CN111472371B

CN111472371B - Comprehensive ecological prevention and control structure and method for easily weathered soft rock high and steep slope

Info

Publication number: CN111472371B
Application number: CN202010345494.2A
Authority: CN
Inventors: 付宏渊; 查焕奕; 曾铃; 史振宁; 邱祥
Original assignee: Changsha University of Science and Technology
Current assignee: Changsha University of Science and Technology
Priority date: 2020-04-27
Filing date: 2020-04-27
Publication date: 2021-06-15
Anticipated expiration: 2040-04-27
Also published as: CN111472371A

Abstract

The invention discloses an easily weathered soft rock high and steep slope comprehensive ecological prevention and control structure which comprises at least one graded ecological prevention and control structure, wherein the graded ecological prevention and control structure comprises a soft rock curing layer fixedly attached to a soft rock slope, an internal drain pipe and a bidirectional drain board, the internal drain pipe is inserted into the soft rock slope through the soft rock curing layer, the bidirectional drain board is laid on the surface of the soft rock curing layer, and the bidirectional drain board is communicated with the internal drain pipe; and an ecological concrete layer and a plant-growing concrete layer are sequentially paved on the surface of the bidirectional drainage plate outwards. The bidirectional drainage plate is formed by splicing a plurality of shallow bidirectional drainage blocks, and each shallow bidirectional drainage block comprises a drainage plate wall, a drainage channel, a water guide hole and a drainage pipe hole. And excavating the soft rock side slope on the easily weathered soft rock high-steep side slope from top to bottom in a grading manner, and treating the easily weathered soft rock high-steep side slope on the excavated soft rock side slope by adopting the comprehensive ecological control structure for the easily weathered soft rock high-steep side slope. The drainage effect is good, and the protective effect is good.

Description

Comprehensive ecological prevention and control structure and method for easily weathered soft rock high and steep slope

Technical Field

The invention belongs to the technical field of civil engineering, and relates to an easily weathered soft rock high-steep slope comprehensive ecological prevention and control structure and a prevention and control method thereof.

Background

The soft rock high and steep slope damage is a cyclic gradual instability process, and the surface layer of the soft rock high and steep slope is very easy to be weathered and broken under the action of rainfall, light and heat, so that shallow layer instability of the soft rock high and steep slope is caused; and (3) weathering and destabilizing the new section formed after the soft rock high and steep slope is destabilized again under the action of rainfall, light and heat, and circulating the steps, so that the soft rock high and steep slope is subjected to gradual shallow layer destabilization from the surface to the inside. Meanwhile, a large amount of waste soft rock is generated in the excavation process of the soft rock high and steep side slope, and if the soft rock waste residues are not used, material waste and ecological damage are inevitably caused; after excavation, the soft rock high and steep slope is lack of surface soil and nutrient substances required by vegetation growth, so that the slope does not have a soil environment required by vegetation growth, and the treatment and greening difficulty is high.

The common method for greening the soft rock high and steep slope mainly comprises artificial grass planting, earthwork net grass planting, prefabricated lattice turf paving, foreign soil spray seeding, thick-layer base material spraying, three-dimensional vegetation net, vegetation bags, vegetation type porous concrete slope protection and the like. However, because of the soft rock slope crack development, poor water retention, large slope and poor soil fixation condition, the existing greening method has certain application range and limitation, and has a plurality of defects in the practical application process:

the artificial grass planting is a traditional side slope plant protection measure for manually sowing grass seeds on a slope surface, is the simplest vegetation method, and is mainly used for solidifying the side slope by utilizing the mechanical effects of deep root anchoring and shallow root reinforcement of a plant root system and the hydrological effects of reducing pore pressure, weakening splash erosion and controlling runoff. The method is not suitable for the protection of the soft rock high and steep slope because the soft rock high and steep slope lacks surface soil and nutrient substances required by vegetation growth.

The spraying seeding of foreign soil is mainly to spray the mixed liquid of plant seeds, fertilizer, fiber, stabilizer and water uniformly to the slope for greening. However, the method is suitable for the slope surface with small gradient and flatness, the base layer has limited thickness, the soil fixation and water retention are poor, the combination of the alien soil and the bedrock is weak, the alien soil is easy to erode and lose under the condition of strong rainfall to cause surface alien soil loss, the alien soil is peeled off, and the later degradation is serious, so the method is not suitable for the protection of the slope surface of the soft rock high and steep slope. The patent numbers are: CN102986418B, name: the spray-seeding base material for southern side slope and its preparation process features that the spray-seeding base material is used in southern area for side slope incapable of being greened or with poor greening effect under common conditions, and has high net hanging cost and poor scour resistance. When the slope is steep, the soil erosion is serious, and the water and soil are easy to wash out particularly when the rainfall is heavy.

The geotechnical net grass planting is a composite slope plant protection measure integrating slope surface reinforcement and plant protection, which is started to be used in more than ten years. But the construction period is long, the cost is high and the like. Especially in high and steep slopes, the construction difficulty is greater. And after the adopted thermoplastic resin net is aged, secondary pollution is easily formed in soil, and the environment is not protected.

The organic base material spray seeding or spray mixing plant growing is to spray and bond the mixture of plant seeds, organic plant growing base, cement, adhesive such as buffering agent or synthetic resin and water on the slope to form thick organic layer. The patent numbers are: CN104542220B, patent name: the plant-growing net blanket for slope restoration and the slope restoration method are suitable for various uneven slopes. The ecological environment of the side slope can be improved in a short period, the ecological benefit is huge, the benefit period is long, the manufacturing cost is low, the materials are easy to obtain, the maintenance cost is low, considerable economic benefit is achieved, a good landscape effect is created, the vegetation net blanket is easy to peel off, and the method is not suitable for repairing the high and steep side slope of the easily weathered soft rock.

The vegetation type porous concrete slope protection is characterized in that a mixture of seeds, a water-retaining agent, organic matters, fertilizers and the like is filled in pores of porous concrete, and then watering is carried out to promote plants to germinate. The patent numbers are: CN205024695U, patent name: the patent of an ecological slope protection lawn structure adopts the method, and the technology has the characteristics of stable structure, beautiful appearance and regularity. But the construction period is long, the cost is high, the specific gravity of the plant concrete is large, the inorganic porous material comprises zeolite, kaolin, bentonite, diatomite and vermiculite, the pores are small, and the cost is high. Has no function of preserving soil moisture and fertilizer, uses common fertilizer as fertilizer, has short fertilizer effect and low mechanical strength. Small water permeability coefficient, less than 15% water absorption and large shrinkage. The construction difficulty of large-scale high and steep slopes is high. The vegetation growing on the porous concrete is usually withered and dead due to insufficient moisture and nutrients and a high-alkali environment, and the application of the vegetation is severely restricted. The portland cement is alkaline and not beneficial to the rooting and the germination of plant seeds, and the influence of the pH value of the spraying and mixing base material on the growth and the development of plants is mainly shown in the aspects of the effectiveness of soil nutrients, the activity of soil microorganisms, the growth and the resistance of plant root systems, the composition of plant communities and the like. For this purpose, auxiliary binders (such as red clay, calcium superphosphate) and pH buffers are added to the spray-mixed base material, and pH adjustment is performed by using their own acidity and alkalinity and buffering property and the acidity generated by hydrolysis of the red clay with high amount of activated aluminum, so that the pH value of the spray-mixed base material is reduced from strong alkalinity to neutrality, thereby being suitable for plant growth.

So far, the research on ecological restoration of rock slopes at home and abroad mainly focuses on the aspects of novel ecological materials, ecological planting matrixes, slope protection construction methods and the like, and the greening planting of the high and steep slope surfaces of soft rock is greatly progressed, but the following problems to be solved still exist:

1. when the ecological protection construction of the soft rock slope is carried out, the problems of poor greening protection effect, falling of foreign soil, scouring of the slope surface, low construction efficiency and the like are frequently encountered, and the greening effect of the slope engineering is seriously influenced.

2. The alien soil used for alien soil spray seeding mostly adopts excellent soil which has high nutritive value and good cohesiveness and can promote the growth of plants, the construction cost is high, and the acquisition of materials is difficult.

3. The slope of the soft rock high and steep slope is larger, the construction of the traditional anchor rod, frame and soil replacement spray-seeding method is extremely difficult, the single protection method has poor protection effect, and the later maintenance cost is too high.

4. The conventional artificial soil is sprayed to a slope surface (foreign soil spray seeding) to form a vegetation lawn, the period is long, the slope surface is almost unprotected, and easily weathered soft rock side slopes are easy to fall off, slide and collapse under the weathering effect, so that a great number of potential safety hazards are brought to road and railway transportation.

In view of the above, in order to improve the construction quality and efficiency of ecological protection of the easily weathered soft rock high and steep slope and improve the stress performance and integrity of the protective structure, the invention of the ecological protection method for the soft rock slope, which has the advantages of good integrity of the vegetation soil layer and the soft rock, good greening effect of the slope, simple construction, wide material source and low cost, is urgently needed.

Disclosure of Invention

The embodiment of the invention aims to provide an easily weathered soft rock high and steep slope comprehensive ecological prevention and control structure, which aims to solve the problems of poor greening effect of the existing high and steep slope engineering and the problems of high construction cost and high material acquisition difficulty.

The embodiment of the invention also aims to provide a comprehensive ecological prevention and control method for the easily weathered soft rock high and steep slope, so as to solve the problems that the traditional prevention and control method is poor in protection effect and high in later maintenance cost, and soft rock is easy to fall, slip and collapse, so that a plurality of potential safety hazards are brought to road and railway transportation.

The technical scheme adopted by the embodiment of the invention is that the comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slope comprises at least one graded ecological prevention and control structure, wherein the graded ecological prevention and control structure comprises a soft rock curing layer fixedly attached to the soft rock side slope, an internal drain pipe and a bidirectional drain board, the internal drain pipe is inserted into the soft rock side slope through the soft rock curing layer, the bidirectional drain board is laid on the surface of the soft rock curing layer, and the bidirectional drain board is communicated with the internal drain pipe;

and an ecological concrete layer and a plant-growing concrete layer are sequentially paved on the surface of the bidirectional drainage plate outwards.

Further, the ecological concrete layer is composed of completely weathered soft rock disintegrating soil, clay, sodium alginate and CaCl of the protected soft rock slope in a mass ratio of 66:20:3:1:10₂The ecological concrete prepared by the solution and the plant culture solution is formed by spray-seeding;

the plant-growing concrete layer is formed by spraying plant-growing concrete prepared from grass seeds, shrub seeds and ecological concrete in a mass ratio of 1:1: 20-1: 1: 50;

the thickness of the ecological concrete layer and the thickness of the plant-growing concrete layer are both 15-30 cm.

Furthermore, the bidirectional drainage plate is formed by splicing a plurality of shallow bidirectional drainage blocks;

the shallow bidirectional drainage block comprises a drainage plate wall, drainage channels, a water guide hole and a drainage pipe hole, wherein the drainage channels are arranged in parallel at certain intervals and longitudinally penetrate through the drainage plate wall from top to bottom; the plurality of water guide holes are arranged in parallel at certain intervals, transversely penetrate through the wall of the drainage plate from left to right and are communicated with the plurality of drainage channels; a plurality of drainage pipe holes vertically penetrate through the drainage plate wall from front to back at certain intervals and are respectively communicated with the drainage channel; the internal drain pipe is communicated with the drain pipe hole.

Furthermore, among the plurality of drainage channels, the drainage channel close to the front end face of the drainage plate wall is communicated with the front end face of the drainage plate wall, the drainage channel close to the rear end face of the drainage plate wall is communicated with the rear end face of the drainage plate wall, and gauze filtering layers with the aperture of 1mm and the thickness of 50mm are fixed on the front end face and the rear end face of the drainage plate wall.

Furthermore, the shallow bidirectional drainage blocks are of a cuboid structure, two adjacent shallow bidirectional drainage blocks are connected through an I-shaped bidirectional drainage plate interface on the side surface to form a bidirectional drainage plate, and drainage channels of all the shallow bidirectional drainage blocks are communicated in a one-to-one correspondence manner;

the width of the interface of the bidirectional drainage plate interface with the I-shaped side surface is equal to the thickness of the shallow bidirectional drainage block;

the wall of the drainage plate is provided with a plurality of soil nail holes which are separated by a certain distance and vertically penetrate through the drainage plate from front to back, and the shallow bidirectional drainage block is fixed on the soft rock slope through soil nails penetrating through the soil nail holes.

Further, the soft rock curing layer is formed by spraying a super-hydrophobic mud rock modifier which is prepared from distilled water, calcium oxide, potassium chloride, polyvinylidene fluoride and dimethylformamide or N-methylpyrrolidone according to the mass ratio of 66:10:20:1:3, and the thickness of the super-hydrophobic mud rock modifier is 15-30 cm.

Furthermore, slope top drainage ditches are arranged at the tops of the bidirectional drainage plates, the ecological concrete layer and the vegetation concrete layer, slope top drainage pipes, permeable concrete and a gravel layer are sequentially arranged in the slope top drainage ditches from top to bottom, and the slope top drainage pipes are communicated with drainage channels of the bidirectional drainage plates;

the bottom parts of the soft rock curing layer, the bidirectional drainage plate, the ecological concrete layer and the vegetation concrete layer are provided with gravel filter layers, and one end of each gravel filter layer extends into the soft rock side slope;

the gravel filtering layer is provided with a slope bottom drainage ditch below one end far away from the soft rock slope, and a crushed falling platform is arranged above one side of the slope bottom drainage ditch far away from the soft rock slope.

Furthermore, the gravel filtering layer consists of a fine gravel layer, a coarse gravel layer and a water-resisting layer which are sequentially arranged from top to bottom, the thicknesses of the fine gravel layer and the water-resisting layer are both 10cm, and the thickness of the coarse gravel layer is 30 cm.

The other technical scheme adopted by the embodiment of the invention is that the comprehensive ecological prevention and control method for the easily weathered soft rock high and steep side slope is to excavate the soft rock side slope on the easily weathered soft rock high and steep side slope from top to bottom in a grading manner, and treat the easily weathered soft rock high and steep side slope on the excavated soft rock side slope by adopting the comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slope, and the specific steps are as follows:

step S1, side slope excavation: excavating a soft rock side slope on the easily weathered soft rock high-steep side slope, and finishing the slope;

step S2, constructing a slope top drainage system: excavating a slope top drainage ditch at the slope top of the soft rock slope, laying permeable geotextile on two sides of the slope top drainage ditch, and sequentially arranging a slope top drainage pipe, a gravel layer and permeable concrete on the permeable geotextile from bottom to top;

step S3, constructing a soft rock solidified layer: preparing distilled water, calcium oxide, potassium chloride, polyvinylidene fluoride and dimethylformamide or N-methylpyrrolidone into a super-hydrophobic mudstone modifier according to the mass ratio of 66:10:20:1:3, spraying the super-hydrophobic mudstone modifier to the surface of a finished soft rock slope in an in-situ spraying manner, wherein the spraying thickness is 10-20 cm, then laying a plastic film, sealing for 24-72 hours, and spraying or brushing a soft rock curing agent for reinforcement for the second time, wherein the reinforcement thickness is 5-10 mm;

step S4, laying internal drain pipe: after reinforcement is carried out for 24-72 hours, fixing an internal drainage pipe along the slope surface of the soft rock side slope, and inserting the internal drainage pipe with the length of 5-6 m into the soft rock side slope through the soft rock curing layer at an angle of 3-5 degrees with the horizontal line;

step S5, constructing a protective net: hanging a net along the slope of the soft rock slope to construct a protective net;

step S6, paving a bidirectional drainage plate: fixing each shallow layer bidirectional drainage block on the surface of the soft rock slope by using a soil nail, wherein the included angle between the axis of a drilling hole of the soil nail and the soft rock slope surface to be treated is 90 degrees, and the length of the soil nail is 2-3 m;

step S7, constructing an ecological concrete layer: mixing clay, sodium alginate and CaCl₂Preparing ecological concrete by using a plant culture solution and the completely weathered soft rock disintegrating soil of the soft rock slope according to a mass ratio of 20:3:1:10:66, sequentially spraying the ecological concrete from left to right and from bottom to top by using a foreign soil spraying and sowing machine, uniformly spraying the ecological concrete on a bidirectional drainage plate twice, wherein the spraying and sowing thickness is 15-30 cm;

step S8, constructing a vegetation concrete layer: preparing grass seed seeds, shrub seeds and ecological concrete into plant-growing concrete according to the mass ratio of 1:1: 20-1: 1:50, sequentially spraying the plant-growing concrete by using a soil dressing spray-seeding machine from left to right and from bottom to top, uniformly spraying the plant-growing concrete three times onto the surface of a soft rock high and steep side slope, wherein the spraying thickness is 15-30 cm, covering improved soil by using non-woven fabrics after spraying, and paving surface drainage grooves communicated with a slope bottom drainage ditch on the surface of the side slope;

step S9, constructing a slope bottom drainage system: and arranging a gravel filtering layer at the bottom of the soft rock side slope, excavating a slope bottom drainage ditch and arranging a crushing platform.

Further, the sorting slope in step S1 refers to: brushing a slope and setting out, cleaning residual soft rock during excavation, cleaning the surface layer of the slope, backfilling larger pits of the slope surface, cleaning the bare rock surface by using a high-pressure water gun, and reinforcing the bare rock body of the slope according to the weathering degree of the easily weathered soft rock high-steep slope;

when the weathering degree of the easily weathered soft rock high and steep slope is divided into strong weathering, the exposed rock mass of the slope is reinforced as follows: measuring and paying off, drawing an anchor fixed point diagram, fixing anchors on a slope according to a set distance, arranging the upper and lower adjacent anchors in a staggered manner, wherein the anchor arrangement distance is 1m multiplied by 1 m;

when the weathering degree of the easily weathered soft rock high and steep side slope is medium weathering and weak weathering, the exposed rock mass of the side slope is reinforced as follows: fixing a rock mass crushing part by using an anchor rod, wherein the included angle between the drilling axis of the anchor rod and the slope surface of the soft rock slope to be treated is 45 degrees, the drilling diameter is 15-20 mm larger than the diameter of the anchor rod, and the length of the anchor rod is 3-5 m;

the slope of the excavated soft rock side slope is 45-70 degrees, the slope height is 10m, and the width of a breaking platform of each level of soft rock side slope is 3-4 m.

The embodiment of the invention has the beneficial effects that:

firstly, soft rock curing agent prepared by dissolving polyvinylidene fluoride in dimethylformamide or N-methyl pyrrolidone in solution of calcium oxide and potassium chloride is sprayed to form a soft rock curing agent layer, so that the strength of soft rock on an excavation surface is enhanced, and the water permeation on the surface of a soft rock side slope is effectively reduced; set up inside drain pipe, top of slope drainage system and slope end drainage system to adopt two-way drain bar to communicate inside drain pipe and top of slope drainage system and slope end drainage system, and set up ecological concrete layer and vegetation concrete layer on two-way drain bar, not only discharge soft rock side slope inside pore water and soft rock side slope top ponding, still discharge the water in the novel ecological concrete in top layer, drainage effect is good, the wholeness of vegetation soil layer and soft rock is good. Meanwhile, the gauze with excellent cohesiveness is arranged on two sides of the bidirectional drainage plate, the soft rock curing agent layer, the bidirectional drainage plate and the ecological concrete layer are effectively connected, the integrity of the easily weathered soft rock high and steep slope is enhanced, the transverse water guide hole is formed, the drainage channel of the shallow bidirectional drainage block can be effectively prevented from being blocked, the foreign soil is effectively prevented from falling off and the slope is effectively prevented from being washed away, the greening effect of the soft rock slope protection engineering is guaranteed, and the problem of poor greening effect of the existing high and steep slope engineering is solved.

Secondly, clay, sodium alginate and CaCl are utilized₂The ecological concrete is prepared from the plant culture solution and the completely weathered soft rock disintegrating soil, so that the construction is simple, the materials are obtained locally, the environment is protected, the energy is saved, and the requirement of ecological slope protection is met. Adopts completely weathered soft rock disintegrating soil as ecologyThe main raw materials of the concrete reduce the use of high-quality soil, greatly reduce the construction cost and solve the problems of high construction cost and high material acquisition difficulty of the prior high and steep slope engineering.

Moreover, a feasible protection scheme is provided for the easily weathered soft rock high and steep side slope with different weathering degrees, the combination problem between the two-way drainage plate and the bedrock is solved by adopting a net hanging mode and a soil nail mode, the stripping of the two-way drainage plate and the ecological concrete layer and the stripping of the two-way drainage plate and the soft rock side slope can be effectively prevented, the integrity of the protection structure and the soft rock side slope is good, the vegetation concrete prepared by grass seeds, shrub seeds and the ecological concrete is sprayed to form the vegetation concrete layer, after the green planting is carried out for 12 months, a small amount of fibrous roots of the bermuda penetrate through the vegetation concrete layer 3, the ecological concrete layer 4 and the two-way drainage plate 5 to reach the soft rock side slope surface, the root system is mainly concentrated on the vegetation concrete layer 3, the fibrous root diameter is less than 1.0mm, the root system diameter is mainly concentrated on 0.35-0.70 mm, the root system weight of 0-20 cm depth is about 84.4%, the root system weight of 0-10 cm is about 56, the protective effect is excellent. And only need regularly prune after the grass grows out in later stage can, the later stage maintenance cost is low. Effectively solves the problems of poor protective effect and high later maintenance cost of the traditional control method.

Finally, because the embodiment of the invention carries out reinforcement treatment on the exposed rock mass of the side slope according to the weathering degree of the easily weathered soft rock high-steep side slope in the initial construction stage, and because the comprehensive ecological prevention and control structure of the easily weathered soft rock high-steep side slope of the embodiment of the invention has excellent drainage effect and good integrity of the protection structure and the soft rock side slope, the soft rock is not easy to fall off, slip and collapse; in addition, the soft rock slope bottom of each stage of excavation is provided with the breaking platform to bear the soft rock which is subjected to block falling, sliding and collapse, so that the road and railway transportation is not influenced by comprehensive guarantee. And (3) evaluating the slope stability of the rock slope greening system by adopting a rigid body limit balance method, wherein the safety coefficient of the easily weathered soft rock high and steep slope meets the relevant standard requirements. The problem that soft rock is easy to fall off blocks, slide and collapse to bring a great number of potential safety hazards to road and railway transportation is effectively solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is an overall schematic view of an integrated ecological prevention and control structure of an easily weathered soft rock high and steep slope.

FIG. 2 is a schematic view of a first-level side slope of the comprehensive ecological prevention and control structure of the easily weathered soft rock high and steep side slope.

Fig. 3 is a perspective view of a bi-directional drain plate.

Fig. 4 is a schematic cross-sectional view (in mm) of a bi-directional drainage plate.

FIG. 5 is a schematic left side view (in mm) of a bi-directional drainage panel.

Fig. 6 is a schematic view of the front of a bi-directional drainage plate (in mm).

Fig. 7 is a schematic view of a bi-directional drain board interface (in cm).

Fig. 8 is a diagram showing the effect of the connection of the bidirectional drain board.

FIG. 9 is a schematic cross-sectional view of a gravel pack.

1. Permeable concrete, 2, a gravel layer, 3, a vegetation concrete layer, 4, an ecological concrete layer, 5, a bidirectional drainage plate, 51, a drainage channel, 52, a drainage plate wall, 53, a gauze filtering layer, 54, a water guide hole, 55, a drainage pipe hole, 56, a soil nail hole, 6, a soft rock curing layer, 7, a gravel filtering layer, 71, a fine gravel layer, 72, a coarse gravel layer, 73, a water-proof layer, 8, a slope bottom drainage ditch, 9, an internal drainage pipe, 10, a soil nail and 11, an anchor rod.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slope comprises at least one graded ecological prevention and control structure as shown in figures 1-3, wherein each graded ecological prevention and control structure comprises a soft rock curing layer 6 fixedly attached to the soft rock side slope, an internal drain pipe 9 and a bidirectional drain board 5, the internal drain pipe 9 is inserted into the soft rock side slope through the soft rock curing layer 6, the bidirectional drain board 5 is laid on the surface of the soft rock curing layer 6, the bidirectional drain board 5 is communicated with the internal drain pipe 9, and an ecological concrete layer 4 and a vegetation concrete layer 3 are sequentially and fixedly laid on the bidirectional drain board 5 outwards.

The ecological concrete layer 4 is formed by completely weathered soft rock disintegrating soil, clay, sodium alginate and CaCl in a mass ratio of 66:20:3:1:10 on the protected soft rock slope₂The ecological concrete prepared by the solution and the plant culture solution is formed by two times of uniform spray seeding. In the easily weathered soft rock area, the high-quality clay content is less, the easily weathered soft rock area needs to be transported from an off-site to the off-site, the cost is high, most of the used soft rock is farmland soil, the farmland is damaged, the soft rock disintegrating soil is generally accumulated as waste, geological disasters are easily formed, and the environment is damaged. The fully weathered soft rock disintegrating soil adopting the soft rock slope can reduce the use of high-quality clay, save the cost and prevent the soft rock disintegrating soil from stacking to influence the environment. The sodium alginate is industrial grade sodium alginate, and is brown powder; CaCl₂The solution adopts saturated CaCl₂The solution is colorless transparent solution with the mass concentration of 740 g/L. Because the soft rock itself lacks nutrient elements required by plant growth, the plant can not grow well even if the soft rock is used alone, and the clay is added to provide nutrient substances and soil for plant growth, sodium alginate and CaCl₂The solution exists as modifier, and has the functions of adhering soft rock and clay grains, raising the shear strength of ecological concrete, maintaining water and providing Ca and Na elements. The two-time spray seeding mainly prevents poor bonding effect caused by one-time spray seeding, the first spray seeding mainly plays a role in protecting the drain pipe, and the second spray seeding mainly plays a role in enhancing.

The plant-growing concrete layer 3 is formed by evenly spraying plant-growing concrete prepared from grass seeds, shrub seeds and ecological concrete in a mass ratio of 1:1: 20-1: 1:50 for three times. When the mass ratio of the grass seeds to the shrub seeds to the ecological concrete is 1:1: 20-1: 1:50, the grass seeds and the shrub seeds are easy to germinate and grow, and the situation that the plants grow badly and even die due to over-dense plant density is not easy to occur. The three-time uniform spray seeding is to prevent the poor effect of one-time spray seeding, the three-time uniform spray seeding can ensure that the plant growing concrete is uniformly distributed, is beneficial to plant growth, and the two-time spray seeding plays a role in enhancing. The grass seeds adopt ryegrass, tall fescue and bermuda grass, the shrubs adopt magnolia sieboldii, fructus perillae and robinia pseudoacacia, one or more of the ryegrass, the tall fescue and the bermuda grass in the grass seeds are mixed, and one or more of the magnolia sieboldii, the fructus perillae and the robinia pseudoacacia are mixed.

The thicknesses of the ecological concrete layer 4 and the planting concrete layer 3 are both 30-40 cm, the root systems of ryegrass, tall fescue and bermuda grass, the root systems of magnolia flowers, passiflora edulis and acacia in the juvenile growth period generally grow by about 20-40 cm, and therefore the planting concrete layer is arranged by 30-40 cm. Plant and grow concrete layer 3 and mainly promote the early vegetation of protection, ecological concrete layer 4 mainly plays two-way drain bar 5 of protection and promotes vegetation later stage growth to connect the effect of planting and growing concrete layer 3 and two-way drain bar 5. The gravity of the ecological concrete layer 4 and the vegetation concrete layer 3 is increased due to the overlarge thickness, so that the gliding force is increased, the adhesion of the ecological concrete layer 4 is not facilitated, the ecological concrete layer 4 is easy to peel off, the material waste is caused, and the cost is increased; the thickness of the ecological concrete layer 4 and the vegetation concrete layer 3 is too small to be beneficial to the growth of plants in the early stage of protection.

The two-way drain board 5 is formed by splicing a plurality of shallow two-way drain blocks, the shallow two-way drain blocks are of cuboid structures, the two adjacent shallow two-way drain blocks are connected through the two-way drain board interfaces with I-shaped side faces as shown in figure 7 and can be spliced into the two-way drain board 5 with any size, the drain channels 51 of all the shallow two-way drain blocks are communicated in a one-to-one correspondence mode, and the effect diagram after splicing is shown in figure 8. Meanwhile, the connector of the bidirectional drain board is I-shaped, so that the width of the connector is equal to the thickness of the shallow bidirectional drain block, and the bidirectional drain board 5 can be just inserted into the connector of the I-shaped bidirectional drain board connector.

As shown in fig. 3 to 6, each shallow bidirectional drainage block includes a drainage plate wall 52, drainage channels 51, a water guide hole 54, a drainage pipe hole 55 and a soil nail hole 56, the drainage channels 51 are arranged in parallel at a certain interval and longitudinally penetrate through the drainage plate wall 52 from top to bottom, in the drainage channels 51, the drainage channels 51 near the front end surface of the drainage plate wall 52 communicate with the front end surface of the drainage plate wall 52, and the drainage channels 51 near the rear end surface of the drainage plate wall 52 communicate with the rear end surface of the drainage plate wall 52. In the embodiment of the present invention, the plurality of drainage passages 51 may be arranged to penetrate the drainage plate wall 52 longitudinally from top to bottom in at least two rows as shown in fig. 3, in which case the drainage passages 51 near the front end surface of the drainage plate wall 52 communicate with the front end surface of the drainage plate wall 52, the drainage passages 51 near the rear end surface of the drainage plate wall 52 communicate with the rear end surface of the drainage plate wall 52, or the plurality of drainage passages 51 may be arranged to penetrate the drainage plate wall 52 longitudinally from top to bottom in only one row, in which case the plurality of drainage passages 51 communicate with both the front end surface and the rear end surface of the drainage plate wall 52.

The water guide holes 54 are arranged in parallel at certain intervals, transversely penetrate through the drainage plate wall 52 from left to right and are communicated with the drainage channels 51, and the water guide holes 54 can effectively prevent the drainage channels 51 of the shallow bidirectional drainage block from being blocked. A plurality of drain holes 55 vertically penetrate the drain panel wall 52 from front to rear at a certain interval, and the drain holes 55 communicate with the inner drain pipe 9. The front end face and the rear end face of the drainage plate wall 52 are both fixed with gauze filtering layers 53 with the aperture of 1mm and the thickness of 50mm, and the gauze filtering layers 53 are arranged to better combine the ecological concrete layer 4 and the soft rock curing layer 6 into a whole, filter impurities in water during drainage and protect the bidirectional drainage plate 5 from being blocked. The too large aperture of the gauze filtering layer 53 can cause impurities to flow into the bidirectional drainage plate 5 to block the drainage pipe hole 55, and is not beneficial to the adhesion of the ecological concrete layer 4, so that the ecological concrete layer 4 is peeled off; the aperture of the gauze filtering layer 53 is too small, and the drainage is not smooth.

In addition, a plurality of soil nail holes 56 which are arranged at intervals and vertically penetrate through the drainage plate wall 52 from front to back are arranged on the drainage plate wall 52, the bidirectional drainage block is fixed on the soft rock slope through the soil nails 10 penetrating through the soil nail holes 56, and the soil nail holes 56 are optimally arranged along the central line of the shallow bidirectional drainage block.

The shallow two-way drainage block is made of PVC material, as shown in figure 4, the width multiplied by the length multiplied by the height is 0.5m multiplied by 3m, each shallow two-way drainage block is provided with 5 pairs of drainage channels 51 with the size of 20 multiplied by 40cm, the interval between every two adjacent pairs of drainage channels 51 is 20cm, water guide holes 54 with the diameter of 100mm are transversely arranged at intervals of 1m, the two-way drainage plate 5 is arranged to simultaneously discharge the soft rock side slope and pore water in the ecological concrete layer 4, and the pore water in the ecological concrete layer 4 is prevented from entering the soft rock side slope, so that the integral stability of the soft rock side slope is influenced. The sizes of the drainage plate wall 52, the drainage channels 51 and the water guide holes 54, the interval between two adjacent rows of the water channels 51, the interval between two adjacent water guide holes 54 and the aperture of the water guide holes 54 can be increased or decreased according to the requirements. As shown in fig. 7, in the embodiment of the present invention, the thickness of the bidirectional drainage plate interface is 5cm, the width of the bidirectional drainage plate interface is 50cm, and the overall transverse length of the bidirectional drainage plate interface is 2 m. Because the length of the two-way drain board interface is 2m and the length of the shallow layer two-way drain block is 3m, the three two-way drain board interfaces can be used for connecting two-way drain boards 5, so that the up-and-down connection of the two-way drain boards 5 is realized; two-way drain bars 5 of two-way drain bar interface connection can be used to realize controlling the connection of two adjacent two-way drain bars 5.

The slope top (the tops of the bidirectional drainage plate 5, the ecological concrete layer 4 and the vegetation concrete layer 3) of the soft rock slope is provided with a slope top drainage ditch, a slope top drainage pipe, permeable concrete 1 and a gravel layer 2 are sequentially arranged in the slope top drainage ditch from top to bottom, the slope top drainage pipe is communicated with a drainage channel 51 of the bidirectional drainage plate 5, and the thicknesses of the permeable concrete 1 and the gravel layer 2 are both 50 cm.

The slope bottom of the soft rock side slope (the bottom of the soft rock cured layer 6, the bidirectional drainage plate 5, the ecological concrete layer 4 and the vegetation concrete layer 3) is provided with a gravel filter layer 7, one end of the gravel filter layer 7 extends into the soft rock side slope, the size of the gravel filter layer 7 is 1.5m multiplied by 0.5m, 0.5m is the height of the gravel filter layer 7, and 1.5m is the width of the gravel filter layer 7 which extends into the soft rock side slope by 0.5 m. The lower part of one end, far away from the soft rock side slope, of the gravel filtering layer 7 is provided with a slope bottom drainage ditch 8, and the upper part, far away from one side of the soft rock side slope, of the slope bottom drainage ditch 8 is provided with a crushed falling platform. The top of the bidirectional drainage plate 5 is connected with a slope top drainage ditch, and the bottom of the bidirectional drainage plate is connected with a slope bottom drainage ditch 8 through a gravel filter layer 7. During drainage, the internal drainage pipe 9 can drain accumulated water inside the soft rock side slope to the drainage channel 51 of the bidirectional drainage plate 5 through the drainage pipe hole 55, then the accumulated water on the top of the soft rock side slope is directly drained to the gravel filter layer 7 through the drainage channel 51 of the bidirectional drainage plate 5, and then drained to the slope bottom drainage ditch 8.

As shown in fig. 9, the gravel pack 7 is composed of a fine gravel layer 71, a coarse gravel layer 72 and a water-barrier layer 73, which are arranged in this order from top to bottom, wherein the thickness of each of the fine gravel layer 71 and the water-barrier layer 73 is 10cm, and the thickness of the coarse gravel layer 72 is 30 cm. The bottoms of the soft rock curing layer 6, the bidirectional drainage plate 5, the ecological concrete layer 4 and the vegetation concrete layer 3 are all connected with a fine gravel layer 71. The gravel filtering layer 7 is mainly used for filtering impurities brought out during the drainage of the side slope and preventing the side ditch from being blocked.

The soft rock curing layer 6 is produced by spraying a super-hydrophobic mudstone modifier, and the super-hydrophobic mudstone modifier consists of distilled water, calcium oxide, potassium chloride, polyvinylidene fluoride, dimethylformamide or N-methylpyrrolidone in a mass ratio of 66:10:20:1: 3. Polyvinylidene fluoride (PVDF) is dissolved in Dimethylformamide (DMF) or N-methylpyrrolidone (NMF) to form a semitransparent solution, and when a mixed solution, namely a soft rock curing agent, is sprayed in soft rock, the potential activity of soft rock particles can be excited and physicochemical reactions such as ion exchange and the like can be generated; after being heated and volatilized, Dimethylformamide (DMF) or N-methylpyrrolidone (NMF) can form a layer of compact net-shaped structure super-hydrophobic film on the surface layer of the soft rock, and the super-hydrophobic film can prevent rainwater from permeating and can increase cohesive force among soft rock particles, so that the soft rock slope becomes a whole with high strength. Ca in calcium chloride and potassium chloride²⁺And K⁺Ion replacement of Na in soft rock slope⁺、Li⁺Hydrophilic ions, etc., to improve the improvement effect. The thickness of the soft rock curing agent is 15-30 cm, the soft rock curing layer 6 is operated twice, the second time is mainly used for reinforcing the first time, namely, detecting defects and repairing leakage, and the curing in two times can also play a roleEnhancing the effect.

The preparation method of the soft rock curing agent comprises the following steps: firstly, dissolving calcium oxide and potassium chloride in distilled water to prepare a calcium oxide and potassium chloride solution, dissolving polyvinylidene fluoride in dimethylformamide or N-methylpyrrolidone, and stirring for 30 minutes until the calcium oxide and potassium chloride solution becomes a semitransparent solution; and then, mixing and stirring the calcium oxide and potassium chloride mixed solution and a semitransparent solution prepared by dissolving polyvinylidene fluoride in dimethylformamide or N-methylpyrrolidone for 30-40 minutes to prepare the soft rock curing agent. Polyvinylidene fluoride is dissolved in dimethylformamide or N-methyl pyrrolidone to form semitransparent liquid which can form a film-shaped substance when meeting water, and if the polyvinylidene fluoride is mixed with distilled water firstly, and then calcium oxide and potassium chloride are dissolved in the semitransparent liquid, the mixing is not uniform, and the curing effect is weakened. Therefore, polyvinylidene fluoride is firstly dissolved in dimethylformamide or N-methyl pyrrolidone to prepare a semitransparent solution, calcium oxide and potassium chloride are dissolved in distilled water to prepare a calcium oxide and potassium chloride mixed solution, and then the calcium oxide and potassium chloride mixed solution and the semitransparent solution prepared by dissolving polyvinylidene fluoride in dimethylformamide or N-methyl pyrrolidone are mixed to prepare the required soft rock curing agent.

The comprehensive ecological prevention and control method for the easily weathered soft rock high and steep side slope is characterized in that the soft rock side slope is excavated from top to bottom in a grading manner on the easily weathered soft rock high and steep side slope, the easily weathered soft rock high and steep side slope is treated by adopting a comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slope on the excavated side slope, and the stability of the side slope and the safety during construction can be enhanced by adopting grading treatment.

The method comprises the following steps of treating a high and steep slope of easily weathered soft rock on a certain expressway in Hunan province, wherein the slope is a soft rock slope, the slope height is 53m, the accumulated soil thickness of an upper layer is 3m, a strongly weathered layer is 10m, an intermediate weathered layer is 15m, and the lower part is a slightly weathered layer, so that a grade 5 slope is arranged, as shown in figure 1, the slope height of the grade 1-3 slope is 10m, the platform width is 3m, and the slope is 65 degrees; the height of a 4-grade side slope is 10m, the width of a platform is 4m, the gradient is 60 degrees, the height of a 5-grade side slope is 10m, the width of the platform is 4m, the gradient is 50 degrees, namely the gradient (the included angle between the slope surface and the horizontal plane) of a soft rock side slope is 45-70 degrees, the height of the slope is 10m, and the width of a breaking platform at the bottom of the soft rock side slope is 3-4 m.

The concrete steps of the treatment placement are as follows:

step S1, excavating a soft rock slope on the easily weathered soft rock high and steep slope, and finishing the slope: and brushing a slope and paying off, cleaning residual soft rock during excavation, cleaning the surface layer of the slope, backfilling a large pit on the slope surface, cleaning the bare rock surface by using a high-pressure water gun, and reinforcing the bare rock body of the slope according to the weathering degree of the easily weathered soft rock high-steep slope.

The grade 5 side slope is a highly weathered soft rock high and steep side slope, and the exposed rock mass of the side slope is reinforced as follows: the method comprises the steps of measuring and paying off, drawing an anchor positioning point diagram, fixing anchors on a slope according to a set distance, arranging the upper and lower adjacent anchors in a staggered mode, wherein the distance between the anchors arranged in the embodiment is 1m multiplied by 1m, and the diameter of a drilled hole is 15-20 mm larger than that of the anchors so as to be convenient for grouting and fixing in the later period, and the length of the anchors is 3-5 m. The anchor nail is reinforced to enable the strongly weathered soft rock to become a whole, so that dislocation and slippage of the strongly weathered soft rock are prevented, and later-stage curing treatment is not facilitated.

1-4 grade side slopes, namely the middle weathered soft rock high-steep side slope and the weak weathered soft rock high-steep side slope, are subjected to the following reinforcement treatment on exposed rock masses of the side slopes: to its rock mass breakage department, adopt stock 11 to fix, the drilling axis of stock 11 and the contained angle between the soft rock slope surface of treating are 45, and the drilling diameter is 15~20mm bigger than the diameter of stock 11 to it is fixed to carry out the slip casting in the later stage, and stock 11 length is 3~5 m.

Step S2, constructing a slope top drainage system: at soft rock side slope top excavation slope top escape canal, lay the geotechnological cloth that permeates water in slope top escape canal both sides, and permeate water geotechnological cloth is gone up by the bottom to set gradually slope top drain pipe, gravel layer 2 and the concrete 1 that permeates water, lays gravel layer 2 and prevents that the large granule impurity in the slope top escape canal from getting into the concrete 1 that permeates water and causing the concrete mesopore that permeates water to block up, lays the concrete 1 that permeates water and prevents to lay the gravel layer 2 and the small granule impurity gets into two-way drain bar 5 and blocks up its drainage tube hole 55.

Step S3, constructing the soft rock solidified layer 6: preparing distilled water, calcium oxide, potassium chloride, polyvinylidene fluoride, dimethylformamide or N-methylpyrrolidone into a soft rock curing agent according to the mass ratio of 66:10:20:1:3, spraying the soft rock curing agent to the surface of a finished soft rock slope in an in-situ spraying mode, wherein the spraying thickness is 10-20 cm, laying a plastic film, sealing for 24-72 hours, and spraying or brushing a super-hydrophobic soft rock modifier on the surface of the soft rock curing agent for reinforcement, wherein the reinforcement thickness is 5-10 mm.

Step S4, laying internal drain pipe 9: after 24-72 hours of reinforcement, an internal drain pipe 9 is inserted along the slope surface of the soft rock slope, the internal drain pipe 9 is inserted into the soft rock slope through the soft rock curing layer 6 at an included angle of 3-5 degrees with the horizontal line, and the length of the internal drain pipe is 5-6 m.

Step S5, constructing a protective net: inside drain pipe 9 lays and follows the domatic net of hanging of soft rock side slope after the end, constructs the protection network, makes the better adhesion of soft rock cured layer 6 on inside drain pipe 9 to effectively fixed inside drain pipe 9 makes soft rock cured layer 6, soft rock side slope, inside drain pipe 9 three bond and become a whole. When the hanging net is constructed, the net is unreeled from top to bottom, and two adjacent rolls of protective nets are connected and fixed by binding iron wires. The protective nets are high-zinc-plated prismatic iron wires or high-strength plastic reinforced geonets, the mesh sizes of the protective nets are 5 multiplied by 5cm, and at least 10cm of overlapping is reserved at the joint of two adjacent protective nets.

Step S6, laying the double-layer drainage plate 5: double-layer drainage plates 5 are laid along the slope surface of the soft rock slope, each shallow bidirectional drainage block is fixed on the surface of the soft rock high and steep slope through soil nails 10, the included angle between the drilling axis of each soil nail 10 and the slope surface to be treated is 90 degrees, and the length of each soil nail 10 is 2-3 m.

Step S7, constructing an ecological concrete layer 4: mixing clay, sodium alginate and CaCl₂And the plant culture solution and the completely weathered soft rock disintegrating soil of the soft rock slope are prepared into ecological concrete according to the mass ratio of 20:3:1:10:66, and the ecological concrete is uniformly sprayed on the bidirectional drainage plate 5 by using a foreign soil spraying and sowing machine twice.

Step S8, constructing a vegetation concrete layer 3: mixing three grass seeds (rye, tall fescue and bermuda grass), shrub seeds and ecological concrete, uniformly spraying the mixture on the surface of a soft rock high and steep side slope for three times, spraying the mixture from left to right and from bottom to top by using an alien soil spraying and sowing machine, covering improved soil by using non-woven fabrics after spraying and sowing, paving a surface drainage groove communicated with a slope bottom drainage groove 8 on the surface of the side slope so as to quickly drain surface rainwater in rainfall, and regularly trimming after grass grows out to promote the growth of shrubs.

Step S9, constructing a slope bottom drainage system: and arranging a gravel filtering layer 7 at the slope bottom of the soft rock side slope, excavating a slope bottom drainage ditch 8 and arranging a crushing platform.

The slope stability evaluation is carried out on the rock slope greening system by adopting a rigid body limit balance method, the safety coefficient of the easily weathered soft rock high and steep slope is 1.35, and the requirements of relevant specifications are met. After the green plants are planted for 12 months, the root systems of the dog tooth roots are distributed in the soil with certain horizontal amplitude and vertical depth, and the transverse growth and the longitudinal growth of the root systems form a root system network to a certain extent. The root weight of the bermuda grass is measured and counted by selecting the area of 50 multiplied by 50cm, the bermuda grass is cut to the rock slope surface by a cutting machine, the root system is counted layer by layer according to the depth of 5, 10, 20 and 30cm from the surface layer, a small amount (about 0.3 percent) of fibrous roots penetrate through the vegetation concrete layer 3, the ecological concrete layer 4 and the bidirectional drainage plate 5 to reach the soft rock slope surface, and the root system is mainly concentrated on the vegetation concrete layer 3. The diameters of the fibrous roots are all less than 1.0mm, the diameters of the root systems are mainly concentrated at 0.35-0.70 mm, the weight of the root systems with the depth of 0-20 cm is about 84.4%, and the weight of the root systems with the depth of 0-10 cm is about 56.8%.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. The comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slope is characterized by comprising at least one graded ecological prevention and control structure, wherein the graded ecological prevention and control structure comprises a soft rock curing layer (6) fixedly attached to the soft rock side slope, an internal drainage pipe (9) and a bidirectional drainage plate (5), the internal drainage pipe (9) is inserted into the soft rock side slope through the soft rock curing layer (6), the bidirectional drainage plate (5) is laid on the surface of the soft rock curing layer (6), and the bidirectional drainage plate (5) is communicated with the internal drainage pipe (9);

an ecological concrete layer (4) and a vegetation concrete layer (3) are sequentially paved outwards on the surface of the bidirectional drainage plate (5);

the bidirectional drainage plate (5) is formed by splicing a plurality of shallow bidirectional drainage blocks;

the shallow bidirectional drainage block comprises a drainage plate wall (52), drainage channels (51), water guide holes (54) and a drainage pipe hole (55), wherein the drainage channels (51) are arranged in parallel at intervals and longitudinally penetrate through the drainage plate wall (52) from top to bottom; the plurality of water guide holes (54) are arranged in parallel at certain intervals, transversely penetrate through the drainage plate wall (52) from left to right and are communicated with the plurality of drainage channels (51); a plurality of drainage pipe holes (55) vertically penetrate through the drainage plate wall (52) from front to back at certain intervals and are respectively communicated with the drainage channel (51); the internal drain pipe (9) is communicated with the drain pipe hole (55);

among the plurality of drainage channels (51), the drainage channel (51) close to the front end surface of the drainage plate wall (52) is communicated with the front end surface of the drainage plate wall (52), the drainage channel (51) close to the rear end surface of the drainage plate wall (52) is communicated with the rear end surface of the drainage plate wall (52), and gauze filtering layers (53) with the aperture of 1mm and the thickness of 50mm are fixed on the front end surface and the rear end surface of the drainage plate wall (52);

the shallow bidirectional drainage blocks are of a cuboid structure, two adjacent shallow bidirectional drainage blocks are connected through a bidirectional drainage plate interface with an I-shaped side surface to form a bidirectional drainage plate (5), and drainage channels (51) of all the shallow bidirectional drainage blocks are communicated in a one-to-one correspondence manner;

the drainage plate wall (52) is provided with a plurality of soil nail holes (56) which are separated by a certain distance and vertically penetrate through the drainage plate wall from front to back, and the shallow bidirectional drainage block is fixed on the soft rock slope through soil nails (10) penetrating through the soil nail holes (56);

the top parts of the bidirectional drainage plate (5), the ecological concrete layer (4) and the vegetation concrete layer (3) are provided with a slope top drainage ditch, a slope top drainage pipe, permeable concrete (1) and a gravel layer (2) are sequentially arranged in the slope top drainage ditch from top to bottom, and the slope top drainage pipe is communicated with a drainage channel (51) of the bidirectional drainage plate (5);

the bottom parts of the soft rock curing layer (6), the two-way drainage plate (5), the ecological concrete layer (4) and the vegetation concrete layer (3) are provided with gravel filter layers (7), and one ends of the gravel filter layers (7) extend into the soft rock side slopes;

one end, far away from the soft rock side slope, of the gravel filtering layer (7) is provided with a slope bottom drainage ditch (8), and the slope bottom drainage ditch (8) is provided with a crushing platform above one side, far away from the soft rock side slope.

2. The comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slope as claimed in claim 1, wherein the ecological concrete layer (4) is formed by totally weathered soft rock disintegrating soil, clay, sodium alginate, CaCl and the like of the protected soft rock side slope in a mass ratio of 66:20:3:1:10₂The ecological concrete prepared by the solution and the plant culture solution is formed by spray-seeding;

the plant-growing concrete layer (3) is formed by spraying plant-growing concrete prepared from grass seeds, shrub seeds and ecological concrete in a mass ratio of 1:1: 20-1: 1: 50;

the thickness of the ecological concrete layer (4) and the thickness of the vegetation concrete layer (3) are both 15-30 cm.

3. The comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep slope according to any one of claims 1 to 2, characterized in that the soft rock curing layer (6) is formed by spraying a super-hydrophobic mudstone modifier prepared from distilled water, calcium oxide, potassium chloride, polyvinylidene fluoride and dimethylformamide or N-methylpyrrolidone according to a mass ratio of 66:10:20:1:3, and the thickness of the super-hydrophobic mudstone modifier is 15-30 cm.

4. The comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slopes as claimed in claim 1, wherein the gravel filter layer (7) is composed of a fine gravel layer (71), a coarse gravel layer (72) and a water-resisting layer (73) which are sequentially arranged from top to bottom, the thickness of each of the fine gravel layer (71) and the water-resisting layer (73) is 10cm, and the thickness of the coarse gravel layer (72) is 30 cm.

5. The comprehensive ecological prevention and control method for the easily weathered soft rock high and steep side slope is characterized in that the soft rock side slope is excavated from top to bottom on the easily weathered soft rock high and steep side slope in a grading manner, and the easily weathered soft rock high and steep side slope is treated on the excavated soft rock side slope by adopting the comprehensive ecological prevention and control structure for the easily weathered soft rock high and steep side slope according to claim 4, and the method comprises the following specific steps:

step S2, constructing a slope top drainage system: a slope top drainage ditch is dug at the slope top of the soft rock slope, permeable geotextiles are laid on two sides of the slope top drainage ditch, and a slope top drainage pipe, a gravel layer (2) and permeable concrete (1) are sequentially arranged on the permeable geotextiles from bottom to top;

step S3, constructing a soft rock cured layer (6): preparing distilled water, calcium oxide, potassium chloride, polyvinylidene fluoride and dimethylformamide or N-methylpyrrolidone into a super-hydrophobic mudstone modifier according to the mass ratio of 66:10:20:1:3, spraying the super-hydrophobic mudstone modifier to the surface of a finished soft rock slope in an in-situ spraying manner, wherein the spraying thickness is 10-20 cm, then laying a plastic film, sealing for 24-72 hours, and spraying or brushing a soft rock curing agent for reinforcement for the second time, wherein the reinforcement thickness is 5-10 mm;

step S4, laying internal drain pipe (9): after reinforcement is carried out for 24-72 hours, fixing an internal drainage pipe (9) along the slope surface of the soft rock side slope, and inserting the internal drainage pipe (9) with the length of 5-6 m into the soft rock side slope through the soft rock curing layer (6) at an angle of 3-5 degrees with the horizontal line;

step S6, paving a bidirectional drainage plate (5): fixing each shallow layer bidirectional drainage block on the surface of the soft rock slope by using a soil nail (10), wherein the included angle between the axis of a drilling hole of the soil nail (10) and the soft rock slope surface to be treated is 90 degrees, and the length of the soil nail (10) is 2-3 m;

step S7, constructing an ecological concrete layer (4): mixing clay, sodium alginate and CaCl₂Preparing ecological concrete by using the plant culture solution and the completely weathered soft rock disintegrating soil of the soft rock slope according to the mass ratio of 20:3:1:10:66, sequentially spraying and sowing the ecological concrete on a two-way drainage plate (5) by using a foreign soil spraying and sowing machine from left to right and from bottom to top, and uniformly spraying and sowing the ecological concrete on the two-way drainage plate (5) twice, wherein the spraying and sowing thickness is 15-30 cm;

step S8, constructing a vegetation concrete layer (3): preparing grass seed seeds, shrub seeds and ecological concrete into plant-growing concrete according to the mass ratio of 1:1: 20-1: 1:50, sequentially spraying the plant-growing concrete by using a soil dressing spray-seeding machine from left to right and from bottom to top, uniformly spraying the plant-growing concrete three times onto the surface of a soft rock high and steep side slope, wherein the spraying thickness is 15-30 cm, covering improved soil by using non-woven fabrics after spraying, and paving surface drainage grooves communicated with a slope bottom drainage ditch (8) on the surface of the side slope;

step S9, constructing a slope bottom drainage system: and a gravel filtering layer (7) is arranged at the bottom of the soft rock side slope, a slope bottom drainage ditch (8) is excavated, and a crushing platform is arranged.

6. The comprehensive ecological prevention and treatment method for the easily weathered soft rock high and steep side slope according to claim 5, wherein the finishing slope in the step S1 is: brushing a slope and setting out, cleaning residual soft rock during excavation, cleaning the surface layer of the slope, backfilling larger pits of the slope surface, cleaning the bare rock surface by using a high-pressure water gun, and reinforcing the bare rock body of the slope according to the weathering degree of the easily weathered soft rock high-steep slope;

when the weathering degree of the easily weathered soft rock high and steep side slope is medium weathering and weak weathering, the exposed rock mass of the side slope is reinforced as follows: fixing a rock mass crushing part by using an anchor rod (11), wherein the included angle between the drilling axis of the anchor rod (11) and the slope surface of the soft rock slope to be treated is 45 degrees, the diameter of a drilling hole is 15-20 mm larger than that of the anchor rod (11), and the length of the anchor rod (11) is 3-5 m;