A step-mesh coordinated ecological stabilization system for high and steep loose material source slope surface of debris flow gully

Abstract

The invention discloses a kind of step network coordination ecological stabilization system of high steep loose material source slope surface of debris flow gully, including slope foot stone cage, lower step slope stabilization area and upper hanging net soil fixation area.Stone cage is used to slow down slope foot erosion and support upper step material of slope;Step slope stabilization area is composed of horizontal step and step dry block stone check dam, for shortening slope length, dispersing runoff, blocking loose material migration and providing planting platform;Hanging net soil fixation area includes flexible three-dimensional support layer composed of multiple layers of natural fiber rope net, corrosion-resistant steel wire mesh and anchor rod, for grading constraint weathered layer such as fine particles, gravel and block stone.Natural fiber rope bears particle net fixation, matrix support, soil conservation and soil moisture conservation in early stage of treatment, and is converted into soil organic matter after decomposition, and forms phased protection with steel wire mesh and plant root system, so as to reduce loose material into channel and be started again by debris flow.

Description

Technical Field

[0001] This invention relates to the field of debris flow slope management and stabilization technology, and more specifically to a step-network collaborative ecological stabilization system for steep, loose debris flow source slopes in debris flow gullies. Background Technology

[0002] The formation and development of debris flows are not only controlled by rainfall intensity, confluence conditions, and channel gradient, but also significantly influenced by the quantity and replenishment rate of loose solid material sources within the watershed. On the one hand, in areas traversed by fault zones, bedrock is easily subjected to tectonic compression, shearing, unloading, and long-term weathering, resulting in fractured rock masses with well-developed joints and fissures and poor integrity. These fractured rock masses continuously detach and collapse under the influence of rainfall, freeze-thaw cycles, wet-dry cycles, and gravity, forming a large amount of loose debris on the slope surface and toe. On the other hand, in debris flow gullies with a long history of development, thick layers of ancient debris flow deposits or glacial deposits are often distributed on both sides of the gully. In particular, ancient debris flow deposits or glacial deposits remaining on high terraces or high-lying gully banks typically exhibit characteristics such as wide particle size distribution, loose structure, low degree of cementation, and well-developed localized pores. Under the influence of slope runoff erosion, gully downcutting, slope toe scouring, groundwater seepage, and gravity, such deposits are prone to continuous surface erosion, localized collapse, and slope toe instability. As the gully continues to downcut and the conditions of the bank slope becoming more exposed increase, the material of the high-level loose deposits continuously migrates to the lower slope and accumulates in large quantities on the steep slopes and toes on both sides of the gully.

[0003] Under heavy rainfall conditions, increased surface runoff and higher slope moisture content allow loose material to continuously enter the gully through scouring, sliding, collapse, and rolling. This material can then be reactivated and entrained by floods or subsequent debris flows, thus constituting a long-term and continuous source of debris flow replenishment. Therefore, simply installing barriers and drainage systems within the debris flow gully bed is insufficient to control the continuous replenishment of loose material from the steep slopes on both sides of the gully at its source.

[0004] The management of loose material sources on steep slopes in debris flow gullies is highly complex. These slopes not only suffer from inherent instability but are also continuously coupled with gully downcutting, toe erosion, and debris flow recharge processes. They are characterized by continuous recharge, complex particle size distribution, diverse failure modes, strong dynamic disturbances at the toe, and the potential for disaster effects to propagate downstream along the gully. Therefore, management requires not only controlling surface erosion and localized landslides but also blocking the migration path of loose material from the upper slope to the toe and gully, and reducing the likelihood of it being reactivated or entrained by floods or debris flows.

[0005] Furthermore, the steep, loose material source slopes of debris flow gullies exhibit significant slope position differences from the toe to the crest, with varying controlling destructive mechanisms and remediation requirements at different slope positions. The lower part of the slope, adjacent to the debris flow gully bed, is directly affected by gully downcutting, lateral debris flow scouring, toe erosion, and free face expansion. It also receives loose material rolling down, sliding, or collapsing from the upper slope. Remediation there focuses on mitigating toe erosion, limiting free face development, shortening continuous slope length, dispersing surface runoff, and tiered reception of descending material. The upper part of the slope, far from the gully bed and directly affected by scouring, is subject to long-term weathering, surface runoff erosion, fine particle loss, loosened boulders, and difficulties in the stable attachment of vegetation. Continuous excavation of horizontal steps could easily damage the existing loose deposits or fractured rock structure, increasing construction disturbance and the risk of local instability. Therefore, steep, loose material source slopes should be treated in zones according to differences in slope position, with the lower measures focusing on graded slope stabilization and material fall support, and the upper measures focusing on low-disturbance netting and vegetation restoration.

[0006] Existing slope management technologies often employ relatively independent measures such as toe protection, slope gradation, single-layer mesh reinforcement, or single-material slope protection. These methods are ill-suited to address the challenges of managing steep, high-slope debris flow gullies with multiple slope locations, particle sizes, and coupled failure modes. Toe protection typically focuses on localized support, failing to effectively control loose material on the upper and middle slopes. While continuous slope gradation can shorten slope length, it involves significant construction work and can easily disturb high-level ancient debris flow deposits or fractured rock masses. Single-layer mesh reinforcement or single-material slope protection has limited slope fit, deformation coordination, and loose matrix support capacity, making it difficult to simultaneously address the management needs of different slope locations, particle sizes, and failure modes. Furthermore, existing engineering protection measures often lack effective coordination with vegetation restoration measures. Engineering structures primarily provide short-term stability, while the long-term anchoring function of plant roots is difficult to establish in a timely manner. This results in a significant functional gap between engineering protection and ecological restoration, further hindering the long-term stability management of steep, high-slope debris flow gullies with loose material sources.

[0007] Therefore, it is necessary to propose a zoned, graded, and phased collaborative management technology suitable for steep, loose debris source slopes in debris flow gullies. This technology can mitigate the loss of material at the slope toe while comprehensively controlling the stripping, erosion, sliding, rolling, and collapse of loose material on the slope. By sequentially connecting and gradually replacing the short-term protective function of engineering structures with the long-term anchoring function of plant roots, the technology can achieve the continuous stability of steep, loose debris source slopes and reduce the source of debris flow replenishment. Summary of the Invention

[0008] In view of this, the present invention provides a step-net coordinated ecological stabilization system for steep, loose debris source slopes in debris flow gullies, in order to solve the problems in the prior art such as the disconnect between slope toe protection and slope treatment, large disturbance from continuous slope cutting, the inability of a single net structure to adapt to the differentiated treatment needs of slope toe erosion and upper surface peeling, the inability of a single layer of net to simultaneously constrain coarse and fine particles, insufficient support capacity of vegetation substrate, and the lack of phased connection between engineering protection structures and vegetation restoration.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A step-net coordinated ecological stabilization system for steep, loose debris flow slopes includes: gabions positioned at the toe of the steep, loose slope adjacent to the debris flow gully bed; a stepped slope stabilization zone located at the lower part of the steep, loose slope; and a net-supported soil stabilization zone located at the upper part of the steep, loose slope. The intersection of the stepped slope stabilization zone and the net-supported soil stabilization zone serves as the step-net boundary. The gabions mitigate the scouring and erosion of the slope toe by debris flows, reduce the likelihood of the formation and continued expansion of the free face at the slope toe, and receive loose material that rolls, slides, or collapses from the upper slope. The stepped slope stabilization zone shortens the slope length, disperses runoff, intercepts the migration of loose material, and provides a planting platform. The net-supported soil stabilization zone gradedly constrains weathered layers such as fine particles, gravel, and boulders.

[0011] Furthermore, the gabion includes a corrosion-resistant metal mesh box and boulders filled inside the corrosion-resistant metal mesh box, wherein the boulders are preferably boulders generated during the removal of dangerous rocks on the slope or during the construction of horizontal steps.

[0012] Furthermore, the height of the gabion above the ground is not less than the designed debris flow depth corresponding to the treatment location, and the depth of the gabion body buried below the slope toe base is not less than the designed maximum erosion depth corresponding to the treatment location.

[0013] Preferably, the width of the gabion along the slope normal is 0.8~1.5m, and multiple gabions are set along the length of the ditch. Adjacent gabion cages are continuously arranged along the ditch and connected by binding steel wire, spiral connectors or corrosion-resistant fasteners.

[0014] Furthermore, the stepped slope stabilization zone includes: multiple horizontal steps spaced apart along the contour lines of the slope and dry-laid stone retaining walls set on the slope surface between the steps, in order to shorten the continuous slope length, disperse slope runoff, slow down the migration of loose material along the slope direction, receive sporadic material falling from the upper part, and provide a planting platform for trees and shrubs.

[0015] Preferably, the horizontal steps are formed by local excavation on the original slope surface with minimal disturbance, avoiding the formation of a continuous excavation surface that runs through the entire slope width. The horizontal steps extend along the contour lines, with a width of 0.8~2.0m, and the vertical distance between adjacent horizontal steps is 1.0~2.5m.

[0016] Preferably, the horizontal steps and dry-laid stone retaining walls are constructed in a top-down manner according to the slope position, so as to reduce the disturbance of the original loose accumulation body by continuous excavation.

[0017] Furthermore, the dry-laid stone retaining wall is formed by stacking natural stones or construction-cleaned stones in a staggered manner, with adjacent stones interlocking with each other, and larger gaps between stones are filled with fine-grained soil or gravelly soil formed by horizontal step excavation.

[0018] Furthermore, the angle between the free side slope of the dry-laid stone retaining wall and the horizontal plane is 65°~75°, preferably 70°, and the height of a single-level dry-laid stone retaining wall does not exceed 1.5m.

[0019] Furthermore, the stepped slope can adopt any of the following structural forms: Firstly, when the vertical distance between adjacent horizontal steps is not greater than the design height of a single-level dry-laid stone retaining wall, a dry-laid stone retaining wall shall be set on the slope between the steps. Secondly, when the vertical distance between adjacent horizontal steps is greater than the design height of a single-level dry-laid stone retaining wall, the upper part of the inter-step slope that exceeds the design height is locally shaped by cutting and shaping, and a dry-laid stone retaining wall is set at the bottom of the inter-step slope. For example, the slope between the uppermost dry-laid stone retaining wall and the uppermost horizontal step has a shaped section, and the angle between the shaped section and the horizontal plane is 45°.

[0020] Furthermore, the platform of the horizontal step is provided with a drainage slope that slopes outward or to both sides of the slope to reduce the accumulation of rainwater on the inner side of the horizontal step.

[0021] Furthermore, planting pits are excavated on the horizontal steps, and trees are planted in the planting pits. Preferably, native trees and shrubs with well-developed root systems, drought resistance, tolerance to poor soil, and adapted to the climate conditions of the treatment area are planted on the horizontal steps. Trees are planted in planting pits set on the inner side or middle of the horizontal steps, and shrubs are planted between trees and on the inner side of the dry-laid stone retaining wall.

[0022] Preferably, the height of the lower stepped slope stabilization zone should be 40% to 50% of the total vertical height of the slope to be treated, and preferably not exceed 10m; the remaining upper slope surface should be equipped with a wire mesh stabilization zone. The lower slope is the main area affected by slope toe erosion, free face expansion, and material drop, and should therefore employ stepped slope stabilization; continuous excavation of the upper slope would cause excessive disturbance, so wire mesh stabilization should be used. The 40% to 50% height can balance the needs of lower slope stabilization and upper slope low-disturbance treatment, and preferably not exceed 10m.

[0023] The height of the stepped slope stabilization zone is the preliminary layout range. The actual boundary line of the stepped network should be adjusted in combination with the range of scour influence at the toe of the slope, the position of the shallow sliding rear edge, the range of slope cracks and loosening, and the on-site construction conditions, so that the lower slope body with obvious scour influence at the toe of the slope is located within the stepped slope stabilization zone.

[0024] Furthermore, the mesh-stabilized soil area is located on the upper part of the slope and includes: a natural fiber rope flexible three-dimensional support layer laid along the steep and loose slope, a corrosion-resistant steel wire mesh covering the outside of the natural fiber rope flexible three-dimensional support layer, and anchor rods that fix the natural fiber rope flexible three-dimensional support layer and the corrosion-resistant steel wire mesh to the slope. The lower edges of the natural fiber rope flexible three-dimensional support layer and the corrosion-resistant steel wire mesh extend beyond the boundary line of the stepped mesh and extend downward along the inner slope wall of the uppermost horizontal step. They are fixed to the inner slope wall by anchor rods, so that the stepped slope stabilization area and the mesh-fixed soil stabilization area are continuously connected.

[0025] Furthermore, the natural fiber rope flexible three-dimensional support layer is composed of 4 to 6 layers of natural fiber rope netting arranged sequentially along the slope normal, and adjacent natural fiber rope netting are connected by connecting ropes, knots or biodegradable connectors; each layer of natural fiber rope netting is formed by natural fiber ropes being woven or tied in a cross pattern along the slope longitudinally, laterally or diagonally, so as to avoid the meshes of different layers being completely connected along the slope normal.

[0026] The three-dimensional support layer of this invention requires more than four layers of fiber rope to form a flexible three-dimensional support layer with thickness, so that fine particles, gravel, and small stones are constrained by multiple layers of rope when moving in the normal direction of the slope; six layers or less of fiber rope can control the self-weight, laying difficulty and slope adhesion.

[0027] Preferably, the diameter of the natural fiber rope is 8~30mm (above 8mm ensures the rope has basic tensile strength, abrasion resistance, and embedding capacity; below 30mm maintains flexibility, slope conformability, and weavability). The mesh side length of each layer of natural fiber rope net is 5~10cm (this range takes into account the mesh constraint of fine particles, gravel, and small stones, as well as the convenience of herbaceous seedlings, shrubs, and construction binding), and the total thickness of the flexible three-dimensional support layer is 4~10cm (above 4cm can form an effective three-dimensional support space; within 10cm can avoid the net being too thick, too heavy, and unstable in anchoring).

[0028] Furthermore, the flexible three-dimensional support layer is designed to conform to the uneven shape of the original slope surface. A layer of natural fiber rope netting close to the original slope surface is in contact with the loose particles on the slope surface, and the outer layers of natural fiber rope netting are stacked in sequence and work together to restrict the movement of loose particles outward from the slope.

[0029] Furthermore, the equivalent diameter of the mesh of the corrosion-resistant steel wire mesh is greater than 20cm (the outer steel wire mesh mainly bears the overall covering, anchoring force transmission and large stone displacement restriction, but does not bear fine particle constraint; the mesh is larger than the inner rope mesh, which is conducive to the main trunk of the seedling passing through and thickening later).

[0030] Furthermore, trees are planted in the mesh of the corrosion-resistant steel wire mesh, and herbaceous plants are planted in the mesh of the natural fiber rope flexible three-dimensional support layer.

[0031] Furthermore, the anchor bolt includes: a rod body inserted into the slope soil layer, and a crimp hook integrally connected to the top of the rod body, wherein the crimp hook is crimped into the corrosion-resistant steel wire mesh.

[0032] Furthermore, the anchor bolts are arranged in a rectangular or quincunx pattern, with the horizontal and vertical spacing preferably ranging from 1.0 to 3.0 meters (this range is used to balance the stability of the mesh overlay, the adaptability to slope unevenness, construction disturbance, and project cost). The length of the anchor bolts is determined based on the thickness of the loose layer on the slope, the structure of the soil and rock mass, and the burial depth of the stable soil and rock layer, so that the effective anchoring section of the anchor bolt enters the relatively stable soil and rock layer.

[0033] Furthermore, anchor bolts or auxiliary anchors are densely installed at the concave parts of the slope, at the overlapping parts of natural fiber rope nets and corrosion-resistant steel wire nets, and near the boundary lines of the stepped nets.

[0034] Preferably, before planting trees and shrubs in the area where the soil is stabilized by wire mesh, horizontal construction access roads are excavated at intervals along the contour lines of the slope, and planting holes are set along one or both sides of the horizontal construction access roads. The planting holes are excavated before the flexible three-dimensional support layer is laid; then, the flexible three-dimensional support layer of natural fiber rope is laid and temporarily positioned, and the trees and shrubs are planted in the pre-set planting holes. Then, corrosion-resistant steel wire mesh is laid on the outside of the flexible three-dimensional support layer and fixed as a whole by anchor bolts and mesh pressing components, so that the main trunk or main branches of the plants pass through the mesh of the corrosion-resistant steel wire mesh.

[0035] The present invention has the following beneficial effects: (1) This invention focuses on the entire process of loose material migrating from the slope to the toe and the gully on steep slopes of debris flow gullies. It implements zoned treatment based on the differences in the main destructive mechanisms of the lower and upper parts of the slope. Gabions at the toe are used to mitigate toe erosion and the development of the free face; the lower stepped slope stabilization zone shortens the continuous slope length, disperses surface runoff, and receives the migrating material in stages; the upper wire mesh stabilization zone constrains surface loose particles, supports vegetation substrate, and promotes vegetation restoration while minimizing disturbance to the original slope. Compared to using toe retaining, full-slope tiering, or full-slope wire mesh stabilization alone, this invention improves the matching between treatment measures and slope destructive mechanisms, reducing the possibility of loose material entering the gully and being reactivated by floods or debris flows.

[0036] (2) The composite constraint structure consists of 4 to 6 layers of natural fiber rope netting and an outer layer of corrosion-resistant steel wire mesh. The inner layer of natural fiber rope netting uses multiple layers of rope to wrap, embed and grid-constrain fine particles, gravel and small stones, and undertakes the functions of supporting the vegetation substrate, retaining soil and moisture. The outer layer of corrosion-resistant steel wire mesh undertakes the functions of overall pressing, anchoring force transmission and long-term restriction of the displacement of larger stones, thereby achieving the synergistic stabilization of loose materials of different particle sizes.

[0037] (3) In the early stage of treatment, natural fiber ropes play the roles of particle netting, matrix support, soil conservation and moisture retention. After decomposition, they are transformed into soil organic matter and plant nutrients. They form a phased connection with the medium and long-term engineering protection of corrosion-resistant steel wire mesh and the later ecological soil stabilization of tree, shrub and herbaceous plant roots, thereby improving the vegetation coverage, biodiversity, ecological restoration capacity and long-term stability of the slope. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figure 1 This invention provides a structural schematic diagram of a step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies.

[0040] Figure 2 for Figure 1 A magnified schematic diagram of the structure of part A in the middle.

[0041] Figure 3 This is a schematic diagram showing the combination of a flexible three-dimensional support layer made of natural fiber rope, corrosion-resistant steel wire mesh, and anchor bolts.

[0042] Figure 4 This is a schematic diagram of the anchor bolt structure.

[0043] Figure 5 This is a construction diagram of the area where the soil is stabilized by wire mesh.

[0044] Figure 6 This is a construction site diagram of the stepped slope stabilization zone.

[0045] Figure 7 This is a construction site photo of the area where the soil is stabilized by wire mesh. Detailed Implementation

[0046] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0047] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0049] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments described are only for explaining the technical concept of the present invention and are not intended to limit the scope of protection of the present invention. Conventional adjustments or equivalent substitutions made by those skilled in the art to the structural dimensions, material types, plant configurations, and connection methods without departing from the concept of the present invention should all fall within the scope of protection of the present invention.

[0051] For ease of explanation, the terms "upper part" and "lower part" refer to the upper and lower parts from the foot of the slope towards the top of the slope, respectively; "inner side" refers to the side facing the slope, and "outer side" refers to the side away from the slope.

[0052] The target of this treatment project is a steep, loose slope on one side of the Goulinping debris flow gully in Longnan City, Gansu Province, formed by the collapse, landslide, and long-term weathering of high-level ancient debris flow deposits. The vertical height of the slope is approximately 20 meters. The slope material is mainly composed of a mixture of clay, silt, gravel, and boulders, characterized by a wide particle size distribution, loose structure, and low degree of cementation. Locally, there are signs of bridging pores, loose blocks, and shallow deformation. Due to the continuous downcutting of the gully and the lateral scouring of the debris flow, a free face has formed at the toe of the slope, and high-level deposits are continuously migrating towards the lower part of the slope and the gully bed.

[0053] Based on the site topography, the extent of scour at the toe of the slope, and the characteristics of slope deformation, the lower 10m of the treated slope was designated as a stepped slope stabilization zone, and the upper 10m was designated as a wire mesh reinforcement zone. The intersection of the upper edge of the highest horizontal step and the original slope surface served as the boundary line between the steps and the wire mesh.

[0054] See details Figures 1-5 As shown, this embodiment of the invention discloses a step-net coordinated ecological stabilization system for a steep, loose debris flow gully slope, comprising: a gabion 1 set at the toe of the slope adjacent to the steep, loose slope 100 and the debris flow gully bed 200; a stepped slope stabilization zone 2 set at the lower part of the steep, loose slope 100; and a net-supported soil stabilization zone 3 set at the upper part of the steep, loose slope 100. The intersection line between the stepped slope stabilization zone 2 and the net-supported soil stabilization zone 3 is the step-net boundary line 4.

[0055] The stepped slope stabilization zone 2 includes: multiple horizontal steps 21 spaced apart along the contour lines of the slope surface and dry-laid stone retaining walls 22 set on the slope surface between the steps.

[0056] In a specific embodiment, five levels of horizontal steps 21 are set within the stepped slope stabilization zone 2. Each level of horizontal step is arranged along the contour lines of the slope surface and is set in segments according to the original slope undulations. The original slope body with local stability is preserved between adjacent construction sections to avoid forming a continuous excavation face that runs through the entire slope width.

[0057] Horizontal steps 21 are numbered sequentially from bottom to top as the first level horizontal step to the fifth level horizontal step, where the first level horizontal step is adjacent to the slope foot gabion 1, and the fifth level horizontal step is adjacent to the step network boundary line 4.

[0058] In this embodiment, the elevation of the first-level horizontal step is basically the same as the elevation of the top surface of the gabion at the foot of the slope. The vertical distance between the first-level and second-level horizontal steps is 1.5m, and the width of the first-level horizontal step is 1.0m. The width of the second-level and third-level horizontal steps is 1.2m, and the vertical distance between adjacent horizontal steps is 1.5m. The vertical distance between the third-level and fourth-level horizontal steps is 1.5m, and the width of the fourth-level horizontal step is 1.0m. The vertical distance between the fourth-level and fifth-level horizontal steps is 2.0m, and the width of the fifth-level horizontal step is 1.0m.

[0059] The actual elevation of each level of horizontal step was adjusted in a smooth manner based on the original slope topography, the range of scour at the toe of the slope, and the local height of the slope between steps, so that the fifth level horizontal step is located at the upper edge of the stable slope zone of the steps, and the intersection of its upper slope edge with the original slope surface forms the boundary line of the step network.

[0060] For relatively intact inter-level slopes without significant loosening or bulging, only unstable rocks, loose stones, and surface loose blocks are removed, preserving the original slope shape as much as possible. For areas with localized protrusions, accumulated boulders, developed voids, or significant surface loosening, small-scale slope trimming and reshaping are carried out. For example, the slope between the uppermost dry-laid stone retaining wall 22 and the fifth-level horizontal step 21 has a slope trimming section 5, with an angle of 45° to the horizontal plane. The inter-level slope between the fifth-level and fourth-level horizontal steps uses a combination of dry-laid stone retaining walls and localized slope trimming. A 1.5m high dry-laid stone retaining wall 3 is constructed along the original slope from the fourth-level horizontal step upwards. The remaining approximately 0.5m high inter-level slope above the dry-laid stone retaining wall is trimmed and reshaped, with an angle of approximately 45°. Dry-laid stone retaining walls 3 are used to stabilize the remaining horizontal steps.

[0061] In the above embodiments, the dry-laid riprap retaining wall 22 is preferably constructed using natural riprap obtained during the removal of dangerous rocks from the slope or the excavation of horizontal steps. Larger, more regularly shaped riprap is arranged at the bottom layer of the retaining wall and on the open side, with the riprap staggered and interlocking. Larger gaps between the riprap are preferably filled with smaller riprap and gravelly soil, while localized surface gaps can be filled with fine-grained soil formed during excavation.

[0062] The angle between the free side slope of the dry-laid stone retaining wall 22 and the horizontal plane is 65°~75°, preferably 70°. The height of a single retaining wall does not exceed 1.5m, so that it can maintain stability while having a certain degree of permeability and adaptability to local deformation.

[0063] In some embodiments, the platform of the horizontal step 21 is provided with a drainage slope that slopes outward or to both sides of the slope, so that the runoff formed by rainfall can be discharged in time, and rainwater is prevented from accumulating on the inner side of the horizontal step for a long time and from infiltrating into the interior of the slope.

[0064] In some embodiments, planting pits 6 are excavated on the horizontal step 21, and trees 7 are planted in the planting pits 6. Specifically, planting pits for trees and planting pits for shrubs are provided on the horizontal step 21. The planting pits for trees are arranged on the inner side or middle of the horizontal step, and the planting pits for shrubs are arranged between adjacent trees and on the inner side of the dry-laid stone retaining wall. The trees selected are black locust and ailanthus, which are adapted to the climate and soil conditions of the treatment area, and the shrubs are willow.

[0065] In some embodiments, the gabion 1 is arranged along the extension direction of the ditch and includes a zinc-aluminum alloy wire mesh box and boulders filled in the wire mesh box. Adjacent wire mesh boxes are connected by spiral connectors and corrosion-resistant binding wires to form a continuous and flexible slope toe protection structure.

[0066] In this embodiment, the gabion 1 has a width of 1.0m along the slope normal, is buried 0.3m below the slope toe base 7, and is 0.7m above the slope toe base, with a total height of 1.0m. The elevation of the top surface of the gabion is basically consistent with the elevation of the first-level horizontal step, so that the top surface of the gabion and the first-level horizontal step together form a slope toe support and transition platform.

[0067] The gabion 16 is primarily filled with boulders generated during the removal of dangerous rocks from the slope and the partial excavation of the horizontal steps. Larger, more regularly shaped boulders are placed on the outside, bottom, and top of the gabion, while smaller boulders are used to fill the gaps inside the gabion to reduce the internal voids and improve the overall structural integrity.

[0068] The toe gabion 1 is used to mitigate the scouring and erosion of the toe of the slope by debris flow, limit the continued development of the free face at the toe of the slope, and at the same time bear the boulders and loose debris that roll, slide or collapse from the upper slope.

[0069] In other embodiments, the mesh-stabilized soil zone 3 includes: a natural fiber rope flexible three-dimensional support layer 31 laid along the steep loose slope 100, a corrosion-resistant steel wire mesh 32 covering the outside of the natural fiber rope flexible three-dimensional support layer 31, and an anchor rod 33 that fixes the natural fiber rope flexible three-dimensional support layer 31 and the corrosion-resistant steel wire mesh 32 together to the slope. The lower edges of the natural fiber rope flexible three-dimensional support layer 31 and the corrosion-resistant steel wire mesh 32 cross the step mesh boundary line 4 and extend downward along the inner slope wall of the uppermost horizontal step 21. They are fixed to the inner slope wall by anchor rods 33, so that the stepped slope stabilization zone 2 and the wire mesh soil stabilization zone 3 are continuously connected.

[0070] The flexible three-dimensional support layer 31 of natural fiber rope consists of 4 to 6 layers of natural fiber rope nets 311 arranged sequentially along the slope normal. Adjacent natural fiber rope nets 311 are connected by connecting ropes, knots or biodegradable connectors. Each layer of natural fiber rope net 311 is formed by natural fiber ropes being woven or tied together longitudinally, laterally or diagonally along the slope to avoid the meshes of different layers being completely connected along the slope normal.

[0071] Trees 7 are planted in the mesh of the corrosion-resistant steel wire mesh 32, and herbaceous plants are planted in the mesh of the natural fiber rope flexible three-dimensional support layer 31.

[0072] Anchor rod 33 includes: rod body 331 inserted into the slope rock and soil layer, and crimp hook 332 integrally connected to the top of rod body 331, crimp hook 332 crimped onto corrosion-resistant steel wire mesh 32.

[0073] In this embodiment, before laying the netting in the soil stabilization zone 3, several horizontal, narrow, and short construction access roads 300 are excavated at intervals along the contour lines of the slope. The width of the construction access road 300 is approximately 0.3m, and it is mainly used for locating planting holes, manually digging holes, and planting seedlings.

[0074] The planting hole 6 should be located in an area with a relatively stable slope, a loose layer thickness sufficient to support plant root development, and no obvious venting pores.

[0075] The soil stabilization zone 3 uses a five-layer natural fiber rope net 311 (palm rope net can be used) to form a flexible three-dimensional support layer. Each layer of palm rope is arranged longitudinally, laterally or diagonally along the slope to avoid the mesh of different layers being completely connected along the slope normal.

[0076] In this embodiment, the palm rope has a diameter of 16mm, and the mesh side length of each layer of palm rope net is 8cm. Adjacent palm rope nets are connected by palm fiber connecting ropes, knots, or other biodegradable connectors. After the five layers of palm rope nets are connected, a flexible three-dimensional support layer with a total thickness of approximately 6cm is formed.

[0077] The first layer of palm rope netting, close to the original slope surface, is laid to conform to the uneven shape of the slope and comes into direct contact with the fine particles, gravel, and small stones on the slope. The remaining four layers of palm rope netting are stacked on the outer side in sequence, so that when the loose material on the slope moves outward, it is successively wrapped, embedded, and blocked by the ropes in different directions.

[0078] For areas with slope depressions, concentrated boulders, or areas where the netting is suspended, use auxiliary positioning anchors or natural fiber binding ropes to temporarily attach the palm rope netting to the original slope.

[0079] After the flexible three-dimensional support layer is laid and temporarily positioned, trees and shrubs are planted in the pre-set planting holes. In this embodiment, black locust, ailanthus, sea buckthorn, and willow are selected. The area where the netting is used for soil stabilization is mainly composed of shrubs and herbaceous plants such as willow and sea buckthorn. Black locust or ailanthus are planted only in locations where the slope is relatively stable and the soil layer thickness meets the requirements.

[0080] After planting trees and shrubs, herbaceous plant seeds are sown inside the flexible three-dimensional support layer and on the surface of some vegetation substrates. Fescue and bermudagrass are selected as grass seeds. After sowing, a small amount of fine-grained planting soil is used to cover the seeds, allowing them to penetrate the palm rope mesh and the vegetation substrate, reducing the possibility of them being washed away by rainwater runoff.

[0081] In the early stages of slope treatment, before plant roots have fully penetrated the original slope, palm rope nets play a role in stabilizing, supporting, conserving soil and moisture, and protecting slope debris and vegetation substrate. As the roots of trees, shrubs and herbaceous plants gradually develop and penetrate the original slope, the palm ropes gradually decompose, and their decomposition products are transformed into soil organic matter, serving as a supplementary fertilizer source for plant growth.

[0082] After the trees and shrubs are planted, a zinc-aluminum alloy corrosion-resistant steel wire mesh 32 is placed on the outside of the flexible three-dimensional support layer. The equivalent diameter of the mesh opening of the steel wire mesh 32 is 20cm, and its mesh size is larger than that of the inner palm rope mesh.

[0083] When laying the wire mesh, ensure that the main trunk of the seedling and the exposed end of the anchor rod pass through the corresponding mesh openings. Maintain sufficient growth gap between the plant trunk and the wire mesh (32). If necessary, install flexible isolation sleeves at the contact points to prevent the wire mesh (32) from affecting the later thickening of the seedling trunk.

[0084] After the wire mesh is laid, anchor bolts 33 are arranged in a 2m×2m staggered pattern. The anchor bolts are fixed by mechanical anchoring, so that the anchor bolts penetrate through the loose surface deposits, and their effective anchoring rods are inserted into the relatively stable soil and rock layer. The corrosion-resistant wire mesh and five layers of palm rope mesh are pressed together to the slope surface using crimp hooks.

[0085] Adjacent corrosion-resistant wire mesh panels are connected by overlapping, and the overlapping parts are fixed with corrosion-resistant binding wire or metal connectors. Main anchors or auxiliary anchors are densely installed at mesh overlapping areas, slope depressions, areas with concentrated boulders, and near the boundary lines of the stepped mesh.

[0086] Because the mesh size of the outer layer of corrosion-resistant steel wire mesh 32 is larger than that of the inner layer of palm rope mesh, the corrosion-resistant steel wire mesh 32 mainly bears the role of overall mesh covering, anchoring force transmission and long-term restriction of large stone displacement, while the five layers of palm rope mesh mainly bear the role of mesh fixation of fine particles, gravel and small stones and support of vegetation substrate.

[0087] Finally, a row of anchor bolts is set along the boundary line of the step net to fix the lower edges of the palm rope net and the corrosion-resistant steel wire net together to the inner slope wall of the highest level horizontal step, so that the upper netting soil stabilization area and the lower step slope stabilization area form continuous protection.

[0088] The above embodiments illustrate the specific application of the present invention in the collapse slope of thick ancient debris flow deposits. Depending on the topographic and geological conditions, debris flow dynamic parameters, and vegetation growth conditions of different treated slopes, the size of the gabions, the number and spacing of horizontal steps, the number of layers of natural fiber rope netting, the anchor spacing, the mesh size, and the vegetation configuration can be adjusted accordingly. However, the overall structure of the gabions at the slope toe, the lower stepped slope stabilization zone, and the upper wire mesh soil stabilization zone remains unchanged.

[0089] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0090] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies, characterized in that, include: The gabion (1) is set at the toe of the slope adjacent to the debris flow gully bed (200) on the steep loose slope (100), the stepped slope stabilization zone (2) is set at the lower part of the steep loose slope (100), and the netting soil stabilization zone (3) is set at the upper part of the steep loose slope (100). The intersection line between the stepped slope stabilization zone (2) and the netting soil stabilization zone (3) is the step-net boundary line (4).

2. The step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 1, characterized in that, The stepped slope stabilization zone (2) includes: multiple horizontal steps (21) spaced apart along the contour lines of the slope surface, and dry-laid stone retaining walls (22) set on the slope surface between the steps.

3. The step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 2, characterized in that, The angle between the free side slope of the dry-laid stone retaining wall (22) and the horizontal plane is 65°~75°.

4. The step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 2, characterized in that, The slope between the uppermost dry-laid stone retaining wall (22) and the uppermost horizontal step (21) has a slope shaping section (5), which has an angle of 45° with the horizontal plane.

5. A step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 2, characterized in that, The platform of the horizontal step (21) is provided with a drainage slope that slopes outward or to both sides of the slope to reduce the accumulation of rainwater on the inner side of the horizontal step.

6. A step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 2, characterized in that, Planting pits (6) are dug on the horizontal step (21), and trees (7) are planted in the planting pits (6).

7. A step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to any one of claims 2-6, characterized in that, The mesh-stabilized soil area (3) includes: a natural fiber rope flexible three-dimensional support layer (31) laid along the steep loose slope (100), a corrosion-resistant steel wire mesh (32) covering the outside of the natural fiber rope flexible three-dimensional support layer (31), and anchor rods (33) that fix the natural fiber rope flexible three-dimensional support layer (31) and the corrosion-resistant steel wire mesh (32) together to the slope. The lower edges of the natural fiber rope flexible three-dimensional support layer (31) and the corrosion-resistant steel wire mesh (32) extend beyond the boundary line (4) of the stepped mesh and extend downward along the inner slope wall of the uppermost horizontal step (21). They are fixed to the inner slope wall by anchor rods (33), so that the stepped slope stabilization area (2) and the mesh-fixed soil stabilization area (3) are continuously connected.

8. A step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 7, characterized in that, The natural fiber rope flexible three-dimensional support layer (31) is composed of 4 to 6 layers of natural fiber rope nets (311) arranged sequentially along the slope normal. Adjacent natural fiber rope nets (311) are connected by connecting ropes, knots or biodegradable connectors. Each layer of natural fiber rope net (311) is formed by natural fiber ropes being woven or tied in a cross pattern along the slope longitudinally, laterally or obliquely to avoid the mesh holes of different layers being completely connected along the slope normal.

9. A step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 7, characterized in that, Trees (7) are planted in the mesh of the corrosion-resistant steel wire mesh (32), and herbaceous plants are planted in the mesh of the natural fiber rope flexible three-dimensional support layer (31).

10. A step-network collaborative ecological stabilization system for steep, loose debris source slopes in debris flow gullies according to claim 7, characterized in that, The anchor rod (33) includes: a rod body (331) inserted into the slope soil layer and a crimp hook (332) integrally connected to the top of the rod body (331), the crimp hook (332) being crimped onto the corrosion-resistant steel wire mesh (32).

Images