Crushed geological slope belt cable crane main anchorage and anchor cable construction method thereof

Abstract

The invention relates to the technical field of bridge construction, and provides a broken geological slope belt cable crane main anchorage and an anchor cable construction method.The main anchorage is arranged on slope zones on the two sides of an arch bridge and comprises an anchor beam, a plurality of anchor cables and a plurality of anchorage piers cast-in-place on a slope excavation platform, and the backs of the anchorage piers are obliquely arranged; each anchor beam is arranged between every two adjacent anchor piers, one end of each anchor cable is anchored in deep bed rock of the broken geological slope zone, and the other end of each anchor cable is connected with the corresponding anchor pier; aiming at a mountain slope zone with broken geology, the main anchorage adopts a pre-stress anti-pulling structure, so that large-volume excavation of a gravity type anchorage on a rock mass is avoided, the anchor cable can directly penetrate through a poor stratum by adopting a drilling sleeve follow-up technology, the hole forming difficulty is reduced, and the construction efficiency is improved. The effect of reinforcing the mountain of the broken layer on the back face of the main anchorage is further achieved by adopting a sealing structure for sealing pressure grouting, the integrity and the stress performance of the broken layer are improved, and the situation that the uplift resistance of the main anchorage is affected due to extrusion deformation of the mountain is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and particularly to a main anchor block of a cable crane in a broken geological slope zone and a construction method for its anchor cable. Background Art

[0002] At present, some bridges are built in mountainous areas, especially under the topographic conditions of canyon river valleys. There may be roads to be connected on both sides of the bridge, or it may be directly connected to a tunnel. If there is a road, when constructing prestressed anchor cables, arranging hoisting towers in the conventional way will not only occupy the driving width of the existing road, but also greatly compress the construction operation space, and will seriously affect the safety of social traffic vehicles during hoisting; while choosing conventional structural forms such as gravity-type or earth-anchor-type main anchor blocks, the rock excavation workload is large, and the road traffic must be interrupted during construction.

[0003] The prestressed anchor cable construction technology has been widely used in bridge engineering. The successful engineering experience of using the prestressed anchor cable structure as the cable-suspended anchor of a cable crane proves that the prestressed anchor cable technology is safe and reliable when applied to the anchor block structure of large-scale hoisting facilities. However, this technology is restricted by topographic and geological conditions in actual application. For example, when the slope zones on both sides of the bridge are broken geological zones, there are characteristics such as developed rock joints, fissures and broken rock masses, which will reduce the overall strength and stability of the rock mass, and are not conducive to the anchor cable construction of the anchor block. During the drilling of the drill bit through the broken rock stratum, the situation of drill sticking and hole collapse often occurs, and it is very difficult to form a hole during the anchor cable construction. Summary of the Invention

[0004] The present invention provides a main anchor block of a cable crane in a broken geological slope zone and a construction method for its anchor cable, so as to solve the problems in the prior art that when the construction zone of the main anchor block and its anchor cable is a broken geological slope, a large amount of earth and stone excavation is carried out during the construction of the gravity-type anchor block, the extrusion deformation occurs in the broken geology and reduces the uplift resistance of the main anchor block, and it is difficult to form a hole during the anchor cable construction in the broken geology.

[0005] In a first aspect, the present invention provides a main anchor block of a cable crane in a broken geological slope zone, which is arranged in the slope zones on both sides of an arch bridge and includes: An anchor beam, multiple bundles of anchor cables, and multiple anchor piers cast in place on the platforms excavated on the slope. The back of the anchor pier is inclined. The anchor beam is arranged between two adjacent anchor piers and is used for coiling and fixing the main cable and working cable of the cable crane. One end of the anchor cable is anchored in the deep bedrock of the broken geological slope zone, and the other end thereof can be prestress-anchored and connected to the anchor pier.

[0006] According to the main anchor block of the cable crane in the broken geological slope zone provided by the present invention, the anchor cable is arranged perpendicular to the back wall of the main anchor block, and the included angle between the anchor cable and the horizontal plane is 20-30°.

[0007] According to the main anchor of the cable crane in the broken geological slope zone provided by the present invention, there are three anchor piers, and the three anchor piers are arranged at equal intervals in the first direction. The anchor piers on both sides are connected to at least three of the anchor cables, and the anchor pier in the middle is connected to at least six of the anchor cables.

[0008] According to the main anchor of the cable crane in the broken geological slope zone provided by the present invention, the anchor beam is a cylindrical structure, the cross-sectional diameter of the anchor beam is 2 - 3 m, the anchor beam is vertically connected to the side surface of the anchor pier in the first direction, and the first direction is the same as the axial direction of the anchor beam.

[0009] In the second aspect, the present invention also provides a construction method for the anchor cable of the main anchor of the cable crane in the broken geological slope zone as described in the first aspect, including: According to the terrain and geological conditions of the slope area, select the location and excavate the platform, and set up the anchor pier steel reinforcement frame on the formed platform; Determine the position of the anchor cable holes on the slope surface of the broken rock mass that needs to be drilled; Adopt the casing follow-up hole-forming technology to drill the anchor cable holes at the determined positions; Install the anchor cables in the anchor cable holes and perform grouting in the holes; Connect the end of the anchor cable on the ground to the anchor pier steel reinforcement frame and pour concrete into the anchor pier steel reinforcement frame.

[0010] According to the construction method for the anchor cable of the main anchor of the cable crane in the broken geological slope zone provided by the present invention, the determination of the position of the anchor cable holes on the slope surface of the broken rock mass that needs to be drilled includes: Clean the slope surface of the broken rock mass that needs to be drilled, and excavate the mountain slope into a slope surface that fits the back surface of the anchor pier according to the slope of the back surface of the anchor pier; According to the design requirements, measure and place the positions of the anchor cable holes on the slope surface, and the hole position error does not exceed 50 mm.

[0011] According to the construction method for the anchor cable of the main anchor of the cable crane in the broken geological slope zone provided by the present invention, the adoption of the casing follow-up hole-forming technology to drill the anchor cable holes at the determined positions includes: Adopt the pneumatic dry drilling method for construction. The drill bit sequentially penetrates the strongly weathered siliceous rock layer on the slope surface and enters the moderately weathered slate layer. The steel casing follows the drill bit at the same time. When drilling the strongly weathered siliceous rock layer, the drilling speed is 2.5 - 4.5 m / h. Stop drilling for hole cleaning every 2 m of drilling. After cleaning the loose soil in the hole, continue drilling until the anchorage section of the anchor cable completely enters the moderately weathered slate layer; After drilling is completed, use high-pressure air to remove all the rock powder and water in the anchor cable holes outside the holes, and conduct acceptance inspection of the anchor cable holes.

[0012] According to the cable anchor construction method of the main anchor block of the cable crane in the broken geological slope zone provided by the present invention, installing the cable anchor in the cable anchor hole and performing in-hole grouting includes: Before the cable anchor enters the hole, the hole is cleared again with high-pressure air. After the installation of the cable anchor is completed, the steel casing is pulled out using a reaction frame and a jack, and the cable anchor hole is grouted by the method of secondary pressure grouting.

[0013] According to the cable anchor construction method of the main anchor block of the cable crane in the broken geological slope zone provided by the present invention, connecting one end of the cable anchor located on the ground to the anchor block steel reinforcement frame and pouring concrete into the anchor block steel reinforcement frame includes: A steel conduit for protecting the cable anchor is fixedly installed in the anchor block steel reinforcement frame, the cable anchor is threaded through the steel conduit, the concrete is poured in layers and vibrated in layers, with each layer having a thickness of 30 cm. When pouring the concrete, the concrete of the anchor pier and the anchor beam is poured at one time.

[0014] According to the cable anchor construction method of the main anchor block of the cable crane in the broken geological slope zone provided by the present invention, it further includes: performing prestress tensioning and sealing of the cable anchor.

[0015] For the main anchor block of the cable crane in the broken geological slope zone and its cable anchor construction method provided by the present invention, during the cable anchor construction process, for the mountain slope zone of the broken geological formation, the main anchor block adopts a prestressed anti-pulling structure, avoiding large-scale excavation of the rock mass by the gravity anchor block. At the same time, through the drilling casing follow-up technology, the cable anchor can directly penetrate the poor stratum, greatly reducing the difficulty of hole formation; the sealing structure is adopted at the cable anchor hole mouth for the pressure grouting method, which also achieves the effect of strengthening the broken layer mountain body on the back of the main anchor block, increasing the integrity and load-bearing capacity of the broken layer, and preventing the mountain body from being squeezed and deformed, affecting the anti-pulling force of the main anchor block; the reinforced concrete anchor pier is used to bear the tension of the main cable and the working cable, with a simple structure and mature construction technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a side view of the main anchor block provided by the embodiment of the present invention.

[0018] Figure 2 It is a front view of the main anchor block provided by the embodiment of the present invention.

[0019] Figure 3 It is a schematic structural diagram of the cable anchor provided by the embodiment of the present invention.

[0020] Figure 4 It is a flow chart of the construction method of the cable anchor of the main anchor block of the cable crane in the broken geological slope belt provided by the embodiment of the present invention.

[0021] Reference numerals: 1, anchor beam; 2, cable anchor; 3, anchor pier; 4, platform; 5, cable anchor hole; 6, anchor fitting; 7, grouting pipe; 8, tightening ring; 9, expansion ring; 10, steel strand; 11, guide cap; L1, anchorage section; L2, free section. Detailed implementation manners

[0022] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] The following combines Figures 1-4 to describe a main anchor block of a cable crane in a broken geological slope belt and its construction method of the cable anchor of the present invention.

[0024] As Figures 1-2 shown, a main anchor block of a cable crane in a broken geological slope belt provided by this embodiment is arranged in the slope areas on both banks of the arch bridge, and includes: an anchor beam 1, multiple bundles of cable anchors 2, and multiple reinforced concrete anchor piers 3 cast on the platform 4 excavated on the slope. The back of the anchor pier 3 is inclined. The anchor beam 1 is arranged between two adjacent anchor piers 3 and is used for coiling and fixing the main cable and working cable of the cable crane. One end of the cable anchor 2 is anchored in the deep bedrock of the broken geological slope belt, and the other end thereof can be prestressed and anchored to the anchor pier 3. That is to say, the anchor pier 3 is fixed on the platform 4 of the excavated hard slope by the tensile force of the cable anchor 2.

[0025] The above-mentioned platform 4 is excavated on a reliable rock stratum, so that the back and bottom of the anchor block are both placed on the reliable rock stratum, and the bearing capacity of the platform 4 for the anchor block is not less than 500 Kpa. If the bottom front edge and the upper edge of the back of the anchor block cannot be placed on the reliable rock stratum, the unqualified soil and rock strata can be dug out in a stepped shape and then backfilled with C40 concrete to ensure the reliability of the platform 4.

[0026] Furthermore, the cable anchor 2 is arranged perpendicular to the back wall of the main anchor block, and the included angle between the cable anchor 2 and the horizontal plane is 20-30°. There are three anchor piers 3, and the three anchor piers 3 are arranged at equal intervals along the first direction. Among them, each of the anchor piers 3 on both sides is connected to at least three bundles of cable anchors 2, and the anchor pier 3 in the middle is connected to at least six bundles of cable anchors 2; the anchor beam 1 is a cylindrical structure, the cross-sectional diameter of the anchor beam 1 is 2-3m, the anchor beam 1 is perpendicularly connected to the side surface of the anchor pier 3 along the first direction, and the first direction is the same as the axial direction of the anchor beam 1.

[0027] In a specific embodiment, the main anchor block of the cable crane is arranged in the slope areas on both banks. The surface rock mass broken layer is about 20m thick, with developed joints and fissures, and there is a phenomenon of rock mass wrinkling. The dip angle of the rock stratum is about 45°, perpendicular to the trend of the mountain slope surface, the slope is relatively steep, with a slope of about 45°-60°. The construction range of the main anchor block is excavated into a 67° slope according to the slope of the back surface of the anchor pier 3, and a 6m-wide step is formed by excavating the slope to the bottom plane of the main anchor block, which is convenient for the layout of the main anchor block and the operation of the drilling rig. Among them, each main anchor block includes three anchor piers 3 and two anchor beams 1. The three anchor piers 3 are arranged at equal intervals along the axial direction of the anchor beam 1. The top and the top of each anchor pier 3 are parallel to the horizontal plane. The included angle between the back surface of the anchor pier 3 and the horizontal plane is 113°. The anchor beam 1 is cylindrical, and the cross-sectional diameter is 2.4m. The distance between two adjacent anchor piers 3 is 2m. Each of the anchor piers 3 on both sides is connected to three bundles of cable anchors 2, and the anchor pier 3 in the middle is connected to six bundles of cable anchors 2. Each bundle of cable anchors 2 is perpendicular to the back surface of the main anchor block. Each bundle of cable anchors 2 is 35m long, mainly anchored in the moderately weathered slate stratum. The length of the anchorage section L1 is 20m. The tensile force of each anchor bundle is 1872KN, and 12 bundles total 22464KN.

[0028] As Figure 3As shown, in a specific embodiment, the cable anchor 2 uses high-strength low-relaxation prestressed steel strands 10 of 12Φj15.24mm and a strength grade of 1860 Mpa. The corresponding anchor fitting 6 is of the 0VM15-12 type. Before installation, ensure that each steel strand 10 is straight, evenly arranged, rust-removed and degreased. The anchorage section L1 is in a corrugated shape, and the free section L2 is in a straight shape. Place the cut steel strands 10 smoothly on the working bench, measure the length of the anchorage section L1 and the designed length of the cable anchor 2. Insert centering isolation expansion rings 9 within the range of the anchorage section L1 at an interval of 1.0 m, and tie a tightening ring 8 between two expansion rings 9. After the anti-corrosion treatment of the free section L2 of each steel strand 10, put on a PVC pipe with a certain strength. Then install the grouting pipe 7 at the middle position of the cable anchor 2. The grouting pipe 7 passes through the central hole of the expansion ring 9 in the anchorage section L1 and is limited in the middle of the steel strand bundle 10 by the tightening ring 8 in the free section L2. The slurry outlet of the grouting pipe 7 extends to about 0.5 m from the bottom of the hole. The slurry outlet pipe is 2 m long, close to the grouting pipe 7, and is limited and fixed in the middle of the steel strand bundle 10 by the expansion ring 9 with two middle holes. The expansion ring 9 with two middle holes is 1.0 m from the hole mouth for hole mouth sealing before grouting. Finally, put on a guide cap 11 at the end of the cable anchor 2.

[0029] Figure 4 is a schematic flow chart of the cable anchor construction method for the main anchor block of the cable crane in the broken geological slope zone provided by the present invention. As Figure 4 shown, the method includes: Step 101: According to the topography and geological conditions of the slope zone, select the location and excavate the platform 4, and set up the anchor block steel reinforcement frame on the formed platform 4.

[0030] Step 102: Determine the positions of the cable anchor holes 5 on the slope surface of the broken rock mass to be drilled.

[0031] In some specific embodiments, step 102 includes: Clean the slope surface of the broken rock mass to be drilled, remove the loose soil on the surface, excavate the mountain slope according to the slope of the back of the anchor pier 3 to fit the back of the anchor pier 3, and make the width of the platform 4 at the bottom of the anchor pier 3 be 6 m. Ensure that the width of the construction platform 4 at the front edge of the main anchor block should not be less than 2 m, and do a good job in the safety protection of the edge. Before the drilling construction, according to the slope elevation drawing, accurately measure and place the positions of the anchor holes on the slope surface according to the design requirements, and the hole position error shall not exceed 50 mm.

[0032] Step 103: Use the casing follow-up hole-forming technology to drill the cable anchor holes 5 at the determined positions.

[0033] In some specific embodiments, step 103 includes: The pneumatic dry drilling method shall be adopted for construction, and the wet drilling method shall not be used to ensure that the construction of the cable anchor 2 will not deteriorate the engineering geological conditions of the slope rock mass and ensure the bonding performance of the hole wall. The HT-500 type hydraulic down-the-hole drill of Hangtuo Heavy Industry with an air consumption of 18 - 25 m³ / min can be selected. The bit diameter is 146 mm, and the hole-forming diameter is 158 mm. The bit passes through the strongly weathered siliceous rock layer on the slope surface in sequence and enters the moderately weathered slate layer. The drilling method of simultaneous follow-up of steel casing shall be adopted. When drilling the strongly weathered siliceous rock layer, the drilling speed is 2.5 - 4.5 m / h. Stop drilling for hole cleaning every 2 m of drilling. The BLT-25A-185KW air compressor can be used. The air pressure for hole cleaning is 0.3 - 0.45 MPa. After cleaning the loose soil in the hole, continue drilling until the integrity of the mountain body is relatively good, and then the drilling speed can be appropriately increased until the entire anchorage section L1 of the cable anchor 2 enters the moderately weathered slate layer completely.

[0034] After the drilling is completed, use high-pressure air to remove all the rock powder and water in the cable anchor hole 5 outside the hole. The specific operation is as follows: when the drilling reaches the designed depth of the hole, do not stop drilling immediately, and keep the drill stable for 1 - 2 minutes to prevent the bottom of the hole from not meeting the requirements of the designed hole diameter. After the drilling is completed, use high-pressure air with a wind pressure of 0.2 - 0.4 MPa to remove all the rock powder and water in the hole outside the hole, and there shall be no sediment and water sticking, so as not to reduce the bonding strength between the cement mortar and the rock mass of the hole wall.

[0035] After that, conduct the acceptance of the cable anchor hole 5. Only after passing the acceptance can the cable-laying process be carried out. During the hole inspection process, the drill bit shall be advanced smoothly without impact or jitter. The length of the drill tool inspection and delivery shall meet the designed anchor hole depth, and the drill shall be withdrawn smoothly. There shall be no obvious splashing of dust and water when blowing the hole with high-pressure air. At the same time, it is required to recheck the hole position, inclination and azimuth of the anchor hole. After each sub-item process of the anchor hole construction is qualified, it can be considered that the anchor hole drilling inspection is qualified. Then, pull out the drill pipe and drill tool one by one, clean and stack the tools neatly, block the orifice of the cable anchor hole 5 to prevent sundries from entering the hole.

[0036] The casing follow-up hole-forming technology in this embodiment refers to that during the drilling process, the casing is pressed in while drilling. This method can prevent the collapse of the hole wall or the filling of the drilling hole with quicksand during the drilling process, thus ensuring the stability of the drilling hole and the safety of the construction. A telescopic collar can be processed on the upper part of the drill bit to clamp the steel casing. When the drill is drilling forward, the drill bit and the casing advance simultaneously. When the drill is drilling backward, the collar on the upper part of the drill bit retracts into the drill bit and does not drive the casing to rotate. The length of each section of the steel casing is the same as that of the drill pipe, and the casings are connected by screw threads.

[0037] Step 104: Install the cable anchor 2 in the cable anchor hole 5 and conduct in-hole grouting.

[0038] In some specific embodiments, a C22560 single-cylinder piston grouting machine is used for the grouting machine, with a working pressure of up to 1.5 MPa and good pressure-holding effect; for the installation of the anchor cable 2, a drill is used in cooperation with manual labor to send it into the anchor cable hole 5. Before the anchor cable 2 enters the hole, high-pressure air is used to clean the hole again to ensure that there are no sundries in the hole. When installing the anchor cable 2, it is required to be pushed forward parallel to the designed inclination angle and azimuth strictly, without jittering, twisting or moving, to prevent the cable from becoming loose or blocked during the process; After the installation of the anchor cable 2, the grouting pipe 7 and the outlet grouting pipe at the hole opening are completed, a reaction frame and a 50t jack are used to pull out the steel casing. At a position 1.0 m above the hole opening, the gap between the anchor cable 2 in the hole and the hole wall is blocked with hemp rope to a thickness of about 0.2 m, and then the hole opening section of 0.8 m above the hemp rope position is blocked tightly with polyurethane to form a hole opening sealing structure. When the polyurethane solidifies to meet the requirements of grouting pressure-holding, grouting starts; specifically, first place the reaction frame at the position of the anchor cable hole 5, align the hole opening on the reaction frame with the anchor cable hole 5, place the jack on the reaction frame, connect the steel casing to the telescopic section of the jack, start the jack, and pull out and disassemble the steel casing section by section.

[0039] The grouting adopts the method of secondary pressure grouting. The strength of the cement slurry is not less than 35 MPa. First, use the grouting machine to inject cement slurry into the grouting pipe 7. The weight ratio of cement to water is 1:2. The grouting pressure is generally controlled at 0.3 - 0.5 MPa. The slurry flows out from the outlet of the grouting pipe 7 at the bottom of the anchor cable hole 5 until the slurry flows out of the outlet grouting pipe, then close the valve of the outlet grouting pipe, and then close the valve of the grouting pipe 7. After maintaining for 3 hours, open the valve of the outlet grouting pipe, and then open the valve of the grouting pipe 7 to inject cement slurry into the grouting pipe 7. The weight ratio is cement: water: expansive agent = 1:1:0.1. After the sediment water in the hole is discharged from the outlet grouting pipe, close the valve of the outlet grouting pipe, and continue to grout under pressure. After the pressure rises to 1.5 MPa, maintain the pressure for 30 minutes until the hole no longer takes in slurry or cement slurry oozes out from the surface of the excavated rock layer, so as to achieve the effect of permeation grouting on the broken rock layer on the back of the main anchor block and the effect of filling the slurry in the anchorage section L1. Finally, close the valve of the grouting pipe 7.

[0040] With such a setting, the first injected cement slurry is relatively thin and the pressure is relatively low, aiming to make its ability to penetrate the broken rock layer stronger. The second injected cement slurry is relatively thick and the pressure is relatively high, aiming to make the pores in the broken rock layer more saturated and the slurry in the anchorage section L1 more dense.

[0041] Furthermore, 24 hours after the grouting is completed, the cement slurry for rock layer permeation grouting has solidified, and the polyurethane blocking the hole opening can be removed. When removing, first soften the solidified polyurethane blocking the anchor cable hole opening with high-temperature hot air, and then use a hook clamp to scrape it off, to prevent the anchor cable in the hole from affecting the transfer of part of the tension of the anchor cable to the anchorage end and the unqualified elongation of the tension during the tensioning process after the construction of the anchor block concrete.

[0042] Step 105: Connect one end of the anchor cable 2 located on the ground to the anchor steel frame, and pour concrete on the anchor steel frame.

[0043] In some embodiments, step 105 includes: fixing a steel conduit for protecting the anchor cable 2 in the anchor reinforcement frame, the anchor cable 2 is passed through the steel conduit, and the concrete is poured and vibrated in layers, with each layer being 30 cm thick. When pouring concrete, the concrete of the anchor pier 3 and the anchor beam 1 are poured at the same time.

[0044] Specifically, the main anchor is a C40 reinforced concrete structure, and the anchor reinforcement frame adopts a standardized steel formwork. Before pouring concrete, a Φ130×4mm steel conduit for protecting the anchor cable 2 is buried in the anchor reinforcement frame. The anchor cable 2 is located in the steel conduit to prevent the anchor cable 2 from being wrapped by concrete and unable to extend freely during tensioning. The buried position of the steel conduit should be accurate and firmly fixed with steel bars or steel sections to prevent it from moving during concrete pouring. After checking that the formwork, steel bars and embedded parts meet the requirements, the pouring of concrete is started. The rock surface is rinsed clean before pouring. The concrete is poured and vibrated in layers, with a thickness of 30 cm for each layer. When pouring concrete, the concrete of the anchor pier 3 and the anchor beam 1 must be poured continuously at the same time. After the concrete pouring is completed, the curing time shall be no less than 7 days.

[0045] In this embodiment, the method further includes step 106 : performing prestressing of the anchor cable 2 .

[0046] Specifically, after the strength of cement slurry in the anchor hole and the strength and setting period of concrete of the main anchor have reached the design requirements, the prestressed tensioning of anchor cable 2 is applied. The jack and oil gauge used for tensioning must be calibrated and used in combination. The tensioning force and elongation are controlled dually, with tensioning force control as the main method and elongation verification as the check method. The difference between the actual elongation and the theoretical elongation should be controlled within 6%. When placing the jack, ensure that the jack and anchor cable 2 are on the same axis when tensioning. The tensioning process is carried out in 3 stages, namely: For the design tensioning stress of 60%, 80% and 100%, the tensioning process should be smooth, and the exposed length of the steel strand 10 at each level should be recorded respectively. When tensioning to 100% of the design tensioning stress, the actual elongation is calculated, and the actual elongation is compared with the theoretical elongation. The error is within 6% and it is qualified. After the tensioning is completed, the excess steel strand 10 outside the anchor 6 should be cut off by a grinding wheel cutter, and a length of not less than 5 cm should be reserved outside the anchor 6 to prevent slipping. Finally, C30 anchor sealing is used.

[0047] Furthermore, it also includes: setting corresponding observation points on the excavated platform 4 and the slope top to establish a slope displacement monitoring network. Total stations, GPS and other measurement devices can be used to connect each observation point to form a complete displacement monitoring network, which mainly focuses on the main anchor of the slope platform 4, the slope excavation surface and the points where deformation may occur. The change of each observation value of these points is compared with the first observation value, and a time-displacement curve graph is drawn. By analyzing the curve, the deformation trend of the slope body can be judged, the safety of the slope body can be predicted in time, and a basis for whether to adopt strengthening measures in the follow-up can be provided.

[0048] According to the terrain and geological conditions on both sides of the bridge, the present invention anchors the cable to the mountain bodies on both sides and uses prestressed anchor cables to anchor the main anchor. Due to the adoption of the prestressed cable-type main anchor technology, the excavation workload is small, the interference to highway traffic is minimized, the hoisting construction process is greatly simplified, and the construction safety can be better guaranteed.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A main anchor of a cable crane in a broken geological slope zone, characterized in that Set on the slope areas on both sides of the arch bridge, including: An anchor beam (1), multiple bundles of anchor cables (2), and multiple anchor piers (3) cast in place on the platforms (4) excavated from the slope. The back of the anchor pier (3) is inclined. The anchor beam (1) is arranged between two adjacent anchor piers (3) and is used to coil and fix the main cable and working cable of the cable crane. One end of the anchor cable (2) is anchored in the deep bedrock of the fractured geological slope zone, and the other end can be prestressed and anchored to the anchor pier (3).

2. The main anchor of the cable crane for the broken geological slope zone according to claim 1, characterized in that The anchor cable (2) is arranged perpendicular to the back wall of the main anchor block, and the included angle between the anchor cable (2) and the horizontal plane is 20 - 30°.

3. The main anchor of the cable crane for the fractured geological slope zone according to claim 1, characterized in that, There are three anchor piers (3), and the three anchor piers (3) are arranged at equal intervals in the first direction. Each of the anchor piers (3) on both sides is connected to at least three anchor cables (2), and the anchor pier (3) in the middle is connected to at least six anchor cables (2).

4. The main anchor of the cable crane for the broken geological slope zone according to claim 3, characterized in that, The anchor beam (1) is a cylindrical structure, the cross-sectional diameter of the anchor beam (1) is 2 - 3m, and the anchor beam (1) is vertically connected to the side surface of the anchor pier (3) in the first direction, and the first direction is the same as the axial direction of the anchor beam (1).

5. A construction method for the cable of the main anchor of the cable crane in the fractured geological slope belt as described in any one of claims 1-4, characterized in that, Including: According to the terrain and geological conditions of the slope area, select and excavate the platform (4), and set the anchor block steel reinforcement frame on the formed platform (4); Determine the position of the anchor cable hole (5) on the slope surface of the fractured rock mass to be drilled; Adopt the casing following hole-forming technology to drill the anchor cable hole (5) at the determined position; Install the anchor cable (2) in the anchor cable hole (5) and carry out in-hole grouting; Connect the end of the anchor cable (2) on the ground to the anchor block steel reinforcement frame and pour concrete into the anchor block steel reinforcement frame.

6. The construction method of the cable of the main anchor of the cable crane in the broken geological slope zone according to claim 5, characterized in that, The determination of the position of the anchor cable hole (5) on the slope surface of the fractured rock mass to be drilled includes: Clean the slope surface of the fractured rock mass to be drilled, and excavate the mountain slope into a slope surface that fits the back of the anchor pier (3) according to the slope of the back of the anchor pier (3); According to the design requirements, measure and place the position of the anchor cable hole (5) on the slope surface, and the hole position error does not exceed 50mm.

7. The construction method of the cable of the main anchor of the cable crane in the broken geological slope zone according to claim 5, characterized in that, The adoption of the casing following hole-forming technology to drill the anchor cable hole (5) at the determined position includes: Construct by pneumatic dry drilling method. The drill bit passes through the strongly weathered siliceous rock layer on the slope surface into the moderately weathered slate layer in turn, and the steel casing follows the drill bit at the same time. When drilling the strongly weathered siliceous rock layer, the drilling speed is 2.5 - 4.5m / h. Stop drilling for hole cleaning every 2m of drilling. After cleaning the loose soil in the hole, continue drilling until the anchoring section (L1) of the anchor cable (2) completely enters the moderately weathered slate layer; After drilling is completed, use high-pressure air to remove all the rock powder and water in the anchor cable hole (5) outside the hole and carry out the acceptance of the anchor cable hole (5).

8. The cable construction method of the main anchor of the cable crane for the broken geological slope belt according to claim 5, characterized in that, The installation of the anchor cable (2) in the anchor cable hole (5) and the in-hole grouting include: Before the cable anchor (2) is inserted into the hole, the hole is re-cleared with high-pressure air. After the cable anchor (2) is installed, the steel casing is pulled out using a reaction frame and a jack, and the cable anchor hole (5) is grouted by the method of secondary grouting under pressure.

9. The construction method of the cable of the main anchor of the cable crane in the broken geological slope zone according to claim 5, characterized in that, Connecting one end of the cable anchor (2) located on the ground to the anchor block steel reinforcement frame and pouring concrete into the anchor block steel reinforcement frame includes: Fixing and installing a steel conduit for protecting the cable anchor (2) in the anchor block steel reinforcement frame, threading the cable anchor (2) through the steel conduit, and the concrete is poured in layers and vibrated in layers, with each layer having a thickness of 30 cm. When the concrete is poured, the concrete of the anchor pier (3) and the anchor beam (1) is poured at one time simultaneously.

10. The cable construction method of the main anchor of the cable crane for the fractured geological slope belt according to claim 5, characterized in that, It also includes: Performing prestress tensioning and anchor sealing of the cable anchor (2).

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