Underground diaphragm wall structure and construction method thereof

Abstract

The invention discloses an underground diaphragm wall structure and a construction method thereof, and belongs to the technical field of underground diaphragm walls. The joint of the first-order reinforcement cage and the second-order reinforcement cage is improved, so that a formed construction joint between the first-order wall body and the second-order wall body is not a flat joint any more, but is a special-shaped joint formed by compounding multiple types of lines, the length of the joint is greatly prolonged, the moisture permeation difficulty is increased, and the waterproof effect is enhanced. Meanwhile, the first-order reinforcement cage and the second-order reinforcement cage are not in simple lap joint any more, but are combined in a lock catch connection mode and a plug pin connection mode, various stress modes such as pulling, twisting and bending can be borne, the connection strength is good, and stress transmission is continuous. In addition, the width of the reinforcement cage at the joint of the first-order reinforcement cage and the second-order reinforcement cage is not changed, and meanwhile, the structural strength of the joint is enhanced due to the addition of the first plate body, the second plate body and the steel pipe.

Description

Technical Field

[0001] The present invention relates to the technical field of ground-connected walls, and more specifically, to a ground-connected wall structure and a construction method thereof. Background Art

[0002] The underground continuous wall structure is a trenching machine used on the ground in foundation engineering, mainly used as a water interception, anti-seepage, load-bearing and water retaining structure. As the first and most important construction link of deep foundation pit engineering, the underground continuous wall structure plays an important role in stabilizing the stratum and ensuring the safety of the internal structure of the deep foundation pit in the construction of deep foundation pit engineering.

[0003] The underground connecting wall is usually constructed by the joint pipe method. However, this method has the following problems: there is a risk of leakage when using the slot joint pipe method, and the stress transfer is not continuous; due to the large contact surface of the joint pipe connection, a large mechanical pull-out force is generally required, and a large mechanical equipment is required in the equipment selection, which is not very economical in practical application. Therefore, in the patent with application number 202210079452.8, a method for constructing an underground cast-in-place continuous wall and its connection structure are disclosed. By setting the corresponding first nested joint and the second nested joint, and adopting an effective movable buckle connection structure, the concrete walls constructed with different hole sequences are connected into an effective whole. However, the reinforcement width of the underground connecting wall formed by this method at the joint is smaller than the width of the main body of the steel cage, which is the weak point of the underground connecting wall structure. At the same time, the construction joint between the first poured wall and the later poured wall is a flat joint, which is prone to leakage. Summary of the invention

[0004] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0005] In order to achieve these purposes and other advantages according to the present invention, a construction method of a ground-connected wall structure is provided, comprising:

[0006] Guide wall construction, mud preparation, slotting between guide walls to form a sequence of slot holes, using mud to protect the wall during slotting, and then removing the sediment at the bottom of the slot;

[0007] A first-order steel bar cage is arranged below the first-order slot hole, and a first joint is arranged at the end of the first-order steel bar cage facing the second-order slot hole, the first joint comprises a first plate body with an Ω-shaped horizontal cross-sectional profile, the first plate body extends from the top to the bottom of the first-order steel bar cage, and the two side edges of the first plate body respectively extend to the outside of the two side walls of the first-order steel bar cage and leave a gap with the hole wall of the first-order slot hole, the outer walls of the two flat plate parts of the first plate body are both provided with C-shaped lock buckles, the arc-shaped portion of the first plate body protrudes out of the first-order steel bar cage, and a steel pipe is coaxially arranged in the arc-shaped portion of the first plate body, a first branch pipe is connected between the outer wall of the steel pipe and the arc-shaped portion of the first plate body along the radial direction of the steel pipe, the steel pipe wall and the arc-shaped portion of the first plate body are both provided with a first through hole connected with the first branch pipe, a latch is arranged in the first through hole, the tail of the latch is provided with a sliding slope and extends into the steel pipe, and the head of the latch is flush with the outer wall of the arc-shaped portion of the first plate body;

[0008] Temporary casting templates are respectively provided between the two sides of the first plate body and the hole wall of the first-order slot hole for separation, and the two temporary casting templates are connected into one body by a connecting piece with a π-shaped horizontal cross-sectional profile, and the first plate body and the two temporary casting templates are used together as concrete templates for pouring concrete in the first-order slot hole, and the horizontal plate body of the connecting piece is supported against the end wall of the first-order slot hole;

[0009] Concrete is poured in the first-order slots to form a first-order wall, and the temporary pouring formwork and connectors are removed after the first-order wall reaches the designed strength;

[0010] Slotting is performed next to the first-order slot hole to form a second-order slot hole. During the slotting process, mud is used to protect the wall, and then the sediment at the bottom of the slot is removed;

[0011] A second-sequence steel bar cage is arranged below the first-sequence slot hole, and a second joint is arranged at the end of the second-sequence steel bar cage facing the first-sequence wall body, and the second joint comprises a second plate body with an Ω-shaped horizontal cross-sectional profile, the second plate body extends from the top to the bottom of the second-sequence steel bar cage, and the outer walls of the two flat plate parts of the second plate body are provided with locking tubes corresponding to the two C-shaped locking buckles respectively, and the locking tubes are inserted into the C-shaped locking buckles corresponding thereto, the arc-shaped portion of the second plate body is recessed into the second-sequence steel bar cage and the radius of the arc-shaped portion of the second plate body is greater than the radius of the arc-shaped portion of the first plate body, the arc-shaped portion of the second plate body is coaxially sleeved outside the arc-shaped portion of the first plate body, and the arc-shaped portion of the second plate body is connected to a second branch pipe on the wall surface facing the second-sequence steel bar cage, the second branch pipe is coaxial with the first branch pipe, and a second through hole communicating with the second branch pipe is opened on the arc-shaped portion of the second plate body;

[0012] A compression tube is inserted into the steel tube, and a round bucket is coaxially connected to the lower end of the compression tube. The outer diameter of the large opening of the round bucket is adapted to the inner diameter of the steel tube, and the inclination of the outer wall of the round bucket is adapted to the sliding slope of the tail of the latch. When the compression tube descends, the outer wall of the round bucket pushes the latch to be inserted from the first branch tube into the second branch tube, and then the compression tube is pulled out from the steel tube;

[0013] Concrete is poured in the secondary slots and steel pipes to form secondary walls.

[0014] Preferably, the guide wall adopts an inverted L-shaped guide wall, poured with C25 concrete, and double-layer steel mesh is arranged vertically and horizontally in the wall. Mud pipelines are reserved on the outside of the guide wall. The top surface of the guide wall is 50 to 100 mm above the ground to ensure that the mud level in the groove is more than 50 cm higher than the groundwater level. The net distance between the wall surfaces inside the guide wall is determined according to the design thickness of the underground continuous wall, and a margin of 80 mm is reserved.

[0015] Preferably, the slurry uses bentonite, soda ash, CMC and water as raw materials, and the usage ratio of bentonite, soda ash, CMC and water is (6-8):(0.3-0.5):(0.05-0.08):100;

[0016] The mud preparation process includes: using water to prepare soda ash into a soda ash liquid with a mass concentration of 10-20%, using water to prepare CMC into a CMC liquid with a mass concentration of 1.5%, adding 1 / 3 of the remaining water into a mixer, starting the mixer, and then continuously adding water while adding bentonite and soda ash liquid, stirring for 3 minutes, adding CMC liquid and continuing to stir, and the stirred mud is used after standing for 24 hours.

[0017] Preferably, when mud wall protection is adopted, a 3PN type mud pump is used for transportation, and a 4PL type mud pump is used for recovery, and a mud circulation pipeline is formed by the mud pump and the PE pipe.

[0018] Preferably, the grooving process includes: using a hydraulic grab to perform grooving operations when constructing coarse sand and silty sand, silty clay, silty sand, silty clay, and medium-coarse sand layers in the backfill soil; when the hydraulic grab grabs the bottom strongly weathered rock layer, the conventional hydraulic grab grooving method cannot meet the grooving requirements, and rotary drilling is used to construct the grooving in the strongly weathered rock layer;

[0019] The standard slot hole adopts three-sequence slotting, that is, dig the two sides first, then dig the middle. When grabbing, the outer edge of the grab bucket teeth is aligned with the limit mark line, and the middle position of the inner bucket body is close to the inner guide wall, that is, the middle position of the inner side of the grab bucket body is tangent to the guide wall when grabbing. During the slotting process, the verticality is checked and corrected in time to ensure that the verticality of the slot wall meets the specification requirements;

[0020] During the rock breaking process, the rock layers at both ends of the slot are broken first, and then the middle rock layers are broken to ensure the lateral verticality of the slot.

[0021] Preferably, the sediment at the bottom of the tank is removed by using an air lift reverse circulation method.

[0022] The present invention also provides a ground-connected wall structure, which is constructed using the above-mentioned construction method.

[0023] The present invention includes at least the following beneficial effects: the construction joint between the first-order wall and the second-order wall formed by the construction method of the present application is no longer a flat joint, but a special-shaped joint with a plurality of linear composites, which greatly extends the joint length, increases the difficulty of water penetration, and enhances the waterproof effect. At the same time, the first-order steel cage and the second-order steel cage are no longer simply overlapped, but a combination of two connection methods, a lock connection and a pin connection, which can withstand various stress forms such as pulling, twisting, and bending, and has good connection strength and continuous stress transfer. In addition, the width of the steel cage at the connection between the first-order steel cage and the second-order steel cage does not change, and the structural strength of the connection is also enhanced due to the addition of the first plate body, the second plate body and the steel pipe.

[0024] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A top view of a first-order slot hole according to an embodiment of the present invention;

[0026] Figure 2 A top view of a first-order steel cage located in a first-order slot hole according to an embodiment of the present invention;

[0027] Figure 3 A top view of the temporary casting template according to an embodiment of the present invention inserted into a first-order slot hole;

[0028] Figure 4 A top view of a first-order wall according to an embodiment of the present invention;

[0029] Figure 5 A top view of the connection between the second-sequence steel cage and the first-sequence steel cage according to an embodiment of the present invention;

[0030] Figure 6 It is a vertical cross-sectional view of the first-sequence steel cage and the second-sequence steel cage connected by the pressing pipe and the round bucket pushing the latch according to the embodiment of the present invention;

[0031] Figure 7 It is a top view of the first-order wall and the second-order wall described in the embodiment of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0033] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] like Figures 1 to 7 As shown, the present invention provides a construction method of a ground-connected wall structure, comprising:

[0035] S1, guide wall construction, mud preparation, slotting between guide walls to form a sequence of slot holes 1 (such as Figure 1 As shown in the figure), mud is used to protect the wall during the slotting process, and then the sediment at the bottom of the slot is removed;

[0036] Specifically, the guide wall adopts an inverted L-shaped guide wall, poured with C25 concrete, and double-layer steel meshes are arranged vertically and horizontally inside the wall. Mud pipelines are reserved on the outside of the guide wall. The top surface of the guide wall is 50 to 100 mm above the ground to ensure that the mud level in the groove is more than 50 cm higher than the groundwater level. The net distance between the wall surfaces inside the guide wall is determined according to the design thickness of the underground continuous wall, and a margin of 80 mm is reserved.

[0037] The guide wall construction process includes site leveling, measurement and positioning, guide wall trench excavation and compaction, steel bar binding, guide wall formwork installation, concrete pouring, and guide wall formwork removal.

[0038] Site leveling: φ600 mixing piles are set on both sides of the ground connection wall and interlocked with each other by 100mm to reinforce the trench wall. After the site treatment and reinforcement are completed, the guide wall construction begins.

[0039] Measurement and positioning: Based on the plane control points on site, the outer contour of the underground structure given in the design drawings is measured to complete the measurement and positioning of the underground continuous wall guide wall at the construction site and the elevation measurement. Considering the size requirements of the main structure layer after the underground continuous wall is completed, the verticality and width of the underground continuous wall are strictly controlled during the construction process.

[0040] Excavation and compaction of the guide wall trench: Before excavating the earthwork of the guide trench, the construction personnel must be familiar with and master the relevant positions in the drawings in advance, check the axes to ensure accuracy, and take good protection. The construction personnel should do a good job of technical briefing before construction. The excavation of the earthwork is first excavated by an excavator to a moderate depth, and then the last 30cm is excavated manually. Over-excavation and cutting of the roots are strictly prohibited. In order to prevent water accumulation in the trench and side wall collapse during the excavation process, a water collection pit should be excavated in time, and a water pump should be prepared for open drainage. During nighttime construction, the procedures should be arranged reasonably to prevent wrong excavation or over-excavation. Lighting facilities should be installed on the construction site as needed, and obvious signs should be set up in dangerous areas. The disturbed earthwork in the foundation trench should be cleaned manually, and the bottom of the foundation trench should be cleaned out in time with the excavator. After completion, the slope should be repaired manually.

[0041] Rebar binding: The raw materials used for the steel bars are strictly subject to double control, with factory quality certificates, and can only be used after passing the retest. Before processing the steel bars, the steel bars used are visually inspected, straightened, and rusted to make the steel bar surface clean, free of damage, oil, etc. Taking full account of the later load conditions, the guide wall steel bars use double-layer bidirectional steel mesh, the longitudinal steel bar lap length is 30d, the joints are staggered, and the percentage of the joint area in the 1.3 times lap length area cannot exceed 50%. In order to ensure the correct position of the steel bars and the thickness of the protective layer, support steel bars are added between the inner and outer steel bars, with no less than 1 per 1.0m, and arranged in a plum blossom shape. Cement mortar protective layer pads are placed on the outside of the steel bars. The steel bars are controlled vertically with hanging wires, and the horizontality is measured and controlled with a level.

[0042] Installation of guide wall formwork: The guide wall formwork is assembled with wooden formwork. The formwork is calculated before supporting the formwork to avoid expansion and explosion. To prevent the formwork from displacement during concrete pouring and ensure the overall stability of the formwork, it is firmly connected with the internal and external steel pipe frames and the soil on both sides of the guide wall groove, and square wood is used to support the opposing formwork. The template joints should be tight to avoid the formation of honeycomb surface due to exposed slurry. The formwork is coated with a release agent to make the concrete surface smooth and reduce resistance to facilitate sinking.

[0043] Concrete pouring: The guide wall structure is poured with C25 concrete, and a concrete pump truck is used to pump concrete into the formwork for pouring. To prevent the tank truck load from causing excessive displacement and deformation of the guide ditch, the concrete pump truck is kept at a safe distance of about 5m from the guide ditch. The concrete is poured evenly in layers, with balanced material discharge, symmetrical pouring on both sides, and rising at the same time to avoid uneven sinking of the guide ditch or tilting of the side wall. After the guide wall concrete is poured, it is covered with plastic film and watered to keep the concrete surface moist to prevent cracking. Before the guide wall concrete reaches the designed strength and is well supported, no heavy machinery or transportation equipment is allowed to drive beside it to prevent the guide wall from being compressed and deformed.

[0044] Removal of guide wall formwork: The formwork can be removed only after the concrete strength of the guide wall reaches 75% of the design strength. After removal, it should be immediately covered with plastic film or geotextile, and concrete maintenance should be done well. At the same time, three 100mm×100mm wooden squares should be set at 300mm from the bottom of the ditch and the top of the guide wall and in the middle, with a horizontal spacing of 2m, and the soil should be backfilled into the guide wall ditch to prevent the guide wall from moving. Before backfilling the soil, a safety mesh should be laid on the top of the guide wall, and railings and colored flags should be set on both sides of the guide wall to ensure construction safety.

[0045] Specifically, the slurry uses bentonite, soda ash, CMC and water as raw materials, and the usage ratio of bentonite, soda ash, CMC and water is (6-8):(0.3-0.5):(0.05-0.08):100;

[0046] The mud preparation process includes: using water to prepare soda ash into a soda ash liquid with a mass concentration of 10-20%, using water to prepare CMC into a CMC liquid with a mass concentration of 1.5%, adding 1 / 3 of the remaining water into a mixer, starting the mixer, and then continuously adding water while adding bentonite and soda ash liquid, stirring for 3 minutes, adding CMC liquid and continuing to stir, and the stirred mud is used after standing for 24 hours.

[0047] When mud is used for wall protection, a 3PN mud pump is used for transportation and a 4PL mud pump is used for recovery. The mud pump and PE pipe form a mud circulation pipeline.

[0048] During the trenching operation, the mud liquid level in the trench should be maintained at the highest level that does not cause overflow.

[0049] On-site technicians regularly test the mud to ensure that all performance indicators of the mud meet the standards before putting it into use.

[0050] The desander installed on the top of the mud pool is opened from time to time to remove sand. The technical staff adjusts the mud performance indicators in time to reduce the sand content of the recovered mud and improve the wall protection performance.

[0051] Specifically, during trenching construction, the bottom of the wall of this project enters the strongly weathered rock layer or reaches the slightly weathered rock. The method of combining hydraulic grab bucket and rotary drilling to form trenches is used. The specific method is as follows:

[0052] When constructing the coarse sand and fine sand, silty clay, fine sand, silty clay, and medium-coarse sand layers in the backfill soil, a hydraulic grab is used for trenching. When the hydraulic grab reaches the strongly weathered rock layer at the bottom, the conventional hydraulic grab trenching method cannot meet the trenching requirements. Rotary drilling is used for trenching in the strongly weathered rock layer.

[0053] According to the geological survey report, since the foundation soil in the area where this project is located is loose and greatly affected by the tide, in order to ensure the safety and quality of the ground-anchored wall construction, a typical start-up was carried out before the regional ground-anchored wall construction, and construction parameters were collected. The problems found were analyzed and solved before the formal construction was carried out;

[0054] The standard slot hole adopts three-sequence slotting, that is, dig the two sides first, then dig the middle. When grabbing, the outer edge of the grab bucket teeth is aligned with the limit mark line, and the middle position of the inner bucket body is close to the inner guide wall, that is, the middle position of the inner side of the grab bucket body is tangent to the guide wall when grabbing. During the slotting process, the verticality is checked and corrected in time to ensure that the verticality of the slot wall meets the specification requirements;

[0055] During the rock breaking process, the drill bit is prone to tilt due to the inclination of the rock layer or the uneven hardness of the formation, which causes the slot hole to tilt. At this time, the operator should carefully observe the correction display device and strictly control the verticality of the rock entry. If the slot section is deflected, the slot wall is repeatedly corrected by the correction device until it meets the design requirements, and then the construction can be continued. During the rock breaking process, the rock layers at both ends of the slot hole are broken first, and then the middle rock layer is broken to ensure the horizontal verticality of the slot hole. Since the rock entry and slotting construction time is relatively long, in order to maintain the stability of the soil above the slot section, the specific gravity and viscosity of the mud can be increased.

[0056] Specifically, when changing slurry, removing sand and cleaning slag, the air lift reverse circulation method is used to remove the sediment at the bottom of the tank.

[0057] After the trench is completed, the "underground continuous wall sediment removal and mud collection and treatment system method" is used for sand removal. The sediment at the bottom of the trench is replaced by the "duct air lift reverse circulation closed slurry replacement method", and then the mud purification and sand removal system and the new set of mud treatment equipment system are used for sand removal, which reduces the sand content of the mud and improves the quality of the ground-connected wall joints.

[0058] The mud purification system is equipped with two desanders. After the trough is formed, the desander on site is used to remove sand and replace the mud. The other desander is installed in the mud storage tank to perform secondary purification on the mud recovered during concrete pouring, which ensures the mud desandering effect.

[0059] The thickness of the sediment after cleaning the bottom of the tank should not be greater than 200mm. One hour after the cleaning of the bottom of the tank and the replacement of the mud, the mud weight at 200mm above the design elevation of the bottom of the tank should not be greater than 12kN / m 3 .

[0060] S2, a first-order steel cage 2 is arranged below the first-order slot 1 (such as Figure 2As shown in the figure, the first joint is provided at the end of the first-order steel cage 2 facing the second-order slot hole 10, and the first joint includes a first plate body 3 with an Ω-shaped horizontal cross-sectional profile, the first plate body 3 extends from the top to the bottom of the first-order steel cage 2, and the two sides of the first plate body 3 extend to the outside of the two side walls of the first-order steel cage 2 and leave a gap with the hole wall of the first-order slot hole 1, and the outer walls of the two flat plate parts of the first plate body 3 are both provided with C-shaped lock buckles 4, and the arc-shaped part of the first plate body 3 faces the first-order steel cage 2 and a steel pipe 5 is coaxially arranged in the arc-shaped portion of the first plate body 3, a first branch pipe 6 is connected between the outer wall of the steel pipe 5 and the arc-shaped portion of the first plate body 3 along the radial direction of the steel pipe 5, a first through hole communicating with the first branch pipe 6 is opened on the wall of the steel pipe 5 and the arc-shaped portion of the first plate body 3, a latch 7 is arranged in the first through hole, a sliding slope is arranged at the tail of the latch 7 and extends into the steel pipe 5, and the head of the latch 7 is flush with the outer wall of the arc-shaped portion of the first plate body 3.

[0061] Specifically, the head of the latch pin 7 and the outer wall of the arc-shaped portion of the first plate body 3 can be connected by virtual welding to prevent the latch pin 7 from slipping off the first branch pipe 6 during the lifting process of the first steel cage 2. However, the firmness of the virtual welding connection is not good, so when the pressing tube 14 is subsequently inserted into the steel pipe 5 and the round bucket 15 at the lower end of the pressing tube 14 pushes the tail of the latch pin 7, the head of the latch pin 7 can easily disconnect from the arc-shaped portion of the first plate body 3.

[0062] Specifically, at the same height on the steel pipe 5, a plurality of first branch pipes 6 can be evenly spaced along the circumference of the steel pipe 5 to form a group of first branch pipes 6, and a first through hole is correspondingly opened on the wall of the steel pipe 5 and the arc-shaped portion of the first plate body 3 for each first branch pipe 6, and a pin 7 is correspondingly provided in each first branch pipe 6.

[0063] More specifically, multiple layers of first branch pipes 6 may be arranged at different heights on the steel pipe 5 , and a latch 7 may be correspondingly arranged in each first branch pipe 6 .

[0064] Specifically, the process of setting a first-order steel cage 2 in a first-order slot hole 1 is as follows:

[0065] A lifting ring is welded on the first-order steel cage 2. The two main bars of the first-order steel cage 2 are welded on both sides at the intersection of the two main bars and the distribution bars at the lifting ring position. Starting from the lifting ring position, the first nine distribution bars and the main bars should be welded on both sides, and the distribution bars should be fully welded. The three distribution bars and the main bars at the lifting point should be welded on both sides, and the closing bars should be fully welded. Before lifting the steel cage, ensure that all welding points have been welded. It is strictly forbidden to cause the steel bars to fall off due to lack of welding or leakage during the lifting process. Check the preparation of each rigging, whether the clamp ring and wire rope model meet the requirements of the technical briefing and the requirements of the special safety plan for the lifting of the steel cage. It is strictly forbidden to use unqualified slings. The crane station site must be flat and compacted, and two ropes for manual auxiliary installation must be tied to facilitate the control of the position of the steel cage during installation.

[0066] Before the crawler crane is in place, the assistant will hang the main and auxiliary shoulder poles on the corresponding main and auxiliary crawler crane hooks. After the main crawler crane and auxiliary crawler crane are in place, the crane commander will check the position to ensure correct position. After the position is completed, the commander crawler crane will slowly drop the shoulder pole to the surface layer distribution reinforcement of the first-order steel cage 2, and then the assistant will connect the wire rope on the shoulder pole with the lifting ring and lock it with a shackle.

[0067] The lifting can only be carried out after the technical personnel and safety officer have inspected and qualified the welding quality of the first-order steel cage 2, the safety performance of the lifting equipment, and the connection between the wire rope and the lifting ring and lifting point. During the lifting operation, all the actions of the crane are uniformly arranged and directed by the lifting commander, and there must not be multiple people commanding the scene, which would cause chaos. Under the command of the lifting commander, the main and auxiliary crawler cranes slowly lift the first-order steel cage 2 horizontally about 0.5m from the ground, and suspend the steel cage for about 10 to 15 minutes to check the welding quality. At the same time, the safety officer will once again check whether the connection between the lifting ring, lifting point, shackle, and wire rope is intact, and whether there is any problem of excessive deformation of the steel cage.

[0068] After the lower part of the first-series steel cage 2 is hoisted to 200mm~300mm from the ground and inspected to be correct, the crane commander will command the main and auxiliary crawler cranes to slowly lift the first-series steel cage 2. During the lifting process, the auxiliary crane does not need to lift the pull rod too much, but only needs to control the tail of the first-series steel cage 2 at a distance of 1~2m from the ground.

[0069] After the lower part of the first-order steel cage 2 is hoisted, the main hoist rotates to the left (or right) side, and the auxiliary hoist rotates to the appropriate position. After the horizontal hoisting operation of the first-order steel cage 2 is completed, the two cranes slowly rotate under the command of the hoisting commander and leave the welding platform first. At this time, the main and auxiliary cranes rotate slowly. When the first-order steel cage 2 leaves the welding platform, the main crane slowly rises and the auxiliary crane slowly descends, and the first-order steel cage 2 is vertically rotated, that is, the first-order steel cage 2 is converted from the horizontal hoisting of two cranes to the main hoist to vertically hoist the first-order steel cage 2. In this process, the main crane slowly lifts the first-order steel cage 2 upwards. At this time, the wire rope sling under the shoulder pole of the main crane slowly slides to one side due to the lifting of the first-order steel cage 2. The lifting force of the main crane will gradually increase until the total weight of the first-order steel cage 2 (including the weight of the hoist), and the lifting force of the auxiliary crane will gradually decrease until the wire rope is loosened and continues to be lengthened. The sling of the auxiliary crane can be separated from the auxiliary shoulder pole beam at any time according to the situation. The command crane operator directs the removal of the lifting point of the auxiliary crane on the first order steel cage 2, and then moves away from the lifting operation range. In this stage, the command personnel must coordinate the actions of the two cranes.

[0070] During the horizontal movement after being lifted from the welding platform, the first-series steel cage 2 should be operated carefully, slowly and steadily during lifting and moving. At the same time, a towing rope is tied to the lower end of the first-series steel cage 2 for manual operation to prevent the cage from shaking and causing the groove wall to collapse and the first-series steel cage 2 itself to produce irreversible deformation.

[0071] Instruct the main crane to move the first-order steel cage 2 to the corresponding slot section, and slowly put the first-order steel cage 2 into the slot after alignment. When it is placed at the shackle at the lower end of the wire rope, stop lowering it, and use two shoulder poles to carry the first-order steel cage 2 at the slot hole. After ensuring that it is firmly carried and does not slide down, the rope operator climbs up the first-order steel cage 2 and hangs the wire rope on the lifting ring, and continues to lower the first-order steel cage 2. Finally, the ground-connected wall is suspended and positioned in the slot through the carrying pole, and the main crane wire rope is removed to proceed to the next step. After entering the slot and positioning, the crane should travel smoothly, and the traction rope should be pulled on the lower first-order steel cage 2. The first-order steel cage 2 is placed at the slot section and kept horizontal.

[0072] The main hoist must be used alone to hoist the first-order steel cage 2, and the first-order steel cage 2 should be suspended vertically during the hoisting process. After hoisting the first-order steel cage 2 into the slot, use the hoisting beam to penetrate the final hoisting ring of the first-order steel cage 2 and place it on the top surface of the guide wall. Check the plane position and elevation deviation of the first-order steel cage 2 into the slot, and adjust the position and elevation to make the hoisting position of the first-order steel cage 2 meet the design requirements.

[0073] S3, temporary casting templates 8 are respectively provided between the two sides of the first plate body 3 and the hole wall of the first sequence slot hole 1 for partition (such as Figure 3As shown), the two temporary casting templates 8 are connected into one by a connecting piece 9 with a π-shaped horizontal cross-sectional profile, the first plate body 3 and the two temporary casting templates 8 are used together as a concrete template for pouring concrete in the first-order slot hole 1, and the horizontal plate body of the connecting piece 9 is supported against the end wall of the first-order slot hole 1;

[0074] The connecting member 9 connects the two temporary casting templates 8 into one, so that the two temporary casting templates 8 can be supported on both sides of the first plate body 3 at the same time. Since the relative positions of the two temporary casting templates 8 are fixed by the connecting member 9, the temporary casting templates 8 can directly match the width of the first-order slot hole 1, and there is no need to position the temporary casting templates 8, thereby improving the template support efficiency.

[0075] Since the connector 9 in the prior art only connects the temporary casting template 8 into one, although the connector 9 does not contact the side wall of the first-order slot hole 1 over a large area, reducing the pull-out force of the template, it also lacks support for the side wall of the first-order slot hole 1, increasing the risk of hole wall collapse. Therefore, in this technical solution, a connector 9 with a π-shaped horizontal cross-sectional profile is used, so that the transverse plate of the connector 9 is supported against the end wall of the first-order slot hole 1, further strengthening the support effect on the end wall of the first-order slot hole 1 adjacent to the second-order slot hole 10.

[0076] S4, pouring concrete in the first-order slot hole 1 to form a first-order wall (such as Figure 4 As shown), and after the first-order wall reaches the design strength, the temporary casting formwork 8 and the connecting parts 9 are removed;

[0077] Specifically, the trench section of this project uses underwater C35 self-mixed concrete, which has good workability and fluidity. The slump of the concrete is controlled at 160mm to 210mm.

[0078] When two conduits are used for pouring in the same trench section at the same time, the distance between them should not be greater than 3m, the distance between the conduit and the trench section joint should not be greater than 1.5m, the concrete surface should rise evenly, and the height difference of the concrete surface at each conduit should not be greater than 0.5m. The concrete must be poured before final setting.

[0079] In order to meet the burial depth of the first pouring conduit and the continuity of subsequent concrete pouring, the supply of concrete must be guaranteed. The first batch should be at least 60m deep. 3 Concrete pouring can begin. When the concrete reaches the pipe embedding condition, four tank trucks (10m 3 / car) for continuous pouring, and the pouring process is symmetrical.

[0080] The concrete tank truck directly pours concrete into the funnel, and the initial pouring volume should meet the buried depth of the conduit of more than 1.5 meters (about 10 cubic meters). Concrete must be poured continuously, and the actual height of the top surface of each part of the concrete should be measured every 2 meters according to the concrete pouring height, and records should be made to ensure that the conduit is buried 2 to 6 meters in the concrete.

[0081] Concrete pouring adopts the conduit method. The conduit should be a round spiral quick connector with a wall thickness of no less than 5mm and a diameter of 250mm. The conduit must be straight, sealed, and easy to disassemble and assemble. The "O" type sealing ring used in the conduit joint must be complete and must not cause water leakage. The conduit must be strictly inspected before use. After passing the inspection, it must be pre-connected and sealed for acceptance. Each section must be tightly connected and watertight tested. The closed water pressure must not be less than 0.6-1.0Mpa. After passing the inspection, it will be numbered and used. Use a concrete pouring frame to hang the conduit into the specified position of the slot section, and install a square funnel on the top of the conduit.

[0082] The slump should be tested before pouring concrete, and concrete test blocks should be prepared during the pouring process. A group of compression test pieces should be made for each unit slot section concrete, and a group of impermeability test pieces should be made for every 5 slot sections, and records should be kept.

[0083] According to the drawing requirements, the final elevation of concrete should be 0.5 to 0.8m higher than the design elevation.

[0084] Specifically, the removal of the temporary casting formwork 8 and the connecting parts 9 is combined with the concrete pouring, and the concrete pouring records and the on-site test blocks are used as the basis for controlling the removal time of the temporary casting formwork 8. The removal starts from the initial setting of the concrete test blocks, and is removed every 10 to 20 minutes, with each removal of 100 to 300 mm.

[0085] S5, slotting is performed next to the first-order slot hole 1 (such as Figure 5 As shown), a second-order slot hole 10 is formed, and mud is used to protect the wall during the slotting process, and then the sediment at the bottom of the slot is removed;

[0086] The slotting process of the second-order slot hole 10 can be carried out by referring to the construction process of the first-order slot hole 1.

[0087] S6, a second-order steel cage 11 is arranged below the first-order slot 1 (such as Figure 5As shown), the second joint is provided at the end of the second-sequence steel cage 11 facing the first-sequence wall, and the second joint includes a second plate body 12 with an Ω-shaped horizontal cross-sectional profile, the second plate body 12 extends from the top to the bottom of the second-sequence steel cage 11, and the outer walls of the two flat plate parts of the second plate body 12 are provided with locking tubes corresponding to the two C-shaped locking buckles 4 respectively, and the locking tubes are inserted into the C-shaped locking buckles 4 corresponding thereto, the arc-shaped portion of the second plate body 12 is recessed into the second-sequence steel cage 11 and the radius of the arc-shaped portion of the second plate body 12 is greater than the radius of the arc-shaped portion of the first plate body 3, the arc-shaped portion of the second plate body 12 is coaxially sleeved outside the arc-shaped portion of the first plate body 3, and the arc-shaped portion of the second plate body 12 is connected to the wall surface in the second-sequence steel cage 11 with a second branch pipe 13, the second branch pipe 13 is coaxial with the first branch pipe 6, and a second through hole connected to the second branch pipe 13 is opened on the arc-shaped portion of the second plate body 12;

[0088] Specifically, when a plurality of first branch pipes 6 are evenly spaced at the same height on the steel pipe 5 along the circumference of the steel pipe 5, a plurality of second branch pipes 13 are correspondingly arranged on the arc portion of the second plate 12 at the same height as the plurality of first branch pipes 6 to form a second branch pipe 13 group, and each second branch pipe 13 corresponds to a first branch pipe 6;

[0089] Specifically, when multiple layers of first branch pipes 6 are respectively arranged at different heights on the steel pipe 5 , correspondingly, a second branch pipe 13 is arranged on the arc portion of the second plate body 12 for each first branch pipe 6 group.

[0090] Specifically, the installation process of the second-sequence steel cage 11 can refer to the installation process of the first-sequence steel cage 2.

[0091] The locking tube on the second-sequence steel cage 11 is inserted into the C-shaped locking tube 4 on the first-sequence steel cage 2, which not only forms a connection between the first-sequence steel cage 2 and the second-sequence steel cage 11, but also plays a positioning role for the arc-shaped portion of the second plate body 12 to be sleeved outside the arc-shaped portion of the first plate body 3, and also plays a positioning role for the second branch pipe 13 to be coaxially located on the extension line of the axis of the first branch pipe 6.

[0092] S7, insert the pressure tube 14 (such as Figure 6 As shown), the lower end of the pressing tube 14 is coaxially connected with a round bucket 15, the outer diameter of the large opening of the round bucket 15 is adapted to the inner diameter of the steel tube 5, and the inclination of the outer wall of the round bucket 15 is adapted to the sliding slope of the tail of the latch 7. During the descending process of the pressing tube 14, the outer wall of the round bucket 15 pushes the latch 7 from the first branch pipe 6 to the second branch pipe 13, and then the pressing tube 14 is pulled out from the steel tube 5;

[0093] After the pin 7 is inserted from the first branch pipe 6 into the second branch pipe 13, two connection modes, namely a lock connection and a pin 7 connection, are generated between the first-sequence steel cage 2 and the second-sequence steel cage 11. The connection can withstand various stress forms such as pulling, torsion, bending, etc., has good connection strength, and continuous stress transfer.

[0094] Since the outer diameter of the large opening of the round bucket 15 is adapted to the inner diameter of the steel pipe 5, and the inclination of the outer wall of the round bucket 15 is adapted to the sliding slope of the tail of the latch 7, the tail of the latch 7 can be basically pushed by the round bucket 15 to be flush with the inner wall of the steel pipe 5. During the descent of the round bucket 15, the space of the steel pipe 5 below the round bucket 15 is continuously reduced, and the gas in this reduced space can flow from the small opening of the round bucket 15 to the pressure pipe 14, and then be discharged from the upper end of the pressure pipe 14, so as to avoid the lower end space of the round bucket 15 being closed to form a high air pressure when the round bucket 15 is descended, thereby hindering the downward movement of the pressure pipe 14.

[0095] S8, pouring concrete in the second-order slot 10 and the steel pipe 5 to form a second-order wall (such as Figure 7 shown).

[0096] Specifically, the concrete pouring construction in the second-order slot 10 can refer to the concrete pouring construction process in the first-order slot 1. The concrete pouring construction in the steel pipe 5 is just to set the number of conduits for pouring concrete to one, and other processes can also refer to the concrete pouring construction process in the first-order slot 1.

[0097] In the above technical solution, the construction joint formed between the first-order wall and the second-order wall is no longer a flat joint, but a special-shaped joint with a variety of line types, which greatly extends the length of the joint, increases the difficulty of water penetration, and enhances the waterproof effect. At the same time, the first-order steel cage 2 and the second-order steel cage 11 are no longer simply overlapped, but a combination of two connection methods: a lock connection and a latch 7 connection. It can withstand various stress forms such as pulling, twisting, and bending, has good connection strength, and continuous stress transmission. In addition, the width of the steel cage at the connection between the first-order steel cage 2 and the second-order steel cage 11 has not changed. At the same time, the structural strength of the connection is strengthened due to the addition of the first plate body 3, the second plate body 12 and the steel pipe 5.

[0098] The present invention also provides a ground-connected wall structure, which is constructed using the above-mentioned construction method. Therefore, the ground-connected wall structure has basically the same advantages as the above-mentioned construction method, so it will not be repeated here.

[0099] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A construction method of a ground-connected wall structure, characterized in that: include: Guide wall construction, mud preparation, slotting between guide walls to form a sequence of slot holes, using mud to protect the wall during slotting, and then removing the sediment at the bottom of the slot; A first-order steel bar cage is arranged below the first-order slot hole, and a first joint is arranged at the end of the first-order steel bar cage facing the second-order slot hole, the first joint comprises a first plate body with an Ω-shaped horizontal cross-sectional profile, the first plate body extends from the top to the bottom of the first-order steel bar cage, and the two side edges of the first plate body respectively extend to the outside of the two side walls of the first-order steel bar cage and leave a gap with the hole wall of the first-order slot hole, the outer walls of the two flat plate parts of the first plate body are both provided with C-shaped lock buckles, the arc-shaped portion of the first plate body protrudes out of the first-order steel bar cage, and a steel pipe is coaxially arranged in the arc-shaped portion of the first plate body, a first branch pipe is connected between the outer wall of the steel pipe and the arc-shaped portion of the first plate body along the radial direction of the steel pipe, the steel pipe wall and the arc-shaped portion of the first plate body are both provided with a first through hole connected with the first branch pipe, a latch is arranged in the first through hole, the tail of the latch is provided with a sliding slope and extends into the steel pipe, and the head of the latch is flush with the outer wall of the arc-shaped portion of the first plate body; Temporary casting templates are respectively provided between the two sides of the first plate body and the hole wall of the first-order slot hole for separation, and the two temporary casting templates are connected into one body by a connecting piece with a π-shaped horizontal cross-sectional profile, and the first plate body and the two temporary casting templates are used together as concrete templates for pouring concrete in the first-order slot hole, and the horizontal plate body of the connecting piece is supported against the end wall of the first-order slot hole; Concrete is poured in the first-order slots to form a first-order wall, and the temporary pouring formwork and connectors are removed after the first-order wall reaches the designed strength; Slotting is performed next to the first-order slot hole to form a second-order slot hole. During the slotting process, mud is used to protect the wall, and then the sediment at the bottom of the slot is removed; A second-sequence steel bar cage is arranged below the first-sequence slot hole, and a second joint is arranged at the end of the second-sequence steel bar cage facing the first-sequence wall body, and the second joint comprises a second plate body with an Ω-shaped horizontal cross-sectional profile, the second plate body extends from the top to the bottom of the second-sequence steel bar cage, and the outer walls of the two flat plate parts of the second plate body are provided with locking tubes corresponding to the two C-shaped locking buckles respectively, and the locking tubes are inserted into the C-shaped locking buckles corresponding thereto, the arc-shaped portion of the second plate body is recessed into the second-sequence steel bar cage and the radius of the arc-shaped portion of the second plate body is greater than the radius of the arc-shaped portion of the first plate body, the arc-shaped portion of the second plate body is coaxially sleeved outside the arc-shaped portion of the first plate body, and the arc-shaped portion of the second plate body is connected to a second branch pipe on the wall surface facing the second-sequence steel bar cage, the second branch pipe is coaxial with the first branch pipe, and a second through hole communicating with the second branch pipe is opened on the arc-shaped portion of the second plate body; A compression tube is inserted into the steel tube, and a round bucket is coaxially connected to the lower end of the compression tube. The outer diameter of the large opening of the round bucket is adapted to the inner diameter of the steel tube, and the inclination of the outer wall of the round bucket is adapted to the sliding slope of the tail of the latch. When the compression tube descends, the outer wall of the round bucket pushes the latch to be inserted from the first branch tube into the second branch tube, and then the compression tube is pulled out from the steel tube; Concrete is poured in the secondary slots and steel pipes to form secondary walls.

2. The construction method of the ground-connected wall structure according to claim 1, characterized in that: The guide wall adopts an inverted L-shaped guide wall, poured with C25 concrete, and double-layer steel meshes are arranged vertically and horizontally inside the wall. Mud pipelines are reserved on the outside of the guide wall. The top surface of the guide wall is 50 to 100 mm above the ground to ensure that the mud level in the groove is more than 50 cm higher than the groundwater level. The net distance between the wall surfaces inside the guide wall is determined according to the designed thickness of the underground continuous wall, and a margin of 80 mm is reserved.

3. The construction method of the ground-connected wall structure according to claim 1, characterized in that: The mud uses bentonite, soda ash, CMC and water as raw materials, and the usage ratio of bentonite, soda ash, CMC and water is (6-8):(0.3-0.5):(0.05-0.08):100; The mud preparation process includes: using water to prepare soda ash into a soda ash liquid with a mass concentration of 10-20%, using water to prepare CMC into a CMC liquid with a mass concentration of 1.5%, adding 1 / 3 of the remaining water into a mixer, starting the mixer, and then continuously adding water while adding bentonite and soda ash liquid, stirring for 3 minutes, adding CMC liquid and continuing to stir, and the stirred mud is used after standing for 24 hours.

4. The construction method of the ground-connected wall structure according to claim 1, characterized in that: When mud is used for wall protection, a 3PN mud pump is used for transportation and a 4PL mud pump is used for recovery. The mud pump and PE pipe form a mud circulation pipeline.

5. The construction method of the ground-connected wall structure according to claim 1, characterized in that: The trenching process includes: when constructing the coarse sand and fine sand in the backfill soil, silty clay, fine sand, silty clay, and medium-coarse sand layers, a hydraulic grab is used to form the trench. When the hydraulic grab reaches the strongly weathered rock layer at the bottom, the conventional hydraulic grab trenching method cannot meet the trenching requirements. Rotary drilling is used to form the trench in the strongly weathered rock layer. The standard slot hole adopts three-sequence slotting, that is, dig the two sides first, then dig the middle. When grabbing, the outer edge of the grab bucket teeth is aligned with the limit mark line, and the middle position of the inner bucket body is close to the inner guide wall, that is, the middle position of the inner side of the grab bucket body is tangent to the guide wall when grabbing. During the slotting process, the verticality is checked and corrected in time to ensure that the verticality of the slot wall meets the specification requirements; During the rock breaking process, the rock layers at both ends of the slot are broken first, and then the middle rock layers are broken to ensure the lateral verticality of the slot.

6. The construction method of the ground-connected wall structure according to claim 1, characterized in that: The air lift reverse circulation method is used to remove the sediment at the bottom of the tank.

7. A ground-connected wall structure, characterized in that: The ground-anchored wall structure is constructed using the construction method described in any one of claims 1 to 6.

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