NL2035592A

NL2035592A - Slope flexible ecological supporting structure and construction method

Info

Publication number: NL2035592A
Application number: NL2035592A
Authority: NL
Inventors: Hu Zhaojian; Gong Bin; Ma Min; Peng Zhengyang; Huang Zhen; Xu Yingzi; Ma Shaokun
Original assignee: Univ Guangxi
Priority date: 2023-02-28
Filing date: 2023-08-11
Publication date: 2024-09-06
Also published as: CN116290014A

Abstract

Disclosed are a slope flexible ecological supporting structure and a construction method. After levelling the slope surface, a composite geomembrane is laid on the slope surface, a layer 5 of soil is backfilled on the surface of the geomembrane, then a vegetation protection pad is laid and fixed with U-shaped nails, then an assembled lattice beam is arranged outside the slope, and the assembled lattice beam is fixed on the slope surface through anchor rods and drainage pipes, and finally slope protection vegetation is planted. A drainage pipe is arranged on the slope, and the drainage outlet is arranged on the cross beam of the assembled lattice beam, and the water 10 in the slope is guided to flow out and converge into the drainage ditch through the drainage channel on the cross beam of the assembled lattice beam. The connection between the assembled lattice beam and the lattice beam is fixed by the H-shaped steel bolt at the end of the beam and the splicing plate, and the vegetation protection pad can form a stable anchoring system by closely combining with the slope vegetation. The installation of geomembrane and 15 drainage pipe can improve the anti-water damage ability of slope, reduce the rainwater infiltration on slope and discharge the rainwater after infiltration inside slope. The invention has the advantages of simple overall structure, convenient installation, simple later maintenance and low cost.

Description

Slope flexible ecological supporting structure and construction method

TECHNICAL FIELD

The invention belongs to the field of geotechnical engineering, and in particular to a slope flexible ecological supporting structure and a construction method.

BACKGROUND

Red sandstone soil and sandy soil are easily weathered and softened and disintegrated when meeting water. However, in areas with abundant rainfall in the south, a large number of gullies will be generated on the slope after the soft disintegration caused by rainfall, which will further cause large-scale soil erosion and instability, resulting in serious local ecological damage and the risk of collapse. However, for expansive soil and red clay, it will experience severe dry-wet cycle in rainy season. In the hot summer, expansive soil and red clay will produce many shrinkage cracks, which will reduce the strength of soil and accelerate the destruction of slope stability caused by rainwater infiltration. If reasonable protection forms are not taken, the cutting and embankment slopes built in areas dominated by sandy soil, expansive soil, red clay and red sandstone soil have the characteristics of low strength, poor weathering resistance and large plastic deformation, and are greatly influenced by external weathering factors such as rainfall and temperature. At present, the main supporting measures are rigid support, flexible support and ecological slope protection technology.

Rigid supporting structure has great damage to the natural environment of red sandstone and sandy rock slopes, and the problem of slope settlement has not been solved. Moreover, after a long period of rain in summer, a large number of gully slopes are seriously damaged by water, resulting in low survival rate of vegetation roots. Expansive soil and red clay are not suitable for rigid supporting structures because of their large expansion and deformation. The existing flexible support technologies, such as geogrid and geotextile bag, have some problems, such as complicated construction process, high maintenance cost in the later period, poor durability and unsatisfactory long-term support effect. In addition, the above two supporting methods will still cause soil erosion on the surface of red sandstone slope, and the slope protection and ecological control effects are not satisfactory.

The existing ecological slope protection technology is based on the close growth of roots and soil, and finally forms an anchoring system to protect the surface of the slope. Although it protects the ecological environment with the local area, it has many defects. For example, the red sandstone soil is easy to be destroyed by water and disintegrated, which leads to the failure of slope protection before the formation of dense anchorage system.

SUMMARY

Aiming at the problems of soil erosion, unstable collapse and poor overall stability of special types of slopes such as sandy soil, expansive soil, red clay and red sandstone soil, the invention provides a flexible ecological supporting structure for soil slopes and a construction method, so as to effectively reduce slope settlement, water damage and slope deformation, restore the ecological environment and improve slope stability.

In order to achieve the above purpose, the invention adopts the following technical means:

The invention relates to a slope flexible ecological supporting structure, which comprises a composite geomembrane, a vegetation protection pad, a U-shaped nail, a intercepting ditch, a drainage ditch, an assembled lattice beam, an anchor rod, a drainage pipe, permeable geotextile and slope protection vegetation; the composite geomembrane is laid flat on the inner surface of the slope soil layer and attached to the soil body; the vegetation protection pad is laid flat on the slope surface in each lattice unit and attached to the soil, and fixed on the slope by U-shaped nails; the intercepting ditches are arranged at the top and bottom of the slope, and drainage ditches are arranged at both sides of the slope; the assembled lattice beam is arranged on that surface of the slope, and the assembled lattice beam divides the slope into a plurality of lattice units; the anchor rod comprises a rod body, an anchor pad and a nut; one end of the rod body goes deep into the slope, and the other end of the rod body is exposed out of the slope; the exposed end of the rod body is provided with a thread, and the nut is correspondingly connected with the exposed end of the rod body through the thread; the anchor pad is arranged between the nut and the vegetation protection pad or between the nut and the assembled lattice beam; the outlet of the drainage pipe is arranged in the drainage outlet of the cross beam of the assembled lattice beam; the drainage pipe is deeper than the slope; the drainage pipe is provided with a drainage section, a intercepting section and a drilling section; the drainage section is tightly compacted with soil, and the permeable geotextile is wrapped on the drainage pipe; the revetment vegetation is planted in the vegetation protection pad in the lattice unit.

The vegetation protection pad has a wavy rough surface, and it is a dense net with periodic concavities and convexities, which is made of long-fibre nylon filament wound with high- toughness polyester geogrid or woven by tough polyester filament.

The vegetation protection pad has at least 30% mesh space.

The anchor pad is a steel plate with a thickness greater than 10 mm.

The assembled lattice beams use H-shaped steel components to realize the connection between the lattice beams.

The vegetation protection pad and the joint of the vegetation protection pad overlap at least 150 mm, and the overlapping part is fixed with the U-shaped nail.

The anchor rod spacing is 1 - 2 m, the inclination angle between the anchor and the horizontal plane is 15° - 25°, and the anchor depth exceeds the sliding surface of the slope or the slope depth by 1 m.

The anchoring length of the U-shaped nail is = 30 cm.

The composite geomembrane is provided with groove anchorage at the top of the slope.

The setting method of the slope flexible ecological supporting structure comprises the following steps: (1) Pre-treating the slope: cleaning the trees, roots, humus soil, organic soil, planting soil and garbage in the range to be treated, and levelling the slope. (2) Laying composite geomembrane: firstly, a groove anchorage is set at the top of the slope, then the composite geomembrane is laid on the surface of the slope, and after the composite geomembrane is laid, a layer of soil with a thickness of not less than 20 cm is backfilled and compacted. (3) Measuring and setting out, drilling and positioning: according to the specific slope engineering situation, adjust the position of the drilling rig to make the drilling position, inclination angle and aperture size meet the design requirements, so as to facilitate the hoisting and placement of drainage pipes and assembled lattice beams. (4) Installation of drainage pipes: layout shall be carried out according to the design of lattice units, and inclined drainage pipes shall be adopted to discharge the rich groundwater in the slope and rainwater during surface infiltration; the length of the inclined drainage pipe is more than 2.5 m, and the inclination angle is 8° - 15°, in which the intercepting section should be more than 1.5 m, and there are holes in the intercepting section; the drainage section is tightly compacted with soil, and the drilling section is more than 20 cm, and the outside of the drainage pipe is wrapped tightly with permeable geotextile. (5) Installation of anchor rods: the anchor rods are arranged according to the design of the lattice unit, starting from the bottom of the slope, the anchor holes make the anchor rods pass through the centre of the lattice unit, and the anchor is used to realize the fixation between the anchor rods and the lattice unit; passing the drainage pipe through the reserved drainage outlet in the cross beam of the lattice unit, and finally converging the drainage pipe into the drainage ditch through the drainage channel; the end of the lattice beam is embedded with

H-shaped steel to prevent the concrete structure from being damaged in the process of bearing force; when the end of the selected H-shaped steel is embedded, the exposed length is half of the embedded depth, and then the connection between the lattice beam and the lattice beam is completed through bolts and splicing plates between the H-shaped steels; finally, a lifting pad is placed on the exposed H-shaped steel. (6) Paving vegetation protection pads and excavating intercepting/drainage ditches at the toe of the slope: flatly paving the vegetation protection pads on the surface of the slope in each lattice unit and fixing them with U-shaped nails, wherein the joint of the vegetation protection pads and the protection pads overlaps at least 150mm, and the overlapping parts are fixed with the U-shaped nails.

(7) The anchor rod is closely attached to the centre of the lattice unit and fixed with standard nuts, a layer of cultivated soil is evenly spread on the surface of the vegetation protection pad, and water is sprayed to wet the cultivated soil. (8) Ploughing soil to plant vegetation: performing spray seeding to plant vegetation, selecting non-woven fabric to cover the slope surface, and removing the non-woven fabric after the vegetation grows 3 cm. (9) Excavation of intercepting ditch and drainage ditch.

The invention has the following beneficial effects: 1. The vegetation protection pad can slow down the water damage of the slope after the rainstorm, and form a stable anchoring system by closely combining with the vegetation on the slope. The uneven surface of the vegetation protection pad increases the roughness of the slope, and the combination of the stem and leaf of the slope protection vegetation can weaken the impact of rain and effectively alleviate the generation of gully and soil erosion on the slope. At the same time, because the vegetation protection pad is laid flat on the slope surface, it can effectively reduce the slope settlement and avoid the slope instability and collapse. 2. The drainage outlets on the assembled lattice beam are connected with drainage pipes to reduce rainwater infiltration and restrict slope deformation. The fabricated lattice beam does not need to be poured on site, which reduces the damage to the local environment, and the structure has the characteristics of low cost, convenient construction and shortened construction period. Especially, according to the conditions of the construction site, the construction of the lattice beam can be prefabricated in the factory, and the prefabricated lattice beam members can be directly placed during construction. With the active restraint of the anchor rod and the stability of the lattice beam to the whole slope, the displacement of the slope is effectively limited and the overall stability of the slope is realized. 3. The geomembrane is combined with the drainage pipe to improve the water damage resistance of the slope. By reducing the rainwater infiltration on the slope, the rainwater infiltrated inside the slope is discharged. In the initial stage of slope protection, geomembrane is to reduce erosion and infiltration, improve the survival rate of vegetation, and then use vegetation to grow in exotic soil. With the passage of time, plant roots will further develop and grow, slowly penetrate geomembrane and penetrate into the soil, forming a dense anchoring system, and the anchoring effect will become stronger and stronger, thus playing the role of soil consolidation, slope protection and greening and environmental protection. 4. Conventional intercepting/drainage ditch shall be made at the upper part of intercepting/drainage ditch, which is used to intercept and drain the rainwater at the top and slope surface, prevent the rainwater from scouring the slope surface and infiltrating into the slope body, and reduce the damage to the slope caused by disintegration and collapse of the soil layer when it meets water.

5. After adding anchor rods and prefabricated lattice beams to the slope to improve the overall stability of the slope, the vegetation protection pad, drainage pipe and geomembrane are used to jointly protect the slope from soil erosion, reduce infiltration and timely drainage to solve the problems faced by the red sandstone slope protection. The vegetation on slope 5 protection has excellent regeneration ability, so the vegetation protection pad, drainage pipe and geomembrane are hard to degrade, corrosion resistant and durable, which can realize long-term protection and meet the long-term protection requirements of slope engineering. 6. The overall structure is simple, the installation is convenient, and the later maintenance is simple; All parts of the structure are light in weight, can be mass-produced, have low production cost, and have great economic benefits and broad application prospects.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is a schematic diagram of the layout of the slope flexible ecological supporting structure according to the present invention.

Fig. 2 is a schematic diagram of the anchor rod structure of the slope flexible ecological supporting structure according to the present invention.

Fig. 3 is a schematic diagram of the drainage pipe structure of the slope flexible ecological supporting structure according to the present invention.

Fig. 4 is a schematic diagram of the assembled lattice beam structure of the slope flexible ecological supporting structure of the present invention.

Fig. 5 is a top view of the assembled lattice beam of the slope flexible ecological supporting structure according to the invention.

Fig. 6 is a schematic diagram of the assembled lattice beam connection structure of the slope flexible ecological supporting structure according to the invention.

Fig. 7 shows the steps of setting method of slope flexible ecological supporting structure.

The figures are marked as follows: vegetation protection pad 1, U-shaped nail 2, assembled lattice beam 3, H-shaped steel 4, lifting pad 5, bolt 6, splicing plate 7, drainage channel 8, drainage outlet 9, anchor rod 10, rod body 11, anchor pad 12, standard nut 13, cement mortar 14, drainage pipe 15, drainage section 16, intercepting section 17, drilling section 18, permeable geotextile 19, composite geomembrane 20, intercepting ditch 21, drainage ditch 22, slope protection vegetation 23, soil layer 24, lattice beam cross beam 25 and lattice beam vertical beam 26.

DESCRIPTION OF THE INVENTION

The invention will be described below with reference to the attached figures.

As shown in figures 1 - 5, the slope flexible ecological supporting structure of the present invention comprises a vegetation protection pad 1, a U-shaped nail 2, an assembled lattice beam 3, an anchor rod 10, a drainage pipe 15, a permeable geotextile 19, a composite geomembrane 20, a intercepting ditch 21, a drainage ditch 22 and a slope protection vegetation 23.

The composite geomembrane 20 is laid flat 20 cm below the soil surface of the slope and attached to the soil. The vegetation protection pad 1 is laid flat on the slope surface in each lattice unit and attached to the soil, and fixed on the slope by U-shaped nails 2. The composite geomembrane with groove anchorage at the top of slope is better. intercepting ditches are set at the top and bottom of the slope, and drainage ditches are set at both sides of the slope.

The assembled lattice beam 3 is arranged on the surface of the slope, which divides the slope into several lattice units, and the upper part of the assembled lattice beam 3 is provided with a drainage outlet 9, and the lower part of the drainage outlet is a drainage channel 8.

Assembled lattice beams 3 are connected by H-shaped steel 4. The function of assembled lattice beam is not only to divide the slope into several lattice units, but also to provide drainage channels to drain the water flowing out of the drainage pipe through the assembled lattice beam to prevent the water from scouring the slope.

The anchor rod comprises a rod body, an anchor pad and a nut, one end of the rod body penetrates into the slope, the other end of the rod body is exposed out of the slope, the exposed end of the rod body is provided with a thread, and the nut is correspondingly connected with the exposed end of the rod body through the thread. The anchor pad is arranged between the nut and the vegetation protection pad or between the nut and the assembled lattice beam, and the anchor pad is a steel plate with a thickness greater than 10 mm.. The function of anchor rod is to fix the assembled lattice beam and vegetation protection pad on the slope.

The anchor rod spacing is 1 — 2 m, the inclination angle between the anchor and the horizontal plane is 15° - 25°, and the anchor depth exceeds the sliding surface of the slope or the depth of the slope by 1m. The vegetation protection pad has at least 30% of the mesh space, and the vegetation protection pad has a wavy rough surface, which is a dense mesh with periodic concavities and convexities formed by winding long-fibre nylon filaments with high-toughness polyester geogrids or weaving tough polyester filaments.

The joint of the vegetation protection pad and the vegetation protection pad overlaps at least 150 mm, and the overlapping part is fixed with the U-shaped nail. The anchoring length of U- shaped nail is = 30cm, which can achieve better anchoring effect.

The outlet of the drainage pipe is arranged in the drainage outlet of the cross beam of the assembled lattice beam, and the drainage pipe is deeper than the slope. The drainage pipe is provided with a drainage section, a intercepting section and a drilling section, and the drainage section is tightly compacted with soil, and the permeable geotextile is wrapped on the drainage pipe. The revetment vegetation is planted in the vegetation protection pad in the lattice unit.

The setting method of the slope flexible ecological supporting structure is as follows (as schematically shown in Fig. 7): 1. Pre-treating the slope: clean up trees, roots, humus soil, organic soil, planting soil and garbage in the range to be treated, and level the slope.

2. Laying composite geomembrane: firstly, set the groove anchorage at the top of the slope, and then lay the composite geomembrane on the surface of the slope, taking care not to be wrinkled and suspended when laying. After the composite geomembrane is laid, backfill a layer of soil with a thickness of not less than 20 cm and tamp it. During tamping, be careful not to damage the composite geomembrane.

Measuring and setting out, drilling and positioning: according to the specific slope engineering situation, adjust the position of the drilling rig to make the drilling position, inclination angle and aperture size meet the design requirements, which is convenient for the hoisting and placement of the drainage pipe and assembled lattice beam.

The length of the drainage pipe is more than 2.5 m, the inclination angle is 8°-15°, and the drainage pipe is provided with a drainage section 16, a intercepting section 17 and a drilling section 18. Among them, the intercepting section 17 should be more than 1.5 m, and there are holes in the intercepting section 17, one every 5mm; staggered arrangement is all over the intercepting section 17, and the drainage section 16 has to be tightly compacted with sail, and the drilling section 18 is more than 20 cm; the outside of the drainage pipe must be tightly wrapped with permeable geotextile 19 to avoid sand and stones blocking the drainage pipe.

Grouting cement mortar 14 after the depth of the anchor rod is more than 1m than the local slope sliding surface or slope depth; the anchor rods are arranged according to the matrix type, and the anchor rod spacing is 1-2m; the inclination angle of the anchor hole is 15°-25°; the rod body 11 is provided with a threaded rod on the slope; after the anchor pad 12 is compacted on the surface of the vegetation protection pad 1, it is tightened with the standard nut 13 to tightly combine the vegetation protection pad 1 with the anchor rod 3 and stabilize the slope. 3. Installation of drainage pipes: layout shall be carried out according to the design of lattice units, and inclined drainage pipes shall be adopted to discharge the rich groundwater in the slope and the rainwater during surface infiltration; the length of the inclined drainage pipe is more than 2.5 m, and the inclination angle is 8° - 15°. The intercepting section should be more than 1.5 m, and there are holes in the intercepting section; the drainage section is tightly compacted with soil, and the drilling section is more than 20 cm. The exterior of the drainage pipe is wrapped tightly with permeable geotextile. 4. For the assembled lattice beam 3, firstly, the positions of the anchor rod 10 and the drainage pipe 15 are measured through the anchor hole positioning, and the drainage pipe 15 is placed in advance, and the lattice unit is fixed by using the anchor and the drainage pipe. A drainage channel 8 is arranged between the lattice beam units to facilitate the drainage of the drainage pipe 15. H-shaped steel is embedded at the end of the lattice beam to prevent the concrete structure from being damaged in the process of receiving force; When the selected H-shaped steel is embedded at the end, the exposed length is half of the embedded depth, and then the connection between the exposed H-shaped steels at the end of the lattice beams is completed through the bolts and splicing plates between the lattice beams.

5. Installation of anchor rods: the anchor rods are arranged according to the design of the lattice unit, starting from the bottom of the slope, the anchor holes make the anchor rods pass through the centre of the lattice unit, and the anchor rods are fixed with the lattice unit; passing the drainage pipe through the drainage outlet 9 reserved in the cross beam 25 of the lattice unit, and finally collecting the water discharged by the drainage pipe into the drainage ditch through the drainage channel; H-shaped steel 4 is embedded at the end of the lattice beam to prevent the concrete structure from being damaged in the process of receiving force; the exposed length of the selected H-shaped steel 4 is half of the embedded depth when the end is embedded; then, through the bolts and splicing plates between H-shaped steel 4, the connection between H-shaped steel 4 exposed at the end of the lattice beam is completed, and finally, a lifting pad is placed on the exposed H-shaped steels.

6. Paving vegetation protection pads and excavating intercepting/drainage ditches at the toe of the slope: pave the vegetation protection pad evenly on the slope surface in each lattice unit and fix it with U-shaped nails 2. The joint of the vegetation protection pad and the protection pad overlaps at least 150 mm, and the overlapping part is fixed with the U-shaped nail 2. The rough surface of the vegetation protection pad 1 with regular undulations can effectively resist the erosion of slope rainfall and ensure the growth and development of slope protection vegetation 23; the U-shaped nail 2 is used for fixing the vegetation protection pad 1 on the slope surface; the overlapping part of the vegetation protection pad 1 overlaps with the connection part of the vegetation protection pad 1 by at least 150 mm, and the overlapping part is fixed by the U-shaped nail 2.

7. The anchor rad 10 is closely attached to the centre of the lattice unit and fixed with standard nuts.

A layer of cultivated soil is evenly spread on the surface of the vegetation protection pad, and water is sprayed to wet the cultivated soil.

8. Ploughing soil to plant vegetation: spray plant vegetation, select non-woven fabric to cover the slope surface, and remove the non-woven fabric after the vegetation grows 3cm.

The surface of that vegetation protection pad is cover with a layer of uniformly pave cultivated soil, and water is sprayed to wet the cultivate soil; planting slope protection vegetation, after the vegetation grows and takes shape, the roots can pierce the geomembrane and form the corresponding anchoring system, thus playing the role of soil consolidation, slope protection and greening and environmental protection.

9. Excavation of intercepting ditch and drainage ditch: excavation of intercepting ditch and drainage ditch at the outer edge of slope protection is used to intercept and remove rainwater on the top and slope surface, prevent rainwater from washing the slope surface and infiltrating into the slope body, and reduce the damage to the slope caused by disintegration and collapse of soil layer when it meets water.

Detailed description of the specific embodiment of the present invention can be used by geotechnical engineering professionals to understand the present invention, but the present invention is not limited to the scope of the specific embodiment.

For geotechnical engineering professionals, all inventions and creations using the concept of the present invention are protected within the appended claims and the spirit and scope of the present invention.

Claims

CONCLUSIONS

1. A flexible ecological support structure for a slope, comprising a composite geomembrane, a vegetation protection mat, a U-shaped nail, a catchment ditch, a drainage ditch, a composite lattice girder, an anchor rod, a drain pipe, permeable geotextile and vegetation to protect the slope, wherein — the composite geomembrane is laid flat on the inner surface of the soil layer of the slope and is secured to a ground body, wherein — the vegetation protection mat is laid flat on the slope surface in each lattice unit and is secured to the soil, and is secured to the slope with U-shaped nails; — the catchment ditches are laid at the top and bottom of the slope and the drainage ditches are laid on both sides of the slope; — the composite lattice girder is placed on that surface of the slope and the composite lattice girder divides the slope into a number of lattice units; — the anchor rod comprises a rod body, an anchor disc and a nut; — one end of the rod body penetrates deeply into the slope and the other end of the rod body is exposed from the slope; — the exposed end of the rod body is provided with a thread and the nut is connected to the exposed end of the rod body in a mating manner with the thread; — the anchor disc is fitted between the nut and the vegetation protection mat or between the nut and the composite lattice girder; — the outlet of the drain pipe is located in the outlet of the cross beam of the composite lattice girder; — the drain pipe is located deeper than the slope; — the drain pipe is provided with a drain section, a collection section and a drilling section; — the drain section is closely compacted with soil and the permeable geotextile is wrapped around the drain pipe; and — the revetment vegetation is planted in the vegetation protection cushion in the lattice unit.

2. The flexible ecological support structure for a slope according to claim 1, wherein the vegetation protection mat has an undulating rough surface and is a dense net with alternating hollows and convexities, is made of long-fiber nylon filament wound with a strong polyester geomesh or is woven with strong polyester filament.

3. The flexible ecological support structure for a slope according to claim 1, wherein the mesh space of the vegetation protection mat is at least 30%.

4. The flexible ecological support structure for a slope according to claim 1, wherein the anchor foot is a steel plate with a thickness of more than 10 mm.

5. The flexible ecological support structure for a slope according to claim 1, wherein H-shaped steel parts are used for the composite lattice girders to realize the connection between the lattice girders.

6. The flexible ecological support structure for a slope according to claim 1, wherein the vegetation protection mat and the connection between the vegetation protection mats comprise an overlap of at least 150 mm and the overlapping part is secured with the U-shaped nail.

7. The flexible ecological support structure for a slope according to claim 1, wherein the distance between the anchor rods is 1 - 2 m, the slope angle between the anchor and the horizontal plane is 15° - 25° and the anchor depth is 1 m more than the slope sliding plane or the slope depth.

8. The flexible ecological support structure for a slope according to claim 1, wherein the anchoring length of the U-shaped nail = 30 cm.

9. The flexible ecological support structure for a slope according to claim 1, wherein the composite geomembrane is provided with groove anchoring at the top of the slope.

10. A method for placing a flexible ecological support structure for a slope according to claim 9, which method comprises the following steps: (1) pre-treating the slope: cleaning the trees, roots, humus soil, organic soil, plant soil and waste in the area to be treated and leveling the slope; (2) placing the composite geomembrane: first placing a groove anchorage at the top of the slope, then placing the composite geomembrane on the surface of the slope and after placing the composite geomembrane filling and compacting with a layer of soil with a thickness of at least 20 cm; (3) measuring and setting out, drilling and placing: adapting the position of the drilling rig to the specific slope technical situation in order to make the drilling position, angle of inclination and opening size meet the design requirements, so that the lifting and placing of drainage pipes and composite lattice girders is facilitated;

(4) installation of drainage pipes: carrying out the layout according to the design of lattice girders, and adopting inclined drainage pipes to discharge the excess groundwater in the slope and the rainwater during surface infiltration; wherein the length of the inclined drainage pipe is more than 2.5 m, and the slope angle is more than 2.5 m, wherein the length of the inclined drainage pipe is more than 2.5 m and the slope angle is 8° - 15°, wherein the collection section is more than 1.5 m and there are openings in the collection section, and the drainage section is well compacted with soil and the drilling section is more than 20 cm, and the outside of the drainage pipe is tightly wrapped with permeable geotextile;

(5) installation of anchor rods: placing the anchor rods according to the design of the lattice unit, starting from the bottom of the slope, the anchor holes making the anchor rods pass through the center of the lattice unit, and the anchor is used to realize the fastening between the anchor rods and the lattice unit; the drainage pipe is passed through the reserved drainage hole in the cross beam of the lattice unit, and the drainage pipe finally converges into the drainage ditch through the drainage channel, the end of the lattice girder is embedded with H-shaped steel to prevent the concrete structure from being damaged during the bearing force, wherein when the end of the selected H-shaped steel is embedded, the exposed length is half of the embedded depth, after which the connection between the lattice girders is completed with bolts and connecting plates between the H-shaped steels; finally, a lifting pad is placed on the exposed H-shaped steel;

(6) installation of vegetation protection mats and digging of catchment/drainage ditches at the foot of the slope: installation of the vegetation protection mats flat on the surface of the slope in each trellis unit and fixing them with U-shaped nails, whereby the connection between the vegetation protection mats involves an overlap of at least 150 mm and the overlapping parts fixed with the

U-shaped nails are attached;

(7) fasten it tightly in the center of the trellis unit and secure it with standard nuts, evenly spread a layer of topsoil over the surface of the vegetation protection mat, and spray water to moisten the topsoil;

(8) ploughing the soil to plant vegetation: sowing by spreading to plant vegetation, selecting fleece to cover the slope surface, and removing the fleece after the vegetation has grown 3 cm; and

(9) digging a catchment ditch and drainage ditch.