immediately for processing;

[0035] Drilling should be carried out continuously. When drilling is stopped for some reason, pay attention to setting up warning belts or surrounding equipment around the hole to prevent unauthorized personnel from entering the dangerous area near the bored pile; frequently check the changes in the surface soil around the pile hole; after drilling is completed, install the steel cage and pour concrete as soon as possible to prevent the hole from collapsing due to long empty time;

[0036] If any abnormal phenomenon is found during construction, the cause shall be promptly identified and measures shall be taken to deal with it; after the drilling reaches the designed depth, the hole position, hole diameter, hole depth and hole shape shall be inspected, and the hole inspection record sheet shall be filled in;

[0037] After the bored pile is bored, the pile guard is restored to check the displacement of the casing, and the casing top elevation is verified with a level, as well as the hole diameter, hole depth, hole shape, inclination and hole bottom geology. The hole depth is measured by hanging a 4kg to 6kg cylindrical hammer with a non-contracted measuring rope with a scale accuracy of 2cm, and the measuring rope is frequently re-measured during use;

[0038] Fill in the drilling record carefully when drilling, and make detailed records of the geological conditions of each stratum, and compare them with the drilling geological data provided by the design. If there are any differences, notify the supervision engineer in time;

[0039] According to the design requirements, the rock embedding depth of the pile bottom is no less than 4 times the pile diameter into the moderately weathered rock layer, and the specific data of the uniaxial compressive strength of the pile foundation shall be provided by the design unit;

[0040] After drilling to the designed elevation of the pile bottom, the column piles shall be checked against the geological slag samples of the bearing layer to confirm that they meet the design requirements and then report to the supervision engineer for inspection. If the geological conditions do not meet the requirements, they shall be reported to the supervision engineer and design unit immediately. The hole diameter, hole depth, hole shape, inclination and bottom geology shall be checked by the supervision engineer and the column piles shall be confirmed to be in compliance with the design before the next construction process is carried out.

[0041] Furthermore, in step S3, the method for installing the steel cage and the acoustic detection pipe is as follows:

[0042] The steel cage is processed uniformly at the construction site: the steel cage is processed and manufactured in sections, the basic section length is 11m, and the last section is the adjustment section; the main reinforcement joints are connected by mechanical sleeves, and the main reinforcement joints in the same connection section cannot exceed 50% of the main reinforcements of the same section; the main reinforcement and the reinforcing reinforcement are connected by spot welding to increase the rigidity of the steel cage;

[0043] The reinforcement cage reinforcement protection layer uses ear bars to ensure the thickness of the protection layer between the reinforcement cage and the hole wall; the ear bars are arranged in a group every 2m along the length of the reinforcement cage, with 4 pieces in each group, evenly distributed along the pile body in a plum blossom shape;

[0044] A steel cage processing area is set up under the bridge 1 km away from the bridge deck. The steel bars are transported to the site and hoisted at the hole mouth. The three-point method is used for hoisting. That is, the top of the steel cage is first fixed at two points with the large hook of the crane, and the middle part of the steel cage from 1 / 2 to 1 / 3 is hoisted with a small hook. When hoisting, the middle hoisting point is first lifted to slightly lift the skeleton, and then hoisted at the end point at the same time. After the skeleton leaves the ground, the middle point is stopped, and the end hoisting point is continued to be lifted. As the end hoisting point continues to rise, the middle hoisting point is slowly loosened until the skeleton is perpendicular to the ground, and the hoisting is stopped; the verticality of the steel cage is checked to ensure that the center lines of the upper and lower steel cages are consistent when they are connected; the acoustic detection tube adopts an inner diameter of 57 mm, 3mm thick seamless steel pipe, each pile foundation is equipped with 4 sonic detection pipes, the sonic detection pipes are arranged at equal intervals along the inner side of the pile body reinforcement stirrups and welded to the reinforcement stirrups, the corresponding joints of adjacent sections are marked, and the sonic detection pipes are connected with sleeves; the lower end of the sonic detection pipe is closed and the upper end is covered, there is no foreign matter in the pipe, the connection should be smooth and leak-proof; the bottom of the sonic detection pipe is 5cm away from the bottom of the pile and extends out of the pile head by 50cm; and the heights of the pipe openings of each sonic detection pipe should be consistent; welding or binding is used for fixing. When welding is used, avoid burning through the sonic detection pipe or forming weld nodules on the inner wall of the pipe, and carry out water injection test. If there is leakage, timely welding to ensure that the sonic detection pipe is leak-free.

[0045] Furthermore, in step S3, the method of pouring the micro-expansive concrete is as follows:

[0046] Concrete is mixed centrally at a mixing station. The concrete mix ratio is configured according to underwater concrete. Concrete is transported by concrete tank trucks. The slump, mold temperature and air content of concrete are tested before entering the funnel. The slump should be controlled between 18-22cm and maintain good workability. Concrete is transported by tank trucks. The design volume of concrete for a single pile foundation is 64.4 cubic meters. The number of transport vehicles is determined according to the location of the mixing station and the transportation time to ensure continuous material supply. Due to different hole diameters, the diameters of the drill holes used are different. During the pouring process, the pouring volume will exceed the original design volume. The construction site needs to be prepared for concrete filling.

[0047] The test personnel make concrete test pieces on site for curing under the same conditions, and mark the pile number, date, and concrete grade; record the concrete pouring conditions, pouring time, depth of concrete surface, buried depth of conduit, removal of conduit, and any abnormal phenomena that occur;

[0048] Concrete pouring is done with a steel conduit with an inner diameter of Φ30cm. The inner wall of the conduit should be smooth and round, with a consistent inner diameter and tight joints. The conduit is hoisted in sections by a crane, with threaded connections and anti-loosening devices. The conduit is located in the center of the borehole and a lifting test is carried out before concrete pouring. The lifting capacity of the crane should be compatible with the total weight and friction resistance of all the conduits after they are filled with concrete, and there should be a certain safety reserve.

[0049] After the initial stock of concrete is sufficient for the first batch of concrete to enter the hole, the depth of the conduit buried in the concrete shall not be less than 1m and not more than 3m;

[0050] Concrete should be poured continuously without any pause. During the concrete pouring process, the height of the concrete surface should be measured at any time to correctly calculate the depth of the conduit buried in the concrete. After the first batch of concrete mixture falls, the concrete should be poured continuously. After the ball is cut, the bolt is pulled or the valve is opened, and the first batch of concrete is poured into the bottom of the hole, the height of the concrete surface in the hole should be measured immediately to calculate the buried depth of the conduit. If it meets the requirements, pour normally.

[0051] During concrete pouring, a hammer is used to accurately measure the elevation of the top surface of the concrete, and the buried depth of the conduit is kept within the range of 2 to 6 meters, and the minimum buried depth shall not be less than 1 meter at any time; to prevent the conduit from leaking or the buried pipe from being too deep and unable to be pulled out, resulting in broken piles, the depth of the concrete surface must be carefully detected before pulling out the pipe, and the three-point measurement method is used when measuring the hole with a hammer to prevent mismeasurement; the hammer is generally made into a cone shape, preferably with a flat bottom, with a hammer bottom diameter of 15cm, a height of 12cm, and a weight of 4 to 6kg; the meter mark made of iron sheets on the measuring rope must be reinforced to prevent the meter mark from slipping and causing inaccurate positioning and causing the conduit to leak; a set of spare measuring ropes must be reserved for each pile pouring; detection must be careful and checked with the amount of poured concrete to prevent errors; when the hole depth measurement hammer is approaching the top surface of the pile, the detection must be careful and checked with the amount of poured concrete to prevent mismeasurement. If necessary, a simple concrete sampling cylinder is made on site, and the position when fresh concrete is taken out is the pouring height;

[0052] Underwater concrete should be poured continuously without pauses; the interruption time for removing the guide tube should be shortened, and the pouring time for each pile should not be too long. After the concrete pouring is completed, the hole casing below the ground and below the pile top should be pulled out after the initial setting of the concrete and before the final setting;

[0053] During the pouring process, the position of the top surface of the concrete in the wellbore should be frequently detected to adjust the buried depth of the guide tube in time. During the pouring process, prevent the concrete mixture from overflowing from the top of the funnel or falling from the outside of the funnel into the bottom of the hole, so that the mud contains cement and becomes thick and condensed, resulting in inaccurate detection. During the pouring process, pay attention to the drop of concrete in the pipe and the rise and fall of water level in the hole, measure the height of the concrete surface in the hole in time, and correctly command the lifting and removal of the guide tube;

[0054] When lifting the conduit, keep the axis vertical and the position centered, and lift it slowly and gradually; if the conduit flange is stuck on the steel frame, turn the conduit to disengage the steel frame, and then move it to the center of the drill hole;

[0055] When the conduit is lifted to a certain height above the exposed hole of the flange joint, remove one or two sections of the conduit; at this time, suspend the grouting, first remove the funnel, re-tie the conduit at the wellhead, and hang the lifting equipment, then loosen the joint bolts or quick connectors of the conduit, and at the same time lower the hook used to lift the conduit to hang the lifting ring on the upper end of the conduit to be removed. After all the bolts are removed or the quick connector is removed, lift the conduit to be removed and slowly put it on the ground, then reinsert the funnel into the conduit at the wellhead, calibrate the position, and continue grouting;

[0056] During the pouring process, when the concrete in the conduit is not full and contains air, the subsequent concrete should be poured in slowly.

[0057] Furthermore, in step S4, the method for installing the pile top anchoring steel plate is as follows:

[0058] Before the construction of steel pipe column support, the construction platform below the height of 6m on site adopts gantry support. The gantry support station is arranged according to the position of the pier body and the support position. Each frame must have a reliable connection. The slats and the gantry crossbars must be fully buckled. The walkway plate must be arranged in double pieces. The side uses φ48*3.5mm steel pipes as a castor to ensure stable support.

[0059] Since the height of the longitudinal cross brace is 2.1 meters and the height of the horizontal cross brace is 4.6 meters, a portal bracket is used on site to set up the working platform; when constructing the second horizontal connecting rod and the longitudinal cross brace, two aerial work trolleys are used on site as the manual operation platform, and a 16t crane is used to complete the hoisting of the upper part of the steel structure;

[0060] After the concrete strength of the pile foundation reaches 80% of the design strength, install the anchor steel plate on the previously embedded column foot anchor bolts, use a 16t crane, and use a spirit level to measure the flatness of the anchor steel plate. The error is controlled within 1mm. If the flatness is not met, remove the anchor steel plate, chisel or grind the pile top flat, install the anchor steel plate, and adjust the levelness.

[0061] Furthermore, in step S4, the method for installing and welding the steel pipe columns and diagonal braces is as follows:

[0062] After the installation of the anchor steel plate is completed, the 16t crane is used to hoist the vertical column steel pipe. The pipe diameter is 1200mm, the wall thickness is 20mm, and the total height of the column is 12 meters. The steel pipes of 6 meters each section are used on site, and the construction of the column is completed through welding. When installing each section of the column steel pipe, two lifting rings are welded at one end of the steel pipe to facilitate the use of the crane to place the lifting point. After the crane transfers the steel pipe column to the anchor steel plate, the verticality of the column is immediately adjusted. At the same time, the total station is used to cooperate and monitor and check the verticality of the steel pipe column.

[0063] After the first row of columns are welded and installed, the horizontal connecting steel pipes between the columns are welded at a height of 4600mm along the top of the pile. The diameter of the steel pipe is 600mm. The ends of the horizontal connecting steel pipes are measured and cut on the processing site. The size of the cut must meet the requirements of the drawings. The ends are drawn on the horizontal connecting steel pipes according to the curvature of the steel pipe wall of the column to ensure that the horizontal dimension is not more than 20mm after the weld gap is installed. After the first row of horizontal connecting steel pipes are welded, the longitudinal connecting pipes between the pier and the temporary column are welded and installed. The diameter of the steel pipe is 800mm and it is welded at a height of 2100mm along the top of the pile. The treatment method of the steel pipe ends is the same as that of the horizontal connecting pipes.

[0064] When installing the second row of column steel pipes, weld two limit blocks on the top of the first row of horizontal connecting steel pipes to prevent large shaking when connecting with the second row of horizontal connecting steel pipes; when installing the second row of horizontal connecting steel pipes, use a 16t truck crane to lift the second row of horizontal connecting steel pipes to the top of the first row of horizontal connecting steel pipes, use a spirit level and total station as auxiliary measuring instruments to ensure the verticality of the columns, quickly weld the column steel pipes, and after checking that the verticality of the columns meets the requirements, promptly weld the steel pipes; then weld the second row of horizontal connecting pipes at a welding height of 10600mm. After the second row of horizontal connecting pipes is welded, weld the longitudinal connecting pipes at a welding height of 10600mm. After welding, check the weld quality to ensure that the welding meets the requirements of the drawings.

[0065] The beneficial effects of the present invention are:

[0066] The present invention can enhance the stability of the slope and protect the pier body of the overpass from the influence of the landslide through the construction of the slope footing wall; the temporary anchoring system is constructed by arranging anchor cables for lateral anchoring to generate reverse pulling force on the pier body, so that in the second clearing process, the interference with the pier body and the displacement deformation caused by the second tilting can be reduced; through the temporary anti-dumping device pile foundation construction and the temporary anti-dumping device steel support installation construction, the soil engineering of the on-site construction platform part can be stabilized, and then the tilted pier body can be supported and stabilized, thereby ensuring the sustainability of the slope under complex geological conditions and difficult construction conditions, and ensuring the construction speed and quality. Drilling is carried out according to the principle of successful encryption in sequence, and the anchor section consolidation core mold grouting is carried out in time after the hole is formed to ensure the quality of the hole. The grouting of prestressed anchor cables can form anchor sections and provide an anti-corrosion protection layer for the prestress, and the grouting under a certain pressure can make the grouting body penetrate into the cracks and gaps, thereby consolidating the stratum and increasing the bearing capacity of the stratum, which will greatly improve the anchoring performance and permanence of the prestressed anchor cables. During the entire process of prestressed anchor cable construction, construction quality control is carried out, and the problems detected are corrected in time, so that the quality of the prestressed anchor cables is well controlled, ensuring the sustainability of the slope under complex geological conditions and difficult construction conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a flow chart of the construction of the slope toe wall of the present invention;

[0068] Figure 2 It is a flow chart of the construction of the temporary anchor system of the present invention;

[0069] Figure 3 A flowchart of the pile foundation construction of the temporary anti-dumping device of the present invention;

[0070] Figure 4The present invention is a flowchart of the installation and construction of the steel support of the temporary anti-dumping device. DETAILED DESCRIPTION

[0071] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0073] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0074] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0075] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0076] like Figure 1-4As shown, the present invention provides a temporary anti-dumping support method for a pier body that is tilted due to a landslide, comprising the following steps:

[0077] Step S1, construction of slope retaining wall: firstly, the retaining wall foundation is laid out, then the retaining wall foundation is excavated, then the cushion layer is poured, then the formwork is installed and fixed, and finally the concrete is poured and the formwork is removed for maintenance;

[0078] Step S2, construction of temporary anchoring system: firstly, stake out the anchor hole, then drill the hole, then install the anchor cable, then perform grouting construction of the anchoring section of the strand, then level the foundation of the pier column shoulder beam construction position, then set up a temporary anchoring structure construction platform, then install the pier column shoulder beam, then install the anchor pad and anchor head, then install the PE casing, and finally install the anchor cable and tension;

[0079] Step S3, temporary anti-dumping device pile foundation construction: first pre-embed the steel casing, then put the drilling rig in place and drill holes, then install the steel cage and the acoustic detection pipe, then install the conduit, then pour the micro-expansion concrete, and finally pre-embed the column foot bolts;

[0080] Step S4, installation and construction of steel support for temporary anti-dumping device: first install the anchor steel plate on the pile top, then install and weld the steel pipe columns and diagonal braces, and then pour concrete in the columns.

[0081] Before constructing the slope retaining wall, the design parameters of the retaining wall must be obtained first: the slope retaining wall constructed by the present invention is a gravity retaining wall, and the wall body is made of C25 plain concrete. The wall height is 2m, the width of the top of the wall is 0.75m, the slope of the wall back is 1:0.25, the height of the wall toe is 0.5m, the width is 0.3m, the slope of the bottom of the wall is 0.2:1, and the horizontal width of the bottom is 2.16m. Expansion joints are set every 10 to 16tm along the length of the wall: settlement joints should be set at the place where the bottom stratum of the foundation changes. Expansion joints and settlement joints can be set together, with a width of 20 to 30mm. The top, inner and outer sides of the wall in the joint are filled with asphalt-soaked wooden boards or asphalt hemp tendons, and the filling depth is 200mm. The bearing capacity of the retaining wall base shall not be less than 120kPa, and the base friction coefficient shall not be less than 0.3.

[0082] The specific construction steps of slope footing wall construction are as follows:

[0083] S11. Construction preparation

[0084] Professional technicians will review the drawings and prepare construction plans. After review, they will provide safety and technical training to construction personnel. Material plans will be issued in advance, and incoming materials will be inspected and accepted.

[0085] S12, measurement and setting out

[0086] The surveying personnel will measure and lay out the position of the slope guardrail on site, the on-site workers will use white lime to mark the traces of the foundation pit opening, and the on-site construction personnel will confirm the dimensions before the foundation pit excavation. The foundation pit can only be excavated after the drawings are verified to be correct. During the excavation process, the slope and depth of the foundation pit must be accurately controlled.

[0087] S13, excavation of the footing wall foundation

[0088] Before construction, ground drainage should be done to keep the foundation pit and slope dry. Use an excavator to excavate the foundation of the footing wall. It is required to excavate in layers. Digging is prohibited. After excavating to 20cm from the base, the trench is cleared manually and a light dynamic probe is used to test the foundation bearing capacity. The foundation bearing capacity is required to be no less than 120KPa. If it does not meet the requirements, replacement and filling treatment is required.

[0089] S14, cushion layer pouring

[0090] After the excavation of the foundation pit, the quality inspection, geological survey, supervision, design, owner and other construction units are organized to conduct hidden acceptance of the pit bottom. After confirmation, the on-site construction personnel calculate the volume of C25 cushion concrete and contact the cushion concrete. Since the base is a slope, the slump of concrete should not be too large, and the concrete thickness is controlled at 10cm. The cushion size is controlled to exceed the footing wall by 10cm.

[0091] S15, template installation

[0092] After the cushion concrete is poured and the cushion strength reaches 1.5MPa, the construction personnel can be arranged to process the slope foot wall template. The template uses 1200*2400*16tmm bamboo plywood. 4*7.5cm wooden square horizontal ribs are set behind the bamboo plywood with a spacing of 20cm. Double φ48 steel pipe vertical ribs are used on the outside of the horizontal ribs with a spacing of 60cm. Square wood is used for temporary support on the inside of the template. The vertical ribs on both sides are fixed with φ16 butterfly buckles. After the template installation is completed and the self-inspection is qualified, the supervisor is contacted in time to report the reinforced template. After the inspection is passed, the concrete is poured. When pouring concrete, the material must be laid symmetrically in layers, and the layer thickness must not exceed 30cm. It should be vibrated and compacted with a vibrating rod.

[0093] S16. Formwork removal and maintenance

[0094] After the concrete pouring is completed and the strength reaches 2MPa, the formwork can be removed. After the formwork is removed, it is covered and watered for curing.

[0095] S17, backfilling

[0096] After 7 days of curing of the retaining wall, the earthwork unit shall backfill the front and back of the wall according to the design requirements. When the horizontal slope of the ground behind the retaining wall is greater than 1:5, the soil foundation shall be backfilled after rough treatment of the ground to prevent the fill from sliding along the original ground; the backfill behind the wall must be filled and compacted in layers, and the density shall be handled according to the specific engineering roadbed design requirements; the foundation pit excavated in front of the retaining wall shall be backfilled with original soil after the construction of the retaining wall is completed, and compacted, and the compaction degree shall not be less than 90%.

[0097] The construction method of temporary anchor system is as follows:

[0098] S201. Construction preparation

[0099] Before the anchor cable construction, the site is leveled with an excavator.

[0100] S202, anchor hole position measurement and layout

[0101] The surveying personnel will measure and lay out the anchor point position, including the plane position, vertical position and drilling angle of the drill hole.

[0102] S203, drilling rig in place

[0103] The anchor cable drilling adopts the rock drilling trolley. After the trolley is delivered to the site by the transport vehicle, the equipment is inspected and accepted to ensure that it is in good working condition. Then it moves to the hole location by itself to prepare for drilling.

[0104] S204, drilling and steel casing follow-up

[0105] After the on-site operator debugged the machine, he conducted a test drill on the first hole. During the test drill, the relevant data of the drilling machine and the soil thickness were determined, and the distance to the rock was determined. Through the test drill, the rock formation conditions in the anchoring area were verified. After verification by the owner's supervisor, the drilling depth was determined to ensure the depth of rock penetration. After the drill bit of the drilling rig withdrew from the first hole, a steel casing with a diameter of 165mm was installed. The casing and the drill bit entered the soil layer synchronously. The length of each section of the casing was 1.8m. After each 1.8m, a section was installed, and the casing was tightened manually, and then driven into the soil until the length of the casing continued to advance 50cm relative to the thickness of the overburden layer. The casing was stopped, and the drilling machine drilled into the rock. After reaching the design requirement of more than 9m in thickness, the drilling was stopped, and high-pressure gas was used in time to blow the miscellaneous soil and rock and soil debris in the hole out of the hole.

[0106] S205, Steel Strand Processing and Threading

[0107] After the supervisor and the owner have no objection to the hole depth, the steel strands will be cut on site in a timely manner. The specific length of the steel strands will be calculated according to the length dimensions of the steel strands.

[0108] Calculation of the length of the steel strand: depth into rock (<9m) + thickness of soil covering layer + free section of the steel strand (the distance between the anchor point and the covering soil layer) + 1.2m.

[0109] The number of steel strands cut for each hole is 6. After the steel strands are cut on site, they are tied into bundles and installed as isolation scaffolding in accordance with the requirements of the design drawings.

[0110] Install the strand bundle of the anchoring section. After the strands are tied into bundles and the guide pipes and grouting pipes are installed, the on-site construction personnel will use on-site machinery to deliver the strands into the hole under the witness of the owner and the supervision unit. When delivering the strands on site, it is advisable to use a crane to tie them with nylon slings and deliver them into the anchor hole. Due to the limitations of on-site construction conditions, an excavator and a rock drilling trolley can be used to cooperate with each other to deliver the strand bundle into the hole.

[0111] S206, Grouting

[0112] Grouting construction of the anchoring section of the steel strand. The on-site steel strand bundle is placed in the anchor hole. After obtaining the consent of the supervisor, the grouting material is poured into the hole. The original design on site used M35 cement mortar. Because the mix ratio and the waiting time for relevant experimental strength tests were long, it was inconsistent with the emergency treatment progress of the project. After communicating with the design unit on the use of grouting materials, it was decided to use M30 high-strength non-shrinkage grouting material. According to previous construction results and construction experience, the strength of this grouting material can also fully meet the requirements of the design strength and bond strength of the steel strand. The construction method of M30 high-strength non-shrinkage grouting material is as follows:

[0113] a. Calculate the amount of materials needed based on the depth of the rock hole on site, and prepare grouting materials, grouting equipment, grouting mixer, and reclaimed water on site according to the designed mix ratio.

[0114] b. Start stirring. After pouring the grouting material into the mixer, add a certain proportion of water according to the mix ratio requirements, stir for 3 minutes, and check the consistency of the grouting material to see if it meets the working consistency requirements of the grouting machine (fluidity and workability meet the specification requirements).

[0115] c. Grouting. After the grouting pipe is led out from the grouting machine, it is connected to the grouting of the anchor cable and grouting begins. The grouting pressure is The specific grouting pressure needs to be determined according to the on-site grouting conditions to control the grouting material pressure. During the grouting process, a dedicated person needs to be arranged to detect the grouting material liquid level at the anchor hole position. When the liquid level can be visually observed to reach the hole mouth (casing mouth), the grouting pressure should be reduced in time to allow the liquid level to slowly rise to the hole mouth (casing mouth) and stop grouting.

[0116] d. Grouting. Use the same method to complete the grouting of the remaining two anchor cables. Then check the anchor cable holes that have been grouted. If the liquid level drops, install the grouting pipe on the grouting pipe and start grouting. When the liquid level reaches the hole position, wait for about 5 minutes. If the liquid level does not drop any more, the grouting operation is completed.

[0117] S207, foundation leveling at the construction location of pier column and shoulder beam

[0118] During the construction of the temporary anchor structure, a construction platform needs to be set up. The anchor position is at an elevation of 253.135 and the original ground elevation is Within the scope, the ground is leveled with an excavator and then hardened with C20 concrete.

[0119] S208, temporary anchor structure construction platform

[0120] As the construction volume of the anchor structure is relatively small, during construction, only a movable platform for workers is needed, and the bearing capacity of the foundation is not required to be high. It was decided to use a portal scaffolding as the construction platform. The scaffolding specifications are: width 1.35m, length 1.93m, single-layer height 2.2m, erection height of two layers, and a portal scaffolding platform is installed on each pier.

[0121] The door-type scaffolding is easy, fast and flexible to set up. Place 4*7.5*400cm wooden planks under the door-type scaffolding columns as the scaffolding pads. When the scaffolding height reaches 1.2 meters at the anchoring position, fix the scaffolding. When the scaffolding is fixed laterally, use φ48*3.6mm steel pipes as a brace. Use two steel pipes on one side of the scaffolding to set up and stabilize the scaffolding.

[0122] S209, pier column shoulder beam installation

[0123] The on-site surveyor locates the anchor position and determines the anchor height. Then, according to the requirements of the drawings, the drilling positions are evenly arranged. The hole positions meet the design drawing dimensions. A pneumatic drill with a drill bit of φ28 is used to drill on the pier body. The drilling depth is 0.3m. The debris of each hole is cleaned with an air compressor, and then a hole cleaning brush is used for secondary cleaning to ensure that there are no debris, slag and concrete dust in the hole. Then, a new brush is used to apply the rebar glue. After the bolt anchor section is fully coated with the rebar glue, the steel bar is inserted into the hole in time. If no rebar glue flows out, the above operation is repeated until the liquid glue overflows continuously without bubbling when the rebar is planted into the hole. The remaining three piers are implanted in the hole correctly according to the design dimensions and heights according to the same operation. After the rebar glue reaches the strength (determine the strength time of the rebar glue according to the rebar glue material instructions), the punched steel plate is installed on the anchored bolt. After the steel plates on the four piers are fixed with bolts, a 16t crane is used to lift the 2I36B I-beam and lift it to the designed position. The two ends of the I-beam are manually straightened. First, an electric welder is used to spot weld the connection between the end of the I-beam and the two steel plates. Then, the horizontal position of the I-beam is determined using a level ruler and the reference line of the pier elevation. After verification, if there is no difference between the actual position of the I-beam and the designed position, an electric welder is used to weld from both ends at the same time. After the four steel plates are welded firmly, the tension of the crane is removed. Then, the connection between the I-beam and the steel plate is fully welded as a whole to meet the design welding requirements. When welding the second I-beam, the same method is used to fully weld the I-beam.

[0124] S210, Anchor plate and anchor head installation

[0125] After the I-beam is welded, the steel plate at the anchor cable anchor position is welded. The anchor cable hole position is also determined by the technicians. After the steel plate is welded, the specific position is fine-tuned. After confirming that there is no difference with the designed position, the I-beam and steel plate are fully welded. In the same way, the anchor pad at the fixed end of the anchor cable is fully welded. In addition, it should be noted that when welding the steel plate with a perforated position for the anchor cable, the linear position of the hole for the anchor cable must be ensured to be correct.

[0126] S211, install PE casing

[0127] After each steel strand is derusted and degreased, first apply lubricating oil or anti-corrosion paint on the surface of the anchor cable, then wrap it with plastic sheeting, then apply lubricating oil or anti-corrosion paint on the plastic sheeting, and wrap it with plastic sheeting to form two coatings and two cloths, finally put it into the PE casing, and fill the plastic casing with grease to finally form a double layer of anti-corrosion; a jointless casing should be used for the free section. When there is a joint, the lap length at the joint should be greater than 50mm and sealed with tape.

[0128] S212, installation of anchor cables and tensioning

[0129] After the anchor structure on the pier side is welded, a 16t crane is used to tie the free end of the anchor cable firmly with a nylon belt. Under the command of the construction manager, one end is passed through the anchor end, and the construction personnel install the anchor on the steel strand. After adjusting the crane lifting point, each steel strand is manually pulled to a semi-tensioned state, and the clips are placed in time. After the clips are stressed, the remaining 5 steel strands are placed with clips in the same way as above, so that the clips are in working condition.

[0130] After the grouting of the grouting material is completed and the design strength of the grouting material reaches the tensioning requirement, the steel strand tensioning construction can be carried out.

[0131] Before tensioning the anchor cable, the tensioning equipment needs to be calibrated. During calibration, the jack, oil pipe, bed force gauge and high-pressure oil pump are connected, and the jack is used to actively output force on the press. Repeat the test three times, take the average value, and draw a curve of the jack output (KN) and the pressure (MPa) indicated by the pressure gauge as the basis for tensioning the anchor cable. Because the initial starting pressure of domestic pressure gauges is not exactly the same, the pressure gauge number at the time of calibration must be indicated on the calibration curve, and it must not be replaced during use. The pressure gauge must be recalibrated after it is damaged or the jack is disassembled.

[0132] This tensioning is divided into two times. In the first tensioning, the tensioning stress of each bundle is 6KN, that is, when the tensioning stress of each strand is 1KN, observe the state of the anchor cable. After holding the load for 10 minutes, if the anchor cable is in a normal state, start the second tensioning. The second tensioning reaches 101% of the design load. At this time, observe whether the anchor cable is in a taut state, and then increase the tensioning stress of each strand to 3.37KN, that is, reach the design load of 20KN, which is the locking load of the anchor cable. In the same way, tension the remaining two bundles of anchor cables until all three bundles of anchor cables are tensioned.

[0133] S213, anti-exit measures for clips

[0134] According to the design requirements, after the anchor cable is tensioned, the clip of the anchor must be prevented from withdrawing. Prepare a 5mm steel plate on site, drill two anchor holes around the anchor hole according to the anchor hole position, weld the anchor bolts to the anchor pad, and use bolts to fix the steel plate of the anti-withdrawal clip to the upper part of the anchor.

[0135] The method of temporary anti-dumping device pile foundation construction is as follows:

[0136] S31. Site leveling

[0137] Before bored pile construction, a detailed construction survey is conducted to fully understand the actual situation on site. All technical preparations are strictly carried out, including: on-site verification of construction drawings, calculation of pile position coordinates and elevation. When bored piles are constructed, the construction site should be leveled first. If the bearing capacity of the site foundation cannot meet the construction requirements of the drilling rig, a 2000*6000*18mm steel plate can be placed under the drilling rig construction platform to stabilize the foundation of the drilling rig operation platform.

[0138] S32, measurement and setting out

[0139] After the site is leveled, the pile position coordinates are accurately laid out. After the laying out is completed, the relative positions of the pile centers should be rechecked and measured. After the recheck is correct, no less than two groups of guard piles should be measured and laid out in time to check the pile position and restore the pile hole center during the drilling process. The next process can only be carried out after the re-measurement is qualified by the supervision engineer. The cross line of the pile foundation is also laid out.

[0140] S33, casing burial

[0141] This embodiment adopts the method of casing + C20 concrete to reinforce the hole wall. The casing wall thickness is 14mm. The inner diameter of the casing is 100-200mm larger than the designed pile diameter. The casing top elevation is controlled according to the pile top elevation, and the casing burial depth meets the following requirements:

[0142] The first section of steel casing is drilled with a rotary drill and then placed in the casing + mechanical pressure method. First, use a rotary drill to drill at the pile position using a 1.9m barrel drill. When drilling to a collapsed hole or a boulder on the hole wall, backfill with C20 concrete. After the pouring height exceeds the defect position by 2 meters, stop pouring to allow the concrete to compact and reinforce the hole wall at the collapsed hole or boulder location. After the concrete solidifies, continue drilling with a 1.6m drill bit. If drilling into the medium-weathered rock stratum, no more collapsed holes occur. At this time, install a steel casing with a diameter of φ1800mm and continue drilling into the rock stratum.

[0143] When installing the steel casing, due to limited space on site, a 16t truck crane can be used to lift it into place. After adjusting the verticality, an excavator can be used to press the casing down. The lowering length of the casing is controlled according to the height of the existing reinforced hole wall concrete. The initial plan is to lower the casing length to 3-5 meters below the wellhead. If the bottom of the casing reaches the reinforcement position and can be easily lowered, the steel casing will continue to be lowered. The specific lowering length needs to be determined based on the on-site hole collapse situation.

[0144] If the height of the casing that leaks out of the ground is too high, when drilling into the weathered rock stratum, the drill bit will not be affected by the height of the casing when entering the hole, so construction drilling can be carried out directly; if the casing exceeds the height of the ground when the drill bit enters the hole and affects the drill bit, use an oxygen-acetylene cutter on site to cut off the protruding part before continuing drilling into the weathered rock stratum.

[0145] Because the elevation of the designed ground is 249.5, the original ground elevation on site is different. After measuring the original ground elevation of the 4 pile foundations on site, the original ground elevations of the 4 pile foundations are as follows: the elevation of pile foundation 3-1 is 248.79, which is 0.71m different from the design elevation; the elevation of pile foundation 3-2 is 248.736, which is 0.764m different from the design elevation; the elevation of pile foundation 3-3 is 248.471, which is 1.029m different from the design elevation; the elevation of pile foundation 3-4 is 248.459, which is 1.041m different from the design elevation. In order to ensure that the elevation of the top surface of the pile foundation meets the design elevation and provide construction conditions for the subsequent steel support construction, after drilling the hole, the steel casing of each pile needs to be heightened to make its height reach the design requirement. After the steel casing is welded, the steel cage is installed and the concrete is poured.

[0146] The allowable deviation and inspection method of casing embedment are shown in Table 1:

[0147]

[0148] Table 1

[0149] S34, drilling rig positioning and drilling

[0150] This construction adopts rotary drilling and drilling. Due to the clearance limitation under the beam, a customized 360 rotary drilling rig with a drill rig height of 13m is required. The drill bit diameters are φ1900mm and φ1600mm. The diameter of φ1900mm is mainly used for casing installation and reinforcement of the hole wall when the hole wall is uncontrollable, and the diameter of φ1600mm is mainly used for construction after entering the stable foundation rock layer.

[0151] The rotary drilling rig is transported to the site by a transport vehicle. After the on-site assembly is completed, the equipment is inspected and accepted. After ensuring that the working condition is good, the drilling rig automatically goes to the hole position and prepares to drill. Before the drilling construction, the pile position should be re-measured. The re-measurement should meet the requirement that the hole position center deviation is no more than 5cm, and the drilling can only be started after the re-measurement is qualified by the supervision engineer.

[0152] Before the drilling rig is in place, the base of the drilling rig should be leveled and kept stable without displacement and subsidence, ensuring that the drilling rig does not move or sink during the drilling construction. The hole position should be accurate, so that the initial hole wall is vertical, round and solid. The hole construction should be done with light pressure and slow progress. During the drilling process, in order to prevent accidents such as hole expansion and hole shrinkage, the rotation speed and drilling speed should be slowed down. After the drill bit completely passes through the backfill soil layer, continue drilling at a normal drilling speed.

[0153] First, use a φ1900mm diameter barrel drill bit to drill, which is convenient for installing casing during normal drilling in the original soil layer and reinforcing the hole wall when the hole wall is uncontrollable. During the drilling process, check the hole diameter and verticality frequently. When the hole depth reaches the position of the medium-weathered rock layer, use a φ1600mm diameter drill bit to continue drilling. In response to the geological conditions and record the changes in the soil layer, retain the slag sample and put it in the slag sample box. Generally, take it every two to three meters, and then take it once when there is a geological change. And record the observation data regularly, such as geological conditions, drilling speed, etc. Use different drilling speeds and drilling pressures for different soil layers;

[0154] When drilling in soil layers that are prone to hole collapse, such as sand, soft soil or backfill soil, timely retain image data and ask the design, supervision and owner to confirm the soil layer. If there is a hole collapse or many holes around the hole wall, withdraw the drilling rig in time, use C20 concrete to backfill the area, so that the concrete invades the holes around the pile, and plays a role in compacting and reinforcing the hole wall. After the concrete solidifies, continue to drill the hole. During the drilling process, the drilling speed needs to be reduced and the drilling should be carried out slowly and evenly.

[0155] When pouring concrete in the presence of collapsed holes or large areas of holes around piles, the concrete pouring height needs to be controlled to be more than 2 meters above the collapsed hole or the area with holes around the hole wall. The concrete's own weight pressure is used to squeeze the concrete into the collapsed hole or the pile foundation hole wall with holes around it, forming a relatively dense and stable hole wall, providing favorable construction conditions for subsequent drilling construction.

[0156] When drilling piles that have been backfilled with concrete, a drill bit with a diameter of φ1600 should be used for drilling construction. If the hole collapses or there are isolated rocks in the geology, use the same method as above. After reinforcing the hole wall, continue to use a drill bit with a diameter of φ1600 to drill until the designed hole depth is reached.

[0157] During construction, check the wear and connection parts of the drill bit. If the teeth are worn, repair them in time.

[0158] During the drilling operation, the changes in the ground where the main machine is located should be observed, and if sinking is found, the machine should be stopped and handled in time.

[0159] Drilling should be carried out continuously. When drilling is stopped for some reason, it is necessary to set up a warning belt or surrounding equipment around the hole to prevent unauthorized personnel from entering the dangerous area near the bored pile. Check the changes in the surface soil around the pile hole frequently. After drilling is completed, the steel cage should be installed and concrete should be poured as soon as possible to prevent the hole from collapsing due to long empty time.

[0160] If any abnormal phenomena such as drilling deviation, hole expansion, or hole shrinkage are found during construction, the cause should be found out in time and measures should be taken to deal with it in time. After the drilling reaches the designed depth, the hole position, hole diameter, hole depth and hole shape should be inspected, and the hole inspection record form should be filled in.

[0161] After the bored pile is bored, the pile guard should be restored to check the displacement of the casing, and the casing top elevation should be checked with a level, as well as the hole diameter, hole depth, hole shape, inclination and hole bottom geology. The hole depth is measured by hanging a 4kg to 6kg cylindrical hammer with a non-contracted measuring rope with a scale accuracy of 2cm, and the measuring rope should be re-measured frequently during use.

[0162] When drilling, the drilling records should be filled out carefully and detailed records should be made of the geological conditions of each stratum. At the same time, they should be compared with the drilling geological data provided by the design. If there are any differences, the supervising engineer should be notified in time.

[0163] According to the design requirements, the rock embedding depth of the pile bottom shall be no less than 4 times the pile diameter into the moderately weathered rock layer, and the specific data of the uniaxial compressive strength of the pile foundation shall be provided by the design unit.

[0164] After drilling to the designed elevation of the pile bottom, the column piles shall be checked against the geological slag samples of the bearing layer to confirm that they meet the design requirements and then report to the supervision engineer for inspection. If the geological conditions do not meet the requirements, they shall be reported to the supervision engineer and design unit immediately. The hole diameter, hole depth, hole shape, inclination and bottom geology shall be checked by the supervision engineer and the column piles shall be confirmed to be in compliance with the design before the next construction process is carried out.

[0165] The allowable deviation of bored pile drilling is shown in Table 2:

[0166]

[0167] Table 2

[0168] S35, Clear Hole

[0169] After drilling is completed, the first hole cleaning should be carried out in time. During the first hole cleaning, both the rotary drilling rig and the impact drill use the slag removal method to remove the slag and clean the hole.

[0170] S36, steel cage and acoustic detection pipe installation

[0171] The steel cage is processed uniformly at the construction site. The steel cage is processed and manufactured in sections, with a basic section length of 11m and the last section being an adjustment section. The main reinforcement joints are connected by mechanical sleeves, and the main reinforcement joints in the same connection section cannot exceed 50% of the main reinforcements of the same section. The main reinforcement and the reinforcing ribs are connected by spot welding to increase the rigidity of the steel cage.

[0172] The reinforcement cage reinforcement protection layer uses ear bars to ensure the thickness of the protection layer between the reinforcement cage and the hole wall. The ear bars are arranged in a group every 2m along the length of the reinforcement cage, with 4 pieces in each group, evenly distributed along the pile body in a plum blossom shape.

[0173] A steel cage processing area is set up under the bridge 1 km away from the bridge deck. The steel cage processing area is transported to the flatbed truck by a 16t truck crane, and then transported to the site by the flatbed truck. The steel cage is placed at the hole by a 16t truck crane. The three-point method is used for lifting, that is, the top of the steel cage is first fixed at two points with the large hook of the crane, and the middle part of the steel cage from 1 / 2 to 1 / 3 is lifted by a small hook. When lifting, the middle lifting point is first lifted to slightly lift the skeleton, and then the end point is lifted at the same time. After the skeleton leaves the ground, the middle point is stopped, and the end lifting point is continued to be lifted. As the end lifting point continues to rise, the middle lifting point is slowly relaxed until the skeleton is perpendicular to the ground, and the lifting is stopped. Check the verticality of the steel cage. If there is any bending of the steel bar, it should be straightened to ensure that the center line of the upper and lower steel cages is consistent when they are connected.

[0174] Install the acoustic testing pipe according to the design requirements and ensure that all comprehensive grounding test indicators are qualified.

[0175] The sonic detection pipe adopts a seamless steel pipe with an inner diameter of 57mm and a wall thickness of 3mm. Four sonic detection pipes are set for each pile foundation. The sonic detection pipes are arranged at equal intervals along the inner side of the pile body reinforcement stirrups and welded to the reinforcement stirrups. The corresponding joints of adjacent sections are marked, and the sonic detection pipes are connected by sleeves. The lower end of the sonic detection pipe is closed and the upper end is covered. There is no foreign matter in the pipe. The connection should be smooth and leak-proof. The bottom of the sonic detection pipe is 5cm away from the bottom of the pile and extends 50cm from the pile head. The height of the pipe openings of each sonic detection pipe should be consistent. The fixing method can be welding or binding. When welding is used, it should be avoided to burn through the sonic detection pipe or form a weld nodule on the inner wall of the pipe. A water injection test should be carried out. If there is a leak, it should be repaired in time to ensure that the sonic detection pipe is leak-free.

[0176] The comparison table of steel bar mechanical connection torque values ​​is shown in Table 3:

[0177]

[0178] Table 3

[0179] S37, duct installation

[0180] The conduit is a 30cm steel conduit. The inner wall of the conduit must be smooth and round, the inner diameter is consistent, and the interface is tight. The conduit must be tested for assembly and water tightness before use, and numbered and marked in order from bottom to top. The axis deviation of the conduit after assembly shall not exceed 0.5% of the drilling depth and shall not be greater than 10cm. The nut of the connecting bolt should be on top; the test pressure is 1.5 times the hydrostatic pressure at the bottom of the hole. The length of the conduit is determined by the hole depth and the height of the working platform. The conduit joint flange is added with a conical slip-on, and there shall be no flange at the lower end of the bottom conduit. A spiral threaded joint is used, and an anti-loosening device is installed.

[0181] Place the conduit in the center of the borehole and conduct a lifting test before pouring concrete. The capacity of the conduit lifting equipment should be adapted to the total weight and friction resistance of all conduits after they are filled with concrete, and there should be a certain safety reserve.

[0182] The concrete pouring adopts a 16t truck crane to support the suspended conduit, and a concrete funnel is placed on the top. After the conduit is installed, there is a space of 30-40cm between the bottom of the conduit and the bottom of the hole.

[0183] S38, concrete pouring

[0184] Concrete is mixed centrally at a mixing station. The concrete mix ratio is configured according to underwater concrete. Concrete is transported by concrete tank trucks. The slump, mold temperature and air content of the concrete are tested before entering the funnel. The slump should be controlled between 18-22cm and maintain good workability. Concrete is transported by tank trucks. The design volume of concrete for a single pile foundation is 64.4 cubic meters. The number of transport vehicles is determined according to the location of the mixing station and the transportation time to ensure continuous feeding. Due to different hole diameters, the diameters of the drill holes used are different. During the pouring process, the pouring volume will exceed the original design volume. The construction site needs to be prepared for concrete filling.

[0185] The test personnel made concrete test pieces on site (using 150×150×150mm test pieces) for curing under the same conditions, and marked the pile number, date, and concrete grade. A dedicated person recorded the concrete pouring conditions, pouring time, depth of the concrete surface, buried depth of the conduit, removal of the conduit, and any abnormal phenomena that occurred.

[0186] Concrete pouring is done by using a steel conduit with an inner diameter of Φ30cm. The inner wall of the conduit should be smooth and round, with a consistent inner diameter and tight joints. The conduit is hoisted in sections by a crane, with threaded connections and anti-loosening devices. The conduit should be located in the center of the borehole, and a lifting test should be carried out before concrete pouring. The lifting capacity of the crane should be compatible with the total weight and friction resistance of all conduits after they are filled with concrete, and there should be a certain safety reserve.

[0187] After the initial stock of concrete is sufficient for the first batch of concrete to enter the hole, the depth of the conduit buried in the concrete shall not be less than 1m and not more than 3m;

[0188] Concrete should be poured continuously without any pause. During the concrete pouring process, the height of the concrete surface should be measured at any time to correctly calculate the depth of the conduit buried in the concrete. After the first batch of concrete mixture falls, the concrete should be poured continuously. After the ball is cut, the bolt is pulled or the valve is opened, and the first batch of concrete is poured into the bottom of the hole, the height of the concrete surface in the hole is immediately measured to calculate the buried depth of the conduit. If it meets the requirements, normal pouring can be carried out.

[0189] During concrete pouring, a hammer is used to accurately measure the elevation of the top surface of the concrete, and the buried depth of the conduit is kept within the range of 2 to 6 meters. The minimum buried depth shall not be less than 1 meter at any time. To prevent the conduit from leaking or the buried pipe cannot be pulled out too deeply, resulting in broken piles, the depth of the concrete surface must be carefully detected before pulling out the pipe. When using a hammer to measure the hole, a three-point measurement method is used to prevent mismeasurement. The hammer is generally made into a cone shape, preferably with a flat bottom. The bottom diameter of the hammer is about 15 cm, the height is 12 cm, and the weight is 4 to 6 kg. The meter mark made of iron sheets on the measuring rope must be reinforced to prevent the meter mark from slipping and causing inaccurate positioning and causing leakage of the conduit; a set of spare measuring ropes must be reserved for each pile pouring. Be careful when detecting, and check with the amount of poured concrete to prevent errors. When the hole depth measurement hammer is close to the top surface of the pile, mismeasurement is prone to occur due to the increase in sediment thickness and thickening of mud. The detection must be carried out carefully and the amount of poured concrete must be used to check to prevent mismeasurement. If necessary, a simple concrete sampling cylinder can be made on site, and the position when fresh concrete is taken out is the pouring height.

[0190] Underwater concrete should be poured continuously without pause. The interruption time for removing the guide tube should be shortened as much as possible. The pouring time of each pile should not be too long. After the concrete pouring is completed, the hole casing below the ground and below the pile top should be pulled out after the initial setting of the concrete and before the final setting.

[0191] During the pouring process, the position of the top surface of the concrete in the wellbore should be frequently detected, and the buried depth of the conduit should be adjusted in time. During the pouring process, the concrete mixture should be prevented from overflowing from the top of the funnel or falling from the outside of the funnel into the bottom of the hole, so that the mud contains cement and becomes thick and condensed, resulting in inaccurate detection. During the pouring process, attention should be paid to observing the drop of concrete in the pipe and the rise and fall of water level in the hole, and the height of the concrete surface in the hole should be measured in time to correctly command the lifting and removal of the conduit.

[0192] When lifting the conduit, the axis should be kept vertical and centered, and it should be lifted gradually and slowly. If the conduit flange is stuck on the steel frame, the conduit can be rotated to disengage the steel frame and then moved to the center of the drill hole.

[0193] When the conduit is lifted to a certain height above the exposed hole of the flange joint, one or two sections of the conduit can be removed (depending on the length of each section of the conduit and the height of the working platform from the hole). At this time, suspend the perfusion, first remove the funnel, re-tie the conduit at the wellhead, and hang the lifting equipment, then loosen the joint bolts or quick connectors of the conduit, and at the same time lower the hook used to lift the conduit to hang the lifting ring on the upper end of the conduit to be removed. After all the bolts are removed or the quick connector is removed, lift the conduit to be removed, slowly put it on the ground, then reinsert the funnel into the conduit at the wellhead, correct the position, and continue perfusion. The interruption time for removing the conduit should be shortened as much as possible. Prevent bolts, rubber pads and tools from falling into the hole. Pay attention to safety, and clean the removed pipe sections immediately and stack them neatly.

[0194] During the pouring process, when the concrete in the duct is not full and contains air, the subsequent concrete should be poured in slowly and not poured into the funnel and duct all at once to avoid the formation of high-pressure air bags in the duct.

[0195] When the concrete surface rises to the lower end of the frame, measures can be taken to prevent the steel frame from being lifted up by the concrete:

[0196] ① When the concrete surface approaches and initially enters the steel cage, the bottom of the conduit should be 3m below and 1m above the bottom of the steel cage, and the concrete pouring speed should be slowed down to reduce the upward impact force of the concrete after it comes out of the conduit.

[0197] ② When the concrete in the hole enters the steel skeleton by 4m to 5m, lift the conduit appropriately and reduce the buried length of the conduit to increase the buried depth of the skeleton below the conduit mouth, thereby increasing the grip of the concrete on the steel skeleton.

[0198] ③ When the concrete is poured to the design elevation, if there is no floating slurry on the concrete surface, the concrete height shall be controlled according to the pile top elevation. If there is floating slurry on the concrete surface, when the concrete is poured to the pile top elevation, in order to ensure the anchoring strength of the embedded column foot anchor bolts, pouring can continue until the concrete floating slurry overflows, and pouring shall be stopped until fresh concrete aggregate overflows.

[0199] During the concrete pouring process, fill in the "Concrete Pouring Record" truthfully.

[0200] S39, embedded column base bolts

[0201] After the concrete pouring height reaches the design elevation, before reaching the initial setting state, the column foot anchor bolts are installed. There are two methods for installing the column foot anchor bolts. First, after the steel cage is installed, the column foot anchor bolts are welded to the main reinforcement of the steel cage according to the design height. The column foot steel plate holes are processed with 3mm steel plates to make the column foot anchor bolts. After fixing the anchor bolt position, the positioning steel plate is removed, and then the guide tube is installed and the concrete is poured. Second, when installing the column foot anchor bolts, the positioning steel bar skeleton for controlling the anchor bolts should be made in advance. Limiting steel bars should be welded on each anchor bolt to facilitate the different height positions of the column foot anchor bolt steel bars when placed on the positioning skeleton. The positioning skeleton is made of two hoops and a steel pipe with a diameter of 40mm. The steel bars are made of φ16 circular rings, with a total of 16 positioning holes.

[0202] The column foot anchor bolts must ensure that the center position of the column foot anchor bolts is accurate, and the anchor steel plate can be easily installed after the concrete solidifies.

[0203] The installation and construction method of the temporary anti-dumping device steel support is as follows:

[0204] S41. Install the anchor steel plate on the pile top

[0205] Before the construction of steel pipe column support, the construction platform below the height of 6m on site adopts gantry support. The gantry support station is arranged according to the position of the pier body and the support position. Each frame section must have a reliable connection. The slats and the gantry crossbar must be fully buckled. The walkway board must be arranged in double pieces. The side uses φ48*3.5mm steel pipes as a brace for stable support. A horizontal railing with a height of 1.2m must be installed on the upper part of the construction platform, and there must be a place to hang a safety rope when the operator is operating. On-site high-altitude operators must wear safety belts to work, and high-altitude operations are not allowed without wearing safety belts.

[0206] Since the height of the longitudinal cross brace is 2.1 meters and the height of the horizontal cross brace is 4.6 meters, a portal bracket is used on site to set up the working platform. When constructing the second horizontal connecting rod and longitudinal cross brace, two aerial work platforms are used on site as manual operation platforms, and a 16t crane is used to complete the hoisting of the upper part of the steel structure.

[0207] After the concrete strength of the pile foundation reaches 80% of the design strength, install the anchor steel plate on the previously embedded column foot anchor bolts, use a 16t crane, and use a spirit level to measure the flatness of the anchor steel plate. The error is controlled within 1mm. If the flatness is not met, remove the anchor steel plate, chisel or grind the pile top flat, install the anchor steel plate, and adjust the levelness.

[0208] S42, Steel pipe column and diagonal brace installation and welding

[0209] After the installation of the anchoring steel plate is completed, a 16t crane is used to hoist the vertical column steel pipe. The pipe diameter is 1200mm, the wall thickness is 20mm, and the total height of the column is 12 meters. The steel pipes of 6 meters each section are used on site, and the construction of the column is completed through welding. When installing each section of the column steel pipe, two lifting rings are welded at one end of the steel pipe to facilitate the use of the crane to place the lifting point. After the crane transfers the steel pipe column to the anchoring steel plate, the verticality of the column is immediately adjusted. At the same time, a total station is used to cooperate and monitor and check the verticality of the steel pipe column. The welding construction of steel pipes at different heights uses a lifting construction trolley.

[0210] After the first column is welded and installed, the horizontal steel pipe between the columns is welded at 4600mm along the top of the pile. The diameter of the steel pipe is 600mm. The end of the horizontal steel pipe is measured and cut on the processing site. The cut size must meet the requirements of the drawing. The end is drawn on the horizontal steel pipe according to the curvature of the column steel pipe wall to ensure that the horizontal dimension does not exceed 20mm after the weld gap after installation. After the first horizontal connection pipe is welded, the longitudinal connection pipe between the pier and the temporary column is welded and installed. The diameter of the steel pipe is 800mm. The welding is carried out at 2100mm along the top of the pile. The treatment method of the steel pipe end is similar to that of the horizontal connection pipe. However, it should be noted that the radius of the arc drawn at the end will be different due to different steel pipe diameters. The end position can only be cut after repeated confirmation on site.

[0211] When installing the second steel pipe for the column, two limit blocks can be welded on the top of the first steel pipe to prevent large shaking when docking with the second steel pipe. When installing the second steel pipe, use a 16t truck crane to lift the steel pipe to the top of the first steel pipe, use a level and a total station as auxiliary measuring instruments to ensure the verticality of the column, quickly weld the steel pipe for the column, and after checking that the verticality of the column meets the requirements, weld the steel pipe in time. Then weld the second horizontal connecting pipe with a welding height of 10600mm. After the horizontal connecting pipe is welded, weld the longitudinal connecting pipe with a welding height of 10600mm. The welding method is the same as the welding method for the first longitudinal and transverse steel pipes. After welding, check the quality of the weld to ensure that the welding meets the requirements of the drawings.

[0212] After the installation of the steel pipe columns and the longitudinal and transverse connecting pipes between the columns are completed, the longitudinal connecting braces between the columns should be welded in time. The welding dimensions and methods are the same as the welding method of the steel pipes between the columns.

[0213] S43, Concrete pouring in columns

[0214] The concrete inside the steel pipe of the column is C30 micro-expansive concrete. A truck pump is used for pouring on site. Since the pouring height exceeds 10 meters, according to the specification, corresponding measures should be taken when the concrete pouring height exceeds 2 meters. Since the top of the column is about 4 meters above the beam body, the pump truck cannot be inserted into the pipe at one time, and only the front 2.5-meter hose can be inserted. In order to ensure that the concrete drop is reduced, a 6-meter nylon fire hose connected to the truck pump hose is used as a string tube to pour concrete inside the steel pipe column. The pouring height is the height of the column top.

[0215] The present invention can enhance the stability of the slope and protect the pier body of the overpass from the influence of the landslide through the construction of the slope footing wall; the temporary anchoring system is constructed by arranging anchor cables for lateral anchoring to generate reverse pulling force on the pier body, so that in the second clearing process, the interference with the pier body and the displacement deformation caused by the second tilting can be reduced; through the temporary anti-dumping device pile foundation construction and the temporary anti-dumping device steel support installation construction, the soil engineering of the on-site construction platform part can be stabilized, and then the tilted pier body can be supported and stabilized, thereby ensuring the sustainability of the slope under complex geological conditions and difficult construction conditions, and ensuring the construction speed and quality. Drilling is carried out according to the principle of successful encryption in sequence, and the anchor section consolidation core mold grouting is carried out in time after the hole is formed to ensure the quality of the hole. The grouting of prestressed anchor cables can form anchor sections and provide an anti-corrosion protection layer for the prestress, and the grouting under a certain pressure can make the grouting body penetrate into the cracks and gaps, thereby consolidating the stratum and increasing the bearing capacity of the stratum, which will greatly improve the anchoring performance and permanence of the prestressed anchor cables. During the entire process of prestressed anchor cable construction, construction quality control is carried out, and the problems detected are corrected in time, so that the quality of the prestressed anchor cables is well controlled, ensuring the sustainability of the slope under complex geological conditions and difficult construction conditions.

[0216] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A temporary anti-dumping support method for piers that tilt due to landslides. It is characterized in that The steps include: Step S1, construction of slope retaining wall: firstly, the retaining wall foundation is laid out, then the retaining wall foundation is excavated, then the cushion layer is poured, then the formwork is installed and fixed, and finally the concrete is poured and the formwork is removed for maintenance; Step S2, construction of temporary anchoring system: firstly, stake out the anchor hole, then drill the hole, then install the anchor cable, then perform grouting construction of the anchoring section of the strand, then level the foundation of the pier column shoulder beam construction position, then set up a temporary anchoring structure construction platform, then install the pier column shoulder beam, then install the anchor pad and anchor head, then install the PE casing, and finally install the anchor cable and tension; Step S3, temporary anti-dumping device pile foundation construction: first pre-embed the steel casing, then put the drilling rig in place and drill holes, then install the steel cage and the acoustic detection pipe, then install the conduit, then pour the micro-expansion concrete, and finally pre-embed the column foot bolts; Step S4, installation and construction of steel support for temporary anti-dumping device: first install the anchor steel plate on the pile top, then install and weld the steel pipe columns and diagonal braces, and then pour concrete in the columns.

2. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 1, It is characterized in that In step S1, after pouring the cushion layer, the method for installing and fixing the formwork is as follows: After the foundation pit is excavated, the participating parties conduct a hidden inspection of the pit bottom. After confirmation, the on-site construction personnel calculate the volume of C25 cushion concrete and carry out cushion concrete. Since the base is a slope, the slump of concrete cannot be too large, and the concrete thickness is controlled at 10cm. The cushion size is controlled to exceed the footing wall by 10cm. After the cushion concrete is poured and the cushion strength reaches 1.5MPa, the construction personnel are arranged to process the slope toe wall formwork. The formwork uses 1200*2400*16tmm bamboo plywood. Behind the bamboo plywood, 4*7.5cm wooden horizontal ribs are set with a spacing of 20cm. Double φ48 steel pipe vertical ribs are used on the outside of the horizontal ribs with a spacing of 60cm. Square wood is used for temporary support on the inside of the formwork, and the vertical ribs on both sides are fixed with φ16 butterfly buckles. After the formwork is installed and self-inspected and qualified, the supervisor is contacted in time to report the reinforced formwork. After the inspection is passed, the concrete is poured. When pouring concrete, the material must be symmetrically layered, and the layer thickness must not exceed 30cm, and it must be vibrated densely with a vibrating rod.

3. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 1, It is characterized in that In step S2, the method steps for grouting construction of the anchoring section of the steel strand are as follows: A1. Calculate the amount of materials to be used according to the depth of the rock hole on site, and prepare grouting materials, grouting equipment, grouting mixer, and reclaimed water on site according to the designed mix ratio; A2. Start stirring: After pouring the grouting material into the mixer, add a certain proportion of water according to the mix ratio requirements, stir for 3 minutes, and check the consistency of the grouting material to see if it meets the working consistency requirements of the grouting machine; A3. Grouting: After the grouting pipe is led out from the grouting machine, it is connected to the grouting of the anchor cable and grouting begins. The grouting pressure is The specific grouting pressure needs to be determined according to the on-site grouting conditions to control the grouting material pressure. During the grouting process, a dedicated person needs to be arranged to detect the grouting material level at the anchor hole. When the liquid level visually reaches the hole mouth, the grouting pressure should be reduced in time to allow the liquid level to slowly rise to the hole mouth and stop grouting. A4. Grouting: Follow the same grouting method as above to complete the grouting of the remaining two bundles of anchor cables; then check the anchor cable holes that have been grouted. If the liquid level drops, install the grouting pipe on the grouting pipe and start grouting. When the liquid level reaches the hole mouth, wait for 5 minutes. If the liquid level does not drop any more, the grouting operation is completed.

4. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 3, It is characterized in that In step S2, the method of installing the anchor cable and tensioning is as follows: After the anchor structure on the pier side is welded, use nylon belt to tie the free end of the anchor cable firmly, pass one end through the anchor end, install the anchor on the steel strand, adjust the crane lifting point, manually pull each steel strand to a semi-tensioned state, and place the clip in time. After the clip is stressed, place the clip on the remaining 5 steel strands in the same way as above, so that the clip is in working condition; After the grouting of the anchor cable is completed and the design strength of the grouting material reaches the tensioning requirement, the steel strand tensioning construction can be carried out; Before tensioning the anchor cable, the tensioning equipment needs to be calibrated: During the calibration, the jack, oil pipe, bed force gauge and high-pressure oil pump are connected, and the test is repeated three times on the press machine using the jack's active force output method. The average value is taken and the curve of the jack's force (KN) and the pressure (MPa) indicated by the pressure gauge is drawn as the basis for tensioning the anchor cable; The tensioning is divided into two times. During the first tensioning, the tensioning stress of each bundle is 6KN, that is, when the tensioning stress of each strand is 1KN, the state of the anchor cable is observed. After holding the load for 10 minutes, if the anchor cable is in a normal state, the second tensioning is started. The second tensioning reaches 101% of the design load. At this time, observe whether the anchor cable is in a taut state, and then increase the tensioning stress of each strand to 3.37KN, that is, the locking load of the anchor cable is reached; according to the same method, the remaining two bundles of anchor cables are tensioned until all three bundles of anchor cables are tensioned.

5. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 1, It is characterized in that In step S3, the method for pre-embedding the steel casing is as follows: The first section of the steel casing is drilled with a rotary drill and then placed in the casing + mechanical pressure method. First, use a rotary drill to drill at the pile position with a 1.9m barrel drill. When drilling to the location where there is a collapsed hole or a solitary rock on the hole wall, backfill with C20 concrete. After the pouring height exceeds the defect position by 2 meters, stop pouring to make the concrete compact and reinforce the hole wall at the location where the collapsed hole or solitary rock exists. When the concrete solidifies, continue drilling with a 1.6m drill bit. If there is no more collapsed hole when drilling into the medium-weathered rock layer, install a steel casing with a diameter of φ1800mm and continue drilling into the rock layer. When installing the steel casing, a 16t truck crane is used to lift it into place, and after adjusting the verticality, the casing is pressed down by an excavator. The casing lowering length is controlled according to the height of the reinforced hole wall concrete. The initial length of the casing is 3-5 meters below the wellhead. If the bottom of the casing reaches the reinforced position, the steel casing will continue to be lowered. The specific lowering length needs to be determined according to the on-site hole collapse situation; If the height of the casing that leaks out of the ground is too high, when drilling into the medium weathered rock formation, the drill bit will not be affected by the height of the casing when entering the hole, so the construction drilling can be carried out directly; if the casing exceeds the height of the ground when the drill bit enters the hole, it will affect the drill bit. Use an oxygen-acetylene cutter on site to cut off the protruding part, and then continue drilling into the medium weathered rock formation; After drilling the holes, the steel casing of each pile is raised to reach the design height. After the steel casing is welded, the steel cage is installed and concrete is poured.

6. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 5, It is characterized in that In step S3, the method of positioning the drilling machine and drilling holes is as follows: Before the drilling rig is in place, the base of the drilling rig should be leveled and kept stable without displacement and subsidence. Ensure that the drilling rig does not move or sink during the drilling construction process; the hole position should be accurate, so that the initial hole wall is vertical, round and solid. The hole construction should be carried out with light pressure and slow progress. During the drilling process, in order to prevent the occurrence of hole expansion and hole shrinkage accidents, the rotation speed and drilling speed should be slowed down. After the drill bit completely passes through the backfill soil layer, continue drilling at a normal drilling speed; First, use a φ1900mm diameter barrel drill bit to drill, which is convenient for installing casing during normal drilling in the original soil layer and reinforcing the hole wall when the hole wall is uncontrollable. During the drilling process, check the hole diameter and verticality frequently. When the hole depth reaches the position of the medium-weathered rock layer, use a φ1600mm diameter drill bit to continue drilling. In response to the geological conditions and record the changes in the soil layer, retain the slag sample and put it in the slag sample box. Generally, take it every two to three meters, and then take it once when there is a geological change; and record the observation data regularly and by designated personnel; use different drilling speeds and drilling pressures for different soil layers; When drilling in soil layers prone to hole collapse, timely retain image data and ask the design, supervision and owner to confirm the soil layer; if hole collapse occurs or there are many holes around the hole wall, withdraw the drilling rig in time and backfill the area with C20 concrete to allow the concrete to penetrate into the holes around the piles, which will have a dense and reinforced effect on the hole wall. After the concrete solidifies, continue drilling the hole. During the drilling process, reduce the drilling speed and drill slowly and evenly; When pouring concrete in a collapsed hole or a large area of ​​holes around the pile, the concrete pouring height should be controlled to be more than 2 meters above the collapsed hole or the hole wall with holes around it. The concrete is squeezed into the collapsed hole or the pile foundation hole wall with holes around it by using its own weight pressure to form a relatively dense and stable hole wall, providing favorable construction conditions for subsequent drilling construction; When drilling piles that have been backfilled with concrete, use a drill bit with a diameter of φ1600 for drilling. If there is a collapse or isolated rock geology, use the same method as above, reinforce the hole wall, and continue to use a drill bit with a diameter of φ1600 for drilling until the designed hole depth is reached; During construction, check the wear and tear of the drill bit and the connection parts. If the tooth head is worn, repair it in time. During the drilling operation, observe the changes in the ground where the main machine is located. If sinking is found, the machine should be stopped immediately for processing; Drilling should be carried out continuously. When drilling is stopped for some reason, pay attention to setting up warning belts or surrounding equipment around the hole to prevent unauthorized personnel from entering the dangerous area near the bored pile; frequently check the changes in the surface soil around the pile hole; after drilling is completed, install the steel cage and pour concrete as soon as possible to prevent the hole from collapsing due to long empty time; If any abnormal phenomenon is found during construction, the cause shall be promptly identified and measures shall be taken to deal with it; after the drilling reaches the designed depth, the hole position, hole diameter, hole depth and hole shape shall be inspected, and the hole inspection record sheet shall be filled in; After the bored pile is bored, the pile guard is restored to check the displacement of the casing, and the casing top elevation is verified with a level, as well as the hole diameter, hole depth, hole shape, inclination and hole bottom geology. The hole depth is measured by hanging a 4kg to 6kg cylindrical hammer with a non-contracted measuring rope with a scale accuracy of 2cm, and the measuring rope is frequently re-measured during use; Fill in the drilling record carefully when drilling, and make detailed records of the geological conditions of each stratum, and compare them with the drilling geological data provided by the design. If there are any differences, notify the supervision engineer in time; According to the design requirements, the rock embedding depth of the pile bottom is no less than 4 times the pile diameter into the moderately weathered rock layer, and the specific data of the uniaxial compressive strength of the pile foundation shall be provided by the design unit; After drilling to the designed elevation of the pile bottom, the column piles shall be checked against the geological slag samples of the bearing layer to confirm that they meet the design requirements and then report to the supervision engineer for inspection. If the geological conditions do not meet the requirements, they shall be reported to the supervision engineer and design unit immediately. The hole diameter, hole depth, hole shape, inclination and bottom geology shall be checked by the supervision engineer and the column piles shall be confirmed to be in compliance with the design before the next construction process is carried out.

7. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 6, It is characterized in that In step S3, the method for installing the steel cage and the acoustic detection pipe is as follows: The steel cage is processed uniformly at the construction site: the steel cage is processed and manufactured in sections, the basic section length is 11m, and the last section is the adjustment section; the main reinforcement joints are connected by mechanical sleeves, and the main reinforcement joints in the same connection section cannot exceed 50% of the main reinforcements of the same section; the main reinforcement and the reinforcing reinforcement are connected by spot welding to increase the rigidity of the steel cage; The reinforcement cage reinforcement protection layer uses ear bars to ensure the thickness of the protection layer between the reinforcement cage and the hole wall; the ear bars are arranged in a group every 2m along the length of the reinforcement cage, with 4 pieces in each group, evenly distributed along the pile body in a plum blossom shape; A steel cage processing area is set up under the bridge 1 km away from the bridge deck. The steel bars are transported to the site and hoisted at the hole mouth. The three-point method is used for hoisting. That is, the top of the steel cage is first fixed at two points with the large hook of the crane, and the middle part of the steel cage from 1 / 2 to 1 / 3 is hoisted with a small hook. When hoisting, the middle hoisting point is first lifted to slightly lift the skeleton, and then hoisted at the end point at the same time. After the skeleton leaves the ground, the middle point is stopped, and the end hoisting point is continued to be lifted. As the end hoisting point continues to rise, the middle hoisting point is slowly loosened until the skeleton is perpendicular to the ground, and the hoisting is stopped; the verticality of the steel cage is checked to ensure that the center lines of the upper and lower steel cages are consistent when they are connected; the acoustic detection tube adopts an inner diameter of 57 mm, 3mm thick seamless steel pipe, each pile foundation is equipped with 4 sonic detection pipes, the sonic detection pipes are arranged at equal intervals along the inner side of the pile body reinforcement stirrups and welded to the reinforcement stirrups, the corresponding joints of adjacent sections are marked, and the sonic detection pipes are connected with sleeves; the lower end of the sonic detection pipe is closed and the upper end is covered, there is no foreign matter in the pipe, the connection should be smooth and leak-proof; the bottom of the sonic detection pipe is 5cm away from the bottom of the pile and extends out of the pile head by 50cm; and the heights of the pipe openings of each sonic detection pipe should be consistent; welding or binding is used for fixing. When welding is used, avoid burning through the sonic detection pipe or forming weld nodules on the inner wall of the pipe, and carry out water injection test. If there is leakage, timely welding to ensure that the sonic detection pipe is leak-free.

8. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 7, It is characterized in that In step S3, the method of pouring the micro-expansion concrete is as follows: Concrete is mixed centrally at a mixing station. The concrete mix ratio is configured according to underwater concrete. Concrete is transported by concrete tank trucks. The slump, mold temperature and air content of concrete are tested before entering the funnel. The slump should be controlled between 18-22cm and maintain good workability. Concrete is transported by tank trucks. The design volume of concrete for a single pile foundation is 64.4 cubic meters. The number of transport vehicles is determined according to the location of the mixing station and the transportation time to ensure continuous material supply. Due to different hole diameters, the diameters of the drill holes used are different. During the pouring process, the pouring volume will exceed the original design volume. The construction site needs to be prepared for concrete filling. The test personnel make concrete test pieces on site for curing under the same conditions, and mark the pile number, date, and concrete grade; record the concrete pouring conditions, pouring time, depth of concrete surface, buried depth of conduit, removal of conduit, and any abnormal phenomena that occur; Concrete pouring is done with a steel conduit with an inner diameter of Φ30cm. The inner wall of the conduit should be smooth and round, with a consistent inner diameter and tight joints. The conduit is hoisted in sections by a crane, with threaded connections and anti-loosening devices. The conduit is located in the center of the borehole and a lifting test is carried out before concrete pouring. The lifting capacity of the crane should be compatible with the total weight and friction resistance of all the conduits after they are filled with concrete, and there should be a certain safety reserve. After the initial stock of concrete is sufficient for the first batch of concrete to enter the hole, the depth of the conduit buried in the concrete shall not be less than 1m and not more than 3m; Concrete should be poured continuously without any pause. During the concrete pouring process, the height of the concrete surface should be measured at any time to correctly calculate the depth of the conduit buried in the concrete. After the first batch of concrete mixture falls, the concrete should be poured continuously. After the ball is cut, the bolt is pulled or the valve is opened, and the first batch of concrete is poured into the bottom of the hole, the height of the concrete surface in the hole should be measured immediately to calculate the buried depth of the conduit. If it meets the requirements, pour normally. During concrete pouring, a hammer is used to accurately measure the elevation of the top surface of the concrete, and the buried depth of the conduit is kept within the range of 2 to 6 meters, and the minimum buried depth shall not be less than 1 meter at any time; to prevent the conduit from leaking or the buried pipe from being too deep and unable to be pulled out, resulting in broken piles, the depth of the concrete surface must be carefully detected before pulling out the pipe, and the three-point measurement method is used when measuring the hole with a hammer to prevent mismeasurement; the hammer is generally made into a cone shape, preferably with a flat bottom, with a hammer bottom diameter of 15cm, a height of 12cm, and a weight of 4 to 6kg; the meter mark made of iron sheets on the measuring rope must be reinforced to prevent the meter mark from slipping and causing inaccurate positioning and causing the conduit to leak; a set of spare measuring ropes must be reserved for each pile pouring; detection must be careful and checked with the amount of poured concrete to prevent errors; when the hole depth measurement hammer is approaching the top surface of the pile, the detection must be careful and checked with the amount of poured concrete to prevent mismeasurement. If necessary, a simple concrete sampling cylinder is made on site, and the position when fresh concrete is taken out is the pouring height; Underwater concrete should be poured continuously without pauses; the interruption time for removing the guide tube should be shortened, and the pouring time for each pile should not be too long. After the concrete pouring is completed, the hole casing below the ground and below the pile top should be pulled out after the initial setting of the concrete and before the final setting; During the pouring process, the position of the top surface of the concrete in the wellbore should be frequently detected to adjust the buried depth of the guide tube in time. During the pouring process, prevent the concrete mixture from overflowing from the top of the funnel or falling from the outside of the funnel into the bottom of the hole, so that the mud contains cement and becomes thick and condensed, resulting in inaccurate detection. During the pouring process, pay attention to the drop of concrete in the pipe and the rise and fall of water level in the hole, measure the height of the concrete surface in the hole in time, and correctly command the lifting and removal of the guide tube; When lifting the conduit, keep the axis vertical and the position centered, and lift it slowly and gradually; if the conduit flange is stuck on the steel frame, turn the conduit to disengage the steel frame, and then move it to the center of the drill hole; When the conduit is lifted to a certain height above the exposed hole of the flange joint, remove one or two sections of the conduit; at this time, suspend the grouting, first remove the funnel, re-tie the conduit at the wellhead, and hang the lifting equipment, then loosen the joint bolts or quick connectors of the conduit, and at the same time lower the hook used to lift the conduit to hang the lifting ring on the upper end of the conduit to be removed. After all the bolts are removed or the quick connector is removed, lift the conduit to be removed and slowly put it on the ground, then reinsert the funnel into the conduit at the wellhead, calibrate the position, and continue grouting; During the pouring process, when the concrete in the conduit is not full and contains air, the subsequent concrete should be poured in slowly.

9. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 1, It is characterized in that In step S4, the method for installing the pile top anchoring steel plate is as follows: Before the construction of steel pipe column support, the construction platform below the height of 6m on site adopts gantry support. The gantry support station is arranged according to the position of the pier body and the support position. Each frame must have a reliable connection. The slats and the gantry crossbars must be fully buckled. The walkway plate must be arranged in double pieces. The side uses φ48*3.5mm steel pipes as a castor to ensure stable support. Since the height of the longitudinal cross brace is 2.1 meters and the height of the horizontal cross brace is 4.6 meters, a portal bracket is used on site to set up the working platform; when constructing the second horizontal connecting rod and the longitudinal cross brace, two aerial work trolleys are used on site as the manual operation platform, and a 16t crane is used to complete the hoisting of the upper part of the steel structure; After the concrete strength of the pile foundation reaches 80% of the design strength, install the anchor steel plate on the previously embedded column foot anchor bolts, use a 16t crane, and use a spirit level to measure the flatness of the anchor steel plate. The error is controlled within 1mm. If the flatness is not met, remove the anchor steel plate, chisel or grind the pile top flat, install the anchor steel plate, and adjust the levelness.

10. A temporary anti-dumping support method for a pier body tilted due to a landslide as claimed in claim 1, It is characterized in that In step S4, the method for installing and welding the steel pipe columns and diagonal braces is as follows: After the installation of the anchor steel plate is completed, the 16t crane is used to hoist the vertical column steel pipe. The pipe diameter is 1200mm, the wall thickness is 20mm, and the total height of the column is 12 meters. The steel pipes of 6 meters each section are used on site, and the construction of the column is completed through welding. When installing each section of the column steel pipe, two lifting rings are welded at one end of the steel pipe to facilitate the use of the crane to place the lifting point. After the crane transfers the steel pipe column to the anchor steel plate, the verticality of the column is immediately adjusted. At the same time, the total station is used to cooperate and monitor and check the verticality of the steel pipe column. After the first column is welded and installed, the horizontal connecting steel pipe between the columns is welded at 4600mm along the pile top elevation. The diameter of the steel pipe is 600mm. The end of the horizontal connecting steel pipe is measured and cut on the processing site. The size of the cut must meet the requirements of the drawing. The end is drawn on the horizontal connecting steel pipe according to the curvature of the column steel pipe wall to ensure that the horizontal dimension is not more than 20mm after installation. After the first horizontal connecting steel pipe is welded, the longitudinal connecting pipe between the pier and the temporary column is welded and installed. The diameter of the steel pipe is 800mm. Welding is carried out at 2100mm along the pile top elevation. The treatment method of the steel pipe end is the same as that of the horizontal connecting pipe. When installing the second row of column steel pipes, weld two limit blocks on the top of the first row of horizontal connecting steel pipes to prevent large shaking when connecting with the second row of horizontal connecting steel pipes; when installing the second row of horizontal connecting steel pipes, use a 16t truck crane to lift the second row of horizontal connecting steel pipes to the top of the first row of horizontal connecting steel pipes, use a spirit level and total station as auxiliary measuring instruments to ensure the verticality of the columns, quickly weld the column steel pipes, and after checking that the verticality of the columns meets the requirements, promptly weld the steel pipes; then weld the second row of horizontal connecting pipes at a welding height of 10600mm. After the second row of horizontal connecting pipes is welded, weld the longitudinal connecting pipes at a welding height of 10600mm. After welding, check the weld quality to ensure that the welding meets the requirements of the drawings.

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