Highway high-position landslide disaster retaining structure and design method

Abstract

The application provides a highway high-position landslide disaster retaining structure and a design method, and relates to the technical field of highway geological disaster prevention. The retaining structure comprises: at least one set of local retaining units, which are arranged in the sliding area of the landslide body and are used for restraining the movement of the landslide body in the sliding area; the local retaining unit comprises an anchoring assembly, a reinforcing assembly, a frame assembly and a drainage assembly; a tunnel structure is arranged at a preset position on the highway line to bear the impact energy of the remaining landslide body after being restrained by the local retaining unit. The retaining structure can reduce the engineering cost of high-position landslide disaster treatment and achieve the balance between safety and economy in high-position landslide disaster treatment.

Description

Technical Field

[0001] This application relates to the field of highway geological disaster prevention and control technology, specifically to a retaining structure and design method for highway high-altitude landslide disasters. Background Technology

[0002] In existing technologies for managing high-altitude landslides, common retaining methods are mainly divided into two categories. One type involves deploying retaining structures along the entire landslide body, such as installing anti-slide piles, retaining walls, or cable-stayed structures at the rear, middle, and front edges of the landslide, attempting to prevent the entire landslide from becoming unstable and sliding through large-area reinforcement. The other type involves constructing a separate tunnel or canopy structure at the toe of the slope near the road, utilizing the reinforced concrete shell of the tunnel to directly bear the impact load generated when the landslide slides down, hoping to ensure road safety with a single protective structure.

[0003] However, both of these existing technologies suffer from significant economic drawbacks. Deploying retaining structures across the entire landslide requires extensive construction across the entire landslide body, involving massive amounts of anti-slide piles and anchor cables. This is especially problematic in steep, high-altitude landslide terrain with poor transportation, where material transport and construction difficulties further drive up costs, making the project investment prohibitive. While single-tunnel protection avoids the high costs of full-area reinforcement, the sliding speed and impact energy generated by high-altitude landslides are extremely high. To withstand impact forces far exceeding their bearing capacity, the tunnel structure must significantly increase concrete thickness, steel reinforcement, and foundation depth, similarly leading to a sharp increase in tunnel costs, and sometimes even making implementation impossible due to site limitations. Therefore, existing technologies generally suffer from high project costs in high-altitude landslide disaster management. Summary of the Invention

[0004] Based on this, this application provides a retaining structure and design method for high-altitude landslide disasters along highways, which can reduce the engineering cost of high-altitude landslide disaster control and achieve a balance between safety and economy in high-altitude landslide disaster control.

[0005] In a first aspect, this application provides a retaining structure for high-altitude landslide disasters along highways, comprising: at least one set of local retaining units, wherein the local retaining units are arranged in the sliding area of ​​the landslide body to constrain the movement of the landslide body in the sliding area; each local retaining unit includes an anchoring component, a reinforcement component, a frame component, and a drainage component; one end of the anchoring component is anchored into the stable stratum of the landslide body, and the other end is tensioned and locked to the slope surface of the landslide body to apply anti-sliding force to the landslide body; the reinforcement component is implanted into the slope of the sliding area to form a composite structure with the surrounding rock and soil; the frame component connects the anchoring component and the reinforcement component to form a spatial stress grid on the slope surface of the landslide body to transfer the load applied by the anchoring component to the slope surface; the drainage component passes through the local retaining unit from the slope surface and extends into the interior of the landslide body to drain groundwater; and an open-cut structure is arranged at a predetermined position on the highway route to withstand the impact energy of the remaining landslide body after being constrained by the local retaining units.

[0006] Optionally, the anchoring assembly includes a panel-type pier and an anchor cable; the panel-type pier is attached to the slope surface, the anchor cable passes through the panel-type pier and is anchored into a stable stratum, and the tension end of the anchor cable is locked to the slope surface through the panel-type pier.

[0007] Optionally, the panel-type pier is a reinforced concrete structure, with the side of the panel-type pier facing the inside of the slope body fitting against the excavated slope surface, and the side of the panel-type pier facing the outside of the slope body being provided with anchor cable anchoring holes and drainage holes; the angle between the central axis of the anchor cable anchoring hole and the horizontal plane is 20° to 30°.

[0008] Optionally, the reinforcement component includes a grouting pipe and an anti-slide pile; the grouting pipe is implanted inside the slope of the sliding area, and grout is injected into the surrounding soil and rock through the grouting pipe to form a reinforcement layer; the anti-slide pile is implanted inside the slope of the sliding area to withstand shear force and form a composite reinforcement structure with the grouting pipe.

[0009] Optionally, the frame component is an anchor cable frame beam; the anchor cable frame beam connects the anchoring component and the reinforcing component on the slope surface into a crisscrossing grid structure, the nodes of the anchor cable frame beam are fixedly connected to the anchor heads of the anchoring components, and the beam body of the anchor cable frame beam is fixedly connected to the top of the reinforcing component.

[0010] Optionally, the drainage component is an inclined drainage hole; the inclined drainage hole includes an outer pipe and an inner pipe placed inside the outer pipe, the inner pipe is a flexible pipe with openings in the side wall, the end of the inner pipe is closed, and the starting end of the inner pipe is provided with a water injection interface.

[0011] Optionally, the tunnel structure is a rectangular tunnel or an arched tunnel; the impact resistance level of the tunnel structure is not lower than the peak impact energy of the remaining landslide body after being constrained by the local retaining unit.

[0012] Optionally, the highway high-level landslide disaster retaining structure also includes a dynamic monitoring system, which includes a rain gauge, a surface displacement monitor, a deep displacement monitor, a stress sensor, and an anchor cable force gauge. The rain gauge is installed above the landslide body, the surface displacement monitor and the deep displacement monitor are respectively installed around the local retaining unit and the key stress-bearing parts of the tunnel structure, the stress sensor is attached to the inner wall of the tunnel structure, and the anchor cable force gauge is connected in series to the anchor cable of the anchoring assembly.

[0013] Optionally, the partial support unit and the open-cut structure are arranged sequentially in the downward direction of the landslide, and the open-cut structure is located downstream of the partial support unit; a buffer gap is provided between the partial support unit and the open-cut structure, and the length of the buffer gap is determined according to the movement trajectory of the landslide after being constrained by the partial support unit.

[0014] Secondly, this application provides a design method for retaining structures in response to high-altitude landslides along highways, comprising: acquiring survey data of the landslide body; the survey data including at least the spatial morphological characteristics of the landslide body and the mechanical parameters of the soil and rock mass; calculating the stability coefficient and sliding force distribution of the landslide body using the limit equilibrium method based on the mechanical parameters and a preset stability safety factor; establishing a three-dimensional numerical simulation model, constructing the spatial morphological characteristics into a landslide body topographic grid, using the mechanical parameters and the sliding force distribution as input conditions, simulating the motion trajectory, sliding velocity, and impact energy distribution of the landslide body after instability, and outputting the peak impact energy of each sliding area on the highway route; if the stability coefficient is lower than a preset stability threshold, generating multiple candidate schemes based on the sliding force distribution and the peak impact energy. Each candidate scheme includes a retaining range parameter and a tunnel impact resistance level parameter. For each candidate scheme, the three-dimensional numerical simulation model is invoked, the retaining range parameter of the candidate scheme is input, and the impact energy of the remaining landslide body on the tunnel after partial retaining is simulated. It is then determined whether the impact energy is lower than the bearing capacity corresponding to the tunnel impact resistance level of the candidate scheme. If the impact energy is lower than the bearing capacity corresponding to the tunnel impact resistance level of the candidate scheme, the sum of the retaining structure cost and the tunnel structure cost of the candidate scheme is calculated as the total cost. The retaining range parameter and tunnel impact resistance level parameter corresponding to the candidate scheme with the minimum total cost are determined as the target design parameters. Based on the target design parameters, the layout scheme of the partial retaining unit and the construction scheme of the tunnel structure are output.

[0015] Compared with existing technologies, the beneficial effects of this application are as follows: Local support units are only deployed in key sliding areas; anchoring components apply active anti-sliding force to the landslide body; reinforcement components are embedded inside the slope to form a composite structure to enhance the overall integrity of the slope; frame components connect the two into a spatial stress grid and distribute the load to the slope surface; and drainage components drain groundwater to reduce pore water pressure. The combined effect of these four components effectively constrains landslide movement and significantly reduces sliding thrust and impact energy. The remaining impact energy after reduction by the local support units is borne by the downstream tunnel structure. The tunnel structure only needs to be designed with impact resistance levels based on the remaining energy, avoiding the risk of single tunnel protection failing due to excessive impact energy. Therefore, through the coordinated operation of local support units and tunnel structures, the engineering cost of high-altitude landslide disaster management can be reduced, achieving a balance between safety and economy in high-altitude landslide disaster management. Attached Figure Description

[0016] Figure 1 This is a schematic cross-sectional view of a retaining structure for high-altitude landslide disasters on highways, provided in an embodiment of this application, located in the area to be treated.

[0017] Figure 2 This is a frontal view of the anchoring component provided in an embodiment of this application.

[0018] Figure 3 This is a cross-sectional schematic diagram of the drainage component provided in an embodiment of this application.

[0019] Figure 4 A simulation diagram of the landslide motion trajectory provided in the embodiments of this application.

[0020] Figure 5 This is a real-life schematic diagram of the area to be treated after treatment, provided in an embodiment of this application.

[0021] Figure 6 A schematic diagram illustrating the steps of the design method for a retaining structure for high-altitude landslide disasters along highways, as provided in this application embodiment.

[0022] Attached reference numerals: 10-Highway landslide disaster retaining structure; 1-Partial retaining unit; 11-Anchoring component; 12-Reinforcement component; 13-Frame component; 14-Drainage component; 111-Panel-type pier; 112-Anchor cable; 121-Grouting pipe; 122-Anti-slide pile; 2-Open tunnel structure. Detailed Implementation

[0023] The present application will now be described in further detail with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the subject matter of the present application to the following embodiments; all technologies implemented based on the content of the present application fall within the scope of protection of the present application.

[0024] In the description of the embodiments in this application, "a plurality of" means two or more, unless otherwise expressly specified. The reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] Please refer to Figure 1 , Figure 1 This is a schematic cross-sectional view of a retaining structure for high-altitude landslide disasters on highways, provided in an embodiment of this application, located in the area to be treated.

[0026] The retaining structure 10 for high-altitude landslide disasters along highways may include: At least one set of local support units 1 is provided, which are arranged in the sliding area of ​​the landslide body to restrain the movement of the landslide body in the sliding area. The local support unit 1 includes an anchoring component 11, a reinforcement component 12, a frame component 13, and a drainage component 14. One end of the anchoring component 11 is anchored into the stable stratum of the landslide body, and the other end is tensioned and locked to the slope surface of the landslide body to apply anti-sliding force to the landslide body. The reinforcement component 12 is implanted into the slope of the sliding area to form a composite structure with the surrounding rock and soil. The frame component 13 connects the anchoring component 11 and the reinforcement component 12 to form a spatial stress grid on the slope surface of the landslide body to transfer the load applied by the anchoring component 11 to the slope surface. The drainage component 14 passes through the local support unit 1 from the slope surface and extends into the interior of the landslide body to drain groundwater. The tunnel structure 2 is located at a predetermined position on the highway to withstand the impact energy of the remaining landslide body after being constrained by the local retaining unit 1.

[0027] The treatment area, from top to bottom, includes the creep deformation zone at the rear edge of the landslide, the collapsed accumulation zone in the middle, and the lower roadbed and riverbed impact zone. The treatment area is located in the front-middle part of the high-level landslide and along the road at the toe of the slope. Tension cracks have developed at the rear edge of the landslide, forming a creep deformation body; this area is the core deployment area of ​​local retaining unit 1. The collapsed area is located below the rear edge deformation body, with the collapsed material accumulating on the slope and partially burying the riverbed and roadbed. The road line is laid along the toe of the slope, with the outer side adjacent to the riverbed and the inner side being a rock slope. At the location of the road line, the tunnel structure 2 is arranged downstream of the collapsed area to withstand the impact energy of the remaining landslide material after local retaining. A buffer gap is set between local retaining unit 1 and the tunnel; this gap is determined based on the simulation results of the landslide's movement trajectory.

[0028] The disaster support structure provided in this application embodiment can be used to manage high-altitude landslide disasters along highways. By setting constraint structures and protective structures in different areas of the landslide body, the sliding energy of the landslide body can be gradually reduced and ultimately blocked.

[0029] Among them, the local support unit 1 refers to a group of support structures deployed in the sliding area of ​​the landslide body. It is deployed in the sliding area of ​​the landslide body to constrain the movement of the landslide body in the sliding area. That is, the local support unit 1 does not cover the entire landslide body, but is selectively deployed in the key sliding area of ​​the landslide body where the threat to the highway is the greatest and the sliding force is the most concentrated. It reduces the overall sliding thrust and impact energy of the landslide body through local constraint.

[0030] One end of the anchoring component 11 is anchored into the stable stratum of the landslide body, and the other end is tensioned and locked to the slope surface of the landslide body to apply anti-sliding force to the landslide body; the stable stratum refers to the rock and soil layer below the sliding surface inside the landslide body that has not deformed or slid, and the slope surface refers to the slope surface of the landslide body that is exposed on the ground surface.

[0031] The reinforcement component 12 is implanted into the slope of the sliding area to form a composite structure with the surrounding rock and soil. The composite structure refers to the reinforcement component 12 and the surrounding rock and soil sharing the force and being interlocked to improve the shear resistance and integrity of the slope.

[0032] The frame component 13 connects the anchor component 11 and the reinforcement component 12, forming a spatial stress grid on the slope surface of the landslide body, and transferring the load applied by the anchor component 11 to the slope surface; the spatial stress grid refers to a mesh structure composed of crisscrossing beams or reinforcing strips, which is attached and fixed to the slope surface, dispersing and transferring the tensile force concentrated by the anchor component 11 to a larger area of ​​the slope surface.

[0033] The drainage component 14 extends from the slope surface through the local support unit 1 and into the interior of the landslide body to drain groundwater and prevent groundwater pressure from reducing slope stability.

[0034] The tunnel structure 2 is positioned at a predetermined location on the highway to withstand the impact energy of the remaining landslide mass after being constrained by the partial retaining unit 1. The partial retaining unit 1 and the tunnel structure 2 are spatially separated, with the tunnel structure 2 located downstream of the partial retaining unit 1. A buffer distance is provided between the two, which is determined based on the simulation results of the landslide movement trajectory.

[0035] In a typical treatment area, the treatment area, from top to bottom, includes the creep deformation zone at the rear edge of the landslide, the collapsed accumulation zone in the middle, and the lower roadbed and riverbed impact zone. Tension cracks have developed at the rear edge of the landslide, forming a creep deformation body. The area where this creep deformation body is located is the core layout area of ​​local retaining unit 1. The collapsed area is located below the rear deformation body, where the landslide body has accumulated on the slope and partially buried the riverbed and roadbed. The road line is laid along the toe of the slope, with the outer side adjacent to the riverbed and the inner side being a rock slope. The tunnel structure 2 bears the impact energy of the remaining landslide body moving to the road after being constrained by local retaining unit 1.

[0036] In some embodiments, the anchoring assembly 11 may include a panel-type pad 111 and an anchor cable 112; see below. Figure 2 , Figure 2 This is a schematic elevation view of the anchoring component 11 provided in this embodiment. The panel-type pier 111 is attached to the slope surface. The panel-type pier 111 can be a reinforced concrete structure, distributing the concentrated tension of the anchor cable 112 to the slope surface while providing a stable tension locking foundation for the anchor cable 112. The panel-type pier 111 has a side facing the inside of the slope and a side facing the outside of the slope; the side facing the inside of the slope is attached to the excavated slope surface, which is appropriately modified according to the landslide topography to ensure that the panel-type pier 111 is in close contact with the slope surface; the side facing the outside of the slope is provided with anchor cable anchoring holes and drainage components 14. The anchor cable anchoring holes are used for the anchor cable 112 to pass through, and the drainage holes are reserved for the later installation of drainage components 14. The drainage pipe is fixed with mortar at the panel outlet to prevent it from sliding out under its own weight.

[0037] After passing through the anchoring holes on the panel-type pier 111, the anchor cable 112 can continue to extend into the slope and anchor into the stable stratum, which refers to the undeformed soil and rock layer below the sliding surface. The anchor cable 112 can be composed of multiple bundles of high-strength steel strands, for example, using 6 bundles of steel strands with a diameter of 15.2 mm, to provide sufficient tensile bearing capacity. The incident angle of the anchor cable 112 (i.e., the angle between the anchor cable's central axis and the horizontal plane) can be set to an angle between 20° and 30°, for example, 25°. This angle is determined based on the slope inclination angle and topographic conditions, enabling the anchor cable to pass through the sliding surface in the optimal direction and effectively apply the anti-sliding force to the landslide body.

[0038] The tensioning end of the anchor cable 112 is located outside the panel-type pier 111. After the design load is applied to the anchor cable 112 by the tensioning equipment, the anchor cable 112 is locked to the surface of the panel-type pier 111. The locking load is usually 80% of the design load, thereby applying a lasting anti-sliding force to the landslide body. The panel-type pier has the characteristics of high bearing capacity and small deformation, which can adapt to the construction conditions of steep slope terrain in high-level landslide areas, ensuring the stability and reliability of the anchoring component 11 in complex terrain.

[0039] In some embodiments, the reinforcement component 12 may specifically include a grouting pipe 121 and an anti-slide pile 122. Please continue reading. Figure 1 The grouting pipe 121 is implanted inside the slope of the sliding area. Multiple grout outlet holes are formed on the pipe wall of the grouting pipe 121. Cement grout or other chemical grout is injected into the surrounding soil and rock mass through the grouting pipe 121. The grout diffuses from the outlet holes and fills the pores and fissures of the soil and rock mass. After the grout solidifies, it bonds with the surrounding soil and rock mass to form a unified whole, thereby forming a reinforcement layer with high strength and impermeability inside the slope. This reinforcement layer can significantly improve the integrity and shear resistance of the slope in the sliding area and limit the internal displacement of the landslide.

[0040] Anti-slide piles 122 are also implanted inside the slope in the sliding area. The anti-slide piles 122 are reinforced concrete or steel piles, which penetrate the sliding surface and are embedded in the stable stratum to withstand the shear force generated when the landslide body slides down. The anti-slide piles 122 and the grouting pipes 121 are arranged in a staggered manner in space, for example, in a grid pattern at a certain interval, and the two together form a composite reinforcement structure.

[0041] In this composite reinforcement structure, the reinforcement layer formed by the grouting pipe 121 improves the mechanical properties of the surrounding soil and rock, reducing the earth pressure acting on the anti-slide pile 122. The anti-slide pile 122, as a rigid load-bearing component, directly resists the remaining sliding force and transfers the load to the deep stable strata. The tops of the grouting pipe 121 and the anti-slide pile 122 can be fixedly connected to the frame component 13, so that the load borne by the reinforcement component 12 can be transferred to the slope surface through the frame component 13, working in conjunction with the anti-slide force of the anchoring component 11 to jointly constrain the landslide movement in the local sliding area. The implantation angle and length of the grouting pipe 121 are determined according to the topography of the sliding area and the depth of the sliding surface; the length of the anti-slide pile 122 must ensure that the pile tip penetrates into the stable strata to a certain depth to ensure the anti-slide stability of the anti-slide pile 122.

[0042] In some embodiments, the frame component 13 may be an anchor cable frame beam; please continue reading. Figure 1The anchor cable frame beam connects the anchoring component 11 and the reinforcing component 12 into a crisscrossing grid structure on the slope surface. This grid structure is arranged along the slope surface, closely adhering to and fixed to the slope surface. For example, the anchor cable frame beam can be composed of multiple longitudinal beams and multiple transverse beams intersecting. The longitudinal beams are arranged along the dip direction of the slope surface, and the transverse beams are arranged along the azimuth direction of the slope surface. The intersections of the longitudinal and transverse beams form nodes. Each node corresponds to an anchor head of the anchoring component 11. The nodes of the anchor cable frame beam are fixedly connected to the anchor heads of the anchoring components 11. That is, after the anchor head passes through the pre-reserved holes at the nodes of the frame beam, the anchor cable 112 is locked to the surface of the frame beam through the anchor, thereby transmitting the tension applied by the anchor cable 112 through the nodes to the entire frame beam, and then dispersing it to a larger area of ​​the slope surface.

[0043] The beam body of the anchor cable frame beam is fixedly connected to the top of the reinforcing component 12. The top of the reinforcing component 12 protrudes a certain height from the slope surface and is integrally formed with the bottom of the anchor cable frame beam body by welding or concrete pouring. Through this arrangement, the shear force and anti-slip force borne by the reinforcing component 12 can also be transferred to the frame beam, thereby working in conjunction with the anti-slip force of the anchoring component 11 to form a spatial force-bearing system.

[0044] For example, the grid spacing of the anchor cable frame beam can be 3 meters × 3 meters, consistent with the spacing of the anchor cables 112, grouting pipes 121, and anti-slide piles 122, to ensure that the components are evenly distributed in space and work together to bear the load. The anchor cable frame beam is constructed by on-site casting of reinforced concrete or prefabrication and assembly. Its cross-sectional dimensions and reinforcement can be calculated and determined based on the magnitude of the sliding force and the slope deformation requirements. Through the grid connection of the anchor cable frame beam, the originally dispersed anchoring components 11 and reinforcing components 12 in the local support unit 1 are integrated into a whole load-bearing structure, effectively constraining the local sliding of the landslide body and reducing the transmission of sliding thrust and impact energy to the slope toe.

[0045] In some embodiments, the drainage assembly 14 may be an inclined drainage hole; please refer to Figure 3 , Figure 3 This is a cross-sectional schematic diagram of the drainage component provided in an embodiment of this application. The inclined drainage hole is used to drain groundwater inside the landslide body, reduce groundwater pressure, and prevent the stability of the landslide body from decreasing due to increased water pressure.

[0046] The inclined drainage hole includes an outer pipe and an inner pipe placed inside the outer pipe. The outer pipe can be a rigid pipe, such as a perforated polyethylene pipe (PE pipe) with a diameter of 100 mm. Multiple inlet holes are formed on the wall of the outer pipe to collect groundwater from inside the slope. A filter layer, consisting of two layers of permeable geotextile, is wrapped around the outside of the outer pipe to prevent fine soil particles from the slope from entering and causing blockage. The end of the outer pipe (the end extending into the slope) is wrapped with a bag-shaped permeable geotextile, which further filters fine particles from the groundwater while allowing water to flow smoothly into the outer pipe. The starting end of the outer pipe (the end exposed on the slope surface) passes through a pre-drainage hole on the panel-type support 111 and is fixed with mortar at the panel outlet to prevent the outer pipe from sliding out under its own weight.

[0047] The inner tube is a flexible tube with openings in its sidewalls, such as a 40mm diameter PE hose. The outer diameter of the inner tube is smaller than the inner diameter of the outer tube, allowing the inner tube to be freely inserted, removed, or fixed inside the outer tube. The end of the inner tube (the end that extends into the slope) is sealed to prevent water from entering directly from the end. Multiple spray holes are provided on the sidewalls of the inner tube for spraying high-pressure water when cleaning is required. A water inlet is located at the beginning of the inner tube (the end exposed on the slope surface) for connecting to an external high-pressure water source. Under normal drainage conditions, groundwater enters the outer tube through the inlet holes and filter layer in the outer tube wall, then flows into the inner tube through the gap between the outer and inner tubes or through the spray holes on the sidewalls of the inner tube, and finally exits from the beginning of the inner tube outside the slope. When the inlet holes or filter layer of the outer pipe become clogged with fine soil particles after prolonged use, high-pressure water is injected into the inner pipe through the water injection interface. The high-pressure water is then sprayed outward from the jet holes on the side wall of the inner pipe, forming a spray-type high-pressure water flow that flushes the inner wall of the outer pipe, the inlet holes of the outer pipe, and the filter layer, removing the clogged fine soil particles and restoring drainage capacity. The closed design at the end of the inner pipe ensures that all the high-pressure water flows out from the jet holes on the side wall, preventing water from flowing directly out from the end and reducing the cleaning effect. This inclined drainage hole structure allows for regular cleaning of both the inner and outer pipes without removing the outer pipe, which can extend the service life of the drainage component 14 and ensure long-term drainage of the landslide body.

[0048] Alternatively, as an alternative or supplementary embodiment to the above-mentioned inclined drainage hole, the drainage assembly 14 can also adopt other structural designs that facilitate cleaning or maintenance. For example, the inclined drainage hole can use a perforated PE pipe or a rigid permeable pipe as the inner pipe or directly as the drainage pipe body. This pipe body does not have a built-in jet-type inner pipe, but instead has a reserved operating channel for inserting a vibrating rod. When the drainage performance decreases, a vibrating rod is pushed inward from the starting end of the pipe body. The vibrating rod moves axially inside the pipe body and generates high-frequency vibration. The vibration energy shakes off the fine soil particles attached to the pipe wall and the inlet hole, allowing them to be discharged out of the pipe with the groundwater, thereby clearing the drainage channel.

[0049] In other embodiments, a small vibrator is pre-embedded inside the inclined drainage hole. This vibrator is fixed inside the pipe near its end, and its power cord extends from the beginning of the pipe and connects to an external interface. Under normal use, the vibrator is in standby or inactive. When cleaning is required, the vibrator is charged or directly powered by an external power source, activating it to generate continuous or intermittent vibration. The vibrational energy is transferred through the pipe wall to the surrounding soil and rock mass and filter layer, dislodging the clogging fine soil particles and discharging them with the water flow. This method eliminates the need for external tools, allowing cleaning operations to be completed solely through external power, thus improving maintenance convenience and automation. These various cleaning structures can be flexibly selected based on the landslide soil and rock type, groundwater sediment content, and construction conditions, ensuring that the inclined drainage hole maintains stable drainage capacity during long-term operation.

[0050] In some embodiments, the open-cut structure 2 can be a rectangular open-cut or an arched open-cut; the impact bearing capacity of the open-cut structure 2 is not lower than the peak impact energy of the remaining landslide body after being constrained by the local retaining unit 1. The local retaining unit 1 and the open-cut structure 2 are arranged sequentially in the sliding direction of the landslide body.

[0051] The landslide moves from high-altitude areas to low-altitude areas, that is, from the rear edge towards the toe. Local support unit 1 is positioned in the creep deformation zone at the rear edge of the landslide or in the critical sliding zone at the front and middle part, used to restrain the landslide mass and reduce sliding force and impact energy during the initial or acceleration phase of the landslide movement. Tunnel structure 2 is located on the roadway at the toe of the slope, downstream of local support unit 1, at the end of the landslide's movement path, used to bear the remaining impact energy of the landslide mass after being restrained by local support unit 1.

[0052] A buffer gap is provided between the partial support unit 1 and the open-cut structure 2. The buffer gap refers to the horizontal distance along the downward direction of the landslide, from the downstream boundary of the partial support unit 1 to the upstream boundary of the open-cut structure 2. The length of this buffer gap can be determined based on the movement trajectory of the landslide after being constrained by the partial support unit.

[0053] Specifically, a three-dimensional numerical simulation can be used to simulate the entire process of the landslide moving downstream from the location constrained by the local support unit 1 after instability, by inputting the design parameters of the local support unit 1. The simulation outputs the landslide's trajectory on the slope, sliding velocity, and impact energy attenuation curves along the slope. Please refer to [link / reference]. Figure 4 , Figure 4 A simulation diagram of the landslide motion trajectory provided in the embodiments of this application. Figure 4The diagram uses different colors or arrows to indicate the direction and speed of movement of different parts of the landslide: the creep deformation zone at the rear edge first undergoes tensile cracking and slides downwards; the landslide accelerates along the sliding surface, colliding with and exchanging energy with the already collapsed accumulation zone in the middle; some landslides continue to move downwards as debris flows. The diagram also shows the constraint effect of the placement of local support units on the landslide trajectory; after being constrained by the local support units, the landslide velocity in the core sliding area is significantly reduced, the direction of movement is deflected, and the impact energy attenuates along the path.

[0054] In the simulation results, after being constrained by local support units, the landslide's motion gradually changes from overall sliding to debris flow or discrete block rolling. The direction of motion may deflect, and the velocity decreases with increasing distance traveled. The buffer spacing must be determined to ensure that when the landslide reaches the location of tunnel structure 2, its peak impact energy has already decreased to within the range that the tunnel structure 2's impact resistance rating can withstand. Simultaneously, the buffer spacing should not be too large to avoid additional road occupancy or increased length of tunnel structure 2; nor should it be too small to prevent excessive residual impact energy from overloading tunnel structure 2.

[0055] The tunnel structure 2 is located at the toe of the slope along the highway, specifically downstream of the landslide area. It is designed to withstand the impact energy of the remaining landslide mass after being restrained by the local retaining unit 1 as it moves towards the highway. The impact resistance rating of the tunnel structure 2 is no less than the peak impact energy of the remaining landslide mass after being restrained by the local retaining unit 1. In other words, the design of the tunnel structure 2 must ensure that the maximum impact load (expressed as energy or force) it can withstand is greater than or equal to the peak impact energy of the remaining landslide mass after being reduced by the local retaining unit 1 when it reaches the highway area. This ensures that the tunnel structure 2 will not be damaged or unstable under the impact of the landslide.

[0056] The arched tunnel has an arc-shaped top, utilizing the arch structure to transform impact loads into pressure along the arch axis. It features strong impact resistance and a large span capacity, but its structural width is relatively large. In contrast, the rectangular tunnel has a straight top slab and sidewalls, resulting in a relatively smaller structural width, making it suitable for sections of the route with river access and limited space. Structural calculations show that, with high-strength concrete and reinforced steel bars, the rectangular tunnel's impact resistance can meet the maximum rockfall impact load in that section (i.e., the peak impact energy of the remaining landslide body after constraint by local support unit 1). Therefore, in specific engineering projects, considering topographical conditions, river channel occupancy restrictions, pile foundation beam size, and structural bearing capacity, the rectangular tunnel can be selected as the impact protection structure.

[0057] Please refer to Figure 5 , Figure 5This is a photographic illustration of the area to be treated after treatment, provided in an embodiment of this application. Complete local support units were installed at the rear edge and upper-middle part of the landslide in the area to be treated: panel-type piers with anchor cables are distributed in a grid pattern along the slope, and the anchor cable frame beams connect the panel-type piers into a whole. The longitudinal and transverse beams of the frame beams are clearly visible and closely adhere to the repaired slope surface. The outlets of the inclined drainage holes extend from the reserved holes in the panel-type piers; some outlets show traces of drainage, indicating that the drainage system is functioning normally. In the middle and front edge areas of the landslide, the collapsed debris has been cleared and the slope has been repaired. Areas without support units have maintained their natural vegetation restoration state. At the toe of the slope, a rectangular tunnel is continuously installed along the road line. The tunnel's top slab and sidewalls are made of poured concrete, resulting in a smooth appearance. The outside of the tunnel is adjacent to the river channel, and the river's flood control section has not been encroached upon. The inside of the tunnel is close to the rock slope, and the overall structure is stable. The road surface upstream and downstream of the tunnel is clean and free of debris, allowing vehicles to pass normally. The entire image shows that the landslide and its protective structure are in a stable state after treatment. The local retaining units and the tunnel structure work together to achieve the goal of ensuring safe passage on the highway.

[0058] In some embodiments, the highway high-altitude landslide hazard retaining structure may further include a dynamic monitoring system. This system is used to monitor the landslide body and protective structure in real time during construction and operation, acquiring dynamic change data on landslide deformation, stress on the retaining structure, and environmental factors. This data provides input parameters for the early warning model, ensuring the safety of the project throughout its entire lifecycle. The dynamic monitoring system includes rain gauges, surface displacement monitors, deep displacement monitors, stress sensors, and anchor cable force gauges.

[0059] Rain gauges are deployed above or in open areas surrounding the landslide to collect real-time rainfall data. Rainfall is a key factor inducing instability in high-altitude landslides, and rainfall data serves as an important input parameter for early warning models to determine the trend of landslide stability changes.

[0060] Surface displacement monitoring instruments are deployed around the local support unit 1 and at the core of each sliding zone of the landslide. By setting surface displacement monitoring points upstream, downstream, and at both sides of the local support unit 1, the horizontal and vertical displacements of the slope surface constrained by the local support unit 1 are monitored. The surface displacement monitoring instruments can use Global Navigation Satellite System (GNSS) receivers to achieve automated displacement monitoring with millimeter-level accuracy. Deep displacement monitoring instruments are deployed around the local support unit 1 and at key profile locations within the sliding zone, such as by installing inclinometer tubes and fixed inclinometers in boreholes. These instruments are used to monitor the change in horizontal displacement within the slope's depth range as a function of depth, determining whether accelerated deformation or deep creep has occurred on the sliding surface.

[0061] Stress sensors are attached to the inner wall of the tunnel structure 2, specifically at key stress-bearing locations such as the mid-span of the top slab, the middle of the sidewalls, and the corners between the top slab and sidewalls. These sensors monitor the surface strain and stress distribution of the concrete in the tunnel structure 2 under landslide impact loads, determining whether the actual stress state exceeds the design bearing capacity. When the monitored stress value approaches or exceeds the warning threshold (e.g., 80% of the design value), it indicates that the tunnel structure 2 may be under overload, requiring immediate emergency measures.

[0062] An anchor cable force gauge is connected in series with the anchor cable 112 of the anchoring assembly 11, specifically installed between the anchoring end of the anchor cable and the panel-type pad 111, for real-time monitoring of changes in the anchor cable tension. The anchor cable force gauge can be a vibrating wire force sensor, whose output signal is linearly related to the anchor cable tension. When the landslide body deforms or the sliding force increases, the anchor cable tension increases accordingly; when the monitored anchor cable tension exceeds a certain proportion of the locking load or design load, it indicates that the load on the local retaining unit 1 has increased, requiring early warning and assessment of the safety of the retaining structure.

[0063] All monitoring devices in the dynamic monitoring system can adopt automated data acquisition methods, transmitting monitoring data to the monitoring platform in real time via wired or wireless transmission networks. The monitoring platform can have a built-in early warning model, automatically judging based on preset displacement thresholds (e.g., 10 mm / day surface displacement), stress thresholds (80% of design value), and rainfall thresholds (e.g., 50 mm of cumulative rainfall in 24 hours). When any monitoring indicator exceeds the threshold, the platform can automatically issue an early warning signal to guide construction adjustments or emergency response during operation.

[0064] In other embodiments, for high-altitude landslides that are large in scale, have complex terrain, or have multiple independent sliding zones, the retaining structure for high-altitude landslide disasters along highways may include multiple sets of local retaining units 1. The multiple sets of local retaining units may be arranged sequentially along the sliding direction of the landslide, or arranged in parallel along the transverse direction of the landslide (i.e., perpendicular to the sliding direction), or a combination of longitudinal series and transverse parallel arrangement may be used simultaneously.

[0065] When multiple sets of local support units are arranged sequentially along the sliding direction, the first set of local support units is placed in the core sliding area at the rear edge or upper middle part of the landslide body to apply greater anti-sliding force in the early stage of landslide movement and reduce the main sliding thrust; the second set of local support units is placed in the transition area downstream of the first set to restrain the residual sliding body that still has a large movement speed or impact energy after being restrained by the first set; the subsequent sets of local support units are arranged sequentially downstream to form a multi-level active restraint stepped support system.

[0066] The spacing between each set of local support units is determined based on the landslide trajectory and velocity decay law determined by three-dimensional numerical simulation. The spacing should not be too small to avoid overlapping and waste, nor should it be too large to cause the residual landslide to re-accelerate before the lower-level support units take effect. After multiple sets of local support units are arranged in series along the sliding direction, when the landslide becomes unstable, it passes through the constraints of each set of support units step by step. Its sliding force and impact energy are reduced multiple times, and the remaining impact energy transmitted to the toe of the tunnel structure is significantly reduced, thereby reducing the impact resistance requirements of the tunnel structure or reducing the size of the tunnel structure.

[0067] When multiple sets of local retaining units are arranged side-by-side along the transverse side of a landslide, and the landslide width is large (e.g., exceeding 500 meters) with significant differences in sliding force, sliding surface depth, and topographic conditions across different transverse sections, the landslide can be divided into multiple retaining zones. Each zone contains an independently arranged set of local retaining units. The anchorage length, reinforcement component 12 insertion depth, and frame component 13 grid spacing of each set of local retaining units are independently designed based on the sliding force and geological conditions of that zone. The multiple sets of transversely arranged local retaining units are separated by slope intercepting ditches or expansion joints to prevent uneven settlement or deformation between different zones from affecting each other.

[0068] A buffer distance is maintained between multiple sets of local retaining units and the open-cut structure 2. The output of each set of local retaining units (i.e., the impact energy of the remaining landslide body after being constrained by that set) serves as the input condition for the next set of local retaining units or the open-cut structure. Multi-level coupling analysis is performed through three-dimensional numerical simulation to verify and optimize the design parameters of each set of retaining units step by step. In practical engineering applications, for example, if a landslide body has a creeping deformation body at the rear edge, a collapsed accumulation area in the middle, and a shallow small landslide risk area at the front edge, the first set of local retaining units can be set in the creeping deformation area at the rear edge, and the second set of local retaining units can be set downstream of the collapsed accumulation area in the middle. The two sets of local retaining units work together to constrain the movement of the landslide body.

[0069] Furthermore, for landslides with extremely long longitudinal lengths (exceeding 1000 meters) or multiple sliding surfaces of varying depths, multiple sets of local support units can be arranged in series along the sliding direction. These local support units are deployed sequentially from top to bottom: the first set near the rear edge treats the deep main sliding surface; the second set in the middle treats the intermediate sliding surface and residual sliding force; and the third set at the front edge treats the shallow sliding surface and localized collapses. The spacing between adjacent sets of local support units is determined step-by-step based on the landslide trajectory and velocity recovery distance output from the three-dimensional numerical simulation, ensuring that each level of support unit can apply constraint again before the residual sliding material fully accelerates. The introduction of multiple sets of local support units further reduces the impact energy in stages. The tunnel structure 2 only needs to withstand the minimal residual energy after multiple stages of reduction, thus allowing for the use of a lightweight tunnel or even just a protective net to ensure highway safety.

[0070] In the above implementation process, local retaining units are only deployed in key sliding areas. Anchoring components apply active anti-sliding forces to the landslide body, reinforcement components are embedded inside the slope to form a composite structure to enhance the overall integrity of the slope, frame components connect the two into a spatial stress grid and distribute the load to the slope surface, and drainage components drain groundwater to reduce pore water pressure. These four components work together to effectively constrain landslide movement and significantly reduce sliding thrust and impact energy. The remaining impact energy after reduction by the local retaining units is borne by the downstream tunnel structure. The tunnel structure only needs to be designed with impact resistance levels based on the remaining energy, avoiding the risk of single tunnel protection failing due to excessive impact energy. Therefore, through the coordinated operation of local retaining units and tunnel structures, the engineering cost of high-altitude landslide disaster management can be reduced, achieving a balance between safety and economy in high-altitude landslide disaster management.

[0071] It should be understood that when the components of the highway high-level landslide disaster retaining structure provided in the above embodiments are working, the division of each functional module in the above description is only used as an example. In actual application, the above functions can be assigned to different functional modules as needed. That is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0072] Based on the same concept, this application also provides a design method for a retaining structure for high-altitude landslide disasters along highways. Please refer to [link / reference]. Figure 6 , Figure 6 A schematic diagram illustrating the steps of a design method for a retaining structure against high-altitude landslides along highways, as provided in this application embodiment. The method may include: S61. Obtain the survey data of the landslide body.

[0073] Comprehensive survey methods can be employed to conduct a thorough investigation of high-altitude landslide areas along highways, in order to determine the spatial morphology, scale, deformation characteristics, material structure, and groundwater characteristics of the landslide body. These comprehensive survey methods may include on-site investigation, UAV aerial mapping, ground-penetrating radar detection, on-site displacement monitoring, borehole sampling, and in-situ shear tests.

[0074] Drone aerial mapping is used to acquire the macroscopic topography and boundary range of the landslide body, determining its overall outline and topographic relief. Drilling and ground-penetrating radar are used to locate the depth and morphology of the sliding surface, identifying its spatial distribution and continuity. On-site displacement monitoring is used to determine landslide deformation characteristics, including deformation direction, rate, and stage. Sampling and in-situ shear tests are used to accurately obtain the mechanical parameters of the soil and rock mass. Simultaneously, a combination of on-site sampling, laboratory tests, and in-situ testing is used to acquire the mechanical parameters of the soil and rock mass in each sliding zone. These parameters include cohesion, angle of internal friction, unit weight, elastic modulus, and Poisson's ratio.

[0075] S62. Based on the mechanical parameters and the preset stability safety factor, the stability coefficient and sliding force distribution of the landslide body are calculated using the limit equilibrium method.

[0076] In this regard, the stability coefficient, sliding force magnitude and distribution characteristics of each sliding zone and the entire landslide can be calculated by using the limit equilibrium method, based on the "Design Specification for Prevention and Control of Highway Landslides" (JTG-T 3334-2018) and the obtained soil and rock mechanical parameters (including cohesion, internal friction angle, unit weight, elastic modulus and Poisson's ratio).

[0077] S63. Establish a three-dimensional numerical simulation model, construct the spatial morphological features as a landslide terrain grid, take the mechanical parameters and sliding force distribution as input conditions, simulate the motion trajectory, sliding velocity and impact energy distribution after the landslide body becomes unstable, and output the peak impact energy of each sliding area on the highway line.

[0078] The overall stability level of the landslide is determined by comparing the stability coefficient with a preset stability safety factor. A three-dimensional numerical simulation model is also established, with input parameters including landslide topography, soil and rock parameters, and boundary conditions (such as groundwater characteristics and sliding surface morphology). This model simulates the landslide's trajectory, sliding velocity, and impact energy distribution after instability, thereby identifying the impact risk points and peak impact energy of each sliding zone on the highway and substructure protection. The three-dimensional numerical simulation employs either the discrete element method or the finite difference method. These methods can accurately simulate the synergistic effects of multi-region sliding, i.e., the mutual influence when multiple independent sliding zones instably occur simultaneously or sequentially, as well as the interaction between the landslide and the soil and rock mass, such as the contact and friction between the landslide body and the sliding surface, and between the soil and rock mass within the slope. The simulation results visually reflect the dynamic evolution process after landslide instability, including stages such as landslide fracturing, acceleration, and accumulation, providing a quantitative basis for subsequent protection scheme design.

[0079] S64. If the stability coefficient is lower than the preset stability threshold, multiple candidate schemes are generated based on the sliding force distribution and the peak impact energy. Each candidate scheme includes a support range parameter and a tunnel impact resistance level parameter.

[0080] When the stability coefficient of the landslide calculated using the limit equilibrium method is lower than the preset stability threshold, it indicates that the landslide is in an unstable to basically stable state and requires engineering treatment. In this case, the decision is made to adopt a comprehensive treatment approach of "local active support plus lower open-cut tunnel protection." Based on this decision, multiple candidate solutions are generated according to the sliding force distribution and impact energy peak calculated in step S62.

[0081] Each candidate scheme includes a retaining range parameter and a tunnel impact resistance level parameter. The retaining range parameter defines the layout range of local retaining units on the landslide body, such as covering only the rear edge creep deformation zone, extending to the central collapsed zone, or further covering the front edge shallow collapsed zone; the larger the retaining range, the stronger the restraint effect, but the higher the cost of the retaining structure. The tunnel impact resistance level parameter defines the maximum impact energy (or the corresponding structural strength, reinforcement ratio, and concrete grade) that the tunnel structure can withstand; the higher the impact resistance level, the higher the cost of the tunnel structure. By generating multiple combinations of retaining range and tunnel impact resistance level, a comparative basis is provided for subsequent collaborative optimization.

[0082] S65. For each candidate scheme, call the three-dimensional numerical simulation model, input the support range parameters of the candidate scheme, simulate the impact energy of the remaining landslide body on the tunnel after local support, and determine whether the impact energy is lower than the bearing capacity corresponding to the impact resistance level of the tunnel of the candidate scheme.

[0083] For each candidate scheme generated in S64, the three-dimensional numerical simulation model established in step S62 is called again. The support range parameters of the candidate scheme are used as input conditions. In the model, local support units are set to be deployed only within the specified support range, and simulation is performed according to preset support strength parameters. After running the numerical simulation, the peak value of the remaining impact energy after the landslide body moves from the constrained area to the road at the toe of the slope after instability is output. This peak value of the remaining impact energy is compared with the bearing capacity corresponding to the impact resistance level of the tunnel in the candidate scheme. The judgment condition is: whether the peak value of the remaining impact energy is lower than the bearing capacity corresponding to the impact resistance level of the tunnel. If it is lower, the candidate scheme is feasible in terms of safety; if it is not lower, it means that the tunnel structure under this scheme cannot safely withstand the impact, and the scheme needs to be excluded or the impact resistance level of the tunnel needs to be increased, the support range expanded, and then re-selected. This judgment process ensures that each feasible scheme can meet the safety principle of preventing tunnel structure failure.

[0084] S66. If the impact energy is lower than the bearing capacity corresponding to the impact resistance level of the tunnel in the candidate scheme, the sum of the cost of the retaining structure and the cost of the tunnel structure in the candidate scheme shall be calculated as the total cost; the retaining range parameters and the impact resistance level parameters of the tunnel corresponding to the candidate scheme with the minimum total cost shall be determined as the target design parameters.

[0085] For candidate schemes deemed feasible by S65, the costs of the retaining structure and the open-cut tunnel structure under each scheme are calculated. The cost of the retaining structure is determined based on the retaining range parameters, including the quantity and construction costs of materials such as panel-type pier anchor cables, grouting pipes, anti-slide piles, anchor cable frame beams, and inclined drainage holes; the larger the retaining range, the more anchor cables, grouting pipes, and anti-slide piles are required, and the higher the cost.

[0086] The cost of the tunnel structure is determined based on the tunnel's impact resistance parameters, including concrete strength grade, steel reinforcement ratio, tunnel cross-sectional dimensions, and length. Higher impact resistance requires higher concrete grades and more steel reinforcement, resulting in higher costs. The total cost of the candidate scheme is obtained by adding the cost of the retaining structure to the cost of the tunnel structure. A comparative analysis of the total costs of all feasible schemes is performed, and the retaining range parameters and tunnel impact resistance parameters corresponding to the candidate scheme with the lowest total cost are selected as the target design parameters. This optimization iteration can achieve the design goal of "lowest total cost under safety constraints," avoiding the high costs of full-area retaining and the over-design of a single strong tunnel.

[0087] S67. Based on the target design parameters, output the layout scheme of the local support units and the construction scheme of the tunnel structure.

[0088] The layout scheme of the local support unit includes: within the optimal support range, determining the layout position, anchor length, incident angle, design load and locking load of the panel-type pier anchor cable; determining the implantation depth, spacing and inclination angle of the grouting pipe and anti-slide pile; determining the grid size and cross-sectional reinforcement of the anchor cable frame beam; and determining the length, inclination angle and spacing of the inclined drainage hole.

[0089] The construction scheme for the tunnel structure includes: determining the cross-sectional form (rectangular tunnel or arched tunnel), length, building clearance, concrete strength grade, reinforcement configuration scheme, and the layout of the outer pile foundation support beams based on the optimal impact resistance level of the tunnel.

[0090] The following is a specific embodiment provided in this application to further illustrate the design method of the retaining structure for high-altitude landslide disasters on highways provided in this application.

[0091] A landslide occurred, with collapses of approximately 7,000 cubic meters and 85,000 cubic meters respectively, burying approximately 100 meters of roadbed and riverbed below. This resulted in the interruption of the national highway, blockage of the main river, and a shift of the river channel to the right, threatening the safety of the national highway, the river, villagers on the opposite bank, and a nearby power tower. On-site investigation revealed that, influenced by the landslide, the rear slope had begun to deform and crack, forming a creeping deformed body with a volume of approximately 25,000 cubic meters. The largest crack at the rear edge was approximately 5 cm wide, posing a risk of further collapse. A retaining structure design is required to ensure road accessibility. The specific implementation steps of this application are as follows: Aerial mapping using drones determined the landslide boundary to be 800m × 500m. Nine boreholes were drilled. Through on-site investigation, borehole drilling, and ground-penetrating radar detection, the main potential large-scale landslide area was identified as the soil at the rear edge of the already slidable zone, with a potential sliding surface depth of 10-20m and a volume of approximately 100,000 cubic meters. In addition, there is a risk of shallow, small-scale landslides within the already slidable zone, generally less than 10 cubic meters in volume. Sampling and testing, combined with in-situ shear tests, yielded the following soil and rock mechanical parameters for each area: cohesion 11-14 kPa, internal friction angle 26°-28°, unit weight 20-22 kN / m³, elastic modulus 1.5-2.5 GPa, and Poisson's ratio 0.25-0.30.

[0092] The overall stability coefficient of the landslide was calculated to be 0.97-1.05 using the limit equilibrium method, indicating that it was in an unstable to basically stable state, with a sliding force of about 2000 kN / m. A three-dimensional numerical model was established using the finite difference method, and the simulated peak energy of the landslide impacting the highway area after instability was 10000 kJ, which exceeds the bearing capacity of a conventional open-cut tunnel.

[0093] The soil at the rear edge of the sliding zone and the entire sliding zone area need to be protected. The estimated cost of all the retaining structures is 65 million yuan, which is not economically viable. A single open-cut tunnel cannot withstand the impact energy, so a comprehensive solution of "partial retaining + open-cut tunnel" is adopted.

[0094] For the soil at the rear edge of the sliding zone, a comprehensive support scheme of "panel-type pier anchor cable + steel perforated pipe + steel pipe pile + anchor cable frame beam + inclined drainage hole" is adopted. The anchor cable is 35-55m long, spaced 3m×3m, using 6 bundles of φ15.2mm anchor cables, with an incident angle of 25°, a design load of 750kN, and a locking load of 600kN; the panel thickness is 0.5m; the steel perforated pipe is 9m long, spaced 3m×3m, with an inclination angle of 25°; the inclined drainage hole is 35m long, with an inclination angle of 7°, and is laid out at a spacing of 8m, which can be adjusted according to the actual site conditions. The pipe material is 100mm diameter perforated PE pipe, wrapped with two layers of permeable geotextile as a filter layer to prevent the hole wall from being blocked. The end inside the slope is wrapped with bag-shaped permeable geotextile and tied tightly together with the geotextile of the pipe body. The reinforced concrete panel is pre-reserved with inclined drainage holes, and the panel outlet is fixed with M7.5 mortar to prevent it from sliding out under its own weight.

[0095] Further simulations confirmed that the peak energy of shallow, small landslides within the landslide area had decreased to 800 kJ, necessitating passive protection using a tunnel. The tunnel is 115m long with a structural clearance of 10.05m x 5.0m, meeting the tunnel's load-bearing requirements. The project route borders a river on the outer side and a rock slope on the inner side. An arched tunnel with strong impact resistance would be 15.5m wide, but based on measured cross-sections, the outer side has approximately 5-7m of open space. The large-scale pile foundation beams would be detrimental to structural safety and overall stability. Furthermore, encroachment on the river channel outside the project area is not permitted, making it difficult to meet the structural outline requirements. A rectangular tunnel, with a smaller width than the arched tunnel, allows for feasible pile foundation beam placement on the outer side, making it more feasible for this section of the route. Structural calculations show that the rectangular tunnel's load-bearing capacity can withstand the maximum rockfall impact load within the section. Therefore, considering the existing road utilization and modification, structural load-bearing capacity, and normal usage functionality, a rectangular tunnel is recommended to meet the requirements of this section of the route.

[0096] After optimization, the total cost was reduced to 45 million yuan, saving 30.77% compared to the entire area's support structure.

[0097] Furthermore, by deploying one rain gauge, six GPS displacement monitoring points, three deep displacement monitoring points, eight stress sensors, and 15 anchor cable force gauges on the landslide, an early warning model was established. The displacement early warning threshold was set at 10 mm / d, and the stress early warning threshold was set at 80% of the design value, enabling real-time monitoring and early warning during construction and operation to ensure project safety.

[0098] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A retaining structure for high-altitude landslide disasters along highways, characterized in that, include: At least one set of local support units (1) are arranged in the sliding area of ​​the landslide body to constrain the movement of the landslide body in the sliding area; the local support unit (1) includes an anchoring component (11), a reinforcement component (12), a frame component (13), and a drainage component (14); one end of the anchoring component (11) is anchored into the stable stratum of the landslide body, and the other end is tensioned and locked to the slope surface of the landslide body to apply anti-sliding force to the landslide body; the reinforcement component (12) is implanted into the slope of the sliding area to form a composite structure with the surrounding rock and soil; the frame component (13) connects the anchoring component (11) and the reinforcement component (12) to form a spatial stress grid on the slope surface of the landslide body to transfer the load applied by the anchoring component (11) to the slope surface; the drainage component (14) passes through the local support unit (1) from the slope surface and extends into the interior of the landslide body to drain groundwater; The tunnel structure (2) is set at a predetermined position on the highway to withstand the impact energy of the remaining landslide body after being constrained by the local support unit (1).

2. The retaining structure for high-altitude landslide disasters along highways according to claim 1, characterized in that, The anchoring assembly (11) includes a panel-type pier (111) and an anchor cable (112); the panel-type pier (111) is attached to the slope surface, the anchor cable (112) passes through the panel-type pier (111) and is anchored into the stable stratum, and the tension end of the anchor cable (112) is locked to the slope surface through the panel-type pier (111).

3. The retaining structure for high-altitude landslide disasters along highways according to claim 2, characterized in that, The panel-type pier (111) is a reinforced concrete structure. The side of the panel-type pier (111) facing the inside of the slope body is attached to the excavated slope surface. The side of the panel-type pier (111) facing the outside of the slope body is provided with anchor holes for anchor cables (112) and reserved holes for drainage holes. The angle between the central axis of the anchor holes for anchor cables (112) and the horizontal plane is 20° to 30°.

4. The retaining structure for high-altitude landslide disasters along highways according to claim 1, characterized in that, The reinforcement component (12) includes a grouting pipe (121) and an anti-slide pile (122); the grouting pipe (121) is inserted into the slope of the sliding area, and grout is injected into the surrounding rock and soil through the grouting pipe (121) to form a reinforcement layer; the anti-slide pile (122) is inserted into the slope of the sliding area to withstand shear force and form a composite reinforcement structure with the grouting pipe (121).

5. The retaining structure for high-altitude landslide disasters along highways according to claim 1, characterized in that, The frame component (13) is an anchor cable frame beam; the anchor cable frame beam connects the anchoring component (11) and the reinforcing component (12) on the slope surface to form a crisscrossing grid structure, the nodes of the anchor cable frame beam are fixedly connected to the anchor head of the anchoring component (11), and the beam body of the anchor cable frame beam is fixedly connected to the top of the reinforcing component (12).

6. The retaining structure for high-altitude landslide disasters along highways according to claim 1, characterized in that, The drainage component (14) is an inclined drainage hole; the inclined drainage hole includes an outer pipe and an inner pipe placed inside the outer pipe. The inner pipe is a flexible pipe with openings in the side wall. The end of the inner pipe is closed, and the beginning end of the inner pipe is provided with a water injection interface.

7. The retaining structure for high-altitude landslide disasters along highways according to claim 1, characterized in that, The tunnel structure (2) is a rectangular tunnel or an arched tunnel; the impact resistance level of the tunnel structure (2) is not lower than the peak impact energy of the remaining landslide body after being constrained by the local support unit (1).

8. The retaining structure for high-altitude landslide disasters along highways according to claim 1, characterized in that, The highway high-level landslide disaster retaining structure (10) also includes a dynamic monitoring system, which includes a rain gauge, a surface displacement monitor, a deep displacement monitor, a stress sensor and an anchor cable force gauge. The rain gauge is installed above the landslide body, the surface displacement monitor and the deep displacement monitor are respectively installed around the local retaining unit (1) and the key stress-bearing parts of the tunnel structure (2), the stress sensor is attached to the inner wall of the tunnel structure (2), and the anchor cable force gauge is connected in series to the anchor cable (112) of the anchoring component (11).

9. The retaining structure for high-altitude landslide disasters along highways according to claim 1, characterized in that, The local support unit (1) and the open tunnel structure (2) are arranged sequentially in the downward direction of the landslide body, and the open tunnel structure (2) is located downstream of the local support unit (1); a buffer gap is provided between the local support unit (1) and the open tunnel structure (2), and the length of the buffer gap is determined according to the movement trajectory of the landslide body after being constrained by the local support unit (1).

10. A design method for retaining structures to prevent high-altitude landslides along highways, characterized in that, The method, applied to the retaining structure for high-altitude landslide disasters along highways according to any one of claims 1-9, comprises: Obtain survey data of the landslide body; the survey data shall include at least the spatial morphological characteristics of the landslide body and the mechanical parameters of the soil and rock mass; Based on the aforementioned mechanical parameters and the preset stability safety factor, the stability coefficient and sliding force distribution of the landslide body are calculated using the limit equilibrium method. A three-dimensional numerical simulation model is established, and the spatial morphological features are constructed as a landslide terrain grid. The mechanical parameters and the distribution of sliding force are used as input conditions to simulate the motion trajectory, sliding velocity and impact energy distribution of the landslide after instability, and output the peak impact energy of each sliding area on the highway. If the stability coefficient is lower than the preset stability threshold, then multiple candidate schemes are generated based on the sliding force distribution and the peak impact energy. Each candidate scheme includes a support range parameter and a tunnel impact resistance level parameter. For each candidate scheme, the three-dimensional numerical simulation model is invoked, the support range parameters of the candidate scheme are input, the impact energy of the remaining landslide body on the tunnel after partial support is simulated, and it is determined whether the impact energy is lower than the bearing capacity corresponding to the impact resistance level of the tunnel of the candidate scheme. If the impact energy is lower than the bearing capacity corresponding to the impact resistance level of the tunnel in the candidate scheme, then the sum of the cost of the retaining structure and the cost of the tunnel structure in the candidate scheme is calculated as the total cost; the retaining range parameters and the impact resistance level parameters of the tunnel corresponding to the candidate scheme with the minimum total cost are determined as the target design parameters. Based on the target design parameters, output the layout scheme of the local support unit and the construction scheme of the tunnel structure.

Images