Method for treating collapse of tunnel side and front slope

Abstract

The invention belongs to the technical field of plateau tunnel construction, and particularly relates to a tunnel side and upward slope collapse treatment method which comprises the steps of S5, parameter inversion and model calibration: comparing displacement data monitored in the step S2 with a predicted value of a model in the step S1, when deviation exceeds a preset threshold value, keeping a slope geometric model unchanged, and if the deviation exceeds the preset threshold value, performing model calibration; geomechanical parameters in the model are systematically inversed and adjusted through an iterative algorithm, so that the stability state obtained through calculation of a three-dimensional wedge method is matched with the actual slope state reflected by monitoring data, the model is calibrated, and the geomechanical parameters at least comprise the effective cohesive force and the effective internal friction angle of the sliding surface. According to the tunnel side and upward slope collapse treatment method, through three-dimensional geological modeling and stereographic projection analysis, the geometrical morphology and scale of a potential unstable wedge body can be accurately recognized from the beginning, so that treatment measures are more targeted, and blindness is avoided.

Description

Technical Field

[0001] This invention relates to the field of plateau tunnel construction technology, and in particular to a method for treating tunnel side slope collapse. Background Technology

[0002] The slopes at the exit sections of mountain tunnels often have steep, exposed surfaces due to artificial excavation, which expose and disrupt the original stress balance of the rock mass, making them highly susceptible to collapse. These slopes typically have complex geological conditions, including issues such as karst development and unfavorable combinations of dominant structural planes. Their stability control is a key technical challenge for the safe construction and long-term operation of tunnel projects.

[0003] Currently, the traditional method for treating such collapsed slopes typically employs static design based on a single geological survey, followed by conventional engineering measures such as clearing, anchoring, and drainage. However, this method has significant limitations: the initial geological survey cannot accurately obtain the true mechanical parameters of the soil and rock mass, leading to a large discrepancy between the calculation results based on idealized models and the actual working state of the slope, resulting in insufficient design reliability; the deformation response of the slope during construction is the most direct information reflecting its stability state, but traditional methods lack systematic real-time monitoring data and closed-loop linkage with the design scheme, making it impossible to dynamically adjust and optimize the treatment plan according to the actual performance of the slope, posing a risk of blind construction; especially when there are important structures such as bridge pile foundations at the slope toe, the impact risk of the collapsed body during the clearing process is high, and conventional rigid retaining structures are prone to brittle failure under dynamic load impact, with poor self-adaptive energy dissipation capacity and limited protective effect. Therefore, the present invention solves the shortcomings of the above-mentioned technical problems. Summary of the Invention

[0004] Based on the aforementioned technical problems, this invention proposes a method for treating tunnel side slope collapse.

[0005] This invention proposes a method for treating tunnel side slope collapse, the method comprising, S1. Establishment of Geological Exploration and Dynamic Design Mechanism: Conduct engineering geological exploration to identify the extent of the collapse body, karst development zone and dominant structural planes. By integrating topographic data, stratigraphic interface data, and dominant structural plane occurrence and distribution data, establish a three-dimensional geological model of the slope. Based on the three-dimensional geological model, use stereographic projection method to analyze the spatial combination relationship of dominant structural planes, identify the geometric shape and scale of potential unstable wedges, and use the three-dimensional wedge method to calculate the initial stability coefficient of the slope.

[0006] S2. Staged Clearing and Platform Excavation: Staged clearing and excavation are carried out according to the initial design to form multi-level slopes and multiple wide platforms. The bottom boundary line of the clearing is reserved for the length of the tunnel opening. During this process, the slope surface displacement, crack development and meteorological and hydrological data are monitored for safety, and the monitoring data is fed back to the dynamic design mechanism to guide construction adjustments and optimizations.

[0007] S3. Comprehensive anchoring support: Anchoring works are carried out on the slope after clearing.

[0008] S4. Three-dimensional drainage system layout: Intercepting ditches, rapid flow channels and water diversion channels are laid at the top of the slope, at each level of platform and at the foot of the slope, and inclined drainage holes are set in the slope body to form a three-dimensional drainage system that combines the surface and underground.

[0009] S5. Parameter Inversion and Model Calibration: Compare the displacement data monitored in step S2 with the predicted values ​​of the three-dimensional geological model in step S1. When the deviation exceeds a preset threshold, keep the slope geometry model unchanged and use an iterative algorithm to systematically invert and adjust the geomechanical parameters in the model, so that the stability state calculated by the three-dimensional wedge method matches the actual slope state reflected by the monitoring data, thereby calibrating the model. The geomechanical parameters include at least the effective cohesion of the slip surface. and effective internal friction angle .

[0010] S6. Dynamic Prediction and Scheme Optimization: Using the calibrated model and parameters, the stability coefficient under subsequent working conditions is recalculated. If the predicted value does not meet the safety requirements, the support design scheme is optimized and a design adjustment instruction is generated.

[0011] S7. Support Implementation and Feedback: Carry out support construction according to the optimized plan, continue monitoring, and feed the data back to step S5 to form a closed-loop dynamic design process.

[0012] Preferably, the calculation formula for the three-dimensional wedge method is as follows: ,in, This represents the landslide safety factor.

[0013] and Sliding surfaces and sliding surface The area is expressed in square meters.

[0014] and Sliding surfaces and sliding surface Effective cohesion, measured in kilopascals.

[0015] and Sliding surfaces and sliding surface The internal friction angle, in degrees.

[0016] and For sliding surface and sliding surface The effective normal reaction force, measured in kilonewtons.

[0017] For the crack surface The pore pressure is expressed in kilonewtons.

[0018] The weight of the wedge is expressed in kilonewtons.

[0019] The anchor bolt reinforcement force is expressed in kilonewtons.

[0020] in, .

[0021] .

[0022] ,in, and For the crack surface The angle of inclination and dip, in degrees.

[0023] and For sliding surface Sliding surface Intersection The angle of inclination and dip, in degrees.

[0024] and To strengthen the anchor bolt The angle of inclination and dip, in degrees.

[0025] By employing the above technical solution and calculating the ratio of the anti-sliding force to the sliding force acting on the sliding surface, the stability safety factor of the slope under specific working conditions can be accurately obtained. ,in, , , As directional coefficients, the weight of the wedge, the water pressure in the tension crack, and the anchor reinforcement force are projected onto the direction of the intersection line of the sliding surface to ensure the accuracy of the force system calculation.

[0026] Preferably, the graded clearing in step S2 specifically involves dividing the slope into 9 levels with different slope ratios from top to bottom. The slope ratios for levels 1-4 are 1:0.75, for levels 5-6 they are 1:1, and for levels 7-9 they are 1:1.25. Wide platforms with widths ≥6m and ≥10m are set at elevations of 980m and 1010m, respectively. The length of the reserved tunnel opening is ≥10m.

[0027] Through the above technical solutions, by optimizing the steep slope into 9 steps and setting different slope ratios, the height and slope of the single-stage slope are effectively reduced, and the landslide thrust is dispersed. The wide platforms set at elevations of 980m and 1010m not only serve as operating platforms and transportation channels for construction machinery, improving construction efficiency, but more importantly, they play a key role in unloading, interrupting the continuity of the potential sliding surface, greatly improving the overall stability of the slope. The reserved length of open tunnel of not less than 10m provides a buffer protection zone for the tunnel entrance, ensuring the safety of the tunnel structure during the slope treatment process.

[0028] Preferably, the layout of the three-dimensional drainage system in step S4 includes: setting up a slope top intercepting ditch with a cross section of 40cm×40cm 5 meters outside the slope excavation line, setting up platform intercepting ditches on the wide platforms at each level, and connecting them through a rapid flow channel to guide the collected water to the slope foot diversion channel, and finally discharging it into the downstream river channel.

[0029] Through the above technical solutions, the three-dimensional drainage system constructs a complete drainage system that combines interception, drainage, guidance, and infiltration. The intercepting ditch at the top of the slope intercepts surface runoff 5 meters outside the slope excavation line to prevent it from eroding the slope. The intercepting ditches at each level collect the slope runoff and guide the water safely and quickly to the toe of the slope through the rapid flow channel. The toe drainage channel concentrates the collected water flow into the downstream river channel to avoid eroding the toe of the slope. At the same time, the inclined drainage holes set in the slope can effectively remove deep groundwater and reduce the pore water pressure near the slip surface, thereby significantly improving the shear strength of the soil and rock mass. This system realizes the coordinated management of surface water and groundwater.

[0030] Preferably, the safety monitoring in step S2 includes: setting up ≥22 surface displacement monitoring points, using a high-precision total station for monitoring, with a monitoring frequency of no less than once every 3 days during the construction period, and increasing to once every 3 hours in case of heavy rain or abnormal deformation, and continuing monitoring for ≥3 years after the completion of the project.

[0031] Through the above technical solutions, a dynamic monitoring network for safety monitoring is formed, which includes regular inspections, automatic early warnings, and emergency response. By deploying no fewer than 22 monitoring points, a monitoring network covering key areas of the slope is formed. High-precision total stations are used for periodic measurements, and the monitoring frequency is dynamically adjusted according to the working conditions: once every 3 days under normal circumstances. In the event of heavy rain or abnormal deformation, the emergency plan is immediately activated, and the monitoring frequency is increased to once every 3 hours, so as to achieve real-time capture of potential dangers. Monitoring will continue for 3 years after the completion of the project, providing data support for long-term evaluation of the treatment effect and maintenance decisions.

[0032] Preferably, the anchoring work in step S3 includes, S31. In the middle and lower part of the slope, where the rock mass is fractured or karst is developed, the construction of anchor cable frame beams is used for strong support. Before the graded clearing, a rock-buried retaining dam is also constructed above the bridge pile foundation affected at the toe of the slope. The retaining dam is 145-150 meters long and is used to protect the safety of the structures below during the clearing process.

[0033] S32. Anchor frame beams are constructed to support other areas of the slope.

[0034] S33. Surface protection is carried out by constructing a mesh-covered and sprayed substrate plant slope protection system at the top of the slope.

[0035] Through the above technical solutions, in the key stress areas of the lower part of the slope where stress is concentrated, rock mass is fractured, or karst development is developed, high-prestressed anchor cable frame beams are used for strong support to form a solid bearing ring. In areas with better stability, anchor rod frame beams are used for conventional reinforcement, which is economical and efficient. At the top of the slope, netting and hydroseeding substrate vegetation protection is used to prevent surface weathering and peeling, restore ecology, and beautify the environment. The rock-buried retaining dam constructed at the toe of the slope before clearing serves as an early passive protection measure to effectively prevent falling rocks from impacting and damaging the bridge pile foundations below during the clearing process.

[0036] Preferably, the iterative algorithm used for systematic inversion adjustment in step S5 specifically involves: constructing an objective function with the monitored displacement value as the objective function and the geomechanical parameters as variables. The objective function is the sum of squares of the differences between the calculated displacement and the monitored displacement. The optimal geomechanical parameters are obtained by minimizing the objective function using an optimization algorithm. Specifically: Step 1: Define the objective function: based on the aforementioned monitored displacement values Displacement values ​​calculated by the model The objective function is constructed from the sum of squared residuals. : .

[0037] in The parameter vector to be inverted, i.e. .

[0038] Number of displacement monitoring points.

[0039] Based on parameter vector The third, calculated using the three-dimensional wedge method Displacement values ​​of each monitoring point.

[0040] : No. The actual measured displacement values ​​of each monitoring point.

[0041] The objective function value, the goal of the inversion is to find the value that makes... Minimum parameter vector .

[0042] Step 2, Iterative Optimization Algorithm: Gradient descent is used for automatic optimization, and the parameter update formula is as follows: ,in Number of iterations.

[0043] : No. The parameter estimates at the next iteration.

[0044] The learning rate controls the magnitude of each parameter update.

[0045] The gradient of the objective function at the current parameter values ​​is a vector pointing to... The fastest growing direction has the following component form: ,in It is the first The calculated displacement is for the first... The sensitivity of each parameter.

[0046] Step 3, Termination of calibration: When the difference between the objective function values ​​of two adjacent iterations... The iteration terminates when the value is less than a preset threshold, at which point the corresponding parameter vector... These are the optimal parameters obtained from the inversion, and the model has completed calibration.

[0047] Through the above technical solution, the parameter inversion and model calibration process is essentially a precise calibration that assimilates the numerical model with the actual situation. It uses the real displacement data obtained from field monitoring as the sole standard, and automatically and repeatedly adjusts the geomechanical parameters in the three-dimensional wedge model through optimization algorithms such as gradient descent. This process is achieved by minimizing the objective function between the calculated displacement and the monitored displacement, ultimately making the numerical model no longer an idealized theoretical tool, but a digital twin that can accurately reflect the real mechanical state of the slope. The gradient calculation clarifies the sensitivity of each parameter to the displacement, guides the direction and step size of parameter adjustment, and ensures that the inversion process is fast and convergent.

[0048] Preferably, the dynamic design mechanism in step S2 includes: The geological model building module is used to integrate multi-source data to generate three-dimensional geological models and identify potentially unstable wedges.

[0049] The stability analysis module is used to calculate the slope stability coefficient based on the three-dimensional wedge method.

[0050] The monitoring data interface module is used to receive real-time monitoring data.

[0051] The parameter inversion analysis module is used to perform iterative inversion of geomechanical parameters and model calibration.

[0052] The scheme simulation and optimization module is used to predict stability and optimize support schemes.

[0053] The decision support output module is used to generate design adjustment instructions.

[0054] The above technical solutions integrate the surveying, design, construction, and monitoring processes, breaking down the barriers of information silos in traditional engineering. They enable semi-automated or even automated processes from data collection to model calibration and solution optimization, greatly improving efficiency and reducing human error.

[0055] Preferably, the retaining dam in step S31 includes a dam body, with a buttress fixedly connected to the impact-facing surface of the dam body. A support pile is fixedly connected to the impact-facing surface of the dam body on one side of the buttress. A steel beam bottom beam is fixedly connected to the side surface of the buttress away from the dam body. A steel beam slide rail is fixedly connected to the upper surface of the steel beam bottom beam. A sliding base is slidably engaged on the outer surface of the steel beam slide rail. A hinge seat is fixedly connected to the upper surface of the sliding base and one side surface of the support pile, respectively. An inclined auxiliary pile is hinged between the two hinge seats. A traction anchor rod is fixedly connected to the inner surface of the hinge seat on the sliding base. An L-shaped tension plate is fixedly connected to the upper surface of the end of the steel beam slide rail away from the dam body. The outer surface of the traction anchor rod is slidably engaged with the hole in the tension plate. A fixing bolt is provided on the outer surface of the free end of the traction anchor rod.

[0056] Through the above technical solution, in order to enable the retaining dam to have adaptive energy dissipation capabilities, a sensor monitoring system is also pre-embedded in the dam body to monitor the stress and deformation of the dam body in real time. The tensioning jacks are used to tension the traction anchors, and the position of the tensioned traction anchors is limited by the fixing bolts, thereby changing the inclination angle of the auxiliary piles. When the collapse impacts, it acts on the support piles and auxiliary piles. The auxiliary piles generate controllable small displacements on the steel beam slide rails through the sliding base at the bottom, and absorb and dissipate part of the impact energy through the constraint of the traction anchors and tension plates. Thus, the rigid resistance and flexible energy dissipation mechanism enables the retaining dam to better cope with dynamic load impacts and avoid brittle failure.

[0057] Preferably, pads are fixedly connected to both sides of the dam body at intervals, and a hinged lug is fixedly connected to one side surface of a plurality of the pads. A contraction shaft is hinged to the inner surface of the hinged lug. Side steel beams are also fixedly connected to both sides of the dam body. A tensioning rod is provided between the pads and the side steel beams. A clamping plate with a U-shaped groove is fixedly connected to one side surface of the side steel beam. The outer surface of the contraction shaft is slidably engaged with the U-shaped groove of the clamping plate. A tightening sleeve is threaded onto the outer surface of the free end of the contraction shaft.

[0058] Through the above technical solutions, traditional retaining dams, under overload earth pressure, will develop cracks on both sides due to stress impact, causing the entire dam body to break. Generally, applying more support force to both ends of the dam body can improve the overall performance. After the shrink shaft is inserted into the U-shaped groove, the tightening sleeve is screwed on to compress the tension rod between the pad block and the side steel beam, so that the tension rod applies a certain pre-tightening force to the side of the retaining dam, ensuring the structural integrity of the entire protection system under dynamic load.

[0059] The beneficial effects of this invention are as follows: 1. Through 3D geological modeling and stereographic projection analysis, the geometry and scale of potential unstable wedges were accurately identified from the outset, making treatment measures more targeted and avoiding blind approaches. Real-time safety monitoring enabled the immediate capture of slope deformation anomalies and rapid feedback to the design phase for adjustments, significantly reducing the risk of landslides during construction. A differentiated anchoring strategy combining anchor cable frame beams and anchor rod frame beams was then adopted, with retaining dams pre-installed at the slope toe, forming multiple lines of protection combining active and passive, strong and weak elements. This effectively resisted instability forces at different locations. A three-dimensional system of slope top water interception, platform drainage, slope toe water diversion, and underground drainage effectively controlled the groundwater level and pore water pressure. This key measure directly increased the effective stress on the sliding surface, thereby enhancing the shear strength of the soil and rock mass and fundamentally improving stability.

[0060] 2. By setting parameters for inversion and model calibration, and using real displacement data monitored on-site as a benchmark, the most suitable geomechanical parameters are automatically inverted through iterative algorithms. This makes the calculation model evolve into a digital twin that can accurately reflect the real state of the slope, providing a scientific basis for subsequent prediction and optimization. Using the calibrated model, the stability under subsequent working conditions can be predicted in a forward-looking manner. If the prediction results do not meet the safety requirements, the support scheme can be optimized and design adjustment instructions can be generated before the actual danger occurs, realizing the transformation from passive response to proactive prevention. The entire process constitutes a complete closed loop of data acquisition, model analysis, decision optimization, and implementation feedback, making decisions based on continuously updated data, reducing human experience-based misjudgments, and improving the scientific nature of decisions.

[0061] 3. By grading the clearing and setting up platforms, the steep slopes were divided into nine levels with different slope ratios and wide platforms. This not only reduced the height of each level of slope and dispersed the thrust, but also provided operating space for construction machinery, significantly improving construction efficiency. The wide platforms also served as unloading platforms, improving overall stability. At the same time, through components such as traction anchors, sliding bases, and auxiliary piles, a combination of rigid resistance and flexible energy dissipation was achieved. When subjected to impact, the structure can absorb and dissipate energy through controllable small displacements, avoiding brittle failure and significantly improving the durability and reliability of the passive protection structure under dynamic loads. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of a method for treating tunnel side slope collapse proposed in this invention; Figure 2 This is a system block diagram of the dynamic design mechanism of a tunnel side slope collapse treatment method proposed in this invention; Figure 3 This is a flowchart of the parameter inversion and model calibration of a tunnel side slope collapse treatment method proposed in this invention. Figure 4 This is a flowchart illustrating the process of a retaining dam for a method of treating tunnel side slope collapse proposed in this invention. Figure 5 This is a three-dimensional view of the dam body structure of a method for treating tunnel side slope collapse proposed in this invention; Figure 6 This is a three-dimensional view of the purlin structure of a method for treating tunnel side slope collapse proposed in this invention; Figure 7 This is a three-dimensional view of the tightening sleeve structure of a method for treating tunnel side slope collapse proposed in this invention. Figure 8 This is a three-dimensional view of the traction anchor structure of a tunnel side slope collapse treatment method proposed in this invention.

[0063] In the diagram: 1. Dam body; 2. Buttress; 3. Support pile; 4. Steel beam bottom beam; 5. Steel beam slide rail; 6. Sliding base; 7. Hinge seat; 8. Auxiliary pile; 9. Traction anchor; 10. Tensioning plate; 11. Fixing bolt; 12. Pad; 13. Hinge ear plate; 14. Contraction shaft; 15. Side steel beam; 16. Tensioning rod; 17. Clamping plate; 18. Tightening sleeve. Detailed Implementation

[0064] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0065] Reference Figures 1-8 A method for treating tunnel side slope collapse, the method comprising: like Figure 1 As shown, S1, geological exploration and dynamic design mechanism establishment: conduct engineering geological exploration to identify the scope of the collapse body, karst development zone and dominant structural planes. By integrating topographic data, stratigraphic interface data, and dominant structural plane occurrence and distribution data, establish a three-dimensional geological model of the slope. Based on the three-dimensional geological model, use stereographic projection method to analyze the spatial combination relationship of dominant structural planes, identify the geometric shape and scale of potential unstable wedges, and use the three-dimensional wedge method to calculate the initial stability coefficient of the slope.

[0066] S2. Staged Clearing and Platform Excavation: Staged clearing and excavation are carried out according to the initial design to form multi-level slopes and multiple wide platforms. The bottom boundary line of the clearing is reserved for the length of the tunnel opening. During this process, the slope surface displacement, crack development and meteorological and hydrological data are monitored for safety, and the monitoring data is fed back to the dynamic design mechanism to guide construction adjustments and optimizations.

[0067] S3. Comprehensive anchoring support: Anchoring works are carried out on the slope after clearing.

[0068] S4. Three-dimensional drainage system layout: Intercepting ditches, rapid flow channels and water diversion channels are laid at the top of the slope, at each level of platform and at the foot of the slope, and inclined drainage holes are set in the slope body to form a three-dimensional drainage system that combines the surface and underground.

[0069] S5. Parameter Inversion and Model Calibration: Compare the displacement data monitored in step S2 with the predicted values ​​of the three-dimensional geological model in step S1. When the deviation exceeds a preset threshold, keep the slope geometry model unchanged and use an iterative algorithm to systematically invert and adjust the geomechanical parameters in the model, so that the stability state calculated by the three-dimensional wedge method matches the actual slope state reflected by the monitoring data, thereby calibrating the model. The geomechanical parameters include at least the effective cohesion of the slip surface. and effective internal friction angle .

[0070] S6. Dynamic Prediction and Scheme Optimization: Using the calibrated model and parameters, the stability coefficient under subsequent working conditions is recalculated. If the predicted value does not meet the safety requirements, the support design scheme is optimized and a design adjustment instruction is generated.

[0071] S7. Support Implementation and Feedback: Carry out support construction according to the optimized plan, continue monitoring, and feed the data back to step S5 to form a closed-loop dynamic design process.

[0072] The calculation formula for the three-dimensional wedge method is as follows: ,in, This represents the landslide safety factor.

[0073] and Sliding surfaces and sliding surface The area is expressed in square meters.

[0074] and Sliding surfaces and sliding surface Effective cohesion, measured in kilopascals.

[0075] and Sliding surfaces and sliding surface The internal friction angle, in degrees.

[0076] and For sliding surface and sliding surface The effective normal reaction force, measured in kilonewtons.

[0077] For the crack surface The pore pressure is expressed in kilonewtons.

[0078] The weight of the wedge is expressed in kilonewtons.

[0079] The anchor bolt reinforcement force is expressed in kilonewtons.

[0080] in, .

[0081] .

[0082] ,in, and For the crack surface The angle of inclination and dip, in degrees.

[0083] and For sliding surface Sliding surface Intersection The angle of inclination and dip, in degrees.

[0084] and To strengthen the anchor bolt The angle and dip of the slope, in degrees, are used to calculate the ratio of the anti-sliding force to the sliding force acting on the sliding surface, thereby accurately determining the stability safety factor of the slope under specific working conditions. ,in, , , As directional coefficients, the weight of the wedge, the water pressure in the tension crack, and the anchor reinforcement force are projected onto the direction of the intersection line of the sliding surface to ensure the accuracy of the force system calculation.

[0085] The graded clearing described in step S2 specifically involves dividing the slope into 9 levels with different slope ratios from top to bottom. The slope ratios for levels 1-4 are 1:0.75, for levels 5-6 they are 1:1, and for levels 7-9 they are 1:1.25. Wide platforms with widths ≥6m and ≥10m are set at elevations of 980m and 1010m, respectively. The reserved tunnel opening length is ≥10m. By optimizing the steep slope into 9 steps with different slope ratios, the height and gradient of a single slope are effectively reduced, and the landslide thrust is dispersed. The wide platforms at elevations of 980m and 1010m not only serve as operating platforms and transportation channels for construction machinery, improving construction efficiency, but more importantly, they act as crucial unloading platforms, interrupting the continuity of the potential sliding surface and greatly improving the overall stability of the slope. The reserved opening length of no less than 10m provides a buffer protection zone for the tunnel entrance, ensuring the safety of the tunnel structure during the slope treatment process.

[0086] The layout of the three-dimensional drainage system described in step S4 includes: setting up a slope top intercepting ditch with a cross-section of 40cm×40cm 5 meters outside the slope excavation line; setting up platform intercepting ditches on each of the wide platforms; and connecting them through a rapid flow channel to guide the collected water to the slope toe diversion channel, which is then discharged into the downstream river. The three-dimensional drainage system constructs a complete drainage system combining interception, drainage, guidance, and infiltration. The slope top intercepting ditch intercepts surface runoff 5 meters outside the slope excavation line to prevent it from scouring the slope. The platform intercepting ditches at each level collect surface runoff and guide the water safely and quickly to the slope toe through the rapid flow channel. The slope toe diversion channel concentrates the collected water flow into the downstream river, avoiding scouring of the slope toe. At the same time, the inclined drainage holes set in the slope can effectively remove deep groundwater and reduce the pore water pressure near the slip surface, thereby significantly improving the shear strength of the soil and rock mass. This system achieves the coordinated management of surface water and groundwater.

[0087] The safety monitoring described in step S2 includes: setting up ≥22 surface displacement monitoring points, using high-precision total stations for monitoring, with a monitoring frequency of no less than once every 3 days during the construction period, and increasing to once every 3 hours in case of heavy rain or abnormal deformation, and continuous monitoring for ≥3 years after project completion. The safety monitoring constitutes a dynamic monitoring network with regular inspections, automatic early warning, and emergency response. By setting up no less than 22 monitoring points to form a monitoring network covering key areas of the slope, and using high-precision total stations for periodic measurements, the monitoring frequency is dynamically adjusted according to the working conditions: once every 3 days under normal circumstances, and when heavy rain or abnormal deformation is detected, the emergency plan is immediately activated, and the monitoring frequency is increased to once every 3 hours to achieve real-time capture of potential dangers. The continuous 3-year operation period monitoring after project completion provides data support for long-term evaluation of the treatment effect and maintenance decisions.

[0088] The anchoring work mentioned in step S3 includes, S31. In the middle and lower part of the slope, where the rock mass is fractured or karst is developed, the construction of anchor cable frame beams is used for strong support. Before the graded clearing, a rock-buried retaining dam is also constructed above the bridge pile foundation affected at the toe of the slope. The retaining dam is 145-150 meters long and is used to protect the safety of the structures below during the clearing process.

[0089] S32. Anchor frame beams are constructed to support other areas of the slope.

[0090] S33. Surface protection is achieved by constructing a hydroseeding substrate plant slope protection system at the top of the slope. In the critical stress areas of the middle and lower parts of the slope, where stress is concentrated, rock is fractured, or karst is developed, high-prestressed anchor cable frame beams are used for strong support to form a solid load-bearing ring. In areas with better stability, conventional reinforcement is carried out using anchor frame beams, which is economical and efficient. At the top of the slope, a hydroseeding substrate plant slope protection system is used to prevent surface weathering and peeling, restore the ecology, and beautify the environment. A rock-buried retaining dam is constructed at the toe of the slope before clearing, serving as an early passive protection measure to effectively prevent falling rocks from impacting and damaging the bridge pile foundations below during the clearing process.

[0091] Through 3D geological modeling and stereographic projection analysis, the geometry and scale of potential unstable wedges were accurately identified from the outset, making treatment measures more targeted and avoiding blind approaches. Real-time safety monitoring can instantly capture slope deformation anomalies and quickly feed them back to the design stage for adjustments, greatly reducing the risk of landslides during construction. Then, a differentiated anchoring strategy combining anchor cable frame beams and anchor rod frame beams was adopted, and a retaining dam was pre-installed at the slope toe, forming a multi-layered protection line that combines active and passive, strong and weak elements, effectively resisting instability forces at different locations. Through a three-dimensional system of slope top water interception, platform drainage, slope toe water diversion, and underground drainage, the groundwater level and pore water pressure were effectively controlled. This key measure directly increased the effective stress of the sliding surface, thereby enhancing the shear strength of the rock and soil mass and improving stability from the root.

[0092] like Figure 1 as well as Figure 3 As shown, the iterative algorithm used for systematic inversion adjustment in step S5 specifically involves: constructing an objective function with the monitored displacement value as the objective function and the geomechanical parameters as variables. The objective function is the sum of squares of the differences between the calculated displacement and the monitored displacement. The optimal geomechanical parameters are obtained by minimizing the objective function using an optimization algorithm. Specifically: Step 1: Define the objective function: based on the aforementioned monitored displacement values Displacement values ​​calculated by the model The objective function is constructed from the sum of squared residuals. : .

[0093] in The parameter vector to be inverted, i.e. .

[0094] Number of displacement monitoring points.

[0095] Based on parameter vector The third, calculated using the three-dimensional wedge method Displacement values ​​of each monitoring point.

[0096] : No. The actual measured displacement values ​​of each monitoring point.

[0097] The objective function value, the goal of the inversion is to find the value that makes... Minimum parameter vector .

[0098] Step 2, Iterative Optimization Algorithm: Gradient descent is used for automatic optimization, and the parameter update formula is as follows: ,in Number of iterations.

[0099] : No. The parameter estimates at the next iteration.

[0100] The learning rate controls the magnitude of each parameter update.

[0101] The gradient of the objective function at the current parameter values ​​is a vector pointing to... The fastest growing direction has the following component form: ,in It is the first The calculated displacement is for the first... The sensitivity of each parameter.

[0102] Step 3, Termination of calibration: When the difference between the objective function values ​​of two adjacent iterations... The iteration terminates when the value is less than a preset threshold, at which point the corresponding parameter vector... The optimal parameters obtained from the inversion are then used to complete the model calibration. The parameter inversion and model calibration process is essentially a precise calibration that assimilates the numerical model with the actual situation. It uses the real displacement data obtained from field monitoring as the sole standard and automatically and repeatedly adjusts the geomechanical parameters in the three-dimensional wedge model through optimization algorithms such as gradient descent. This process is achieved by minimizing the objective function between the calculated displacement and the monitored displacement. Ultimately, the numerical model is no longer an idealized theoretical tool, but a digital twin that can accurately reflect the real mechanical state of the slope. The gradient calculation clarifies the sensitivity of each parameter to the displacement, guides the direction and step size of parameter adjustment, and ensures that the inversion process is fast and convergent.

[0103] like Figure 2 As shown, the dynamic design mechanism in step S2 includes: The geological model building module is used to integrate multi-source data to generate three-dimensional geological models and identify potentially unstable wedges.

[0104] The stability analysis module is used to calculate the slope stability coefficient based on the three-dimensional wedge method.

[0105] The monitoring data interface module is used to receive real-time monitoring data.

[0106] The parameter inversion analysis module is used to perform iterative inversion of geomechanical parameters and model calibration.

[0107] The scheme simulation and optimization module is used to predict stability and optimize support schemes.

[0108] The decision support output module generates design adjustment instructions, integrating surveying, design, construction, and monitoring into a unified whole. This breaks down the barriers of information silos in traditional engineering, enabling semi-automated or even automated processes from data collection to model calibration and scheme optimization. This greatly improves efficiency and reduces human error.

[0109] By setting parameter inversion and model calibration, and using real displacement data monitored on-site as a benchmark, the most suitable geomechanical parameters are automatically inverted through iterative algorithms. This makes the calculation model evolve into a digital twin that can accurately reflect the real state of the slope, providing a scientific basis for subsequent prediction and optimization. Using the calibrated model, the stability under subsequent working conditions can be predicted in a forward-looking manner. If the prediction results do not meet the safety requirements, the support scheme can be optimized and design adjustment instructions can be generated before the actual danger occurs, realizing the transformation from passive response to proactive prevention. The entire process constitutes a complete closed loop of data acquisition, model analysis, decision optimization, and implementation feedback, making the decision based on continuously updated data, reducing human experience misjudgment, and improving the scientific nature of the decision.

[0110] like Figures 4-8 As shown, in order to enable the retaining dam to have adaptive energy dissipation capacity, in step S31, the retaining dam includes a dam body 1. A buttress 2 is fixedly connected to the impact-facing surface of the dam body 1. A support pile 3 is fixedly connected to the impact-facing surface of the dam body 1 on one side of the buttress 2. A steel beam bottom beam 4 is fixedly connected to the surface of the buttress 2 away from the dam body 1. A steel beam slide rail 5 is fixedly connected to the upper surface of the steel beam bottom beam 4. A sliding base 6 is slidably engaged with the outer surface of the steel beam slide rail 5. A hinge seat 7 is fixedly connected to the upper surface of the sliding base 6 and one side surface of the support pile 3, respectively. An inclined auxiliary pile 8 is hinged between the two hinge seats 7. A traction anchor rod 9 is fixedly connected to the inner surface of the hinge seat 7 on the sliding base 6. An L-shaped tension plate 10 is fixedly connected to the upper surface of the end of the steel beam slide rail 5 away from the dam body 1. The outer surface of the traction anchor 9 is slidably sleeved with the hole on the tension plate 10. The free end of the traction anchor 9 is provided with a fixing bolt 11. The dam body 1 of the retaining dam is also pre-embedded with a sensor monitoring system for real-time monitoring of the dam stress and deformation. The traction anchor 9 is tensioned by tensioning jacks, and the position of the traction anchor 9 after tensioning is limited by the fixing bolt 11, thereby changing the inclination angle of the auxiliary pile 8. When the collapse impacts, it acts on the support pile 3 and the auxiliary pile 8. The auxiliary pile 8 generates a controllable small displacement on the steel beam slide rail 5 through the sliding base 6 at the bottom, and absorbs and dissipates part of the impact energy through the constraint of the traction anchor 9 and the tension plate 10. The rigid resistance and flexible energy dissipation mechanism enables the retaining dam to better cope with the impact of dynamic loads and avoid brittle failure.

[0111] Both sides of the dam body 1 are fixedly connected with spaced blocks 12. One side surface of several blocks 12 is fixedly connected with hinged lugs 13, and a contraction shaft 14 is hinged to the inner surface of the hinged lugs 13. Side steel beams 15 are also fixedly connected to both sides of the dam body 1. Tensioning rods 16 are installed between the blocks 12 and the side steel beams 15. One side surface of the side steel beams 15 is fixedly connected with a clamping plate 17 with a U-shaped groove. The outer surface of the contraction shaft 14 is slidably engaged with the U-shaped groove of the clamping plate 17. The free surface of the contraction shaft 14... The outer surface of the end has a threaded sleeve with a tightening sleeve 18. Under overload earth pressure, traditional retaining dams will crack on both sides due to stress impact, causing the entire dam body to break. Generally, applying more support force to both ends of the dam body can improve the overall performance. After the shrink shaft 14 is inserted into the U-shaped groove, the tightening sleeve 18 is screwed on to compress the tension rod 16 between the pad block 12 and the side steel beam 15, so that the tension rod 16 applies a certain pre-tightening force to the side of the retaining dam, ensuring the structural integrity of the entire protection system under dynamic load.

[0112] By grading the clearing and setting up platforms, the steep slope was divided into nine levels with different slope ratios and wide platforms. This not only reduced the height of each level of slope and dispersed the thrust, but also provided operating space for construction machinery, significantly improving construction efficiency. The wide platforms also served as unloading platforms, improving overall stability. At the same time, through components such as traction anchors 9, sliding bases 6, and auxiliary piles 8, a combination of rigid resistance and flexible energy dissipation was achieved. When subjected to impact, the structure can absorb and dissipate energy through controllable small displacements, avoiding brittle failure and significantly improving the durability and reliability of the passive protection structure under dynamic loads.

[0113] Working principle: In a specific embodiment of the present invention, the original data such as topography, strata, and dominant structural planes are obtained through geological survey, and then graded clearing, anchoring support, and drainage system layout are carried out, with safety monitoring throughout the process; The monitoring data is compared with the model predictions, and the geomechanical parameters are inverted using an iterative algorithm. The stability after the next construction step is predicted using the calibrated model, and the design is optimized. Construction is carried out according to the optimized plan, and monitoring continues. The data is then fed back to intelligent learning and model calibration. In the three-dimensional geological model analysis, structures that need to be protected, such as bridge pile foundations, were identified at the toe of the slope. It was also predicted that the clearing construction may trigger the risk of landslide impact. Based on this, it was decided to construct the retaining dam before clearing. During the clearing process, the impact force generated by the collapsed body or falling rocks acts on the impact-facing surface of the retaining dam, namely the support piles 3 and auxiliary piles 8. The inclination angle of the auxiliary piles 8 is adjusted by predicting the impact force. That is, the tensioning jack is used to tension the traction anchor 9, so that the sliding base 6 produces a controllable small displacement on the steel beam slide rail 5. The position of the tensioned traction anchor 9 is limited by the fixing bolts 11, thereby changing the inclination angle of the auxiliary piles 8. At this time, when the impact force hits the dam body 1, the traction anchor 9 connected to the sliding base 6 is stretched under the constraint of the tensioning plate 10. This process converts the huge impact kinetic energy into frictional force and material strain energy, thereby absorbing and dissipating a part of the energy. The remaining impact force is transmitted to the dam body 1 and buttress 2 through the auxiliary piles 8 and the support piles 3, and is ultimately resisted by the weight of the dam body itself and the bearing capacity of the foundation, which forms a defense mechanism of first being flexible and then rigid. To prevent the dam from cracking at both ends under impact, the tension rod 16 is pre-tightened by tightening the sleeve 18, and lateral restraint is applied to both sides of the dam by the pad block 12 and the side steel beam 15 to ensure its integrity.

[0114] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for treating tunnel side slope collapse, characterized in that: The treatment methods include, S1. Establishment of Geological Exploration and Dynamic Design Mechanism: Conduct engineering geological exploration to identify the extent of the collapse body, karst development zone and dominant structural planes. By integrating topographic data, stratigraphic interface data, and dominant structural plane occurrence and distribution data, establish a three-dimensional geological model of the slope. Based on the three-dimensional geological model, use stereographic projection method to analyze the spatial combination relationship of dominant structural planes, identify the geometric shape and scale of potential unstable wedges, and use the three-dimensional wedge method to calculate the initial stability coefficient of the slope. S2. Staged Clearing and Platform Excavation: Staged clearing and excavation are carried out according to the initial design to form multi-level slopes and multiple wide platforms. The bottom boundary line of the clearing is reserved for the length of the tunnel opening. During this process, the slope surface displacement, crack development and meteorological and hydrological data are monitored for safety and fed back to the dynamic design mechanism to guide construction adjustments and optimizations. S3. Comprehensive anchoring support: Anchoring works are carried out on the slope after clearing. S4. Three-dimensional drainage system layout: intercepting ditches, rapid flow channels and water diversion channels are laid at the top of the slope, at each level of platform and at the foot of the slope, and inclined drainage holes are set in the slope body to form a three-dimensional drainage system that combines the surface and underground. S5. Parameter Inversion and Model Calibration: Compare the displacement data monitored in step S2 with the predicted values ​​of the three-dimensional geological model in step S1. When the deviation exceeds a preset threshold, keep the slope geometry model unchanged and use an iterative algorithm to systematically invert and adjust the geomechanical parameters in the model, so that the stability state calculated by the three-dimensional wedge method matches the actual slope state reflected by the monitoring data, thereby calibrating the model. The geomechanical parameters include at least the effective cohesion of the slip surface. and effective internal friction angle ; S6. Dynamic prediction and scheme optimization: Using the calibrated model and parameters, the stability coefficient under subsequent working conditions is recalculated. If the predicted value does not meet the safety requirements, the support design scheme is optimized and a design adjustment instruction is generated. S7. Support Implementation and Feedback: Carry out support construction according to the optimized plan, continue monitoring, and feed the data back to step S5 to form a closed-loop dynamic design process.

2. The method for treating tunnel side slope collapse according to claim 1, characterized in that: The calculation formula for the three-dimensional wedge method is as follows: ,in, The landslide safety factor; and Sliding surfaces and sliding surface The area, in square meters; and Sliding surfaces and sliding surface The effective cohesive force, measured in kilopascals; and Sliding surfaces and sliding surface The internal friction angle, in degrees; and For sliding surface and sliding surface The effective normal reaction force, in kilonewtons; For the crack surface Pore ​​pressure, measured in kilonewtons; The weight of the wedge is expressed in kilonewtons. The anchor bolt reinforcement force is expressed in kilonewtons. in, ; ； ,in, and For the crack surface The angle of inclination and dip, in degrees; and For sliding surface Sliding surface Intersection The angle of inclination and dip, in degrees; and Strengthening the anchor bolt The angle of inclination and dip, in degrees.

3. The method for treating tunnel side slope collapse according to claim 2, characterized in that: The graded clearing in step S2 specifically involves dividing the slope into 9 levels with different slope ratios from top to bottom. The slope ratios for levels 1-4 are 1:0.75, for levels 5-6 they are 1:1, and for levels 7-9 they are 1:1.

25. Wide platforms with widths ≥6m and ≥10m are set at elevations of 980m and 1010m, respectively. The length of the reserved tunnel opening is ≥10m.

4. The method for treating tunnel side slope collapse according to claim 3, characterized in that: The layout of the three-dimensional drainage system in step S4 includes: setting up a slope top intercepting ditch with a cross section of 40cm×40cm 5 meters outside the slope excavation line, setting up platform intercepting ditches on the wide platforms at each level, and connecting them through a rapid flow channel to guide the collected water to the slope foot diversion channel, and finally discharging it into the downstream river channel.

5. The method for treating tunnel side slope collapse according to claim 4, characterized in that: The safety monitoring described in step S2 includes: setting up ≥22 surface displacement monitoring points, using a high-precision total station for monitoring, with a monitoring frequency of no less than once every 3 days during the construction period, and increasing to once every 3 hours in case of heavy rain or abnormal deformation, and continuing monitoring for ≥3 years after the completion of the project.

6. The method for treating tunnel side slope collapse according to claim 5, characterized in that: The anchoring work mentioned in step S3 includes, S31. In the middle and lower part of the slope, where the rock mass is fractured or karst is developed, the construction of anchor cable frame beams is used for strong support. Before the graded clearing, the construction of a rock-buried retaining dam above the bridge pile foundation affected at the slope toe is also included. The retaining dam is 145-150 meters long and is used to protect the safety of the structures below during the clearing process. S32. Construct anchor frame beams for support in other areas of the slope; S33. Surface protection is carried out by constructing a mesh-covered and sprayed substrate plant slope protection system at the top of the slope.

7. The method for treating tunnel side slope collapse according to claim 6, characterized in that: The systematic inversion adjustment using an iterative algorithm in step S5 specifically involves: constructing an objective function with the monitored displacement value as the objective function and geomechanical parameters as variables. The objective function is the sum of squares of the differences between the calculated displacement and the monitored displacement. The optimal geomechanical parameters are obtained by minimizing this objective function using an optimization algorithm. Specifically: Step 1: Define the objective function: based on the aforementioned monitored displacement values Displacement values ​​calculated by the model The objective function is constructed from the sum of squared residuals. : ； in The parameter vector to be inverted, i.e. ; The number of displacement monitoring points; Based on parameter vector The first number calculated using the three-dimensional wedge method Displacement values ​​at each monitoring point; : No. The actual measured displacement values ​​of each monitoring point; The objective function value, the goal of the inversion is to find the value that makes... Minimum parameter vector ; Step 2, Iterative Optimization Algorithm: Gradient descent is used for automatic optimization, and the parameter update formula is as follows: ,in Number of iterations; : No. The parameter estimates at the next iteration; The learning rate controls the magnitude of each parameter update. The gradient of the objective function at the current parameter values ​​is a vector pointing to... The fastest growing direction has the following component form: ,in It is the first The calculated displacement is for the first... Sensitivity of each parameter; Step 3, Termination of calibration: When the difference between the objective function values ​​of two adjacent iterations... The iteration terminates when the value is less than a preset threshold, at which point the corresponding parameter vector... These are the optimal parameters obtained from the inversion, and the model has completed calibration.

8. The method for treating tunnel side slope collapse according to claim 7, characterized in that: The dynamic design mechanism described in step S2 includes: The geological model building module is used to integrate multi-source data to generate three-dimensional geological models and identify potential unstable wedges; The stability analysis module is used to calculate the slope stability coefficient based on the three-dimensional wedge method. The monitoring data interface module is used to receive real-time monitoring data; The parameter inversion analysis module is used to perform iterative inversion of geomechanical parameters and model calibration; The scheme simulation and optimization module is used to predict stability and optimize support schemes; The decision support output module is used to generate design adjustment instructions.

9. A method for treating tunnel side slope collapse according to claim 8, characterized in that: The retaining dam described in step S31 includes a dam body (1), with a buttress (2) fixedly connected to the impact-facing surface of the dam body (1). A support pile (3) is fixedly connected to one side of the buttress (2) to the impact-facing surface of the dam body (1). A steel beam bottom beam (4) is fixedly connected to the surface of the buttress (2) away from the dam body (1). A steel beam slide rail (5) is fixedly connected to the upper surface of the steel beam bottom beam (4). A sliding base (6) is slidably engaged on the outer surface of the steel beam slide rail (5). The upper surface of the sliding base (6) is connected to the... A hinge seat (7) is fixedly connected to one side surface of the support pile (3), and an inclined auxiliary pile (8) is hinged between the two hinge seats (7). A traction anchor rod (9) is fixedly connected to the inner surface of the hinge seat (7) on the sliding base (6). An L-shaped tension plate (10) is fixedly connected to the upper surface of the end of the steel beam slide rail (5) away from the dam body (1). The outer surface of the traction anchor rod (9) is slidably sleeved with the hole on the tension plate (10). A fixing bolt (11) is provided on the outer surface of the free end of the traction anchor rod (9).

10. A method for treating tunnel side slope collapse according to claim 9, characterized in that: The two sides of the dam body (1) are fixedly connected with pads (12) at intervals. A hinged ear plate (13) is fixedly connected to one side surface of a plurality of the pads (12). A shrink shaft (14) is hinged to the inner surface of the hinged ear plate (13). Side steel beams (15) are also fixedly connected to the two sides of the dam body (1). A tensioning rod (16) is provided between the pads (12) and the side steel beams (15). A clamping plate (17) with a U-shaped groove is fixedly connected to one side surface of the side steel beams (15). The outer surface of the shrink shaft (14) is slidably engaged with the U-shaped groove of the clamping plate (17). A tightening sleeve (18) is threaded onto the outer surface of the free end of the shrink shaft (14).

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