A tunnel side slope collapse treatment method

Abstract

The present application belongs to the technical field of highland tunnel construction, in particular to a tunnel side and upward slope collapse treatment method, the treatment method comprises S5, parameter inversion and model calibration: comparing the displacement data monitored in step S2 with the predicted value of the model in step S1, when the deviation exceeds the preset threshold, the slope geometric model is kept unchanged, the geomechanical parameters in the model are systematically inverted and adjusted by using the iterative algorithm, the stability state calculated by the three-dimensional wedge method is matched with the actual state of the slope reflected by the monitoring data, so as to calibrate the model, and the geomechanical parameters at least include the effective cohesion and effective internal friction angle of the sliding surface. The tunnel side and upward slope collapse treatment method accurately identifies the geometric shape and size of the potential unstable wedge body from the beginning through three-dimensional geological modeling and stereographic projection analysis, so that the treatment measures are more targeted, and blindness is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of highland tunnel construction, and particularly relates to a tunnel side and upward slope collapse treatment method. BACKGROUND

[0002] The side slope of the mountain tunnel exit section often forms a high and steep free face due to artificial excavation, which exposes and destroys the original stress balance of the rock mass, and is prone to induce collapse disasters. Such side slopes usually have complex geological conditions, such as karst development, unfavorable combination of dominant structural planes, etc., and the stability control is a key technical problem for safe construction and long-term operation of the tunnel project.

[0003] At present, for the treatment of such collapse side slopes, the traditional method usually adopts static design based on the results of one-time geological survey, and then carries out conventional engineering measures such as clearing, anchoring and drainage. However, this method has significant limitations: the initial geological survey is difficult to completely and accurately obtain the real mechanical parameters of the rock-soil mass, resulting in a large difference between the calculation results based on the idealized model and the actual working state of the side slope, and the design reliability is insufficient; the deformation response of the side slope during construction is the most direct information reflecting its stability state, but the traditional method lacks systematic real-time monitoring data and closed-loop linkage of the design scheme, and cannot dynamically adjust and optimize the treatment scheme according to the actual performance of the side slope, and there is 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 collapse body during the clearing process is high, and the conventional rigid retaining structure is prone to brittle failure under dynamic load impact, has poor self-adaptive energy dissipation capacity, and has limited protection effect, so the present application solves the above technical problems. SUMMARY

[0004] Based on the above technical problems, the present application provides a tunnel side and upward slope collapse treatment method.

[0005] The tunnel side and upward slope collapse treatment method provided by the present application comprises,

[0006] S1, a geological survey and dynamic design mechanism is established: engineering geological survey is carried out to identify the collapse body range, karst development area and dominant structural plane, a three-dimensional geological model of the side slope is established by integrating topographic data, stratigraphic interface data, dominant structural plane occurrence and distribution data, the spatial combination relationship of the dominant structural plane is analyzed by using the stereographic projection method based on the three-dimensional geological model, the geometric shape and scale of the potential unstable wedge are identified, and the initial stability coefficient of the side slope is calculated by using the three-dimensional wedge method.

[0007] S2, hierarchical clearing and platform excavation: hierarchical clearing and excavation is performed according to the initial design to form multiple levels of slopes and multiple wide platforms, the bottom boundary line of the clearing is reserved for the length of the tunnel open cut, and safety monitoring of the surface displacement of the slope, crack development and meteorology and hydrology is performed during the process, and the monitoring data is fed back to the dynamic design mechanism to guide construction adjustment and optimization.

[0008] S3, comprehensive anchoring support: anchoring engineering is implemented on the slope after clearing.

[0009] S4, three-dimensional drainage system layout: a water interception ditch, a rapid flow channel and a water diversion channel are laid out at the top of the slope, each level of platform and the slope toe, and an upward inclined drainage hole is provided in the slope body to form a three-dimensional drainage system combining the ground and the underground.

[0010] S5, parameter inversion and model calibration: the displacement data monitored in step S2 is compared with the predicted value of the three-dimensional geological model in step S1, when the deviation exceeds the preset threshold, the slope geometry model is kept unchanged, the geomechanical parameters in the model are systematically inverted and adjusted using an iterative algorithm, so that the stability state calculated by the three-dimensional wedge method matches the actual state of the slope reflected by the monitoring data, thereby calibrating the model, the geomechanical parameters at least include the effective cohesion of the sliding surface and the effective internal friction angle .

[0011] S6, dynamic prediction and scheme optimization: using the calibrated model and parameters, the stability coefficient under the subsequent working condition is recalculated, if the predicted value does not meet the safety requirement, the support design scheme is optimized, and a design adjustment instruction is generated.

[0012] S7, support implementation and feedback: support construction is performed according to the optimized scheme, and data is continuously monitored and fed back to step S5 to form a closed-loop dynamic design process.

[0013] Preferably, the calculation formula of the three-dimensional wedge method is:

[0014] , wherein, is the landslide safety factor.

[0015] and are the areas of the sliding surface and the sliding surface , respectively, in square meters.

[0016] and are the effective cohesion of the sliding surface and the sliding surface , respectively, in kilopascals.

[0017] and are the sliding surfaces and the sliding surfaces are the internal friction angles of the sliding surfaces in degrees.

[0018] and are the effective normal forces of the sliding surfaces and the sliding surfaces in kN.

[0019] are the pore water pressures on the tension crack surface in kN.

[0020] are the wedge weights in kN.

[0021] are the anchoring forces in kN.

[0022] wherein, .

[0023] .

[0024] wherein, and are the dip and dip direction of the tension crack surface in degrees.

[0025] and are the dip and dip direction of the intersection line of the sliding surface , the sliding surface in degrees.

[0026] and are the dip and dip direction of the anchoring force in degrees. Through the above technical solution, the stability safety factor of the slope under a specific working condition is accurately obtained by calculating the ratio of the anti-sliding force to the sliding force acting on the sliding surface

[0027] wherein, , , , are the direction coefficients, which respectively project the wedge weight, the tension crack water pressure and the anchoring force to the direction of the intersection line of the sliding surfaces to ensure the accuracy of the force system calculation.

[0028] Preferably, the grading in step S2 is specifically: dividing the slope into 9 levels, setting different slope ratios from top to bottom, wherein the slope ratios of the 1st-4th levels are 1:0.75, the slope ratios of the 5th-6th levels are 1:1, the slope ratios of the 7th-9th levels are 1:1.25, and setting wide platforms with a width of ≥6m and ≥10m at the elevations of 980m and 1010m respectively, and the length of the reserved tunnel open cut is ≥10m.

[0029] Through the above technical solution, by optimizing the high and steep slope into 9 levels of steps and setting different slope ratios, the height and slope of the single level slope are effectively reduced, and the landslide thrust is dispersed. The wide platforms set at the elevations of 980m and 1010m not only serve as operation platforms and transportation channels for construction machinery, improving the construction efficiency, but more importantly, they play a key role as unloading platforms, interrupting the continuity of the potential sliding surface and greatly improving the overall stability of the slope. The length of the reserved open cut of not less than 10m provides a buffer protection zone for the tunnel portal, ensuring the safety of the tunnel structure during the slope treatment process.

[0030] Preferably, the layout of the three-dimensional drainage system in step S4 includes: setting a slope top intercepting ditch with a cross section of 40cm×40cm 5 meters outside the slope excavation line, setting platform intercepting ditches on each level of the wide platform, and connecting them through rapid flow channels to guide the water to the slope foot drainage channel, and finally drain into the downstream river.

[0031] Through the above technical solution, the three-dimensional drainage system builds a complete drainage system combining interception, drainage, guidance and seepage. The slope top intercepting ditch intercepts surface runoff outside the slope body 5 meters outside the slope excavation line to prevent it from eroding the slope. The platform intercepting ditches on each level collect slope runoff and safely and quickly guide the water to the slope foot through the rapid flow channels. The slope foot drainage channel concentrates the collected water flow and drains it into the downstream river, avoiding erosion of the slope foot. Meanwhile, the upward inclined drainage holes set in the slope body can effectively drain deep groundwater, reduce the pore water pressure near the sliding surface, and thus significantly improve the shear strength of the rock-soil body. This system realizes the coordinated management of surface water and groundwater.

[0032] Preferably, the safety monitoring in step S2 includes: laying ≥22 surface displacement monitoring points, using high-precision total stations for monitoring, monitoring frequency not less than once every 3 days during construction, and increasing to once every 3 hours during heavy rain and abnormal deformation, and continuously monitoring for ≥3 years after the completion of the project.

[0033] Through the technical scheme, the safety monitoring forms a dynamic monitoring network of timed patrol, automatic early warning and emergency response, a monitoring network covering key regions of the slope is formed by arranging no less than 22 monitoring points, periodic measurement is performed by using a high-precision total station, and the monitoring frequency is dynamically adjusted according to the working condition: once every 3 days under normal circumstances, and once every 3 hours when rainstorm or deformation anomaly is found, so that real-time capture of the dangerous situation is realized, and 3-year operation period monitoring after the project is completed provides data support for long-term evaluation of the treatment effect and maintenance decision.

[0034] Preferably, the anchoring engineering in step S3 comprises,

[0035] S31, in the broken rock mass or karst development area of the lower part of the slope, a cable frame beam is constructed for strong support, and before grading and clearing, a rock buried head retaining dam is constructed above the affected bridge pile foundation at the slope toe, the length of the retaining dam is 145-150 meters, and the retaining dam is used for protecting the safety of the lower structure during the clearing process.

[0036] S32, an anchor rod frame beam is constructed in other regions of the slope for support.

[0037] S33, a hanging net spray substrate plant protection slope is constructed at the top of the slope for surface protection.

[0038] Through the technical scheme, in the key stress area of stress concentration, broken rock mass or karst development in the lower part of the slope, a high-prestressed cable frame beam is used for strong support to form a solid load-bearing ring, in the area with good stability, a conventional anchor rod frame beam is used for reinforcement, which is economical and efficient, and at the top of the slope, a hanging net spray substrate plant protection slope is used, which can not only prevent surface weathering and peeling, but also restore ecology and beautify the environment, and the rock buried head retaining dam constructed at the slope toe before clearing is used as a passive protection measure, which effectively prevents impact damage to the bridge pile foundation caused by falling stones during the clearing process.

[0039] Preferably, in step S5, the iterative algorithm is used for systematic inversion adjustment, specifically: taking the monitored displacement value as a target function and taking the geomechanical parameters as variables, a target function is constructed, the target function is the square sum of the difference between the calculated displacement and the monitored displacement, the target function is minimized by an optimization algorithm to obtain the optimal geomechanical parameters, and the optimal geomechanical parameters are specifically:

[0040] First step, define the target function: the residual square sum of the above-mentioned monitored displacement value and the model calculated displacement value to construct the target function :

[0041] .

[0042] wherein : parameter vector to be inverted, i.e. .

[0043] : number of displacement monitoring points.

[0044] : displacement value of the i-th monitoring point calculated by the 3D wedge method based on the parameter vector .

[0045] : actual measured displacement value of the i-th monitoring point.

[0046] : objective function value, the goal of inversion is to find the parameter vector that makes the objective function value .

[0047] Second step, iterative optimization algorithm: gradient descent method is used for automatic optimization, and the parameter update formula is:

[0048] , where : iteration number.

[0049] : parameter estimation value at the i-th iteration.

[0050] : learning rate, which controls the amplitude of each parameter update.

[0051] : gradient of the objective function at the current parameter value, which is a vector pointing to the direction of the fastest growth of the objective function, and its component form is:

[0052] , where is the sensitivity of the i-th calculated displacement to the j-th parameter. : when the difference between the objective function values of the adjacent two iterations is less than the preset threshold value, the iteration is terminated, and the corresponding parameter vector at this time is the optimal parameter obtained by inversion, and the model is completed calibration.

[0053]

[0054] ​​​​​​​By the technical solution, the parameter inversion and model calibration process is essentially a precise calibration of data assimilation between the numerical model and the actual situation, which takes the real displacement data obtained by field monitoring as the only standard, automatically and repeatedly adjusts the geomechanical parameters in the three-dimensional wedge method model through optimization algorithms such as gradient descent, the process is realized by minimizing the objective function between the calculated displacement and the monitored displacement, and finally 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 calculation of the gradient clearly shows the sensitivity of each parameter to the displacement, guiding the direction and step of parameter adjustment, and ensuring the rapid convergence of the inversion process.

[0055] Preferably, the dynamic design mechanism in step S2 comprises:

[0056] A geological model construction module for integrating multi-source data to generate a three-dimensional geological model and identify potential unstable wedges.

[0057] A stability analysis module for calculating the slope stability coefficient based on the three-dimensional wedge method.

[0058] A monitoring data interface module for receiving real-time monitoring data.

[0059] A parameter inversion analysis module for performing iterative inversion and model calibration of geomechanical parameters.

[0060] A scheme simulation and optimization module for predicting stability and optimizing support schemes.

[0061] A decision support output module for generating design adjustment instructions.

[0062] By the technical solution, the survey, design, construction, and monitoring are integrated into one, breaking down the barriers of traditional engineering information silos, achieving a semi-automatic or even automatic process from data collection to model calibration and scheme optimization, greatly improving efficiency and reducing human error.

[0063] Preferably, the dam in step S31 comprises a dam body, a buttress is fixedly connected to the impact surface of the dam body, a support pile is arranged on one side of the buttress and fixedly connected to the impact surface of the dam body, a steel beam bottom beam is fixedly connected to the side surface of the buttress away from the dam body, a steel beam sliding rail is fixedly connected to the upper surface of the steel beam bottom beam, a sliding base is slidingly connected to the outer surface of the steel beam sliding rail, a hinged seat is fixedly connected to the upper surface of the sliding base and one side surface of the support pile, respectively, an auxiliary pile in an inclined shape is hinged between the two hinged seats, a traction anchor rod is fixedly connected to the inner surface of the hinged seat on the sliding base, an L-shaped tensioning plate is fixedly connected to the upper surface of one end of the steel beam sliding rail away from the dam body, the outer surface of the traction anchor rod is slidingly connected to the hole on the tensioning plate, and a fixing bolt is arranged on the free end of the traction anchor rod.

[0064] Through the technical scheme, in order to make the dam have self-adaptive energy dissipation, the dam body is further embedded with a sensor monitoring system for monitoring the stress and deformation of the dam body in real time, the traction anchor rod is tensioned by a tensioning jack, and the position of the traction anchor rod after tensioning is limited by the fixing bolt, so as to change the inclination of the auxiliary pile. When the collapse body impacts, the auxiliary pile generates a controllable small displacement on the steel beam sliding rail through the sliding base at the bottom, and absorbs and dissipates part of the impact energy through the constraint of the traction anchor rod and the tensioning plate, so that the mechanism of rigid resistance and flexible energy dissipation makes the dam better cope with dynamic load impact and avoid brittle failure.

[0065] Preferably, the two side surfaces of the dam body are fixedly connected with spacers in a spaced distribution, one side surface of a plurality of the spacers is fixedly connected with a hinged lug plate, the inner surface of the hinged lug plate is hinged with a contraction shaft, and the two side surfaces of the dam body are further fixedly connected with side steel beams, respectively. A tensioning rod is arranged between the spacers and the side steel beams, a clamping plate with a U-shaped groove surface is fixedly connected to one side surface of the side steel beam, the outer surface of the contraction shaft is slidingly connected with the U-shaped groove surface of the clamping plate, and a tightening sleeve is threadedly connected to the free end of the outer surface of the contraction shaft.

[0066] Through the technical scheme, the traditional dam generates cracks on both sides due to stress impact under super load soil pressure, so that the whole dam body is broken. More support force is applied to both ends of the dam body to improve the overall performance, and then the contraction shaft is inserted into the U-shaped groove, and the tightening sleeve is screwed, so that the tensioning rod between the spacer and the side steel beam is extruded, the tensioning rod applies a certain pre-tightening force to the side of the dam, and the structural integrity of the whole protection system under dynamic load is ensured.

[0067] The beneficial effects in the application are:

[0068] 1. Through three-dimensional geological modeling and stereographic projection analysis, the geometric shape and scale of potential unstable wedge are accurately identified from the beginning, making the treatment measures more targeted and avoiding blindness. Through real-time safety monitoring, abnormal deformation of the slope can be captured in time and quickly fed back to the design link for adjustment, greatly reducing the landslide risk in the construction process. Then, a differentiated anchoring strategy combining anchor cable frame beams and anchor rod frame beams is adopted, and a retaining dam is pre-set at the slope toe to form a multi-line protection line combining active and passive, strong and weak, effectively resisting the instability force of different parts. Through the three-dimensional system of slope top water interception, platform drainage, slope toe water diversion and underground drainage, the groundwater level and pore water pressure are effectively controlled. This key measure directly increases the effective stress of the sliding surface, thereby enhancing the shear strength of the rock-soil body and improving the stability from the root.

[0069] 2. By setting parameter inversion and model calibration, the real displacement data monitored on site is used as the scale, and the geomechanical parameters most consistent with the actual situation are automatically inverted through an iterative algorithm, which 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 advance. If the prediction result does not meet the safety requirements, the support scheme can be optimized before the actual danger occurs to generate design adjustment instructions, realizing the transition from passive response to active prevention. The entire process constitutes a complete data acquisition, model analysis, decision optimization, and implementation feedback loop, enabling decisions to be based on continuously updated data, reducing human error, and improving the scientific nature of decisions.

[0070] 3. By grading and platform setting, the high and steep slope is divided into 9 levels, and different slope ratios and wide platforms are set, which not only reduces the height of single-level slope and disperses the thrust, but also provides operating space for construction machinery, significantly improving construction efficiency and improving overall stability as unloading platforms. At the same time, through components such as traction anchor rods, sliding bases, and auxiliary piles, rigid resistance and flexible energy dissipation are combined. When impacted, the structure can absorb and dissipate energy through controllable micro-displacement, avoiding brittle failure and significantly improving the durability and reliability of passive protection structures under dynamic loads. BRIEF DESCRIPTION OF DRAWINGS

[0071] Figure 1 A schematic diagram of a tunnel side slope collapse treatment method proposed by the present application;

[0072] Figure 2 A system block diagram of the dynamic design mechanism of a tunnel side slope collapse treatment method proposed by the present application;

[0073] Figure 3A program block diagram of parameter inversion and model calibration of a tunnel side slope collapse treatment method is provided in the present application.

[0074] Figure 4 A work flow chart of a retaining dam of a tunnel side slope collapse treatment method is provided in the present application.

[0075] Figure 5 A perspective view of a dam body structure of a tunnel side slope collapse treatment method is provided in the present application.

[0076] Figure 6 A perspective view of a supporting pier structure of a tunnel side slope collapse treatment method is provided in the present application.

[0077] Figure 7 A perspective view of a tightening sleeve structure of a tunnel side slope collapse treatment method is provided in the present application.

[0078] Figure 8 A perspective view of a traction anchor rod structure of a tunnel side slope collapse treatment method is provided in the present application.

[0079] In the figure: 1, dam body; 2, supporting pier; 3, supporting pile; 4, steel beam bottom beam; 5, steel beam sliding rail; 6, sliding base; 7, hinged seat; 8, auxiliary pile; 9, traction anchor rod; 10, tensioning plate; 11, fixing bolt; 12, cushion block; 13, hinged lug plate; 14, contraction shaft; 15, side steel beam; 16, tensioning rod; 17, clamping plate; 18, tightening sleeve. DETAILED DESCRIPTION

[0080] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments.

[0081] Referring to Figures 1-8 A tunnel side slope collapse treatment method, the treatment method comprising,

[0082] As Figure 1 shown, S1, geological survey and dynamic design mechanism establishment: engineering geological survey is performed, the collapse body range, karst development area and advantage structural plane are identified, the three-dimensional geological model of the slope is established by integrating the terrain data, stratum interface data, advantage structural plane occurrence and distribution data, the spatial combination relationship of the advantage structural plane is analyzed based on the three-dimensional geological model by using the stereographic projection method, the geometric shape and scale of the potential unstable wedge body are identified, and the initial stability coefficient of the slope is calculated by using the three-dimensional wedge method.

[0083] S2, hierarchical clearing and platform excavation: hierarchical clearing and excavation is performed according to the initial design to form multiple levels of slopes and multiple wide platforms, the bottom boundary line of the clearing is reserved for the length of the tunnel open cut, and safety monitoring of the surface displacement of the slope, crack development and meteorology and hydrology is performed during the process, and the monitoring data is fed back to the dynamic design mechanism to guide construction adjustment and optimization.

[0084] S3, comprehensive anchoring support: anchoring engineering is implemented on the slope after clearing.

[0085] S4, three-dimensional drainage system layout: a water interception ditch, a rapid flow channel and a water diversion channel are laid out at the top of the slope, the platforms at each level and the slope toe, and an upward inclined drainage hole is arranged in the slope body to form a three-dimensional drainage system combining the ground and the underground.

[0086] S5, parameter inversion and model calibration: the displacement data monitored in step S2 is compared with the predicted value of the three-dimensional geological model in step S1, when the deviation exceeds the preset threshold, the slope geometric model is kept unchanged, the geomechanical parameters in the model are systematically inverted and adjusted using an iterative algorithm, so that the stability state calculated by the three-dimensional wedge method matches the actual state of the slope reflected by the monitoring data, thereby calibrating the model, the geomechanical parameters at least include the effective cohesion and the effective internal friction angle .

[0087] S6, dynamic prediction and scheme optimization: using the calibrated model and parameters, the stability coefficient under the subsequent working condition is recalculated, if the predicted value does not meet the safety requirement, the support design scheme is optimized, and a design adjustment instruction is generated.

[0088] S7, support implementation and feedback: support construction is performed according to the optimized scheme, and data is continuously monitored and fed back to step S5 to form a closed-loop dynamic design process.

[0089] The calculation formula of the three-dimensional wedge method is:

[0090] , wherein, is the landslide safety factor.

[0091] and are the areas of the sliding surface and the sliding surface , respectively, in square meters.

[0092] and are the effective cohesion of the sliding surface and the sliding surface , respectively, in kilopascals.

[0093] and Sliding surfaces and sliding surface The internal friction angle, in degrees.

[0094] and For sliding surface and sliding surface The effective normal reaction force, measured in kilonewtons.

[0095] For the crack surface The pore pressure is expressed in kilonewtons.

[0096] The weight of the wedge is expressed in kilonewtons.

[0097] The anchor bolt reinforcement force is expressed in kilonewtons.

[0098] in, .

[0099] .

[0100] ,in, and For the crack surface The angle of inclination and dip, in degrees.

[0101] and For sliding surface Sliding surface Intersection The angle of inclination and dip, in degrees.

[0102] and Strengthening 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.

[0103] The grading prescription in step S2 is as follows: the slope is divided into 9 levels, and different slope ratios are set from top to bottom, wherein the slope ratios of the 1st to 4th levels are 1:0.75, the slope ratios of the 5th to 6th levels are 1:1, and the slope ratios of the 7th to 9th levels are 1:1.25; a wide platform with a width of ≥6m and ≥10m is respectively set at the elevation of 980m and the elevation of 1010m; and the length of the reserved tunnel and open cut is ≥10m. By optimizing the high and steep slope into 9 levels of steps and setting different slope ratios, the height and slope of a single level of the slope are effectively reduced, and the landslide thrust is dispersed. The wide platforms set at the elevations of 980m and 1010m not only serve as operation platforms and transportation channels for construction machinery, improving the construction efficiency, but also play a key role as unloading platforms, interrupting the continuity of the potential sliding surface and greatly improving the overall stability of the slope. The length of the reserved tunnel and open cut of not less than 10m provides a buffer protection zone for the tunnel portal, ensuring the safety of the tunnel structure during the slope treatment process.

[0104] The layout of the three-dimensional drainage system in step S4 includes: setting a slope top intercepting ditch with a cross section of 40cm*40cm outside the slope excavation line by 5m, setting platform intercepting ditches on each level of the wide platform, and connecting them through rapid flow channels to guide the water to the slope foot drainage channel, and finally to the downstream river. The three-dimensional drainage system builds a complete drainage system combining interception, drainage, guidance and seepage. The slope top intercepting ditch intercepts surface runoff outside the slope first outside the slope excavation line by 5m to prevent it from eroding the slope. The platform intercepting ditches on each level collect slope runoff and safely and quickly guide the water to the slope foot through rapid flow channels. The slope foot drainage channel concentrates the collected water flow and drains it into the downstream river, avoiding erosion of the slope foot. Meanwhile, the upwardly inclined drainage holes set in the slope body can effectively drain deep groundwater, reduce the pore water pressure near the sliding surface, and thus significantly improve the shear strength of the rock-soil body. This system realizes the coordinated management of surface water and groundwater.

[0105] The safety monitoring in step S2 includes: laying ≥22 surface displacement monitoring points, using high-precision total station for monitoring, monitoring frequency not less than once every 3 days during construction period, and increasing to once every 3 hours during heavy rain or abnormal deformation, and continuously monitoring for ≥3 years after the completion of the project. The safety monitoring constitutes a dynamic monitoring network of regular patrol, automatic early warning and emergency response. By laying not less than 22 monitoring points to form a monitoring network covering the key areas of the slope, periodic measurements are made using high-precision total station, and the monitoring frequency is dynamically adjusted according to the working conditions: once every 3 days under normal circumstances, and once every 3 hours immediately after heavy rain or abnormal deformation is found to realize real-time capture of dangerous situations. The 3-year operation period monitoring after the completion of the project provides data support for long-term evaluation of the treatment effect and maintenance decision-making.

[0106] The anchoring engineering in step S3 includes,

[0107] S31, in the lower rock mass broken or karst development area in the slope, construction anchor frame beam for strong support, and before grading clear side, also includes construction rock buried retaining dam above the affected bridge pile foundation at the slope toe, the length of the retaining dam is 145-150 meters, for protecting the safety of the underlying structure during the process of clearing the side.

[0108] S32, construction anchor rod frame beam for support in other areas of the slope.

[0109] S33, construction hanging net spray substrate plant protection slope for surface protection at the top of the slope, in the lower part of the stress concentration, rock mass broken or karst development key stress area, use high prestressed anchor frame beam for strong support, form a solid load circle, in the area with good stability, use anchor rod frame beam for conventional reinforcement, economic and efficient, at the top of the slope, use hanging net spray substrate plant protection slope, both prevent surface weathering and peeling, and restore ecology, beautify the environment, construction of rock buried retaining dam at the slope toe before clearing the side, as a passive protection measure, effectively prevent the impact damage of falling stone on the underlying bridge pile foundation during the process of clearing the side.

[0110] Through three-dimensional geological modeling and stereographic projection analysis, the geometric shape and size of the potential unstable wedge are accurately identified from the beginning, making the treatment measures more targeted and avoiding blindness. Through real-time safety monitoring, the abnormal deformation of the slope can be captured in time and quickly fed back to the design link for adjustment, greatly reducing the landslide risk during construction. Then, a differentiated anchoring strategy combining anchor frame beam and anchor rod frame beam is adopted, and a retaining dam is pre-set at the slope toe, forming a multi-line defense line combining active and passive, strong and weak, effectively resisting the instability force of different parts. Through the three-dimensional system of slope top water interception, platform drainage, slope toe water diversion and underground drainage, the groundwater level and pore water pressure are effectively controlled. This key measure directly increases the effective stress of the sliding surface, thereby enhancing the shear strength of the rock-soil mass and improving the stability from the root.

[0111] As shown in Figure 1 and Figure 3 , in step S5, the iterative algorithm is used for systematic inversion adjustment, specifically: taking the monitoring displacement value as the objective function and the geomechanical parameters as the variables, the objective function is constructed, which is the sum of the squares of the residuals of the calculated displacement and the monitoring displacement. The objective function is minimized by an optimization algorithm to obtain the optimal geomechanical parameters, specifically:

[0112] First step, define the objective function: the residual sum of squares of the above monitoring displacement value and the model calculated displacement value to construct the objective function :

[0113] .

[0114] where : the parameter vector to be inverted, i.e. .

[0115] : the number of displacement monitoring points.

[0116] : the displacement value of the th monitoring point calculated by the 3D wedge method based on the parameter vector .

[0117] : the actual measured displacement value of the th monitoring point.

[0118] : the objective function value, the goal of inversion is to find the parameter vector that makes .

[0119] Second step, iterative optimization algorithm: the gradient descent method is used for automatic optimization, and the parameter update formula is:

[0120] where : the number of iterations.

[0121] : the parameter estimation value at the th iteration.

[0122] : the learning rate, which controls the amplitude of each parameter update.

[0123] : the gradient of the objective function at the current parameter value, which is a vector pointing to the direction in which increases fastest, and its component form is:

[0124] where is the sensitivity of the th calculated displacement to the th parameter.

[0125] Third step, termination calibration: when the difference between the objective function values of the adjacent two iterations is less than the preset threshold, the iteration is terminated, and the corresponding parameter vector That is, the optimal parameters obtained by inversion, the model completes calibration, and the parameter inversion and model calibration process is essentially the accurate calibration of data assimilation between the numerical model and the actual situation. It takes the real displacement data obtained by field monitoring as the only standard, automatically and repeatedly adjusts the geomechanical parameters in the three-dimensional wedge method model through optimization algorithms such as gradient descent, and realizes the minimization of the objective function between the calculated displacement and the monitored displacement. Finally, 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 calculation of the gradient clearly shows the sensitivity of each parameter to the displacement, guides the direction and step of parameter adjustment, and ensures the rapid convergence of the inversion process.

[0126] As shown in Figure 2 , the dynamic design mechanism in step S2 includes:

[0127] A geological model construction module for integrating multi-source data to generate a three-dimensional geological model and identify potential unstable wedges.

[0128] A stability analysis module for calculating the slope stability coefficient based on the three-dimensional wedge method.

[0129] A monitoring data interface module for receiving real-time monitoring data.

[0130] A parameter inversion analysis module for performing iterative inversion of geomechanical parameters and model calibration.

[0131] A scheme simulation and optimization module for predicting stability and optimizing support schemes.

[0132] A decision support output module for generating design adjustment instructions, integrating surveying, design, construction, and monitoring into one, breaking down the barriers of traditional information silos, and realizing a semi-automatic or even automatic process from data collection to model calibration and scheme optimization, greatly improving efficiency and reducing human error.

[0133] By setting parameter inversion and model calibration, the real displacement data obtained by field monitoring is used as the scale, and the geomechanical parameters that best meet the actual situation 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 advance. If the prediction result does not meet the safety requirements, the support scheme can be optimized before the actual danger occurs, and design adjustment instructions can be generated, realizing the transition from passive response to active prevention. The entire process forms a complete data collection, model analysis, decision optimization, and implementation feedback loop, enabling decisions to be based on continuously updated data, reducing human error, and improving the scientific nature of decisions.

[0134] As Figures 4-8 shown, in order to make the retaining dam has self-adaptive energy dissipator, then the retaining dam in step S31 includes dam body 1, the impact surface of the dam body 1 is fixedly connected with the buttress 2, one side of the buttress 2 is provided with the support pile 3 fixedly connected with the impact surface of the dam body 1, the side surface of the buttress 2 away from the dam body 1 is fixedly connected with the steel beam bottom beam 4, the upper surface of the steel beam bottom beam 4 is fixedly connected with the steel beam sliding rail 5, the outer surface of the steel beam sliding rail 5 is slidingly connected with the sliding base 6, the upper surface of the sliding base 6 and the side surface of the support pile 3 are respectively fixedly connected with the hinged seat 7, the auxiliary pile 8 in an inclined shape is hinged between the two hinged seats 7, the inner surface of the hinged seat 7 on the sliding base 6 is fixedly connected with the traction anchor rod 9, the upper surface of the one end of the steel beam sliding rail 5 away from the dam body 1 is fixedly connected with the L-shaped tension plate 10, the outer surface of the traction anchor rod 9 is slidingly connected with the hole on the tension plate 10, the outer surface of the free end of the traction anchor rod 9 is provided with the fixed bolt 11, the dam body 1 of the retaining dam is further embedded with a sensor monitoring system for real-time monitoring of dam stress and deformation, the traction anchor rod 9 is tensioned by the tensioning jack, and the position of the traction anchor rod 9 after tensioning is limited by the fixed bolt 11, so as to change the inclination of the auxiliary pile 8, when the collapse body impacts, the support pile 3 and the auxiliary pile 8 are acted on, the auxiliary pile 8 produces a controllable small displacement on the steel beam sliding 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 rod 9 and the tension plate 10, so that the mechanism of rigid resistance and flexible energy dissipation makes the retaining dam better cope with dynamic load impact and avoid brittle failure.

[0135] The two side surfaces of the dam body 1 are fixedly connected with the cushion block 12 in a spaced distribution, wherein the side surface of the plurality of cushion blocks 12 is fixedly connected with the hinged lug plate 13, the inner surface of the hinged lug plate 13 is hinged with the contraction shaft 14, the two side surfaces of the dam body 1 are further respectively fixedly connected with the side steel beam 15, the tension rod 16 is arranged between the cushion block 12 and the side steel beam 15, the side surface of the side steel beam 15 is fixedly connected with the clamping plate 17 with a U-shaped groove surface, the outer surface of the contraction shaft 14 is slidingly connected with the U-shaped groove surface of the clamping plate 17, the outer surface of the free end of the contraction shaft 14 is threadedly connected with the tightening sleeve 18, the two sides of the conventional retaining dam are cracked due to stress impact under the overload soil pressure, so that the whole dam is broken, generally more support force is applied to the two ends of the dam body to improve the overall performance, and then the contraction shaft 14 is inserted into the U-shaped groove, the tightening sleeve 18 is screwed, so as to extrude the tension rod 16 between the cushion block 12 and the side steel beam 15, the tension rod 16 applies a certain pre-tightening force to the side of the retaining dam, and the structural integrity of the whole protection system under dynamic load is ensured.

[0136] By hierarchical clearing and platform setting, the high and steep slope is divided into 9 levels, and different slope ratios and wide platforms are set, which not only reduces the height of single slope and disperses the thrust, but also provides operation space for construction machinery, significantly improves the construction efficiency, and improves the overall stability as an unloading platform, and through traction anchor rod 9, sliding base 6, auxiliary pile 8 and other components, the combination of rigid resistance and flexible energy dissipation is realized, when impacted, the structure can absorb and dissipate energy through controllable micro displacement, avoid brittle failure, and significantly improve the durability and reliability of the passive protection structure under dynamic load.

[0137] Working principle: in specific embodiments, the present application obtains original data such as terrain, stratum and advantage structure surface through geological survey, then performs hierarchical clearing, anchoring support and drainage system layout, and performs safety monitoring throughout the process;

[0138] The monitoring data is compared with the predicted value of the model, the iterative algorithm is used to invert the geomechanical parameters, the calibrated model is used to predict the stability after the next construction, the design is optimized, the construction is performed according to the optimized scheme, and the monitoring is continued, and the data is fed back to intelligent learning and model calibration again;

[0139] In three-dimensional geological model analysis, it is identified that there are structures such as bridge pile foundations that need to be protected at the slope toe, and the risk of collapse body impact caused by clearing is predicted, accordingly, it is decided to construct the retaining dam in advance before clearing;

[0140] During the clearing process, the impact force generated by the collapse body or falling stone acts on the impact surface of the retaining dam, that is, the support pile 3 and the auxiliary pile 8, the inclination of the auxiliary pile 8 is adjusted through the predicted impact force, that is, the traction anchor rod 9 is tensioned through the tensioning jack, so that the sliding base 6 generates controllable micro displacement on the steel beam sliding rail 5, and the position of the traction anchor rod 9 after tensioning is limited through the fixing bolt 11, so as to change the inclination of the auxiliary pile 8, at this time, when the impact force impacts the dam body 1, the traction anchor rod 9 connected with the sliding base 6 is stretched under the constraint of the tensioning plate 10, this process converts a large amount of impact kinetic energy into friction and material strain energy, thereby absorbing and dissipating part of the energy;

[0141] The remaining impact force is transmitted to the dam body 1 and the buttress 2 through the auxiliary pile 8 and the support pile 3, and the dam body itself and the foundation bearing capacity are used to finally resist, which forms a defense mechanism of first soft and then hard;

[0142] In order to prevent the dam body from cracking at both ends under impact, the pre-tightening force of the tensioning rod 16 is applied by tightening the pipe sleeve 18, the lateral constraint force of the dam body on both sides is applied through the cushion block 12 and the side steel beam 15, and the integrity is ensured.

[0143] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for treating tunnel side slope collapse, characterized in that: The treatment method includes: 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. 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. Construct a surface protection layer by spraying a substrate with netting and planting vegetation on the top of the slope. The retaining dam described in step S31 includes a dam body. A buttress is 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 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 with 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. 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 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 third, 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.

7. The method for treating tunnel side slope collapse according to claim 6, 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.

8. A method for treating tunnel side slope collapse according to claim 7, characterized in that: Both sides of the dam body are fixedly connected with spaced pads. 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.

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