A complex geology high and steep slope drainage system and a construction method thereof

Abstract

The application discloses a complex geological high and steep slope water drainage system and a construction method thereof. The system comprises a waterlogging pool arranged at the top of the slope, a stone retaining wall arranged in the middle of the slope, a high-pressure concrete layer and an upper anchor rod riveted in the upper slope, a drainage ditch and a lower anchor rod riveted in the lower slope, a water inlet of the drainage ditch connected with the waterlogging pool through a lower inspection well, a slope drainage pipe and an upper inspection well, and a water outlet of the drainage ditch connected with a water storage pool through a drainage ditch. The rainwater convergence and transportation efficiency are remarkably improved through the multi-node and multi-channel design. In terms of structural safety, the slope sliding and scouring damage are effectively prevented through the multiple anchoring, protection and anti-filtration drainage system. In terms of resource utilization, the drainage end is connected with the water storage facility, the rainwater can be used for agricultural irrigation, and the water resource utilization rate is improved. In terms of adaptability, the system can stably operate in the complex terrain such as the loess plateau, many gullies and steep slopes, and the safety and durability of the drainage system are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of drainage construction technology, and particularly to drainage construction of slopes, specifically a drainage system and construction method for steep slopes with complex geology. Background Technology

[0002] In the Loess Plateau region, there are many mountains and hills, and villages are often surrounded by gullies, plateaus or low-lying areas. During the rainy season, rainfall is concentrated and surface runoff accumulates quickly. The lack of a systematic integrated design for water collection, water conveyance, erosion prevention and slope protection makes it very easy for soil erosion to occur and waterlogging to occur, affecting the safety of residents' lives and property.

[0003] In some villages surrounded by ditches and with terrain that is high on one side and low on the other, water flows into the low-lying areas and then drains into the bottom of the ditches. As a result, the slopes of the ditches are constantly eroded by rainwater, causing serious soil loss on the ditches and waterlogging in the farmland at the bottom of the ditches. Ultimately, this greatly affects the safety of residents' living and travel in the area. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art, and to provide a drainage system for complex geological steep slopes and its construction method.

[0005] This invention is achieved through the following technical solution: In one aspect, the present invention provides a drainage system for steep slopes in complex geological conditions, including a flood control pond and a stone retaining wall.

[0006] The flood storage pond is built in a low-lying area on the top platform of the slope. An upper inspection well is built in the flood storage pond, which is connected to the slope drainage pipe. A water interception ditch is excavated on the top platform of the slope near the slope. The water interception ditch is connected to the slope drainage pipe through the drainage pipe of the water interception ditch.

[0007] The stone retaining wall is built in the middle of the slope, dividing the slope into an upper slope and a lower slope.

[0008] A lower inspection well is built on the lower slope, which is adjacent to the stone retaining wall. The lower inspection well is connected to the upper inspection well through a slope drainage pipe pre-embedded in the upper slope. A drainage outlet is provided on the lower inspection well.

[0009] A drainage ditch is constructed along the downslope direction, directly adjacent to the lower inspection well. The inlet of the drainage ditch is connected to the outlet of the lower inspection well, and a drainage ditch bedding layer is constructed at the bottom of the drainage ditch.

[0010] A drainage ditch is built at the bottom of the lower slope, and the inlet of the drainage ditch is connected to the outlet of the drainage canal. A rainwater sedimentation tank is built along the bank of the drainage ditch, and the rainwater sedimentation tank is connected to the drainage ditch through an inlet hole. A water storage tank is built on the other side of the rainwater sedimentation tank, and the water storage tank is connected to the rainwater sedimentation tank.

[0011] The upper slope has a slope protection trench excavated on its surface. A high-pressure concrete layer is poured into the slope protection trench, and a steel mesh is fixedly connected to the surface of the high-pressure concrete layer. Several upper anchor rods are evenly distributed in the high-pressure concrete layer. The bottom end of the upper anchor rod passes through the high-pressure concrete layer and is anchored to the depth of the upper slope. The top end of the upper anchor rod is fixedly connected to the steel mesh through the anchor rod connecting bar.

[0012] The bottom of the drainage ditch is evenly distributed with several lower anchor rods. The bottom end of the lower anchor rod passes through the bottom plate and the cushion layer of the drainage ditch and is anchored to the depth of the lower slope. The top end of the lower anchor rod is fixedly connected to the steel reinforcement of the bottom plate of the drainage ditch through the anchor rod connecting bar.

[0013] As a preferred technical solution of the present invention, a retaining wall foundation is constructed at the bottom of the stone retaining wall, and multiple drainage holes are provided on the stone retaining wall.

[0014] As a preferred technical solution of the present invention, the back side of the stone retaining wall is filled with river gravel as a filter layer, and the top of the river gravel is provided with filter soil.

[0015] As a preferred technical solution of the present invention, a non-woven fabric is fixed tightly against the back of the stone retaining wall, and the non-woven fabric covers the water inlet of the drainage hole on the stone retaining wall.

[0016] As a preferred technical solution of the present invention, an energy dissipation pool is constructed between the drainage ditch and the drainage channel, the inlet of the energy dissipation pool is connected to the outlet of the drainage ditch, and the outlet of the energy dissipation pool is connected to the inlet of the drainage channel.

[0017] As a preferred technical solution of the present invention, multiple platforms are successively constructed along the downslope direction on the lower slope, and the drainage ditch and its bottom drainage ditch cushion layer are all built on the platforms at each level.

[0018] As a preferred embodiment of the present invention, the anchor rod connecting bar is welded and fixed to the top of the upper anchor rod / lower anchor rod, and four anchor rod connecting bars are provided, which are evenly distributed along the periphery of the upper anchor rod / lower anchor rod; multiple sets of positioning mechanisms are provided at intervals on the upper anchor rod / lower anchor rod, and each set of positioning mechanisms includes four positioning brackets welded and fixed to the upper anchor rod / lower anchor rod, which are evenly distributed along the periphery of the upper anchor rod / lower anchor rod.

[0019] As a preferred technical solution of the present invention, the anchor rod connecting bar is an L-shaped steel bar, one section of which is welded and fixed to the upper anchor rod / lower anchor rod, and the other section extends along the outside of the upper anchor rod / lower anchor rod; the positioning bracket is a Z-shaped steel bar, the bottom two sections of which are welded and fixed to the upper anchor rod / lower anchor rod, and the top section is set away from the upper anchor rod / lower anchor rod.

[0020] As a preferred embodiment of the present invention, the upper anchor rod is a Ф22@500mm anchor rod with a length of 8m, and the lower anchor rod is a Ф22@500mm anchor rod with a length of 4m.

[0021] In another aspect, the present invention provides a construction method for the above-mentioned drainage system for steep slopes in complex geological conditions, comprising the following steps: S1. Excavate flood storage ponds and intercepting ditches At the platform at the top of the slope, a 40m×40m flood storage pond with a depth of 5m was excavated. The structure was built with mortar-grouted stone masonry to collect rainwater in the flood storage pond. A water interception ditch was excavated on the side near the slope to prevent mud from overflowing everywhere.

[0022] S2. Directional crossing of slope drainage pipe ① Entrance and exit location: Due to the depth of the ravine and the steepness of the slope, pipe jacking is required to cross the upper steep slope. First, use a pipeline guide to find the directional drilling location and mark the entry point at the bottom of the pond and the exit point on the slope with lime.

[0023] ② Pipeline Assembly: Polyethylene pipes are used for slope drainage. The polyethylene pipes are transported to the site and cleaned with pipe cleaning equipment to ensure that there are no debris inside the pipes. The pipes are assembled in sections, and the weld bevels are inspected for flaws. There should be no sharp notches or grooves on the weld edges of the joint surfaces. After the pipelines are assembled, anti-corrosion treatment and strength tests are carried out. The test medium is compressed air, the strength test pressure is 1.05MPa, and the tightness test is 0.81MPa. After passing the tests, the pipeline crossing construction can proceed.

[0024] ③ Drilling guidance: The drilling rig is installed on the line connecting the entry point and the exit point. After installation, a trial run is conducted. The guide hole is drilled according to the design curve, and the inclination angle and deviation are strictly controlled. During the drilling process, mud is prepared to ensure that the guide head is smooth. After the guide hole is completed, the drill bit is removed and the reamer is replaced to reverse the reaming process to form the hole.

[0025] ④ Pipeline pullback: Lay the pullback pipeline at the predetermined position, weld the pull-back head, and immediately pull back the pipeline after the hole enlargement construction is completed. Use sandbags to support the pull-back pipeline to prevent the anti-corrosion layer from being damaged during the pullback process, and finally complete the construction of the slope drainage pipe.

[0026] S3. Inspection well installation Lower and upper inspection wells are installed at the inlet and outlet of the slope drainage pipe, respectively. Both the lower and upper inspection wells are made of precast concrete. The lower and upper inspection wells are mechanically connected to the inlet and outlet of the slope drainage pipe using a flexible rubber ring. After cleaning the joint area, the rubber ring is embedded with the assistance of a special tool, and the sealant is filled tightly.

[0027] S4. Clearing and trimming the upper slope A slope protection trench is excavated on the upper slope surface, and a high-pressure concrete layer is poured inside the slope protection trench. A steel mesh is fixedly connected to the surface of the high-pressure concrete layer to reduce the risk of landslide.

[0028] S5. Clearing and repairing the lower slope Multiple platforms are constructed on the lower slope, starting from the drainage outlet of the lower inspection well, with a platform constructed every 2m vertically. A 200mm cover layer is reserved from the designed slope surface, which will be removed during the construction of the drainage ditch. Each platform serves as an anti-slip groove for the drainage ditch, reducing the risk of the drainage ditch structure sliding downwards under its own weight and reducing the erosion caused by the kinetic energy of the water. At the same time, it also serves as an operating platform for the construction of the lower anchor bolts.

[0029] S6. Anchor Bolt Construction Upper anchor bolts, 8m long and Ф22@500mm in diameter, were driven into the high-pressure concrete layer above the upper slope at 2m intervals. The anchor bolt holes were drilled using a waterless drilling method with a hole diameter of 90mm. After drilling, the upper anchor bolts were slowly driven into the designed positions in the holes, followed by bottom grouting. The pull-out resistance met the specifications. Positioning brackets were welded to the upper anchor bolts at 2m intervals to ensure that the upper anchor bolts were centered after being lowered into the holes. Anchor bolt connecting bars were welded to the ends of the upper anchor bolts and then welded and fixed to the steel mesh.

[0030] Lower anchor bolts, 4m long and Ф22@500mm in diameter, are driven into the upper part of the slope at 2m intervals above each step. The anchor bolt holes are drilled using a waterless drilling method with a hole diameter of 90mm. After drilling, the upper anchor bolts are slowly driven into the designed positions in the holes, and then grouting is performed using the bottom grouting method. The pull-out resistance meets the specifications. Positioning brackets are welded to the lower anchor bolts at 2m intervals to ensure that the lower anchor bolts are centered after being driven into the drilled holes. Anchor bolt connecting bars are welded to the ends of the lower anchor bolts and are used to fix them to the bottom reinforcement of the drainage ditch.

[0031] S7. Construction of stone retaining wall At the lower inspection well, a masonry retaining wall is constructed using mortar-grouted stone masonry. Drainage holes with a diameter of 8mm are arranged alternately at 2m intervals. Two layers of geotextile are laid at the inlet of the drainage holes and fixed to the back of the masonry retaining wall. A 400mm thick layer of river gravel is filled at the back of the masonry retaining wall as a filter layer to ensure that water inside the masonry retaining wall can be effectively drained. The drainage holes at the bottom of the masonry retaining wall are 1m above the ground in front of the wall to prevent water from flowing back into the wall.

[0032] S8. Drainage ditch construction After removing the overburden layer on the lower slope, a C-type concrete cushion layer is poured as the drainage ditch cushion layer. Once the concrete reaches the required strength, the bottom slab reinforcement and side wall reinforcement of the drainage ditch are tied. At the same time, the anchor rod connecting bars at the ends of the lower anchor rods are welded and fixed to the tied bottom slab reinforcement of the drainage ditch. The formwork is erected, and concrete is poured. An expansion joint is set every 5m and sealed with polyurethane sealant. A stilling basin is set at the end of the drainage ditch. The stilling basin is connected to the drainage ditch at the bottom of the slope. The drainage ditch is connected to the rainwater sedimentation tank and the water storage tank for irrigating farmland.

[0033] For drainage of steep slopes with complex geological conditions, existing drainage systems are simple culverts with limited rainwater collection range and insufficient drainage capacity. Furthermore, they are prone to overflow, slope erosion, and pipe blockage during periods of concentrated rainfall. The failure to effectively integrate drainage facilities with ecological utilization leads to water waste.

[0034] Compared with the existing technology and its problems, the beneficial effects of the present invention are as follows: 1) This invention improves the poor anti-sliding stability of different base layers such as backfill soil, silt, and rock by using the method of anchor bolts + masonry drainage ditch. This makes the anchor bolts firmly connected to the masonry drainage ditch, reduces the scouring of the drainage ditch by steep slope water flow, and diverts rainwater collected in the village to the bottom of the ditch to irrigate farmland, thereby achieving "water saving" and reuse of water resources and meeting the requirements of energy conservation and emission reduction.

[0035] 2) This invention significantly improves rainwater collection and transportation efficiency through multi-node and multi-channel design; in terms of structural safety, it effectively prevents slope slippage and erosion damage through multiple anchoring, protection and reverse filtration drainage systems; in terms of resource utilization, the drainage end is connected to the water storage facility to ensure that rainwater can be used for agricultural irrigation and improve water resource utilization rate; in terms of adaptability, it can operate stably in complex terrains such as the Loess Plateau and gullies and steep slopes, significantly improving the safety, durability and comprehensive benefits of the drainage system.

[0036] 3) This invention organically integrates rainwater collection and storage, slope spraying and anchoring and retaining wall reinforcement, underground pipe drainage, open channel drainage and water storage facilities for reuse, forming a collaborative operation system; it enables rainwater to be used for irrigation after buffering and energy dissipation, thereby improving water resource utilization; and it adopts a multi-channel and directional drilling layout for complex terrains such as the Loess Plateau and gullies and steep slopes to ensure the safe and reliable operation of the drainage system under harsh geological conditions. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0038] Figure 1 This is a front view of the system of the present invention.

[0039] Figure 2 This is a top view of the system of the present invention.

[0040] Figure 3 for Figure 2 Sectional view 1-1 in the image.

[0041] Figure 4 for Figure 3 Enlarged view of the masonry retaining wall.

[0042] Figure 5 This is a structural schematic diagram of the upper anchor rod / lower anchor rod in the system of the present invention.

[0043] In the diagram: 1-Reinforcing mesh, 2-High-pressure concrete, 3-Anchor bolt connecting bar, 4-Upper anchor bolt, 5-Lower inspection well, 6-Drainage outlet, 7-Stone retaining wall, 8-Drainage ditch bedding layer, 9-Drainage ditch, 10-Drainage hole, 11-Upper inspection well, 12-Filter layer soil, 13-Flood pond, 14-Rainwater sedimentation tank, 15-Drainage ditch, 16-Energy dissipation tank, 17-Intercepting ditch, 18-Lower anchor bolt, 19-Slope drainage pipe, 20-River gravel, 21-Inlet hole, 22-Non-woven fabric, 23-Retaining wall foundation, 24-Water storage tank, 25-Reinforcing steel support, 26-Intercepting ditch drainage pipe. Detailed Implementation

[0044] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which this invention pertains. Example 1

[0045] like Figures 1 to 5 As shown, this embodiment provides a drainage system for a steep slope in complex geological conditions, including a flood pool 13 and a stone retaining wall 7.

[0046] The flood pond 13 is built in a low-lying area on the top platform of the slope. An upper inspection well 11 is built in the flood pond 13, and the upper inspection well 11 is connected to the slope drainage pipe 19. A water interception ditch 17 is excavated on the top platform of the slope near the slope. The water interception ditch 17 is connected to the slope drainage pipe 19 through the water interception ditch drainage pipe 26.

[0047] The stone retaining wall 7 is built in the middle of the slope, dividing the slope into an upper slope and a lower slope.

[0048] A lower inspection well 5 is constructed on the lower slope, immediately adjacent to the stone retaining wall 7. The lower inspection well 5 is connected to the upper inspection well 11 via a slope drainage pipe 19 pre-embedded in the upper slope. A drainage outlet 6 is provided on the lower inspection well 5. This is a preferred embodiment of the present invention. A drainage ditch 9 is constructed along the downslope direction, directly adjacent to the lower inspection well 5. The inlet of the drainage ditch 9 is connected to the outlet 6 of the lower inspection well 5. A drainage ditch cushion layer 8 is constructed at the bottom of the drainage ditch 9.

[0049] A drainage ditch 15 is constructed at the bottom of the lower slope, and the inlet of the drainage ditch 15 is connected to the outlet of the drainage channel 9. A rainwater sedimentation tank 14 is constructed along the bank of the drainage ditch 15, and the rainwater sedimentation tank 14 is connected to the drainage ditch 15 through the inlet hole 21. A water storage tank 24 is constructed on the other side of the rainwater sedimentation tank 14, and the water storage tank 24 is connected to the rainwater sedimentation tank 14.

[0050] A slope protection trench is excavated on the upper slope surface, and a high-pressure concrete layer 2 is poured in the slope protection trench. A steel mesh 1 is fixedly connected to the surface of the high-pressure concrete layer 2. Several upper anchor rods 4 are evenly distributed in the high-pressure concrete layer 2. The bottom end of the upper anchor rod 4 passes through the high-pressure concrete layer 2 and is anchored to the depth of the upper slope. The top end of the upper anchor rod 4 is fixedly connected to the steel mesh 1 through the anchor rod connecting bar 3.

[0051] The bottom of the drainage ditch 9 is evenly distributed with several lower anchor rods 18. The bottom end of the lower anchor rod 18 passes through the bottom plate of the drainage ditch 9 and the drainage ditch cushion layer 8 and is anchored to the depth of the lower slope. The top end of the lower anchor rod 18 is fixedly connected to the bottom plate reinforcement of the drainage ditch 9 through the anchor rod connecting bar 3.

[0052] In practice, a retaining wall foundation 23 is built at the bottom of the stone retaining wall 7, and multiple drainage holes 10 are opened on the stone retaining wall 7.

[0053] In practice, river gravel 20 is filled on one side of the back of the stone retaining wall 7 as a filter layer, and filter soil 12 is placed on top of the river gravel 20.

[0054] In practice, a non-woven fabric 22 is fixed tightly against the back of the stone retaining wall 7, and the non-woven fabric 22 covers the water inlet of the drainage hole 10 on the stone retaining wall 7.

[0055] In practice, a stilling basin 16 is constructed between the drainage ditch 9 and the drainage ditch 15. The inlet of the stilling basin 16 is connected to the outlet of the drainage ditch 9, and the outlet of the stilling basin 16 is connected to the inlet of the drainage ditch 15.

[0056] In practice, multiple platforms are constructed sequentially along the downslope direction on the lower slope, and the drainage ditch 9 and its bottom drainage ditch cushion layer 8 are built on the platforms at each level.

[0057] In specific implementation, the anchor rod connecting bar 3 is welded and fixed to the top of the upper anchor rod 4 / lower anchor rod 18. There are four anchor rod connecting bars 3, which are evenly distributed along the periphery of the upper anchor rod 4 / lower anchor rod 18. Multiple sets of positioning mechanisms are arranged at intervals on the upper anchor rod 4 / lower anchor rod 18. Each set of positioning mechanisms includes four positioning brackets 25 that are welded and fixed to the upper anchor rod 4 / lower anchor rod 18. The four positioning brackets 25 are evenly distributed along the periphery of the upper anchor rod 4 / lower anchor rod 18.

[0058] In specific implementation, the anchor rod connecting bar 3 adopts L-shaped steel bar, one section of which is welded and fixed to the upper anchor rod 4 / lower anchor rod 18, and the other section extends along the outside of the upper anchor rod 4 / lower anchor rod 18; the positioning bracket 25 adopts Z-shaped steel bar, the bottom two sections of which are welded and fixed to the upper anchor rod 4 / lower anchor rod 18, and the top section is set away from the side of the upper anchor rod 4 / lower anchor rod 18.

[0059] In practice, the upper anchor bolt 4 is an 8m long Ф22@500mm anchor bolt, and the lower anchor bolt 18 is a 4m long Ф22@500mm anchor bolt. Example 2

[0060] like Figures 1 to 5 As shown, this embodiment provides a construction method for the drainage system of complex geological steep slopes described in Embodiment 1, including the following steps: S1. Excavate 13 flood storage ponds and 17 intercepting ditches. At the platform at the top of the slope, a 40m×40m flood pond 13 with a depth of 5m is excavated. The structure is made of masonry and rainwater is collected in the flood pond 13. A water interception ditch 17 is excavated on the side near the slope to prevent mud from overflowing everywhere.

[0061] S2. Slope drainage pipe 19 directional crossing ① Entrance and exit location: Due to the depth of the ravine and the steepness of the slope, pipe jacking is required to cross the upper steep slope. First, use a pipeline guide to find the directional drilling location and mark the bottom of the pond 13 and the exit point of the slope with lime.

[0062] ② Pipeline assembly: Slope drainage pipe 19 uses polyethylene pipe. The polyethylene pipe is transported to the site and cleaned with pipe cleaning equipment to ensure that there are no debris inside the pipe. The pipe is assembled in sections and the weld bevels are inspected for flaws. There should be no sharp notches or grooves on the weld edge of the joint surface. After the pipeline is assembled, anti-corrosion treatment and strength test are carried out. The test medium is compressed air. The strength test pressure is 1.05MPa and the tightness test is 0.81MPa. After passing the test, the pipeline crossing construction can proceed.

[0063] ③ Drilling guidance: The drilling rig is installed on the line connecting the entry point and the exit point. After installation, a trial run is conducted. The guide hole is drilled according to the design curve, and the inclination angle and deviation are strictly controlled. During the drilling process, mud is prepared to ensure that the guide head is smooth. After the guide hole is completed, the drill bit is removed and the reamer is replaced to reverse the reaming process to form the hole.

[0064] ④ Pipeline pullback: Lay the pullback pipeline at the predetermined position, weld the pull-back head, and immediately pull back the pipeline after the hole enlargement construction is completed. Use sandbags to support the pull-back pipeline to prevent the anti-corrosion layer from being damaged during the pullback process, and finally complete the construction of slope drainage pipe 19.

[0065] S3. Inspection well installation Lower inspection wells 5 and upper inspection wells 11 are installed at the inlet and outlet of the slope drainage pipe 19, respectively. Both lower inspection wells 5 and upper inspection wells 11 are precast concrete inspection wells. The lower inspection wells 5 and upper inspection wells 11 are mechanically connected to the inlet and outlet of the slope drainage pipe 19 using a flexible rubber ring. After cleaning the joint area, the rubber ring is embedded with the assistance of a special tool, and the sealant is filled tightly.

[0066] S4. Clearing and trimming the upper slope A slope protection trench is excavated on the upper slope surface, and a high-pressure concrete layer 2 is poured in the slope protection trench. A steel mesh 1 is fixedly connected to the surface of the high-pressure concrete layer 2 to reduce the risk of landslide.

[0067] S5. Clearing and repairing the lower slope On the lower slope, a multi-level platform is constructed. Starting from the drainage outlet 6 of the lower inspection well 5, a platform is constructed at a vertical interval of 2m. A 200mm covering layer is reserved from the designed slope surface, which will be removed when the drainage ditch 9 is constructed. Each level of platform serves as an anti-slip groove for the drainage ditch 9, reducing the risk of the drainage ditch 9 structure sliding downwards under its own weight and reducing the erosion caused by water kinetic energy. At the same time, it also serves as an operating platform for the construction of the lower anchor bolts.

[0068] S6. Anchor Bolt Construction Upper anchor rods 4, each 8m long and Ф22@500mm in diameter, are driven into the high-pressure concrete layer 2 on the upper slope at 2m intervals. The anchor rods are drilled using a waterless drilling method with a hole diameter of 90mm. After drilling, the upper anchor rods 4 are slowly driven into the designed position in the hole, and then grouting is performed using the bottom grouting method. The pull-out resistance meets the specifications. Positioning brackets 25 are welded to the upper anchor rods 4 at 2m intervals to ensure that the upper anchor rods 4 are centered after being lowered into the drilled hole. Anchor rod connecting bars 3 are welded to the ends of the upper anchor rods 4 and then welded and fixed to the steel mesh 1.

[0069] Lower anchor rods 18, 4m long and Ф22@500mm in diameter, are driven into the upper part of each step on the lower slope at 2m intervals. The anchor rods are drilled using a waterless drilling method with a hole diameter of 90mm. After drilling, the upper anchor rods 4 are slowly driven into the designed position in the hole, and then grouting is performed using the bottom grouting method. The pull-out resistance meets the specifications. Positioning brackets 25 are welded to the lower anchor rods 18 at 2m intervals to ensure that the lower anchor rods 18 are centered after being driven into the hole. Anchor rod connecting bars 3 are welded to the ends of the lower anchor rods 18. The anchor rod connecting bars 3 are used to fix and connect with the bottom plate reinforcement of the drainage ditch 9.

[0070] S7. Stone retaining wall 7. Construction At the lower inspection well 5, a stone retaining wall 7 is constructed using mortar-grouted stone masonry. Drainage holes 10 with a diameter of Ф8mm are arranged alternately at 2m intervals. Two layers of geotextile are laid at the inlet of the drainage holes 10 and fixed to the back of the stone retaining wall 7. A 400mm thick layer of river gravel 20 is filled at the back of the stone retaining wall 7 as a filter layer to ensure that the water inside the stone retaining wall 7 can be effectively drained. The drainage holes 10 located at the bottom of the stone retaining wall 7 are 1m above the ground in front of the wall toe to prevent water from flowing back into the wall.

[0071] S8. Drainage ditch 9 construction After removing the overburden layer on the lower slope, a C20 concrete cushion layer is poured as the drainage ditch cushion layer 8. After the concrete reaches the required strength, the bottom slab reinforcement and side wall reinforcement of the drainage ditch 9 are tied. At the same time, the anchor connecting bars 3 at the ends of the lower anchor rods 18 are welded and fixed to the tied bottom slab reinforcement of the drainage ditch 9. The formwork is erected and concrete is poured. An expansion joint is set every 5m and sealed with polyurethane sealant. An energy dissipation pool 16 is set at the end of the drainage ditch 9. The energy dissipation pool 16 is connected to the drainage ditch 15 at the bottom of the slope. The drainage ditch 15 is connected to the rainwater sedimentation pool 14 and the water storage pool 24 for irrigation of farmland.

[0072] For the construction method of the drainage system of the above-mentioned complex geological steep slope, the following technical quality requirements apply when the slope drainage pipe 19 is directionally crossed in step S2: 1) When drilling, the measurement and layout should be carried out in detail to make the entry and exit points of the soil in a straight line. When drilling the guide hole, the crossing trajectory should be calculated and entered into the computer first. Two to three artificial magnetic field coils should be set between the two straight lines to monitor the trajectory of the drill rod in real time and correct it in time, so as to ensure that the crossing trajectory does not exceed the design range.

[0073] 2) The reamer should be used for 5 stages of reaming and at least one hole cleaning. The difference between each reaming stage should not exceed 200mm. Different reamers should be used depending on the soil type. The reamer should be kept running at high speed while the drill rod travels slowly. This can effectively grind the rock into powder when working in rock layers. The drilling operator should observe the data displayed on the reaming instrument and adjust the drilling machine in time to ensure a good hole is formed.

[0074] 3) Before pulling the pipe, carefully check whether the transfer case, U-ring, and connecting pin are flexible and strong, check whether each component meets the tensile strength requirements, and check whether each nut is tightened to ensure that each component is operating normally.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A drainage system for steep slopes in complex geological conditions, characterized in that: Including a flood pond (13) and a stone retaining wall (7); The flood pond (13) is built in a low-lying area on the top platform of the slope. An upper inspection well (11) is built in the flood pond (13), and the upper inspection well (11) is connected to the slope drainage pipe (19). A water interception ditch (17) is excavated on the top platform of the slope near the slope. The water interception ditch (17) is connected to the slope drainage pipe (19) through the water interception ditch drainage pipe (26). The stone retaining wall (7) is built in the middle of the slope, dividing the slope into an upper slope and a lower slope; A lower inspection well (5) is built on the lower slope, which is adjacent to the stone retaining wall (7). The lower inspection well (5) is connected to the upper inspection well (11) through the slope drainage pipe (19) pre-embedded in the upper slope. A drainage outlet (6) is set on the lower inspection well (5). A drainage ditch (9) is constructed along the downslope direction, which is directly connected to the lower inspection well (5). The inlet of the drainage ditch (9) is connected to the outlet (6) of the lower inspection well (5). A drainage ditch cushion layer (8) is constructed at the bottom of the drainage ditch (9). A drainage ditch (15) is constructed at the bottom of the lower slope. The inlet of the drainage ditch (15) is connected to the outlet of the drainage channel (9). A rainwater sedimentation tank (14) is constructed along the bank of the drainage ditch (15). The rainwater sedimentation tank (14) is connected to the drainage ditch (15) through the inlet hole (21). A water storage tank (24) is constructed on the other side of the rainwater sedimentation tank (14). The water storage tank (24) is connected to the rainwater sedimentation tank (14). The upper slope has a slope protection trench excavated on the slope surface, and a high-pressure concrete layer (2) is poured in the slope protection trench. A steel mesh (1) is fixedly connected to the surface of the high-pressure concrete layer (2). Several upper anchor rods (4) are evenly distributed in the high-pressure concrete layer (2). The bottom end of the upper anchor rod (4) passes through the high-pressure concrete layer (2) and is anchored to the depth of the upper slope. The top end of the upper anchor rod (4) is fixedly connected to the steel mesh (1) through the anchor rod connecting bar (3). The bottom of the drainage ditch (9) is evenly distributed with several lower anchor rods (18). The bottom end of the lower anchor rod (18) passes through the bottom plate of the drainage ditch (9) and the drainage ditch cushion layer (8) and is anchored to the depth of the lower slope. The top end of the lower anchor rod (18) is fixedly connected to the bottom plate reinforcement of the drainage ditch (9) through the anchor rod connecting bar (3).

2. The drainage system for steep slopes in complex geological conditions according to claim 1, characterized in that: The bottom of the stone retaining wall (7) is constructed with a retaining wall foundation (23), and multiple drainage holes (10) are opened on the stone retaining wall (7).

3. A drainage system for steep slopes in complex geological conditions according to claim 2, characterized in that: The back side of the stone retaining wall (7) is filled with river gravel (20) as a filter layer, and the top of the river gravel (20) is covered with filter soil (12).

4. A drainage system for steep slopes in complex geological conditions according to claim 3, characterized in that: Non-woven fabric (22) is fixed tightly against the back of the stone retaining wall (7), and the non-woven fabric (22) covers the water inlet of the drainage hole (10) on the stone retaining wall (7).

5. A drainage system for steep slopes in complex geological conditions according to claim 4, characterized in that: A stilling basin (16) is built between the drainage ditch (9) and the drainage ditch (15). The inlet of the stilling basin (16) is connected to the outlet of the drainage ditch (9), and the outlet of the stilling basin (16) is connected to the inlet of the drainage ditch (15).

6. A drainage system for steep slopes in complex geological conditions according to claim 5, characterized in that: Multiple platforms are constructed along the downslope direction on the lower slope, and the drainage ditch (9) and its bottom drainage ditch cushion layer (8) are built on each level of platform.

7. A drainage system for steep slopes in complex geological conditions according to claim 6, characterized in that: Anchor rod connecting bars (3) are welded and fixed to the top of the upper anchor rod (4) / lower anchor rod (18). There are four anchor rod connecting bars (3), which are evenly distributed along the periphery of the upper anchor rod (4) / lower anchor rod (18). Multiple sets of positioning mechanisms are spaced apart on the upper anchor rod (4) / lower anchor rod (18). Each set of positioning mechanisms includes four positioning brackets (25) that are welded and fixed to the upper anchor rod (4) / lower anchor rod (18). The four positioning brackets (25) are evenly distributed along the periphery of the upper anchor rod (4) / lower anchor rod (18).

8. A drainage system for steep slopes in complex geological conditions according to claim 7, characterized in that: The anchor rod connecting bar (3) adopts L-shaped steel bar. One section of the L-shaped steel bar is welded and fixed to the upper anchor rod (4) / lower anchor rod (18), and the other section extends along the outside of the upper anchor rod (4) / lower anchor rod (18). The positioning bracket (25) adopts Z-shaped steel bar. The bottom two sections of the Z-shaped steel bar are welded and fixed to the upper anchor rod (4) / lower anchor rod (18), and the top section is set away from the side of the upper anchor rod (4) / lower anchor rod (18).

9. A drainage system for steep slopes in complex geological conditions according to claim 8, characterized in that: The upper anchor (4) is an 8m long Ф22@500mm anchor, and the lower anchor (18) is a 4m long Ф22@500mm anchor.

10. A construction method for a drainage system on a complex geological steep slope as described in claim 9, characterized in that, Includes the following steps: S1. Excavate a flood storage pond (13) and a drainage ditch (17). At the platform at the top of the slope, a flood pond (13) was excavated. The structure was built with mortar-grouted stone masonry to collect rainwater in the flood pond (13). A water interception ditch (17) was excavated on the side close to the slope. S2. Slope drainage pipe (19) directional crossing ① Entrance and exit location: Pipe jacking is required to cross the upper steep slope; firstly, use the pipeline guide instrument to find the directional drilling location and mark the bottom of the pond (13) and the exit point of the slope; ② Pipeline assembly: The slope drainage pipe (19) is made of polyethylene pipe. The polyethylene pipe is transported to the site, the pipe is assembled in sections, and then the pipeline crossing construction is carried out. ③ Drilling guidance: The drilling rig is installed on the line connecting the entry point and the exit point. The guide hole is drilled according to the design curve. After the guide hole is completed, the hole is reamed by a hole expander. ④ Pipeline pullback: The pullback pipeline is laid out at the predetermined position, and the pull-back head is welded. After the hole enlargement construction is completed, the pipeline pullback is carried out immediately to finally complete the construction of the slope drainage pipe (19); S3. Inspection well installation Lower inspection wells (5) and upper inspection wells (11) are installed at the inlet and outlet of the slope drainage pipe (19), respectively. The lower inspection wells (5) and upper inspection wells (11) are mechanically connected to the inlet and outlet of the slope drainage pipe (19) with flexible rubber rings. S4. Clearing and trimming the upper slope A slope protection trench is excavated on the upper slope surface, and a high-pressure concrete layer (2) is poured in the slope protection trench. A steel mesh (1) is fixedly connected to the surface of the high-pressure concrete layer (2) to reduce the risk of landslide. S5. Clearing and repairing the lower slope On the lower slope, a multi-level platform is built. Starting from the drainage outlet (6) of the lower inspection well (5), a platform is built at a certain distance in the vertical direction. Each level of platform serves as an anti-slip groove for the drainage ditch (9), reducing the risk of the drainage ditch (9) structure sliding downwards under its own weight, reducing the scouring of water flow energy, and also serving as an operating platform for the construction of the lower anchor rod (4). S6. Anchor Bolt Construction An 8m long upper anchor rod (4) is driven into the upper slope above the high-pressure concrete layer (2). The anchor rod is drilled using a waterless drilling method. After drilling, the upper anchor rod (4) is slowly sent into the designed position in the hole, and then grouting is performed using the bottom grouting method. A positioning bracket (25) is welded on the upper anchor rod (4), and an anchor rod connecting bar (3) is welded to the end of the upper anchor rod (4). The anchor rod connecting bar (3) is then welded and fixed to the steel mesh (1). A 4m long lower anchor rod (18) is driven into the upper part of each step of the lower slope. The anchor rod is drilled using a waterless drilling method. After drilling is completed, the upper anchor rod (4) is slowly sent into the designed position in the hole, and then grouting is performed using the bottom grouting method. The lower anchor rod (18) is welded with a positioning bracket (25), and the lower anchor rod (18) is welded with an anchor rod connecting bar (3) at the end. The anchor rod connecting bar (3) is used to fix and connect with the bottom plate reinforcement of the drainage ditch (9). S7. Stone retaining wall (7) construction A stone retaining wall (7) is constructed at the lower inspection well (5) using mortar-grouted stone masonry, and drainage holes (10) are arranged. Geotextile is laid at the inlet of the drainage holes (10) and fixed to the back of the stone retaining wall (7). River gravel (20) is filled at the back of the stone retaining wall (7) as a filter layer. The drainage holes (10) at the bottom of the stone retaining wall (7) are 1m above the ground in front of the wall toe to prevent water from flowing back into the wall. S8. Drainage ditch (9) construction A C20 concrete cushion layer is poured as the cushion layer of the drainage ditch (8). After its strength meets the requirements, the bottom plate reinforcement and side wall reinforcement of the drainage ditch (9) are tied. At the same time, the anchor connecting bar (3) at the end of the lower anchor rod (18) is welded and fixed to the bottom plate reinforcement of the drainage ditch (9). The formwork is erected and concrete is poured. A stilling pool (16) is set at the end of the drainage ditch (9). The stilling pool (16) is connected to the drainage ditch (15) at the bottom of the slope. The drainage ditch (15) is connected to the rainwater sedimentation pool (14) and the water storage pool (24) for irrigating farmland.

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