Active toughness protection method and structure for overtopping without collapse / collapse retarding of small and medium-sized earth and rockfill dams

Abstract

The invention belongs to the technical field of water conservancy projects, and particularly relates to an overtopping-free / slow-collapse active toughness protection method and structure for small and medium-sized earth and rockfill dams, and the method comprises the following steps: taking soil on site, measuring the physical and mechanical properties of the soil, determining the scouring damage characteristics of the soil according to the measured physical and mechanical indexes, and predicting the scouring damage starting position of a dam body; according to the scouring damage characteristics and the scouring damage starting position, the downstream of the earth-rock dam is divided into a key protection area and a general protection area in the elevation direction; a flexible slope fixing three-way restraint layer is laid on the upper portion of the earth and rockfill dam soil foundation; an elastic energy dissipation bidirectional restraint layer is laid on the upper portion of the flexible slope fixing three-way restraint layer; and an ecological anchoring one-way restraint layer is laid on the elastic energy dissipation two-way restraint layer. The method is easy and convenient to construct, low in cost, good in ecological benefit, low in carbon emission and high in deformation coordination capacity, and an efficient, economical, environment-friendly and tough solution strategy is provided for active scour prevention and collapse retarding of small and medium-sized earth and rockfill dams under the over-standard flood condition.

Description

Technical Field

[0001] The present invention belongs to the technical field of water conservancy engineering, and particularly relates to an active toughness protection method and structure for small and medium-sized earth-rock dams to prevent overtopping without failure / slow failure. Background Technique

[0002] In recent years, climate change and intensified human activities have led to frequent extreme hydrological events, and the threat of floods exceeding design standards to the safety of small and medium-sized earth-rock dams has become increasingly severe. Current earth-rock dam protection technologies mostly rely on rigid structures (such as reinforced concrete facing) or single ecological measures (such as vegetation slope protection), and there are significant defects: although rigid structures have strong anti-scouring performance, they are costly, have poor ecological compatibility, and are difficult to adapt to dam deformation; vegetation slope protection is ecologically friendly, but the shear strength of roots is low, and it is easy to peel off and fail under flood scouring; temporary measures (such as temporarily piling up slopes with flood control bags, temporary spillways, etc.) rely on emergency rescue experience, lack systematic design, and are difficult to cope with the coupling effect of seepage and scouring. Research shows that the breach of earth-rock dams is a chain process driven by the dual mechanisms of overtopping water flow scouring and internal seepage erosion. The traditional "passive emergency" mode belongs to the temporary rush repair when encountering floods exceeding design standards, and cannot meet the integrated protection efficiency of "anti-scouring - seepage guiding - filter - ecology" and the demand for resilience disaster prevention in the whole life cycle.

[0003] The resilience of reservoir dam projects refers to the ability of the reservoir dam system to restore its basic functions and stable operation state after being disturbed by heavy rain floods, sudden earthquakes, strong human activities, etc., or after engineering emergencies such as overtopping, leakage, landslides, and cracks occur. Improving engineering resilience in a changing environment is a sign of the high-quality development of water projects in the new era. Building an active resilience protection system for the whole life cycle of small and medium-sized earth-rock dams, developing new structures to achieve both safe, stable, and ecological operation during the normal operation period and resilience protection during extreme flood periods, and promoting the upgrade of protection technology from "passive emergency" to "active resilience" have become urgent needs in the current field of small and medium-sized earth-rock dam protection.

[0004] Therefore, it is necessary to design an active toughness protection method and structure for small and medium-sized earth-rock dams to prevent overtopping without failure / slow failure to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide an active toughness protection method and structure for small and medium-sized earth-rock dams to prevent overtopping without failure / slow failure, and by constructing a protection system with "one-way - two-way - three-way" constraint gradient functions in the "surface layer - middle layer - deep layer", to achieve the coordinated protection of "anchoring - energy dissipation - anti-sliding" within the whole life cycle of the earth-rock dam.

[0006] To achieve the above purpose, the present invention provides the following solution: An active toughness protection method for small and medium-sized earth-rock dams to prevent overtopping without failure / slow failure, including the following steps:

[0007] Take soil samples on-site and measure the physical and mechanical properties of the soil. Determine the erosion failure characteristics of the soil and predict the starting position of the dam body erosion failure based on the measured physical and mechanical indexes.

[0008] According to the erosion failure characteristics and the starting position of the erosion failure, divide the downstream of the earth-rock dam along the elevation direction into a key protection area and a general protection area.

[0009] Lay a flexible slope-fixing three-way constraint layer on the upper part of the earth-rock dam foundation. Among them, the number of geotextile bags in the flexible slope-fixing three-way constraint layer in the key protection area is greater than that in the flexible slope-fixing three-way constraint layer in the general protection area.

[0010] Lay an elastic energy-dissipating two-way constraint layer on the upper part of the flexible slope-fixing three-way constraint layer.

[0011] Lay an ecological anchoring one-way constraint layer on the upper part of the elastic energy-dissipating two-way constraint layer.

[0012] Based on the active toughness protection method for small and medium-sized earth-rock dams of the present invention that do not collapse or slowly collapse when overflowing, the steps of taking soil samples on-site and measuring the physical and mechanical properties of the soil, determining the erosion failure characteristics of the soil and predicting the starting position of the dam body erosion failure according to the measured physical and mechanical indexes include:

[0013] Take soil samples on-site and measure the physical and mechanical properties of the soil. Conduct erosion test simulation and meshless large deformation numerical simulation based on the physical and mechanical indexes of the dam-building soil materials to determine the erosion failure characteristics of the taken soil samples and predict the starting position of the dam body erosion failure.

[0014] Based on the active toughness protection method for small and medium-sized earth-rock dams of the present invention that do not collapse or slowly collapse when overflowing, the steps of dividing the downstream of the earth-rock dam along the elevation direction into a key protection area and a general protection area include:

[0015] Set the dam crest and the dam toe of the earth-rock dam as the key protection area, and set the area between the dam crest and the dam toe of the earth-rock dam as the general protection area.

[0016] Based on the active toughness protection method for small and medium-sized earth-rock dams of the present invention that do not collapse or slowly collapse when overflowing, the flexible slope-fixing three-way constraint layer is laid on the surface of the earth-rock dam foundation in the form of a geogrid wrapped outside the geotextile bags. The geogrid penetrates into the interior of the earth-rock dam foundation, and the geotextile bags are restricted from slipping through embedded flexible reinforcement. During laying, the geotextile bags are laid in a staggered stacking manner. The number of laying layers of the geotextile bags in the key protection area is greater than that in the general protection area. During the laying process of the geotextile bags, overall compaction is carried out. Geogrids are laid between the geotextile bags and the dam surface of the earth-rock dam foundation and between two adjacent layers of geotextile bags to form the flexible slope-fixing three-way constraint layer.

[0017] Active ductile protection method for medium and small-sized earth-rock dams to prevent overtopping and slow erosion, when laying the elastic energy-dissipating bi-directional constraint layer, lay a plurality of honeycomb units on the surface of the flexible slope-fixing tri-directional constraint layer, fix adjacent honeycomb units, and fill the honeycomb units with fill soil to form the elastic energy-dissipating bi-directional constraint layer.

[0018] Active ductile protection method for medium and small-sized earth-rock dams to prevent overtopping and slow erosion, the honeycomb unit includes geocell and / or waste tires.

[0019] Active ductile protection method for medium and small-sized earth-rock dams to prevent overtopping and slow erosion, when laying the ecological anchoring uni-directional constraint layer, lay a geogrid mat on the surface of the elastic energy-dissipating bi-directional constraint layer, and set turf vegetation on the surface of the geogrid mat to form the ecological anchoring uni-directional constraint layer, and connect the geogrid mat and the honeycomb unit through nylon binding straps.

[0020] Active ductile protection method for medium and small-sized earth-rock dams to prevent overtopping and slow erosion, select the grass seed variety of turf vegetation according to the plant transpiration suction intensity and the shape of plant root distribution. When sowing grass seeds on the surface of the geogrid mat, inoculate fungal organisms in the root soil body of the turf vegetation, and utilize the mutualistic symbiotic relationship between the fungal organisms and the turf vegetation roots to improve the tensile strength of the turf vegetation roots and realize and strengthen the biological anchoring and ecological anchoring capabilities.

[0021] The protection structure used in the active ductile protection method for medium and small-sized earth-rock dams to prevent overtopping and slow erosion includes a flexible slope-fixing tri-directional constraint layer for laying on the soil foundation dam surface of the earth-rock dam, an elastic energy-dissipating bi-directional constraint layer for laying on the surface of the flexible slope-fixing tri-directional constraint layer, and an ecological anchoring uni-directional constraint layer for laying on the surface of the elastic energy-dissipating bi-directional constraint layer. Among them, the number of geotextile bags of the flexible slope-fixing tri-directional constraint layer is determined according to the key protection area and the general protection area.

[0022] Among them, the surface ecological anchoring uni-directional constraint layer enhances the reinforcement-soil friction force through plant roots, improves the anti-scour ability of the dam surface and maintains the green ecological function; the middle-layer elastic energy-dissipating bi-directional constraint layer uses the elastic energy-dissipating characteristics of the porous structure to disperse the water flow impact. At the same time, the bi-directional constraint effect can enhance the soil strength, and provide a buffer space for the growth of the surface vegetation roots and avoid piercing the lower geotextile bag flexible reinforcement layer; the deep-layer elastic energy-dissipating bi-directional constraint layer restricts the deep sliding instability through the reinforced anchoring effect of the geotextile bag flexible wrapping, and at the same time plays the role of seepage guiding and filtration, and inhibits the internal soil seepage erosion damage.

[0023] The protection structure used in the active ductility protection method for medium and small-sized earth-rock dams that do not breach or slowly breach when overflowed based on the present invention further includes a number of anchor rods. The number of the anchor rods is arranged in an array along the slope direction of the earth-rock dam foundation. The anchor rods sequentially pass through the ecological anchoring unidirectional constraint layer, the elastic energy dissipation bidirectional constraint layer, and the flexible slope stabilizing tri-directional constraint layer and then are inserted into the earth-rock dam foundation.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] 1) Hierarchical multi-directional gradient protection system: A "surface layer - middle layer - deep layer" gradually deepening protection structure is proposed, combined with a "unidirectional - bidirectional - tri-directional" multi-level reinforced constraint mechanism, realizing the synergistic effect of "anchoring - energy dissipation - anti-sliding" for the first time and breaking through the limitations of traditional single protection technologies.

[0026] 2) Multi-material functional collaborative design: Integrating the ecological anchoring layer, the elastic energy dissipation layer, and the flexible slope stabilizing layer, through the material interface coupling effect, realizing the integrated protection of "scour resistance - seepage guidance - filtration - ecology".

[0027] 3) Active ductility protection mechanism: Under the condition of super-standard flood, through hierarchical energy re-distribution, the goal of "not breaching or slowly breaching when overflowed" is achieved, while meeting the requirements of dam slope stability and ecological function during the normal period.

[0028] 4) Improvement of disaster resistance ability: Significantly enhancing the scour resistance and seepage resistance of earth-rock dams, reducing the risk of dam breach under the condition of super-standard flood.

[0029] 5) Good ecological environmental protection: The surface vegetation realizes unidirectional anchoring and slope protection to maintain ecological functions, and the middle layer can be used for solid waste recycling.

[0030] 6) Economical and efficient construction: The construction material cost is lower than that of traditional rigid structures. After being hit by floods, the construction restoration only involves the surface layer or the middle layer, and the construction period for function restoration is short and the efficiency is high.

[0031] 7) Strong deformation adaptability: The deformation of earth-rock dams is generally large, and conventional rigid protection structures are prone to cracking and damage. This flexible protection structure can coordinate the deformation of the dam body and is applicable to the risk removal and reinforcement of old dam bodies and new construction projects of medium and small-sized earth-rock dams.

[0032] 8) Full life cycle protection: Taking into account the green, safe and stable state during the normal period and the ductility emergency protection during the extreme flood period. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings:

[0034] Figure 1 Schematic diagram of the decomposition of the gradient function module of the protection structure of the present invention;

[0035] Figure 2 Schematic diagram of the implementation process flow of the protection method of the present invention;

[0036] Figure 3 Schematic diagram of the overall laying of the protection structure of the present invention;

[0037] Figure 4 Schematic diagram of the laying of the flexible slope protection three-way constraint layer of the present invention;

[0038] Figure 5 Schematic diagram of the laying of the elastic energy dissipation two-way constraint layer of the present invention;

[0039] Figure 6 Schematic diagram of the laying of the ecological anchoring one-way constraint layer of the present invention;

[0040] Figure 7 Schematic diagram of the planar laying of the flexible slope protection three-way constraint layer of the present invention;

[0041] Figure 8 Schematic diagram of the planar laying of the elastic energy dissipation two-way constraint layer of the present invention;

[0042] Figure 9 Schematic diagram of the planar laying of the ecological anchoring one-way constraint layer of the present invention;

[0043] Figure 10 Schematic diagram of the mutual anchoring of each constraint layer of the present invention;

[0044] Figure 11 Schematic diagram of using waste tires as the elastic energy dissipation two-way constraint layer of the present invention;

[0045] Figure 12 Schematic diagram of the adjustable anchoring device of the present invention.

[0046] Among them, 1. Earth-rock dam soil foundation; 2. Geotextile bag; 3. Geocell; 4. Reinforced mesh mat; 5. Turf vegetation; 6. Geogrid; 7. Nylon binding belt; 8. Waste tire; 9. Larger nylon binding belt; 10. Anchor bolt; 11. Cushion block; 12. Bolt. Specific implementation manners

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0049] Referring to Figures 1 to 12 As shown, the present invention provides an active ductility protection method for medium and small-sized earth-rock dams to prevent overtopping and slow breach, including the following steps:

[0050] Take soil on-site and measure the physical and mechanical properties of the soil. Determine the erosion failure characteristics of the soil according to the measured physical and mechanical indexes and predict the starting position of the dam body erosion failure.

[0051] According to the erosion failure characteristics and the starting position of the erosion failure, divide the downstream of the earth-rock dam along the elevation direction into a key protection area and a general protection area.

[0052] Lay a flexible slope-fixing three-way constraint layer on the upper part of the earth foundation 1 of the earth-rock dam. Among them, the number of geotextile bags 2 in the flexible slope-fixing three-way constraint layer in the key protection area is greater than the number of geotextile bags 2 in the flexible slope-fixing three-way constraint layer in the general protection area.

[0053] Lay an elastic energy-dissipating two-way constraint layer on the upper part of the flexible slope-fixing three-way constraint layer.

[0054] Lay an ecological anchoring one-way constraint layer on the upper part of the elastic energy-dissipating two-way constraint layer.

[0055] Through the ecological anchoring one-way constraint layer, the elastic energy-dissipating two-way constraint layer, and the flexible slope-fixing three-way constraint layer, a step-by-step protection function with "one-way-two-way-three-way" multi-level reinforcement and strengthening effects deployed in a large depth along the "surface layer-middle layer-deep layer" is realized. Each anti-erosion layer is interconnected and complements each other to form a large-depth multi-level step-by-step protection mechanism of "anchoring-energy dissipation-slip resistance", improving the anti-erosion ability of the earth-rock dam under extreme flood conditions, and at the same time maintaining structural stability and ecological friendliness.

[0056] Further, the step of taking soil on-site and measuring the physical and mechanical properties of the soil, determining the erosion failure characteristics of the soil according to the measured physical and mechanical indexes, and predicting the starting position of the dam body erosion failure includes:

[0057] Take soil samples on-site and measure the physical and mechanical properties of the soil. Conduct scouring test simulations and meshless large deformation numerical simulations based on the physical and mechanical indices of the dam construction soil materials to determine the scouring failure characteristics of the taken soil samples and predict the starting positions of dam scouring failures.

[0058] The simulated scouring test is a similarity law model scouring test, and the meshless large deformation numerical method is the PD-SPH coupling method.

[0059] Furthermore, the steps of zoning the downstream of the rock-fill dam along the elevation direction into a key protection area and a general protection area include:

[0060] Set the crest and toe of the rock-fill dam as the key protection area, and set the area between the crest and toe of the rock-fill dam as the general protection area.

[0061] Let the scouring erosion intensity on the dam surface be E, then the empirical formula can be expressed as:

[0062]

[0063] In the formula:

[0064] E: Scouring erosion intensity on the dam surface.

[0065] k: Constant term, used to adjust the dimension and reference value of the formula.

[0066] Q: Overflow discharge, unit is m 3 / s.

[0067] v: Water flow velocity, unit is m / s.

[0068] t: Water flow duration, unit is s.

[0069] f r : Water flow regime correction factor (take a larger value for turbulent flow and a smaller value for uniform flow).

[0070] G: Particle size distribution parameter of the dam material (the larger the particles, the better the erosion resistance, and the larger the value).

[0071] C: Proportion of non-cohesive soil content (the higher the cohesive soil content, the better the erosion resistance, and the smaller the value).

[0072] S: Dam slope gradient (the steeper the slope, the larger the value).

[0073] M: Erosion resistance parameter of the protective layer material (the stronger the erosion resistance of the protective layer material, the smaller the value).

[0074] W: Pre-construction water content of the dam (the higher the water content, the lower the erosion resistance, and the larger the value).

[0075] V: Vegetation coverage (the higher the vegetation coverage, the better the erosion resistance, and the smaller the value).​

[0076] C e : Environmental condition correction factor (considering the influence of water temperature and rainfall conditions, the value is adjusted according to specific circumstances).

[0077] α, β, γ, δ: Empirical coefficients used to adjust the influence degree of each factor on the scouring erosion intensity (the values need to be obtained by fitting test data).

[0078] Calculate the scouring erosion intensity E of the dam surface by the above formula. Combine the results of the simulated scouring test and the meshless large deformation numerical method to optimize the protection structure. The downstream area of the earth-rock dam can be divided into a key protection area and a general protection area. Specifically, the dam crest and the toe area of the earth-rock dam are used as the key protection areas, and the other downstream areas are used as the general protection areas.

[0079] Take the dam crest of the earth-rock dam as the key protection area to prevent overtopping and breach; set the toe of the earth-rock dam as the key protection area to prevent scouring at the dam site caused by overtopping overflow and resulting in dam break failure; set the area between the dam crest and the dam site as the general protection area to prevent deep gullies from being generated on the downstream surface of the dam body due to overtopping overflow.

[0080] Furthermore, the flexible slope-fixing three-way constraint layer is laid on the surface of the earth-rock dam subgrade 1 in the form of geogrid 6 wrapped around geotextile bag 2 on the outside. The geogrid 6 penetrates into the interior of the earth-rock dam subgrade 1. The geotextile bag 2 is restricted from slipping by the embedded flexible reinforcement. During laying, the geotextile bags 2 are laid in a staggered stacking manner. The laying layer number of the geotextile bags 2 in the key protection area is greater than that in the general protection area. The geotextile bags 2 are integrally rolled during the laying process. Geogrid 6 is laid between the geotextile bags 2 and the dam surface of the earth-rock dam subgrade 1 and between adjacent two layers of geotextile bags 2 to form a flexible slope-fixing three-way constraint layer.

[0081] The geotextile bags 2 are laid in a staggered stacking manner. The laying thickness of the geotextile bags 2 is adjusted according to the protection position. The laying thickness is larger in the key protection areas of the dam crest and the toe. And the thickness at the toe gradually increases with the decrease of elevation. The other parts can be laid in a single layer. The joints of each laying area are laid with transitional connection; after the geotextile bags 2 are laid, a small hand-pushed vibrating rolling device is used for layer-by-layer integral rolling; finally, the geogrid 6 is used to reinforce the earth-rock dam filling body on the inner side and wrap the outermost geotextile bag 2 on the outside. The meshed structure of the geogrid 6 and the interlocking effect with the rockfill are used to further restrict the slipping of the outermost geotextile bag 2, and then anchor the geotextile bag 2; the geogrid 6 on the pressure-bearing side is horizontally laid, and the geogrid 6 on the upper wrapping side is "Z"-shaped wrapped to effectively restrict the lateral movement of the geotextile bag 2 and reduce the dam body deformation; the laying method of the geogrid 6 is simple and fast, and has the advantages of high tensile strength and low cost; at the same time, part of the geogrid 6 reinforces the earth-rock dam filling body inward, and its meshed structure has a strong interlocking effect with the rockfill, providing overall seismic reinforcement ability.

[0082] Furthermore, when laying the elastic energy-dissipating bi-directional constraint layer, a plurality of honeycomb units are laid on the surface of the flexible slope-fixing tri-directional constraint layer, and adjacent honeycomb units are fixed. Fill soil is filled into the honeycomb units to form the elastic energy-dissipating bi-directional constraint layer.

[0083] The elastic energy-dissipating bi-directional constraint layer provides a buffer zone for the ecological anchoring uni-directional constraint layer and the flexible slope-fixing tri-directional constraint layer on the surface. The buffer zone is used for plant growth and root development, and avoids plant roots from penetrating deeply and piercing the geotextile bags of the deep flexible slope-fixing tri-directional constraint layer.

[0084] Furthermore, the honeycomb unit includes a geocell 3 and / or a waste tire 8.

[0085] The geocell 3 is filled with fill soil, and the fill soil is a mixture of soil and rock. The interlocking effect between the geocell 3 and the soil and rock materials strengthens the overall stability of the dam body, and effectively restricts the lateral cumulative slip of the rockfill body on the dam crest. The planar bi-directional constraint of the geocell 3 provides a strong lateral confinement effect on the internal soil body, increases the friction force between the geocell 3 and the soil body, effectively restricts soil deformation, further improves the stability of the dam slope, reduces soil erosion, and improves the stability of the slope. The holes on the wall of the geocell 3 are beneficial to the development of vegetation roots, contribute to protecting the slope stability, and at the same time conform to the environmental protection concept. It can also be realized by using the modified waste tire 8, that is, cutting off the upper and lower edges of the waste tire 8, retaining the tire surface and punching holes on the surface, and connecting the tires with a large-sized nylon binding band 9 to form a bi-directional constraint layer. Using the waste tire 8 instead of the geocell 3 can realize the reuse of waste, conform to the concept of sustainable development, and at the same time make full use of the self-strength of the waste tire 8 to improve the material utilization rate and the structural economic benefit. By reserving small holes on the lower side of the geocell 3 or the modified waste tire 8, the nylon binding band 7 is passed through the small holes and the geogrid 6, and the geocell 3 and the geogrid 6 are connected in an interlaced binding connection manner to anchor the geocell 3. The pores at the connection part are filled with dam building soil materials.

[0086] Furthermore, when laying the ecological anchoring uni-directional constraint layer, a geogrid mat 4 is laid on the surface of the elastic energy-dissipating bi-directional constraint layer, and turf vegetation 5 is arranged on the surface of the geogrid mat 4 to form the ecological anchoring uni-directional constraint layer. The geogrid mat 4 is connected to the honeycomb unit by a nylon binding band 7.

[0087] Furthermore, according to the transpiration suction intensity of the plant and the distribution shape of the plant roots, the grass seed variety of the turf vegetation 5 is selected. When sowing grass seeds on the surface of the geogrid mat 4, fungal organisms are inoculated into the root soil body of the turf vegetation 5. By using the mutualistic symbiotic relationship between the fungal organisms and the roots of the turf vegetation 5, the tensile strength of the roots of the turf vegetation 5 is improved, and the biological anchoring and ecological anchoring capabilities are realized and strengthened.

[0088] The ecological anchoring unidirectional constraint layer effectively improves the stability and safety of the structure. The geogrid mat 4 is easy to construct without special construction equipment, and the formed flexible structure has extremely high adaptability to the foundation deformation, reducing the influence of the foundation deformation caused by loading on the reinforced structure itself; the geocell 3 and the geogrid mat 4 have excellent stress diffusion effects and seismic resistance performance, can adapt to the deformation caused by poor geological conditions, and reduce the influence of environmental erosion; at the same time, the geogrid mat 4 is provided with a dense rib grid to prevent rodents from digging holes, damaging the structural integrity and generating potential piping channels. After the geogrid mat 4 is laid, grass seeds are sown and covered with soil, and after cultivation, biological anchoring of the soil on the dam surface can be realized, improving the anti-deformation and anti-scouring capabilities of the surface turf; at the same time, the grass layer can beautify the environment and further enhance the ecological friendliness.

[0089] Select herbaceous varieties with a large soil suction generated by the transpiration of vegetation to give full play to the advantages of the biological anchoring technology. Specifically, for the slope protection and erosion prevention structure, it involves selecting vegetation grass species that can generate a large soil suction through transpiration. When considering the transpiration of grass vegetation for slope protection and soil fixation, the grass vegetation can effectively increase the suction not only within the root depth range but also below the root depth range. This increased suction helps to enhance the shear strength of the soil and at the same time reduce the permeability coefficient, thereby improving the erosion prevention ability downstream of the earth-rock dam. The selection of specific grass species needs to be considered in combination with local conditions and relevant test experiments.

[0090] When laying the soil layer of the grass surface, the compaction degree of the actual soil should be adapted to the selection of grass vegetation and the slope protection requirements. For example, when the grass species is selected as Bermuda grass vegetation, the compaction degree of the soil needs to be controlled at 95% to ensure the growth of Bermuda grass and achieve the purpose of slope protection and soil fixation.

[0091] When sowing grass seeds, fungal organisms can be inoculated in the soil at the root of the grass surface vegetation. Utilizing the mutualistic symbiotic relationship between microorganisms and vegetation roots, the tensile strength of the grass roots can be further increased, realizing and strengthening the biological anchoring and ecological anchoring capabilities. The fungal species need to be adapted to the selection of grass vegetation. For example, when the grass species is selected as vetiver grass vegetation, arbuscular fungal organisms can be selected for inoculation at the root of the grass surface vegetation. At the same time, about 1% of biochar can be incorporated into the soil layer of the grass vegetation to promote the growth of vegetation roots and shorten the formation time of the vegetation protection layer.

[0092] When selecting herbaceous varieties, it is also necessary to consider the root shape and select herbaceous varieties with triangular and exponential distributions for mixed cultivation. Among them, when the root shape shows an exponential distribution, the root density is small along the depth direction, and the roots are mainly dispersed on the surface layer. When the grass roots develop, they are mainly in the upper layer of the geocell 3 and wound around the reinforced mesh mat 4 layer, which can give full play to the characteristics of the exponential root distribution, form a dense root network on the surface of the dam body protection layer, and provide a strong and dense reinforcement and anchoring effect on the surface soil layer in combination with the grid distribution characteristics of the reinforced mesh mat 4, and prevent the herbaceous roots from penetrating too deep and piercing the geotextile bag 2; while the triangular root distribution has a stronger anchoring effect on the middle soil layer than the exponential root distribution. When the roots of this type of grass develop, they can penetrate the small holes on the wall of the geocell 3, and use the root connection to strengthen the connection between the geocell 3 and the grass cortex. Combining the two types of herbaceous varieties can further strengthen the biological anchoring effect of the soil on the surface of the earth-rock dam and improve the anti-deformation and anti-scouring abilities of the surface turf.

[0093] For ecological vegetation selection, it is advisable to choose turf coverage to avoid shrubs, trees, etc. providing a suitable environment for burrowing animals to dig holes.

[0094] The protection structure used in the active ductile protection method for small and medium-sized earth-rock dams to overflow without collapsing / slowly collapsing includes a flexible slope-fixing three-way constraint layer for laying on the dam surface of the earth-rock dam foundation 1, an elastic energy-dissipating two-way constraint layer for laying on the surface of the flexible slope-fixing three-way constraint layer, and an ecological anchoring one-way constraint layer for laying on the surface of the elastic energy-dissipating two-way constraint layer. Among them, the number of geotextile bag 2 layers of the flexible slope-fixing three-way constraint layer is determined according to the key protection area and the general protection area.

[0095] Furthermore, it also includes a number of anchor bolts 10, which are arranged in an array along the slope direction of the earth-rock dam foundation 1. The anchor bolts 10 sequentially pass through the ecological anchoring one-way constraint layer, the elastic energy-dissipating two-way constraint layer, and the flexible slope-fixing three-way constraint layer and then insert into the earth-rock dam foundation 1.

[0096] The entire protection layer is anchored through the reaction force system, and the position of the bolt 12 can be adjusted according to needs, thereby adjusting the anchoring strength.

[0097] The present invention improves the anti-scouring ability of the overall earth-rock dam under extreme flood conditions by arranging a protection structure in the dangerous dam section of the earth-rock dam prone to overtopping and breaching. The discrimination method for the more dangerous dam section of the earth-rock dam can be judged through numerical simulation calculation, empirical formula calculation and analysis, including but not limited to dam body stability analysis, seepage stability analysis, dam body deformation analysis, flood simulation and risk assessment analysis, historical dam breach case analysis, on-site investigation and geological exploration analysis, remote sensing analysis, expert decision-making analysis and other methods.

[0098] The present invention provides a protection structure arranged at the dangerous dam sections of earth-rock dams prone to overtopping and dam break. This anti-scour structure can be applied to the risk removal and reinforcement of existing earth-rock dams, as well as the proactive and resilient protection of under-construction or to-be-built earth-rock dams, achieving the long-term "dual control" goal of the safety of earth-rock dams throughout their life cycle, namely: the reinforcement goal of "stable dam slope and green ecological dam surface" during the normal operation period; the protection goal of "not breaching or slowly breaching when overtopped" during the period of flood exceeding the design standard, with a wide range of applicable scenarios. This method breaks through the traditional protection concept of small and medium-sized earth-rock dams, promoting the upgrade of protection technology from "passive emergency" to "active resilience", and having significant economic, social and environmental benefits.

[0099] The present invention overcomes the defects of the prior art, such as high requirements for materials and construction auxiliary facilities, high technical requirements for construction personnel, insufficient response to extreme climate events, insufficient design and evaluation technical standards, and unreasonable dam surface drainage design. Based on the principle of layered multi-directional reinforcement, by using flexible materials such as natural plant fibers and geosynthetics, it provides an earth-rock dam downstream anti-scour structure and construction method with strong anti-scour ability, stable structure, safety and reliability, and ecological friendliness. It is particularly suitable for using as a protection structure at the parts of earth-rock dams that are prone to overtopping or forming breach, ensuring the stability and safety of small and medium-sized earth-rock dams under extreme conditions; at the same time, due to the use of geosynthetics, the use of materials such as concrete in earth-rock dams is reduced, reducing the engineering quantity and engineering carbon emissions; and the method described in this patent mostly uses local materials, with low material cost, simple and convenient construction, and high engineering economic benefits.

[0100] Example 1:

[0101] Mainly aimed at newly built small and medium-sized earth-rock dams:

[0102] Research on soil and rock properties: Take samples of the earth-rock dam filling soil and rock materials on-site, and determine the physical properties of the filling soil and rock materials according to relevant geotechnical test specifications, including but not limited to the cohesion, internal friction angle, liquid-plastic limit, particle size distribution, soil-water characteristic curve, etc. of the soil.

[0103] Then, based on the physical and mechanical properties of the soil, conduct physical model tests and numerical simulations to predict the downstream failure initiation location, scouring damage situation, and vulnerable parts of the earth-rock dam.

[0104] Dam surface zoning and material preparation: According to the results of physical model tests or numerical simulations, the downstream dam surface of the earth-rock dam is divided into three areas along the elevation direction: the dam crest, the general downstream protection area, and the key downstream protection area. The dam crest area is the key protection area to prevent overtopping and breach; the toe of the dam is the key protection area to prevent scouring at the dam site due to overtopping overflow, causing dam failure; a general protection area is set between the dam crest and the toe of the dam to prevent deep gullies from being generated on the downstream surface of the dam body due to overtopping overflow. Optimize the cross-section of the protection structure according to the test or simulation results. Lay multiple layers of geotextile bags in the key protection areas, where the thickness of the geotextile bags laid at the toe of the dam gradually increases as the elevation decreases. Use a single layer of geotextile bags for paving in the general protection areas. The joints of each paving area are laid with transitional connections.

[0105] Prepare the corresponding paving materials according to the results of structural optimization, including grass seeds, reinforced geogrid mat 4, geocell 3, geogrid 6, and geotextile bag 2. Among them, the reinforced geogrid mat 4 uses a geosynthetic material mat with dense meshes.

[0106] Laying of geotextile bag 2: According to the elevation direction of the downstream dam surface of the earth-rock dam, the dam surface is divided into the dam crest, the general downstream protection area, and the key downstream protection area. The dam crest and the toe of the dam are the key protection areas, and the connecting area between the dam crest and the toe of the dam is the general protection area. In the key protection areas, lay multiple layers of geotextile bag 2, and the thickness of the geotextile bag 2 laid at the toe of the dam gradually increases as the elevation decreases; the remaining areas are laid with a single layer; the joints of each paving area are laid with transitional connections to ensure the integrity and stability of the structure.

[0107] The stacking method of the geotextile bag 2 is interlayer staggered stacking. The upper geotextile bag 2 is stacked in the center of the gap of the lower geotextile bag 2 to ensure the stability of the structure.

[0108] After the laying is completed, use a small vibrating roller to carry out layer-by-layer overall compaction. The number of compaction passes and the compaction speed are determined through on-site tests to ensure the quality of layer-by-layer compaction.

[0109] Laying of geogrid 6: When laying on the downstream slope of the earth-rock dam, lay the geogrid 6 in the way of wrapping the geotextile bag 2, that is, lay the geogrid 6 between the layers of the geotextile bag 2. At the same time, the geogrid 6 needs to wrap the geotextile bag 2. The lower-layer geogrid 6 is laid flat relative to the wrapped geotextile bag 2, and the upper layer is laid in an inverted "Z" shape to limit the lateral movement of the geotextile bag 2 and reduce the deformation of the dam body. The geogrid 6 uses a combined welded forming grid. When the laying width of the geogrid 6 exceeds the width of the roll, use the method of manual bundling to lap the geogrid 6, and it is required that the strength after lapping is not less than 80% of the original strength.

[0110] When laying on the dam crest, it is laid in a way that the geotextile bags 2 on the dam crest are stacked staggeredly, and the geogrid 6 is wrapped around the geotextile bags 2, that is, the geogrid 6 is vertically wrapped around the geotextile bags 2, and both ends penetrate into the earth-rock foundation to limit the lateral movement of the geotextile bags 2 and reduce the deformation of the dam body.

[0111] Laying of geocell 3: The geocell 3 is made of high-density polyethylene material and has good durability and anti-aging performance. Its bottom is connected to the geogrid 6 to form an integrated restraint structure. During the construction process, the geocell 3 is laid on the surface of the geotextile bag 2 layer. The small holes around it are designed to facilitate the growth of vegetation roots. When the plant roots penetrate through the small holes in the geocell 3, the anchoring strength of the soil in the geocell 3 can be strengthened and biological anchoring can be achieved. The pores between the geocell 3 and the geotextile bag 2 are filled with soil to further enhance the compactness and anti-scouring ability of the dam body. In addition, a binding and anchoring structure is used to connect the geocell 3 and the geogrid 6, specifically fixed by binding straps made of nylon material to ensure the synergistic effect between layers.

[0112] Filling soil and sowing grass seeds in the geocell 3: Soil is filled and grass seeds are sown in the geocell 3 to achieve biological anchoring of the soil on the dam surface and improve the anti-deformation and anti-scouring ability of the surface turf. The selection of grass seeds needs to be determined according to the soil suction strength generated by the transpiration of vegetation and the shape of the plant root distribution, and relevant measurements can be obtained through experiments.

[0113] Laying of geogrid mat 4 and grass seed maintenance: The geogrid mat 4 is laid on top of the geocell 3. The geogrid mat 4 is a geosynthetic material and grass seeds are planted on it to achieve biological anchoring of the soil on the dam surface. The geocell 3 and the geogrid mat 4 are connected by binding straps to enhance the stability and safety of the structure. The geogrid mat 4 is provided with a dense grid of ribs to prevent rodents from digging holes and damaging the structural integrity and generating potential piping channels.

[0114] Filling soil and sprinkling water for maintenance on the surface layer of the geogrid mat 4 to promote the growth of grass seeds and the stability of the soil. The thickness of the filled soil needs to be adapted to the selected grass turf vegetation. For example, when the grass seeds are selected as Bermuda grass vegetation, the compaction degree of the soil needs to be controlled at 95% to ensure the growth of Bermuda grass and achieve the purpose of slope protection and soil fixation.

[0115] Special treatment: Part of the geogrid 6 is inserted into the earth-rock dam. Its mesh structure has a strong interlocking effect with the dam-building soil and stone materials, and uses flexible reinforcement and embedding to limit the deep soil slip and provide overall anti-scouring and reinforcement ability. When the geogrid 6 wraps around the geotextile bags 2, different wrapping forms are adopted according to the different positions of the geotextile bags 2. For the single-layer paving part of the geotextile bags 2, a simple "J" type wrapping form is adopted, and for the multi-layer paving part of the geotextile bags 2 at the dam toe, a "Z" type horizontal paving plus an "L" type wrapping is adopted. The geogrid mat 4 is laid on top of the geocell 4, and a binding and anchoring structure is used between the geocell 3 and the geogrid mat 4.

[0116] Add adjustable anchoring device: To achieve adjustable overall anchoring strength of the protection structure, reaction force anchor rods 10 are driven into the earth-rock dam surface and penetrate deep into the dam body. The anchor rods 10 pass through the gaps of geotextile bags 2, the mesh holes of geogrid 6, geocell 3 and reinforced mesh mat 4 and then expose on the surface. The exposed section of the anchor rod 10 has threads and scales on its surface, and a cushion block 11 and a bolt 12 are sleeved on it. The entire protection layer is anchored through the reaction force system. The reaction force anchoring device can adjust the position of the bolt 12 as needed, and thus adjust the anchoring strength.

[0117] Vegetation selection and inoculation: Select plant varieties with relatively large soil suction generated by transpiration, and choose a vegetation layer with a mixed cultivation of triangular distribution and heart-shaped distribution of root systems to strengthen the biological anchoring effect of the upper and middle soils in the protection structure. At the same time, in terms of vegetation selection, it is advisable to choose turf coverage and avoid shrubs, trees, etc., so as to avoid providing a suitable environment for burrowing animals to dig holes.

[0118] Inoculate fungal organisms, such as arbuscular fungi, at the roots of the vegetation in the turf layer to improve the tensile strength of the roots and achieve biological anchoring and ecological anchoring. At the same time, about 1% of biochar can be incorporated into the soil of the turf vegetation layer to promote the growth of vegetation roots and shorten the forming time of the vegetation protection layer.

[0119] Example 2:

[0120] Mainly aimed at earth-rock dam projects that have been in operation for many years and need danger removal and reinforcement:

[0121] Preliminary preparation

[0122] Comprehensive investigation: Conduct a comprehensive investigation on the earth-rock dam, including the dam body leakage situation, dam slope stability, soil physical properties, etc. Through means such as geological exploration, geophysical exploration, and drilling, obtain information on the internal structure and material properties of the original dam body, and provide a basis for the subsequent design of the reinforcement plan.

[0123] Determine key protection areas: According to the investigation results, determine key protection areas such as the dam crest, dam slope, and dam toe. These areas are often the parts with larger dam body deformation, higher leakage risk, or more serious scouring, and need to be key reinforced and protected.

[0124] Optimize the laying plan of the protection structure: Combine the actual situation of the dam body and the investigation data to optimize the laying plan of the protection structure. For example, for areas with serious leakage, the thickness of the anti-seepage layer can be increased or more efficient anti-seepage materials can be used; for dam slopes with poor stability, the structural form, reinforcement range, and material configuration of the reinforcement layer can be adjusted.

[0125] Prepare protective materials: According to the optimized laying plan, prepare corresponding protective materials, including turf, geogrid mats, geocells or waste tires, geotextile bags, geogrids, nylon tie straps, etc. These materials need to meet the corresponding quality standards and performance requirements to ensure the quality and durability of the reinforcement project.

[0126] Construction steps

[0127] Strip the surface soft layer: Use equipment such as small excavators to remove the soft layer on the downstream surface of the earth-rock dam, such as surface vegetation, humus soil, and silt soil layer at the toe of the dam; in particular, when there are cavities under the original slope protection or leakage in the dam body and foundation, it is necessary to strip the surface soil layer to a depth that meets the requirements for subsequent hazard removal and reinforcement.

[0128] Construction of the flexible slope-fixing three-way constraint layer: Lay geotextile bags 2 made of PET polyester material at the bottom of the dam slope, fill them with gravel-soil composite fillers, and control the filling rate at 70% - 80%; the geotextile bags 2 are laid in a staggered stacking manner, with a larger laying thickness at the dam top and toe, and the thickness at the toe gradually thickens as the elevation decreases, and the rest can be laid in a single layer. After laying, use vibration compaction equipment to compact layer by layer to ensure that the geotextile bags 2 are tightly combined with the dam body. Finally, wrap the geotextile bags 2 with geogrids 6, and reinforce the earth-rock dam filling body inside the geogrids 6, and use the interlocking effect of the dam-building soil and stone materials for anchoring to enhance the anti-sliding ability of the deep soil layer.

[0129] Construction of the elastic energy-dissipating two-way constraint layer: Lay the elastic energy-dissipating two-way constraint layer above the flexible slope-fixing three-way constraint layer, and you can choose a geocell 3 or a reinforced soil structure of modified waste tires 8.

[0130] If a geocell 3 is used, lay it above the geotextile bags 2, and fill the geocell 3 with a mixture of soil and stone to form a two-way constraint structure.

[0131] If waste tires 8 are used, cut off the two side edges of the waste tires 8 to form a circular ring component, and connect the tire rings through nylon tie straps 7 to form a two-way constraint layer.

[0132] The geocell 3 or waste tires 8 are anchored and connected to the geogrids 6 through nylon tie straps 7 to ensure the synergy between layers.

[0133] Construction of the ecological anchoring one-way constraint layer: Lay the ecological anchoring one-way constraint layer above the elastic energy-dissipating two-way constraint layer, and use a turf geogrid mat 4, and the geogrid mat 4 is connected to the middle layer structure through nylon tie straps 7.

[0134] Sow grass seeds on the turf reinforcement mesh mat 4, and select grass seeds with well-developed roots and relatively large transpiration suction. The turf coverage rate reaches over 95%. Incorporate 1% biochar into the soil layer of the turf to promote the growth of vegetation roots and shorten the forming time of the protection layer. Maintain the surface grass vegetation, including irrigation, pruning, and pest control, to ensure the healthy growth of the turf vegetation.

[0135] Installation of the anchoring device: To enhance the overall stability of the protection structure, reaction force anchor rods can be driven into the surface of the dam slope. The anchor rod 10 passes through the gaps of the geotextile bags 2, the mesh holes of the geogrid 6, the geocell 3, and the reinforcement mesh mat 4 and then exposes on the surface. The surface of the exposed section of the anchor rod has threads and scales, and a spacer 11 and a bolt 12 are sleeved on it. The spacer 11 is applied on the reinforcement mesh mat 4, and the entire protection layer is anchored through the reaction force system. The position of the bolt 12 can be adjusted as needed, and thus the anchoring strength can be adjusted.

[0136] Example 3:

[0137] Mainly aiming at the preferred replacement of using waste tires 8 in the middle layer, and it is applicable to new construction or danger removal and reinforcement projects at the same time:

[0138] The bi-directional restraint layer can use waste tires 8 to replace the geocell 3. By using tire rings after cutting the two side edges of the waste tires 8, and connecting each tire ring with a large-sized nylon binding strap 9, the geocell 3 can be equivalently replaced. Drill holes at the upper and lower edges of the tire rings, and connect each tire ring with the geogrid 6 and the reinforcement mesh mat 4 as a whole with nylon binding straps. In this way, the project protection cost can be further reduced, and at the same time, waste recycling can be realized.

[0139] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0140] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope of the present invention.

Claims

1. An active toughness protection method for small and medium-sized earth-rock dams that does not collapse or slowly collapses, characterized in that: The following steps are involved: Take soil on site and measure its physical and mechanical properties, determine the soil scouring and damage characteristics based on the measured physical and mechanical indicators, and predict the starting position of dam scouring and damage; According to the scour damage characteristics and the scour damage initiation position, the downstream of the earth-rock dam is divided into a key protection area and a general protection area along the elevation direction; A flexible slope-fixing three-dimensional constraint layer is laid on the upper part of the earth-rock dam foundation (1), wherein the number of geobags (2) of the flexible slope-fixing three-dimensional constraint layer in the key protection area is greater than the number of geobags (2) of the flexible slope-fixing three-dimensional constraint layer in the general protection area; An elastic energy dissipation bidirectional constraint layer is laid on the upper part of the flexible slope consolidation three-directional constraint layer; An ecological anchoring unidirectional constraint layer is laid on the elastic energy dissipation bidirectional constraint layer.

2. The active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 1 is characterized in that: The steps of taking soil on site and measuring the physical and mechanical properties of the soil, determining the scouring and damage characteristics of the soil according to the measured physical and mechanical indicators, and predicting the starting position of the scouring and damage of the dam body include: Soil is collected on site and its physical and mechanical properties are measured. Scour test simulation and gridless large deformation numerical simulation are carried out based on the physical and mechanical indicators of the dam-building soil materials to determine the scour damage characteristics of the soil samples and predict the starting position of scour damage to the dam body.

3. The active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 1 is characterized in that: The step of dividing the downstream of the earth-rock dam into a key protection area and a general protection area along the elevation direction includes: The crest and toe of the earth-rock dam are set as key protection areas, and the area from the crest to the toe of the earth-rock dam is set as a general protection area.

4. The active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 1 is characterized in that: The flexible slope-fixing three-dimensional constraint layer is laid on the surface of the earth-rock dam foundation (1) in the form of a geobag (2) wrapped around the outside of a geogrid (6); the geogrid (6) penetrates deep into the earth-rock dam foundation (1) and restricts the sliding of the geobag (2) by embedding the flexible reinforcement; during laying, the geobag (2) is laid in a staggered stacking manner; the number of layers of the geobag (2) in the key protection area is greater than the number of layers in the general protection area; the geobag (2) is rolled as a whole during laying; and the geogrid (6) is laid between the geobag (2) and the dam surface of the earth-rock dam foundation (1) and between two adjacent layers of geobags (2) to form the flexible slope-fixing three-dimensional constraint layer.

5. The active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 1 is characterized in that: When the elastic energy dissipation bidirectional constraint layer is laid, a plurality of honeycomb units are laid on the surface of the flexible slope-fixing three-way constraint layer, and adjacent honeycomb units are fixed, and soil is filled into the honeycomb units to form the elastic energy dissipation bidirectional constraint layer.

6. The active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 5 is characterized in that: The honeycomb unit comprises a geocell (3) and / or a waste tire (8).

7. The active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 4 is characterized in that: When the ecological anchoring unidirectional constraint layer is laid, a reinforced mesh pad (4) is laid on the surface of the elastic energy dissipation bidirectional constraint layer, and turf vegetation (5) is arranged on the surface of the reinforced mesh pad (4) to form the ecological anchoring unidirectional constraint layer, and the reinforced mesh pad (4) is connected to the honeycomb unit by a nylon binding belt (7).

8. The active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 7 is characterized in that: The grass seed variety of the turf vegetation (5) is selected according to the plant transpiration suction strength and the plant root distribution shape. When the grass seeds are sown on the surface of the reinforced mesh mat (4), fungal organisms are inoculated in the root soil of the turf vegetation (5). The mutually beneficial symbiotic relationship between the fungal organisms and the turf vegetation (5) root system is utilized to improve the tensile strength of the turf vegetation (5) root system, thereby achieving and strengthening the biological anchoring and ecological anchoring capabilities.

9. A protective structure used in the active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to any one of claims 1 to 8, characterized in that: The invention comprises a flexible slope-fixing three-dimensional constraint layer for laying on the dam surface of the earth-rock dam foundation (1), an elastic energy-absorbing two-way constraint layer for laying on the surface of the flexible slope-fixing three-dimensional constraint layer, and an ecological anchoring unidirectional constraint layer for laying on the surface of the elastic energy-absorbing two-way constraint layer, wherein the number of geotextile bags (2) of the flexible slope-fixing three-dimensional constraint layer is determined according to the key protection area and the general protection area.

10. The protective structure obtained by the active toughness protection method for preventing collapse / slow collapse of small and medium-sized earth-rock dams according to claim 9 is characterized in that: It also includes a plurality of anchor rods (10), wherein the plurality of anchor rods (10) are arranged in an array along the slope direction of the earth-rock dam foundation (1), and the anchor rods (10) sequentially pass through the ecological anchoring unidirectional constraint layer, the elastic energy dissipation bidirectional constraint layer, and the flexible slope fixing three-directional constraint layer, and then are inserted into the earth-rock dam foundation (1).

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