A prestressed anchor cable construction method for soft rock slope construction

Abstract

The application relates to the technical field of slope support, in particular to a prestressed anchor cable construction method for soft rock slope construction, which comprises the following steps: S1, drilling, S1.1, first, a common drill bit is installed on a drilling machine, the depth of the drilling hole is selected according to the length of the anchor cable, and then the common drill bit is used to preliminarily drill the hole; S1.2, an eccentric drill bit is selected according to the size of the anchor cable anchoring section, the eccentric drill bit is then installed on the drilling machine, and then the eccentric drill bit is used to drill; S2, anchor cable manufacturing, S3, anchor cable installation, the anchor cable is placed in the drilling hole; S4, grouting, horizontal beam formwork pouring and maintenance; and S5, anchor cable stretching, the anchor cable is stretched by using a stretching tool, and then cutting and anchor sealing are carried out. The application has the effect of improving construction safety.

Description

Technical Field

[0001] This application relates to the technical field of slope protection, and in particular to a prestressed anchor cable construction method for soft rock slope construction. Background Technology

[0002] Currently, with the booming development of engineering construction in recent years, more and more projects are being built on soft rock. However, soft rock has complex and variable characteristics, such as expansibility, softening upon contact with water, and disintegration, and it is prone to drying and cracking in engineering practice. Therefore, further in-depth and detailed research is needed on the deformation characteristics of soft rock. Based on the process control principles in slope engineering, appropriate time, location, and effective protection and reinforcement measures are selected to control the slope process and improve its overall stability. When carrying out slope protection, comprehensive construction methods such as prestressed anchor cable construction, shotcrete and anchor support, retaining wall support, ecological protection, and flexible treatment are implemented based on different predictive indicators and parameter factors.

[0003] The construction of anchor cables generally includes the following steps: First, drilling is carried out, then controlled blasting is performed at the bottom of the borehole to compact the soil-rock mixture at the bottom of the borehole, forming a relatively stable rock and soil mass. At the same time, a cavity is formed at the bottom of the borehole as the anchoring section of the anchor cable. Then, the anchor cable is installed in the borehole, and then grouting is performed.

[0004] In the process of developing this application, the inventors discovered that the technology has at least the following problems: when the blasting is controlled at the bottom of the hole, the shock wave generated by the explosion will cause fragments or sand to fly out of the hole, which reduces safety. Summary of the Invention

[0005] To improve safety, this application provides a prestressed anchor cable construction method for soft rock slope construction.

[0006] This application provides a prestressed anchor cable construction method for soft rock slope construction, which adopts the following technical solution:

[0007] A method for constructing prestressed anchor cables for weak rock slopes includes the following steps:

[0008] S1, Drilling;

[0009] S1.1 First, install a regular drill bit on the drilling rig, select the drilling depth according to the length of the anchor cable, and then use a regular drill bit to perform the initial drilling of the hole;

[0010] S1.2. Select an eccentric drill bit according to the size of the anchor section of the anchor cable, then install the eccentric drill bit on the drilling rig, and then use the eccentric drill bit for drilling;

[0011] S2. Fabricate anchor cables.

[0012] S3. Install the anchor cable and place it inside the borehole;

[0013] S4. Grouting, horizontal grid beam formwork casting and curing;

[0014] S5. Anchor cable stretching: Use a stretching tool to stretch the anchor cable, and then cut and seal it.

[0015] By adopting the above technical solution, the weak rock slope is first surveyed. Then, based on the survey data, the reinforcement locations and their intervals are calculated. Scaffolding is then erected, and a total station is used to mark the locations. Following this, a standard drill bit is installed on the drilling rig, and drilling begins. Once the designed depth is reached, an eccentric drill bit is used to enlarge the hole at the bottom. After drilling is complete, anchor cables are fabricated, the borehole is cleaned, and the anchor cables are installed. Finally, the borehole is grouted. Grouting is performed by injecting grout from the bottom of the hole until grout overflows from the hole opening. After natural solidification, grout is added to the hole opening. Then, the trench for the horizontal beam is excavated, and steel reinforcement is laid to support the formwork for pouring. After the formwork reaches the required strength, it is removed, and then the anchor cables are stretched. After stretching, the anchors are cut and sealed. By using a drilling rig to enlarge the hole at the bottom, the probability of using explosives to enlarge the hole at the bottom is reduced, thereby reducing the probability of sand, gravel and soil splashing, which improves safety. At the same time, it reduces the damage to weak rock by multiple blasts and improves the safety of construction.

[0016] Optionally, in step S1, the drilling machine used for drilling is a high-pressure jet grouting drill.

[0017] By adopting the above technical solutions and using high-pressure jet grouting drilling rigs, it is possible to drill vertical, horizontal, inclined, and inclined holes at multiple angles, which can meet the needs of various strata and different processes.

[0018] Optionally, in step S3, if resistance is encountered during anchor cable installation, it should not be forcibly inserted. Instead, the anchor cable should be removed, the hole cleaned, and then the anchor cable inserted again.

[0019] By adopting the above technical solution, when encountering resistance during the installation of anchor cables, the installation of anchor cables should be stopped, the anchor cables should be removed, and the hole should be cleaned. This reduces the possibility of the anchor cables failing to reach the bottom of the hole due to collapse or sand and gravel inside the hole, thus failing to achieve the expected reinforcement effect. By cleaning the hole, the anchor cables can be installed again, so that the anchoring effect can be maintained.

[0020] Optionally, the anchor cable in step S2 includes steel strands, extrusion anchors, limiting plates, a bearing body, guide caps, and supports. Multiple steel strands are provided, with a fixed length according to construction requirements. Each steel strand has an extrusion anchor at one end. The bearing body has multiple first threading holes for threading the steel strands, and the bearing body abuts against one end of the extrusion anchor. The limiting plate has multiple second threading holes, and the limiting plate abuts against the end of the extrusion anchor away from the bearing body. The guide cap is fitted onto the limiting plate and connected to the bearing body. Multiple supports are provided and spaced apart along the length of the steel strands, and the supports are used to separate multiple steel strands.

[0021] By adopting the above technical solution, during anchor cable fabrication, the length of the anchor cable is first designed based on the data from the site survey. Then, according to the design value, the steel strands are cut to a fixed length using a cutting machine. An appropriate number of steel strands are selected according to the design. The compression anchor is then installed at one end of the steel strands. The shorter ends of multiple steel strands are then passed sequentially through the limiting plate, and the ends of the steel strands furthest from the limiting plate are then passed sequentially through the bearing body, ensuring that both ends of the compression anchor abut against the limiting plate and the bearing body respectively. A guide cap is then fitted onto the limiting plate and connected to the bearing body. Finally, multiple supports are installed along the steel... The strands are spaced evenly along their length and supported sequentially. The supports and strands are then fixed together with binding wire. A grouting pipe is then threaded through the support, forming a single anchor cable. After drilling and cleaning, the anchor cable is installed inside the borehole. The anchor cable structure is simple, using square plates. The fixed-length cutting of the strands reduces waste. Multiple supports expand the strands, creating a lotus root-like structure for tighter anchoring. The supports also help straighten the strands, preventing them from becoming tangled and ensuring even and sufficient stress distribution, thus improving the anchoring effect.

[0022] Optionally, the guide cap has an overflow hole at the end furthest from the carrier.

[0023] By adopting the above technical solution, when grouting the borehole, the grout enters the bottom of the borehole through the overflow hole, and then the grout returns from the bottom of the hole, so that the grout in the borehole is fully filled, making the borehole dense, reducing the pull-out of the anchor cable during the tensioning process, and thus maintaining the anchoring effect.

[0024] Optionally, the guide cap is provided with a connecting component, the connecting component including a first connecting block and a second connecting block, the first connecting block being disposed on the carrier, the second connecting block being integrally disposed on the guide cap, and the second connecting block being threadedly connected to the first connecting block.

[0025] By adopting the above technical solution, after the limiting plate and the carrier body are respectively pressed against the two ends of the compression anchor, the guide cap is put on the limiting plate, the second connecting block on the guide cap abuts against the first connecting block, and then the guide cap is rotated so that the first connecting block and the second connecting block are threadedly connected. Through the set connection component, the connection between the guide cap and the carrier body becomes convenient and quick, and no welding is required to fix it, reducing the damage of welding to the steel strand. At the same time, the set connection component has a simple structure and is easy to operate.

[0026] Optionally, the carrier is provided with an expansion mechanism, which includes an expansion rod, a torsion spring, and an expansion assembly. Multiple expansion rods are rotatably connected to the side wall of the carrier away from the extrusion anchor. Multiple torsion springs are provided on the carrier, and the torsion springs drive the end of the expansion rod away from the carrier to rotate in a direction away from the axis of the guide cap. The expansion assembly is provided on the carrier and is used to restrict the rotation of the expansion rod.

[0027] By adopting the above technical solution, when the anchor cable reaches the specified depth, the expansion component is used to release the restriction on the expansion rod. The torsion spring drives the expansion rod to rotate, and the expansion rod disperses at the expansion hole. Then, grout is injected into the borehole. The expansion rod is set to exceed the diameter of the borehole, and at the same time, the concrete contacts the hole, increasing the anchoring force of the anchor cable and enhancing the anchoring effect.

[0028] Optionally, the expansion assembly includes a steel pipe sleeve, a locking pin, a limiting spring, a limiting plate, and a pushing rod. The steel pipe sleeve is connected to the end of the carrier away from the extrusion anchor, and the steel pipe sleeve has multiple expansion grooves for the expansion rod to rotate. The locking pin is slidably disposed at the end of the expansion rod away from the carrier, and the locking pin abuts against the inner wall of the steel pipe sleeve. The limiting spring is disposed on the expansion rod and connected to the locking pin, and the limiting spring drives the locking pin away from the expansion rod. The limiting plate is slidably connected inside the steel pipe sleeve, and the pushing rod is inserted into the side wall of the limiting plate away from the guide cap. The end of the pushing rod away from the limiting plate passes through multiple brackets in sequence and extends to the outside of the drill hole.

[0029] By adopting the above technical solution, when the anchor cable reaches the specified depth, pressing the push rod causes the limiting plate to slide, the limiting plate to abut against the locking pin, and the locking pin to slide towards the bearing body. The limiting spring is compressed, the locking pin separates from the inner wall of the steel pipe sleeve, and the torsion spring drives the expanding rod to rotate. Multiple expanding rods rotate to form an umbrella shape, and then the push rod is pulled out. The push rod facilitates the straightening of the anchor cable and its movement in the hole, while keeping the anchor cable in a straight state, reducing ineffective tension during stretching, and resulting in better anchoring effect. The push rod also facilitates the release of the restriction on the expanding rod, which is safer than the explosive expansion method used in the prior art. The push rod can also be removed after use, reducing resource waste. The expansion component has a simple structure, reducing the rotation of the expanding rod during anchor cable installation, thus allowing the anchor cable to reach the bottom of the hole smoothly and maintaining the anchoring effect.

[0030] Optionally, the limiting plate is provided with an anti-floating component, the anti-floating component includes a first limiting block, and the limiting plate is provided with a plurality of first limiting blocks. The first limiting blocks slide on the inner wall of the steel pipe sleeve, and the first limiting blocks correspond to the enlarged groove and can slide along the enlarged groove. The first limiting blocks can abut against the rotating end of the enlarged rod and restrict the rotation of the enlarged rod.

[0031] By adopting the above technical solution, when the push rod is pressed, the push rod drives the limiting plate to slide along the steel pipe sleeve. After the limiting plate drives the locking pin to separate from the steel pipe sleeve, the push rod is pressed again. The push rod drives the first limiting block on the limiting plate to slide into the enlarged groove and abut against the rotating end of the enlarged rod. During grouting, since the grout is returned from the bottom of the hole, the grout has floating properties and will drive the enlarged rod to rotate. The first limiting block sets the enlarged rod to abut against it, restricting the rotation of the enlarged rod, improving the stability of the enlarged rod, and thus maintaining the tensile strength of the anchor cable.

[0032] Optionally, the anti-buoyancy component further includes a second limiting block, and a plurality of the second limiting blocks are provided on the carrier. The second limiting blocks correspond to the expanding rod and are used to limit the maximum rotation angle of the expanding rod.

[0033] By adopting the above technical solution, when the anchor cable reaches the designed depth, the expansion component drives the locking pin to separate from the steel pipe head, the torsion spring drives the expansion rod to rotate, the expansion rod abuts against the second limiting block, and then grouting is carried out. The second limiting block further improves the stability of the expansion rod, and transmits the gripping force of the expansion rod on the concrete to the entire anchor cable, thereby improving the anchoring effect.

[0034] In summary, this application includes the following beneficial technical effects:

[0035] 1. By using a drilling rig to enlarge the bottom of the hole, the probability of using explosives to enlarge the bottom of the hole is reduced, thereby reducing the probability of sand, gravel and soil splashing, which improves safety. At the same time, it reduces the damage to weak rock by multiple blasts and improves the safety of construction.

[0036] 2. Once the anchor cable reaches the designated depth, press the push rod. The push rod causes the limiting plate to slide, and the limiting plate abuts against the locking pin, causing the locking pin to slide closer to the load-bearing body. The limiting spring is compressed, and the locking pin separates from the inner wall of the steel pipe sleeve. The torsion spring drives the expanding rods to rotate, and multiple expanding rods rotate until they form an umbrella shape. Then, the push rod is pulled out. The push rod facilitates the straightening of the anchor cable and its movement in the hole. It also keeps the anchor cable in a straight state, reducing ineffective tension during stretching and improving the anchoring effect. The push rod also facilitates the release of the expanding rods, which is safer than the explosive expansion method used in existing technologies. Furthermore, the push rod can be removed after use, reducing resource waste. The simple structure of the expanding assembly reduces the rotation of the expanding rods during anchor cable installation, allowing the anchor cable to reach the bottom of the hole smoothly and maintaining the anchoring effect.

[0037] 3. When the push rod is pressed, the push rod drives the limiting plate to slide along the steel pipe sleeve. After the limiting plate drives the locking pin to separate from the steel pipe sleeve, the push rod is pressed again. The push rod drives the first limiting block on the limiting plate to slide into the enlarged groove and abut against the rotating end of the enlarged rod. During grouting, since the grout is returned from the bottom of the hole, the grout has floating properties and will drive the enlarged rod to rotate. The first limiting block sets the enlarged rod to abut against it, restricting the rotation of the enlarged rod, improving the stability of the enlarged rod, and thus maintaining the tensile strength of the anchor cable. Attached Figure Description

[0038] Figure 1 This is a flowchart illustrating the prestressed anchor cable construction method for soft rock slope construction in the embodiments of this application;

[0039] Figure 2 This is a schematic diagram of the overall structure of the anchor cable in the embodiments of this application;

[0040] Figure 3 This is an exploded view of a portion of the anchor cable structure in an embodiment of this application;

[0041] Figure 4 This is a schematic diagram of the structure of the bracket in the embodiments of this application;

[0042] Figure 5 This is a partial structural cross-sectional view of the anchor cable in an embodiment of this application;

[0043] Figure 6 This is a schematic diagram showing the installation position of the guide block in an embodiment of this application.

[0044] Reference numerals: 100, steel strand; 200, extrusion anchor; 300, limiting plate; 400, bearing body; 500, guide cap; 510, straight pipe section; 520, guide section; 530, overflow hole; 600, bracket; 610, snap-fit ​​groove; 620, binding hole; 700, connecting assembly; 710, first connecting block; 720, second connecting block; 800, expanding mechanism; 810, expanding rod; 811, sliding hole; 820, expanding assembly; 821, steel pipe sleeve; 822, locking pin; 823, limiting spring; 824, limiting plate; 825, push rod; 826, connecting block; 827, guide block; 828, expanding groove; 829, guide groove; 830, anti-buoyancy assembly; 831, first limiting block; 832, second limiting block; 900, grouting pipe. Detailed Implementation

[0045] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0046] This application discloses a method for constructing prestressed anchor cables for soft rock slopes.

[0047] refer to Figure 1 The prestressed anchor cable construction method for soft rock slopes includes the following steps:

[0048] S1. Drilling: Before drilling, first determine the anchor cable position based on the survey results, then use a total station to mark the hole position, and then erect scaffolding; S1.1. First, install a regular drill bit on the high-pressure jet grouting drilling rig, select the drilling depth according to the length of the anchor cable, and then use the regular drill bit for preliminary drilling. When the drilling depth is reached, remove the drill bit; S1.2. Select an eccentric drill bit according to the size of the anchor section of the anchor cable, then install the eccentric drill bit on the drilling rig, and then use the eccentric drill bit for drilling. After drilling is completed, stop drilling in the depth direction. After drilling reaches the design depth, it is necessary to stabilize the drilling for 1-2 minutes. After drilling is completed, use high-pressure air (0.2... S1) Remove all rock powder and water from the borehole (MPa~0.4MPa); S2) Fabricate anchor cables; S3) Install anchor cables: Place the anchor cables inside the borehole. If resistance is encountered during installation, do not force them in. Remove the anchor cables, clean the borehole, and then reinsert them to ensure they reach the specified depth; S4) Grouting, formwork erection and curing of the transverse beam: Grout the borehole using a bottom-up grouting method until grout overflows from the borehole opening. After natural solidification, replenish the grout at the borehole opening. Then excavate the transverse beam trench, lay steel reinforcement to support the formwork, and pour the concrete. Once the required strength is reached, remove the formwork; S5) Anchor cable stretching: Stretch the anchor cables with a stretching tool, then cut them and seal them with concrete.

[0049] refer to Figure 2 and Figure 3 The anchor cable comprises multiple fixed-length steel strands 100 cut by a cutting machine. One end of each steel strand 100 is fixedly connected to a compression anchor 200. A 4-5cm length is reserved at the end of the steel strand 100 with the compression anchor 200. A limiting plate 300 is provided at the 4-5cm reserved end of the steel strand 100. The limiting plate 300 has multiple second threading holes for the steel strands 100 to pass through. The limiting plate 300 abuts against one end of the compression anchor 200. The multiple steel strands 100 are positioned away from each other. One end of the limiting plate 300 is provided with a carrier 400. The carrier 400 has multiple first threading holes for steel strands 100 to pass through. Multiple steel strands 100 pass through multiple first threading holes respectively. The carrier 400 abuts against the end of the extrusion anchor 200 away from the limiting plate 300. A connecting screw is provided on the limiting plate 300. The connecting screw passes through the carrier 400 and is threaded with a connecting nut. The connecting screw and the connecting nut drive the limiting plate 300 and the carrier 400 to press against the extrusion anchor 200.

[0050] refer to Figure 1 and Figure 4 Multiple supports 600 are provided at the ends of multiple steel strands 100 away from the bearing 400. Multiple slots 610 for clamping the steel strands 100 are provided on the supports 600. The multiple steel strands 100 are respectively clamped in the multiple slots 610. The multiple supports 600 are equally spaced along the length of the steel strands 100, and binding holes 620 for passing binding wires are provided on the supports 600. The supports 600 are fixedly connected to the steel strands 100 by binding wires to reduce the slippage of the supports 600 along the length of the steel strands 100.

[0051] refer to Figure 2 and Figure 3 A guide cap 500 is fitted onto the end of the limiting plate 300 away from the carrier 400. The guide cap 500 includes a straight tube portion 510 and a guide portion 520. The straight tube portion 510 and the guide portion 520 are integrally formed. The guide portion 520 is a hollow cone shape, and an overflow hole 530 is opened at the tip of the guide portion 520. The straight tube portion 510 is fitted onto the limiting plate 300. A connecting component 700 is provided at the end of the straight tube portion 510 away from the guide portion 520. The straight tube portion 510 is connected to the carrier 400 through the connecting component 700.

[0052] refer to Figure 2 and Figure 3The connecting assembly 700 includes a second connecting block 720 integrally disposed at one end of the straight tube portion 510 away from the guide portion 520. The second connecting block 720 is cylindrical. A first connecting block 710 is integrally disposed at one end of the carrier body 400 near the limiting piece 300. The second connecting block 720 is sleeved on the first connecting block 710 and the first connecting block 710 and the second connecting block 720 are threadedly connected. The second connecting block 720 abuts against the side wall of the carrier body 400 near the limiting piece 300. The outer diameter of the second connecting block 720 is the same as the outer diameter of the carrier body 400.

[0053] refer to Figure 5 and Figure 6 To increase the anchoring force of the anchor cable, an expansion mechanism 800 is provided on the bearing body 400. The expansion mechanism 800 includes multiple expansion rods 810 rotatably connected to the side wall of the bearing body 400 away from the limiting plate 300. In this embodiment, four are preferred. The four expansion rods 810 are equally spaced along the circumference of the bearing body 400. A torsion spring is fixedly connected to the rotating end of the expansion rod 810. The torsion spring is connected to the bearing body 400 and drives the expansion rod 810 to rotate in a direction away from the circumference of the bearing body 400.

[0054] refer to Figure 5 and Figure 6 An expansion assembly 820 is provided on the support body 400. The expansion assembly 820 includes a steel pipe sleeve 821 fixedly connected to the side wall of the support body 400 away from the extrusion anchor 200. The end of the steel pipe sleeve 821 near the support body 400 has a plurality of expansion grooves 828 for the expansion rod 810 to rotate. A plurality of guide blocks 827 are integrally provided on the steel pipe sleeve 821. The plurality of guide blocks 827 and the expansion grooves 828 are located on the same axis. The guide blocks 827 have guide grooves 829 on the side wall inside the steel pipe sleeve 821. The cross-section of the guide grooves 829 is semi-arc.

[0055] refer to Figure 5 and Figure 6The expanding rod 810 has a sliding hole 811 at the end away from the support body 400. A locking pin 822 is slidably connected in the sliding hole 811. A limiting spring 823 is fixedly connected to the bottom wall of the sliding hole 811. The end of the limiting spring 823 away from the bottom wall of the sliding hole 811 is fixedly connected to the locking pin 822. The limiting spring 823 has the potential to push the locking pin 822 away from the support body 400. The end of the locking pin 822 away from the limiting spring 823 is hemispherical, and the side wall of the locking pin 822 abuts against the inner wall of the guide groove 829. A limiting plate 824 is slidably connected in the steel pipe sleeve 821. The limiting plate 824 is along the length of the steel pipe sleeve 821. The limiting plate 824 has multiple sliding grooves for the steel strand 100 to slide in the direction of sliding, and the inner wall of the sliding groove does not need to abut against the steel strand 100. A connecting block 826 is fixedly connected at the axis of the limiting plate 824. The connecting block 826 is located at the end of the limiting plate 824 near the guide cap 500. The limiting plate 824 and the connecting block 826 have through slots on their side walls away from the guide cap 500. A push rod 825 is inserted into the through slot. The end of the push rod 825 away from the limiting plate 824 passes through multiple brackets 600 in sequence and extends to the opening. The push rod 825 is slidably connected to the multiple brackets 600.

[0056] refer to Figure 1 The bracket 600, the carrier 400 and the limiting piece 300 are all provided with two third threading holes for the grouting pipe 900 to pass through. The grouting pipe 900 passes through multiple threading holes in sequence and extends into the guide cap 500.

[0057] refer to Figure 5 The limiting plate 824 is provided with an anti-floating component 830, which includes four first limiting blocks 831 fixedly connected to the limiting plate 824. The four first limiting blocks 831 are slidably connected in four guide grooves 829, and the first limiting blocks 831 can slide along the guide grooves 829 into the enlarged grooves 828. The first limiting blocks 831 can abut against the locking pins 822 and drive the locking pins 822 to retract into the sliding holes 811. The first limiting blocks 831 slide into the enlarged grooves 828. The 28-inch inner end can abut against the rotating end of the expanding rod 810 and restrict the expanding rod 810 from being reset by buoyancy; four second limiting blocks 832 are fixedly connected to the support body 400. The four second limiting blocks 832 are equally spaced on the support body 400. The four second limiting blocks 832 are located outside the expanding rod 810 and are used to limit the maximum rotation angle of the expanding rod 810, so that when the expanding rod 810 is subjected to shear force, it is transmitted to the support body 400, so that the support body 400 is subjected to the main force.

[0058] The implementation principle of the prestressed anchor cable construction method for weak rock slope construction in this application embodiment is as follows: First, the weak rock slope is surveyed. Then, based on the survey data, the reinforcement locations and their intervals are calculated. Scaffolding is then erected, and a total station is used to place the points. According to the location of the points, a conventional drill bit is installed on a drilling rig, and drilling is performed. When the design depth is almost reached, an eccentric drill bit is used to enlarge the hole at the bottom. After drilling is completed, the anchor cable is fabricated. First, a steel strand 100 is cut using a cutting machine according to the drilling depth. The length of the steel strand 100 should be greater than the drilling depth by 1.5m. Then, an extrusion anchor 200 is installed on the steel strand 100. At one end, multiple steel strands 100 are threaded through the bearing 400 so that the bearing 400 abuts against the compression anchor 200. Then, a limiting piece 300 is installed at the end of the steel strand 100 away from the bearing 400, and the limiting piece 300 is connected to the bearing 400 by connecting bolts and connecting nuts. Then, the guide cap 500 is threaded to the bearing 400. Then, the steel strands 100 are sequentially snapped into the snap-fit ​​grooves 610 on multiple brackets 600. Then, the brackets 600 are fixed with binding wire. Then, the push rod 825 is sequentially passed through the brackets 600 and inserted into the through slot. Then, the grouting pipe 900 is threaded through the third through hole so that the grouting pipe 900 extends to the guide cap 500.

[0059] Then, the borehole is cleaned, and the anchor cable is installed. The prepared anchor cable is placed in the borehole, and the anchor cable is straightened by the push rod 825 until the guide cap 500 is sunk to the bottom of the hole. Then, the steel strand 100 is pulled to press the push rod 825. The push rod 825 drives the limiting plate 824 to slide. The limiting plate 824 drives the first limiting block 831 to abut against the locking pin 822, and drives the locking pin 822 to retract into the sliding hole 811. The spring releases its elastic force and drives the expanding rods 810 to rotate, so that the four expanding rods 810 are umbrella-shaped and abut against the second limiting block 832; continue to press the push rod 825, the push rod 825 drives the first limiting block 831 to slide into the expanding groove 828 and slide along the expanding groove 828 until it abuts against the expanding rod 810, the first limiting block 831 restricts the rotation of the expanding rod 810; then the push rod 825 is pulled out of the through slot and the push rod 825 is removed and drilled.

[0060] Then, grouting is carried out on the borehole using the bottom return grouting method until grout overflows from the borehole opening. After natural solidification, grout is added to the borehole opening. Then, the horizontal grid beam trench is excavated, steel reinforcement is laid to support the formwork, and the concrete is poured. After the strength is reached, the formwork is removed, and then the anchor cables are stretched. After stretching is completed, the anchors are cut and sealed with concrete.

[0061] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for constructing prestressed anchor cables on weak rock slopes, characterized in that, Includes the following steps: S1, Drilling; S1.1 First, install a regular drill bit on the drilling rig, select the drilling depth according to the length of the anchor cable, and then use a regular drill bit to perform the initial drilling of the hole; S1.

2. Select an eccentric drill bit according to the size of the anchor section of the anchor cable, then install the eccentric drill bit on the drilling rig, and then use the eccentric drill bit for drilling; S2. Fabricate anchor cables. S3. Install the anchor cable and place it inside the borehole; S4. Grouting, horizontal grid beam formwork casting and curing; S5. Anchor cable stretching: Use a stretching tool to stretch the anchor cable, and then cut and seal it. The anchor cable mentioned in step S2 includes a steel strand (100), a compression anchor (200), a limiting piece (300), a bearing (400), a guide cap (500), and a bracket (600). An expanding mechanism (800) is provided on the support body (400). The expanding mechanism (800) includes an expanding rod (810), a torsion spring, and an expanding assembly (820). A plurality of expanding rods (810) are rotatably connected to the side wall of the support body (400) away from the compression anchor (200). A plurality of torsion springs are provided on the support body (400). The torsion springs drive the end of the expanding rod (810) away from the support body (400) to rotate in a direction away from the axis of the guide cap (500). The expanding assembly (820) is provided on the support body (400) and is used to restrict the rotation of the expanding rod (810). The expanding assembly (820) includes a steel pipe sleeve (821), a locking pin (822), a limiting spring (823), a limiting plate (824), and a push rod (825). The steel pipe sleeve (821) is connected to the end of the bearing body (400) away from the compression anchor (200), and the steel pipe sleeve (821) has multiple expanding grooves (828) for the expanding rod (810) to rotate. The locking pin (822) is slidably disposed at the end of the expanding rod (810) away from the bearing body (400), and the locking pin (822) is connected to the end of the steel pipe sleeve (821) away from the bearing body (400). 1) The inner wall abuts against the expansion rod (810), the limiting spring (823) is set on the expansion rod (810) and connected to the locking pin (822), the limiting spring (823) drives the locking pin (822) away from the expansion rod (810); the limiting plate (824) is slidably connected inside the steel pipe sleeve (821), the push rod (825) is inserted into the side wall of the limiting plate (824) away from the guide cap (500), one end of the push rod (825) away from the limiting plate (824) passes through multiple brackets (600) in sequence and extends to the outside of the drill hole.

2. The prestressed anchor cable construction method for soft rock slope construction according to claim 1, characterized in that, In step S1, the drilling machine used for drilling is a high-pressure jet grouting drill.

3. The prestressed anchor cable construction method for soft rock slope construction according to claim 1, characterized in that, In step S3, if resistance is encountered during anchor installation, it should not be forced in. Instead, the anchor should be removed, the hole cleaned, and then the anchor should be reinserted.

4. The prestressed anchor cable construction method for soft rock slope construction according to claim 1, characterized in that, The steel strands (100) are provided in multiple lengths according to construction requirements, and each steel strand (100) is provided with an extrusion anchor (200) at one end; the carrier (400) is provided with multiple first threading holes for threading the steel strands (100), and the carrier (400) abuts against one end of the extrusion anchor (200); the limiting plate (300) is provided with multiple second threading holes, and the limiting plate (300) abuts against the end of the extrusion anchor (200) away from the carrier (400); the guide cap (500) is sleeved on the limiting plate (300) and connected to the carrier (400); multiple brackets (600) are provided and spaced apart along the length direction of the steel strands (100), and the brackets (600) are used to separate multiple steel strands (100).

5. The prestressed anchor cable construction method for soft rock slope construction according to claim 4, characterized in that, The guide cap (500) has an overflow hole (530) at the end away from the carrier (400).

6. The prestressed anchor cable construction method for soft rock slope construction according to claim 4, characterized in that, The guide cap (500) is provided with a connecting component (700), the connecting component (700) includes a first connecting block (710) and a second connecting block (720), the first connecting block (710) is disposed on the carrier (400), the second connecting block (720) is integrally disposed on the guide cap (500), and the second connecting block (720) is threadedly connected to the first connecting block (710).

7. The prestressed anchor cable construction method for soft rock slope construction according to claim 1, characterized in that, The limiting plate (824) is provided with an anti-float component (830), the anti-float component (830) includes a first limiting block (831), the limiting plate (824) is provided with a plurality of first limiting blocks (831), the first limiting block (831) slides on the inner wall of the steel pipe sleeve (821), and the first limiting block (831) corresponds to the enlarged groove (828) and can slide along the enlarged groove (828). The first limiting block (831) can abut against the rotating end of the enlarged rod (810) and restrict the rotation of the enlarged rod (810).

8. The prestressed anchor cable construction method for soft rock slope construction according to claim 7, characterized in that, The anti-buoyancy component (830) further includes a second limiting block (832). Multiple second limiting blocks (832) are provided on the carrier (400). The second limiting block (832) corresponds to the expanding rod (810) and is used to limit the maximum rotation angle of the expanding rod (810).

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