An analysis and testing method for failure mechanism of landslides on steep slopes

Abstract

The application provides a kind of steep slope outside fracture control type landslide disaster mechanism analysis test method, belongs to geological disaster analysis technical field, solve the problem that traditional single analysis test method is difficult to comprehensively reveal steep slope outside fracture control sliding mode and disaster mechanism. It includes using geological model, mechanical model, numerical model and physical model to comprehensively analyze and test the disaster mechanism of steep slope outside fracture control type landslide, realizes the consistency test of multi-technical means integration and analysis test result, reveals the disaster mechanism of steep slope outside fracture control type landslide under the action of static force and dynamic force in tectonically active mountain area, provides technical support for disaster prevention and mitigation and risk prevention and control of tectonically active mountain area geological disasters.

Description

Technical Field

[0001] The invention belongs to the technical field of geological disaster analysis, and in particular to an analysis and testing method for the disaster mechanism of a landslide controlled by an external fault on a steep slope. Background Art

[0002] Fault zones, acting as the boundaries of plate movement, continuously reshape the regional geological environment through ongoing seismic activity, stress adjustments, and surface deformation. These zones provide unique boundary conditions and dynamic mechanisms for landslide formation, significantly influencing the development and distribution of landslides along fault zones. Fault-controlled landslides are a type of geological hazard that develops within this context. They are landslides that develop within fault zones and their influence areas and are controlled by fault structures. Faults passing through slopes disrupt the structure and integrity of the rock mass, reducing its mechanical strength and controlling the slope's deformation and stress fields, the development and distribution of the damage zone, and the slope's failure patterns.

[0003] Early studies suggested that slopes controlled by external faults on gently sloping slopes were less stable, while those controlled by external faults on steep slopes were more stable and less prone to large-scale landslides. However, with the planning and construction of numerous major projects in western my country in recent years, and with the in-depth investigation of these projects, numerous large-scale landslides influenced or controlled by external faults on steep slopes have been gradually revealed. These landslides pose a serious threat to the safe construction and operation of these projects, and have attracted considerable attention from relevant scholars. Although existing research has fully recognized the influence and control role of faults on landslide hazards in high mountain and canyon regions, limited research has focused on the mechanisms and risk management of landslides controlled by external faults on steep slopes. This has hindered the comprehensive understanding of the interplay between external faults on steep slopes and the evolution of landslide disasters, hindering the needs of project planning, construction, and disaster prevention and mitigation. This research highlights the limitations of this area and the need for further investigation. Therefore, it is necessary to develop an analytical and testing method for the mechanisms of landslides controlled by external faults on steep slopes. Summary of the Invention

[0004] In response to the above problems, the purpose of the present invention is to provide an analytical testing method for the disaster mechanism of landslides controlled by external faults on steep slopes. The method uses geological models, mechanical models, numerical models and physical models to analyze and test the disaster mechanism of landslides controlled by external faults on steep slopes. It solves the problem that traditional single analytical test methods are difficult to fully reveal the sliding control mode and disaster mechanism of external faults on steep slopes, realizes the consistency test of the integration of multiple technical means and analytical test results, reveals the disaster mechanism of landslides controlled by external faults on steep slopes under static and dynamic actions, and provides technical support for disaster prevention, mitigation and risk control of geological disasters in tectonic active mountainous areas.

[0005] The technical solution adopted in the present invention is as follows:

[0006] A method for analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes, comprising: using geological models, mechanical models, numerical models and physical models to conduct comprehensive analysis and testing on the mechanism of landslide disasters controlled by external faults on steep slopes;

[0007] The geological model is based on technical means to determine the planar and spatial distribution characteristics of landslides and faults, and uses digital elevation models to superimpose ground images to establish a three-dimensional geological model of landslides including faults, and analyzes the sliding control mode and disaster mechanism of the faults outside the steep slope on the slope; the sliding control mode refers to the control mode of the fault on the instability and destruction of the slope, and the sliding control mode includes: the fault passes through the rear edge of the slope and tends to the outside of the slope, the fault inclination angle is greater than the slope gradient, and the rear edge of the slope is bounded by the fault, and sliding deformation occurs toward the free surface outside the slope; the disaster mechanism refers to the key factors and their interaction mechanism of the whole chain and process of the landslide controlled by the faults outside the steep slope from initiation to movement evolution; the key factors are divided into internal factors and external factors, the internal factors include the inclination angle and mechanical properties of the fault zone and the rock mass quality, slope structure and stratum lithology of the slope, and the external factors include rainfall, earthquake and engineering disturbance; the interaction mechanism refers to the coupling effect between the internal and external factors;

[0008] The mechanical model is based on the stress characteristics of the steep slope external fault controlled slope, and establishes a geological-mechanical model of slope stress and deformation. The multi-source loads of gravity, engineering disturbance, earthquake, and rainfall on the slope rock mass are mechanically analyzed using the pseudo-static method. The model reveals the possible locations of deformation and rupture of the steep slope external fault controlled slope, and further analyzes the sliding control mode and disaster mechanism of the fault on the slope rock mass.

[0009] The numerical model is based on the established geological model and mechanical model to construct corresponding two-dimensional and three-dimensional numerical models for analyzing the disaster mechanism of fault-controlled slopes. It describes the response of the slope displacement field, stress field and damage zone under the single factor or the coupled action of multiple factors such as gravity, engineering disturbance, earthquake and rainfall, and reveals the disaster mechanism of deformation and sliding of fault-controlled slopes outside steep slopes. The response law refers to the quantifiable displacement, stress and plastic damage zone evolution characteristics presented by the deformation and sliding failure process of the slope rock mass under the single factor or the coupled action of multiple factors such as gravity, rainfall, earthquake and engineering disturbance.

[0010] The physical model is based on a geological model, a mechanical model, and a numerical model to establish a physical model for analyzing and testing a steep slope with an external fault-controlled slope under earthquake dynamics. The physical model simulates the entire process of deformation and rupture, instability and sliding, and movement evolution of a steep slope with an external fault-controlled slope under strong earthquake conditions, revealing the dynamic characteristics and disaster mechanism of fault-controlled landslides from the perspective of physical model testing. The dynamic characteristics refer to the quantifiable kinematic and energy evolution laws exhibited by a fault-controlled slope in the entire process from deformation to instability under strong earthquakes. The dynamic characteristics include vibration response, motion trajectory, motion speed, and energy conversion.

[0011] Carry out consistency test between the results of physical model test and geological model, mechanical model and numerical model analysis test to reveal the disaster mechanism of external fault-controlled landslides on steep slopes under static and dynamic action in tectonic active mountainous areas.

[0012] Preferably, the technical means of the geological model include data collection, geological survey, profile measurement, engineering investigation, remote sensing interpretation, in-situ testing and geophysical exploration, to determine the planar and spatial distribution characteristics and activity of the fault zone extension length, strike, dip, inclination, and to identify the planar and profile morphological characteristics and material structure composition of the fault-controlled landslide.

[0013] Preferably, the earthquake conditions in the numerical model take into account the peak acceleration of the earthquake motion; in order to analyze the disaster mechanism of the steep slope external fault controlled slope under extreme earthquake conditions, on the basis of the specified peak acceleration of the earthquake motion, the high-level amplification effect of the seismic wave is taken into account, and the maximum value of the peak acceleration of the earthquake motion suffered by the slope is increased by 50-100%; the strength reduction method is used to calculate the stress field, displacement field, plastic zone distribution and disaster evolution characteristics and overall stability of the steep slope external fault controlled slope.

[0014] Preferably, the calculation steps of the strength reduction method are: using f / SRF 、 c / SRF replace f 、 c The value is calculated, f is the actual internal friction coefficient of the material in the numerical model, c is the actual cohesion of the material in the numerical model, SRF is the strength reduction factor and SRF The value of is greater than 1; SRF Gradually increase, when the calculation results do not converge, SRF This is the overall safety factor of the slope, and the calculated maximum shear strain distribution area inside the slope is the potential sliding surface.

[0015] Preferably, the rainfall condition in the numerical model is calculated by bringing the saturation parameters of each material into the numerical model.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] The disaster mechanism of landslides controlled by external faults on steep slopes was analyzed and tested using geological models, mechanical models, numerical models and physical models. This solved the problem that traditional single analytical test methods could not fully reveal the sliding control mode and disaster mechanism of external faults on steep slopes. It realized the integration of multiple technical means and consistency testing of analytical test results, revealed the disaster mechanism of landslides controlled by external faults on steep slopes under static and dynamic forces, and provided technical support for disaster prevention, mitigation and risk control of geological disasters in tectonic active mountainous areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic diagram of a process flow provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a geological model for analyzing the mechanism of landslide disasters controlled by faults outside a steep slope according to an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of a mechanical model for analyzing the mechanism of landslide disasters controlled by external faults on steep slopes provided by an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of a numerical model for analyzing the mechanism of landslide disasters controlled by external faults on steep slopes provided by an embodiment of the present invention;

[0023] Figure 5 A schematic diagram of the change in safety factor of a steep slope external fracture controlled slope based on strength coefficient reduction calculation provided by an embodiment of the present invention;

[0024] Figure 6 Schematic diagram of the physical model for analyzing the mechanism of landslide disasters controlled by external faults on steep slopes provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present invention. It should be understood that the described embodiments are only a portion of the embodiments of the present invention, not all of them. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] The following combination Figures 1-6 The present invention is described in detail.

[0029] Example:

[0030] A method for analyzing and testing the mechanism of landslide disasters controlled by faults outside a steep slope, comprising: using geological models, mechanical models, numerical models, and physical models to comprehensively analyze and test the mechanism of landslide disasters controlled by faults outside a steep slope; faults outside a steep slope are faults that tilt outwards and have an inclination angle greater than the slope gradient;

[0031] The geological model is based on technical means to determine the planar and spatial distribution characteristics of landslides and faults, and uses digital elevation models to superimpose ground images to establish a refined three-dimensional geological model of landslides including faults, and analyze the sliding control mode and disaster mechanism of the faults outside the steep slope on the slope; the technical means of the geological model include data collection, geological survey, profile measurement, engineering survey, remote sensing interpretation, in-situ testing and geophysical exploration, to determine the planar and spatial distribution characteristics and activity of the extension length, direction, dip, and inclination of the fault zone, and to identify the planar and profile morphological characteristics and material structure composition of the fault-controlled landslide; the sliding control mode refers to the effect of the fault on the instability and failure of the slope The control mode of landslide includes: the fault passes through the rear edge of the slope and leans outward, the fault dip angle is greater than the slope gradient, the rear edge of the slope is bounded by the fault, and sliding deformation occurs toward the free surface outside the slope; the disaster mechanism refers to the key factors and their interaction mechanisms in the entire chain and process of landslide control by the fault outside the steep slope from initiation to movement evolution; the key factors are divided into internal factors and external factors, the internal factors include the dip angle and mechanical properties of the fault zone and the rock mass quality, slope structure and stratum lithology of the slope, and the external factors include rainfall, earthquakes and engineering disturbances; the interaction mechanism refers to the coupling effect between internal and external factors;

[0032] The mechanical model is based on the stress characteristics of steep slopes controlled by external faults. A geological-mechanical model of slope stress and deformation is established. The multi-source loads of gravity, engineering disturbance, earthquake, and rainfall are analyzed using the pseudo-static method to reveal the possible locations of deformation and rupture of steep slopes controlled by external faults, and then the sliding control mode and disaster mechanism of the fault on the slope rock mass are analyzed.

[0033] The numerical model is a geological model and a mechanical model established based on geological surveys and theoretical analysis. It constructs corresponding two-dimensional and three-dimensional numerical models for the analysis of the disaster mechanism of fault-controlled slopes. It accurately depicts the response law of the slope displacement field, stress field and damage zone under the single factor or multiple coupling effects of gravity, engineering disturbance, earthquake and rainfall on the slope rock mass, and reveals the deformation and sliding disaster mechanism of fault-controlled slopes outside steep slopes. The response law refers to the quantifiable displacement, stress and The evolution characteristics of the plastic failure zone; the earthquake conditions in the numerical model use the peak acceleration of the earthquake motion. In order to analyze the disaster mechanism of the steep slope external fault controlled slope under extreme earthquake conditions, and taking into account the high-level amplification effect of seismic waves, the maximum value of the peak acceleration of the earthquake motion is increased by 50-100% based on the value specified in GB18306-2015 "China Earthquake Motion Parameter Zoning Map"; the strength reduction method is used to calculate the stress field, displacement field, plastic zone distribution and disaster evolution characteristics and overall stability of the steep slope external fault controlled slope; the calculation steps of the strength reduction method are: in the numerical analysis, use f / SRF 、 c / SRF replace f 、 c The value is calculated, f is the actual internal friction coefficient of the material in the numerical model, c is the actual cohesion of the material in the numerical model, SRF is the strength reduction factor and SRF The value of is greater than 1; SRF Gradually increase, when the calculation results do not converge, SRF is the overall safety factor of the slope. The calculated maximum shear strain distribution area inside the slope is the potential sliding surface. SRF =1, the calculation is based on the actual internal friction coefficient and cohesion of the material; when SRF =2, other material parameters such as deformation modulus remain unchanged, and the material parameters are f 、 c Simultaneously reduce the price by 50% and then replace f 、 c The rainfall condition in the numerical model is calculated by bringing the saturation parameters of each material into the numerical model;

[0034] The physical model is based on geological models, mechanical models, and numerical models, and is based on the principle of material similarity. It is used to establish a physical model for analyzing and testing the disaster mechanism of steep external fault-controlled slopes under earthquake dynamics. The physical model simulates the entire process of deformation and rupture, instability and sliding, and movement evolution of steep external fault-controlled slopes under strong earthquake conditions, revealing the dynamic characteristics and disaster mechanism of fault-controlled landslides from the perspective of physical model experiments. The dynamic characteristics refer to the quantifiable kinematic and energy evolution laws exhibited by fault-controlled slopes throughout the entire process from deformation to instability under strong earthquakes. The dynamic characteristics include vibration response, motion trajectory, motion speed, and energy conversion.

[0035] Carry out consistency test between the results of physical model test and geological model, mechanical model and numerical model analysis test to reveal the disaster mechanism of external fault-controlled landslides on steep slopes under static and dynamic action in tectonic active mountainous areas.

[0036] Taking the Anning River active fault zone, one of the important boundary faults on the eastern edge of the Qinghai-Tibet Plateau, and the steep slope external fault-controlled landslides developed in the nearby areas as an example, the technical solution of the present invention is clearly and completely described.

[0037] A method for analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes, comprising: analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes using geological models, mechanical models, numerical models, and physical models;

[0038] 1. The geological model is based on data collection, geological survey, profile measurement, engineering investigation, remote sensing interpretation, in-situ testing and geophysical exploration to identify the characteristics of the fault zone outside the steep slope, including the extension length, strike, dip, inclination, activity, width of the fracture zone and material structure of the fault zone, as well as the plane and profile characteristics of the fault-controlled landslide and the lithology and structural characteristics of the formation, such as basic geological information. Figure 2 As shown in (a) in .

[0039] By superimposing ground images with digital elevation models, a three-dimensional surface model of the landslide area was established. The stratum lithology data, landslide spatial location information, and fault zone distribution characteristics were integrated to construct a three-dimensional geological model of the fault-controlled landslide in the Anning River Fault Zone, including stratum lithology, landslide boundaries, and fault spatial distribution, type, and occurrence. Figure 2 As shown in (b), the influence and control of the external faults on the steep slope on landslide disasters are analyzed, revealing the mechanism of landslide disasters controlled by the external faults on the steep slope.

[0040] Second, the mechanical model is based on the geological model that has been identified and established, combined with the rock structure and slope structure of the slope where the fault-controlled landslide is located, as well as the characteristics of the fracture development outside the steep slope. After a moderate generalization of the geological model, a mechanical analysis model of the disaster mechanism of the fault-controlled slope outside the steep slope is established. The multi-source loads such as engineering disturbance, earthquake, and rainfall are used for mechanical analysis using the pseudo-static method to reveal the mechanical mechanism, critical conditions and possible sliding failure locations of the deformation and rupture of the steep fault-controlled slope, such as Figure 3 (a) As shown; Carry out the stress and deformation analysis of the whole process from creep and cracking to sliding failure of the steep slope external fault controlled slope, clarify the control effect of the steep slope external fault on the catastrophic evolution of the slope rock mass, and reveal its disaster mechanism, such as Figure 3 (b)

[0041] The specific analysis process is as follows:

[0042] (1) Under the action of gravity, the slope rock mass outside the fault on the steep slope creeps downward along the fault, causing tensile stress and tensile cracking deformation in the rock mass at the rear of the slope. In the lower part of the slope, due to the air-facing conditions, the creep deformation of the slope rock mass along the fault is blocked, and the creep deformation rate and trend are further slowed down, causing the slope rock mass here to undergo slow shear deformation toward the air-facing direction.

[0043] (2) As the upper slope rock mass continues to creep downward and is blocked at the lower part of the slope, the shear stress at the lower part of the slope gradually increases, and the slope rock mass further slowly shears and deforms toward the free surface, and then develops into discontinuous shear damage surfaces. However, there are relatively good rock bridges between the shear damage surfaces.

[0044] (3) During heavy rain, rainwater seeps into the slope from the slope surface and the tensile fracture surface, causing the mechanical properties of the fault to deteriorate. A higher pore water pressure is formed in the rock mass on the shallow surface of the slope, and the rock mass on the slope further creeps and deforms along the fault. The shear stress in the lower part of the slope continues to increase, causing the shear damage surface to continue to extend and expand, and the rock bridge gradually decreases.

[0045] (4) Once the shear damage surface below the slope is completely connected, under the influence of external factors such as heavy rain, earthquake or strong artificial disturbance, the slope rock mass composed of faults and shear damage surfaces will shear off the potential sliding surface and slide down along the fault outside the steep slope, thus forming a landslide disaster.

[0046] 3. Numerical model is a geological model and mechanical model established based on geological survey and theoretical analysis, which includes the numerical calculation model of slope rock structure, lithology and faults outside the steep slope, such as Figure 4 As shown in (a); the established numerical model is 1100m long, 200m high on the right side of the model, 700m high on the left side, with a slope angle of 45° and a total slope height of 500m. The X and Y directions of the left, right and bottom boundaries of the numerical model are constrained boundaries, and the upper part is a free surface. The mesh in the model is divided into triangles, and the mesh density is appropriately increased in the fault zone and the shallow surface of the slope. The slope rock mass in the numerical model includes 7 types, including strongly weathered, weakly weathered, slightly weathered granite and sandstone, and fault zone rock mass. The calculation parameters of each material are shown in Table 1. Calculate the displacement field of the steep slope external fault controlled slope under the conditions of gravity, earthquake, rainfall and coupling. Figure 4 (b)), maximum shear strain (as shown in Figure 4 (c)), plastic failure zone (as shown in Figure 4 (d)), and the calculation of the overall safety factor of the slope based on the strength reduction method (as shown in Figure 5 The earthquake operating conditions include earthquake peak accelerations of 0.1g, 0.2g, 0.3g, and 0.4g.

[0047] Table 1 Material parameters of the numerical model

[0048] Rock mass name Deformation modulus / Mpa <![CDATA[Severity / MNa number -3 > Poisson's ratio Tensile strength / Mpa Internal friction angle / friction Cohesion / Mpa Strongly weathered granite 3500 0.025 0.24 0.05 39 0.8 Weakly weathered granite 10000 0.026 0.22 0.6 47 1.2 Slightly weathered granite 15000 0.027 0.20 1.2 55 1.8 Strongly weathered sandstone 3000 0.0245 0.25 0.02 37 0.7 Weakly weathered sandstone 85000 0.026 0.23 0.4 45 1.1 Slightly weathered sandstone 12000 0.027 0.21 0.9 51 1.6 Fault zone rock mass 1000 0.022 0.3 0 25 0.15

[0049] (1) Displacement field: Slope displacement is significantly affected by faults outside the steep slope. Slope displacement mainly occurs outside the fault. The displacement at the back edge of the fault (upper slope) is relatively large. As it moves downward, it is blocked by the rock mass below the slope and the free surface conditions are limited, so the displacement gradually decreases. Therefore, a rapid displacement reduction zone is formed at the lower part of the slope, and the rock mass undergoes shear deformation, which in turn develops into a potential sliding surface.

[0050] (2) Maximum shear strain: The outer fault of the steep slope has a significant influence on the maximum shear strain of the slope. There are two continuous maximum shear strain bands between the outer fault of the steep slope and the surface of the slope, which means there are two potential sliding surfaces. One is located at the bottom of the slope and is adjacent to the outer fault. Figure 4 The potential sliding surfaces in (b) are located in a similar position. The other one is located in the rock masses of the weakly weathered and strongly weathered zones on the shallow surface of the slope.

[0051] (3) Plastic failure zone: mainly distributed along the outer faults of steep slopes, and also distributed in large areas in strong weathering zones and weak weathering zones. According to the location of the outer faults of steep slopes and the distribution characteristics of the plastic failure zone, the potential sliding surface position can be obtained based on the slope rock mass failure law. Figure 4 The potential sliding surface in the upper part of (c) is close in position.

[0052] By analyzing the displacement field, strain field and damage zone calculated by the numerical model, the influence and control of the external fault of the steep slope on the slope stability are revealed, and the disaster mechanism and catastrophic effect of the landslide controlled by the external fault of the steep slope are analyzed.

[0053] 4. The physical model is a model test that can objectively reflect the response process and response mode of a steep slope controlled by an external fault under earthquake dynamic impact loads. It can describe the catastrophic evolution characteristics of a steep slope controlled by an external fault from deformation and rupture, instability and sliding to catastrophic movement, and reveal the disaster mechanism of a steep slope controlled by an external fault under the action of earthquake dynamics.

[0054] According to the results of geological survey, mechanical analysis and numerical calculation, based on the principle of material similarity, a physical model for analyzing and testing the disaster mechanism of steep slope external fault controlled slope under earthquake dynamic action is established, such as Figure 6 As shown; the test device of the physical model is the existing technology (a dynamic response test device for simulating the lateral impact load of the slope in the extreme earthquake zone disclosed in the patent publication number CN108919339B), which consists of a model box system, a power system and a monitoring system. The model box is 75 cm long, 40 cm wide and 60 cm high. Figure 6 As shown; the power system consists of a slide rail, a bracket and a steel ball. The slide rail is a 65mm diameter pipe with embedded steel wire, fixed to the outer wall of a staircase about 15m high. Different earthquake loads, frequencies and durations are simulated by controlling the release height, time interval and duration of the 1kg steel ball. The dynamic load value is obtained by calculating the potential energy and impact rebound of steel balls placed at different elevations; the dynamic load frequency is obtained by calculating the potential energy and impact rebound of steel balls placed at the same elevation with adjustable equal spacing; the dynamic load duration is obtained by calculating the potential energy and impact rebound of steel balls placed at the same elevation with fixed spacing and periodic movement. The monitoring system consists of a model box side impact load quantification test system and a high-speed camera and data acquisition system to capture the dynamic parameters and microscopic characteristics of the test process.

[0055] On the outer walls of the tempered glass on both sides of the model box, parallel horizontal and vertical reference lines are drawn every 5 cm, and lubricating oil is evenly applied to the inner walls of the tempered glass on the left and right sides of the model box to reduce the influence of friction resistance and boundary effect during the sliding of the sliding body. The test model adopts a layered filling method, and is compacted and filled in layers at intervals of 5 cm. When the pre-designed pressure sensor position is reached, the sensor is wrapped with plastic wrap, tied with a rubber band and buried in the preset position before stacking. After the layered filling is completed, the required geometric dimensions of the model are obtained by artificially cutting the slope. Then let it stand for 24 hours to consolidate under its own gravity. After consolidation is completed, displacement meters are installed at the top and surface of the slope according to the pre-designed positions.

[0056] The prepared model box was placed in a physical model test apparatus, and dynamic response tests were conducted on the specimens under simulated earthquake impact loads. This study characterized the entire catastrophic process of a steep-slope external fault-controlled slope under earthquake dynamics, from tensile deformation to instability initiation to landslide failure. The consistency of the physical model test results with geological, mechanical, and numerical model tests was verified to reveal the sliding control patterns and disaster mechanisms of steep-slope external fault-controlled landslides under static and dynamic forces in tectonic active mountainous areas.

[0057] This example uses the steep slope external fault-controlled landslide developed in the Anning River active fault zone and nearby areas as an example. Using data collection, geological surveys, profiling, engineering surveys, remote sensing interpretation, in-situ testing, and geophysical exploration, the technical means are used to clarify the definition and connotation of steep slope external fault-controlled slopes, identify the spatial combination characteristics of steep slope external faults and slopes, and analyze the impact and control of steep slope external faults on slope stability and catastrophic effects. A four-in-one "geological model-mechanical model-numerical model-physical model" method for analyzing and testing the disaster mechanism of steep slope external fault-controlled landslides is constructed. This method explores the geological hazard effects of fault zones, reveals the disaster mechanism of landslides in tectonic active mountainous areas under the action of internal and external forces, and integrates multiple technical means and analyzes the consistency test of test results. This method provides theoretical support and technical means for the planning and construction of major infrastructure in tectonic active mountainous areas and strong earthquake mountainous areas in western China, as well as for disaster prevention and mitigation.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes, characterized in that: include: Comprehensive analysis and testing of the mechanism of landslide disasters controlled by faults outside steep slopes using geological models, mechanical models, numerical models and physical models; The geological model is based on technical means to determine the planar and spatial distribution characteristics of landslides and faults, and uses digital elevation models to superimpose ground images to establish a three-dimensional geological model of landslides including faults, and analyzes the sliding control mode and disaster mechanism of the faults outside the steep slope on the slope; the sliding control mode refers to the control mode of the fault on the instability and destruction of the slope, and the sliding control mode includes: the fault passes through the rear edge of the slope and tends to the outside of the slope, the fault inclination angle is greater than the slope gradient, and the rear edge of the slope is bounded by the fault, and sliding deformation occurs toward the free surface outside the slope; the disaster mechanism refers to the key factors and their interaction mechanism of the whole chain and process of the landslide controlled by the faults outside the steep slope from initiation to movement evolution; the key factors are divided into internal factors and external factors, the internal factors include the inclination angle and mechanical properties of the fault zone and the rock mass quality, slope structure and stratum lithology of the slope, and the external factors include rainfall, earthquake and engineering disturbance; the interaction mechanism refers to the coupling effect between the internal and external factors; The mechanical model is based on the stress characteristics of the steep slope external fault controlled slope, and establishes a geological-mechanical model of slope stress and deformation. The multi-source loads of gravity, engineering disturbance, earthquake, and rainfall on the slope rock mass are mechanically analyzed using the pseudo-static method. The model reveals the possible locations of deformation and rupture of the steep slope external fault controlled slope, and further analyzes the sliding control mode and disaster mechanism of the fault on the slope rock mass. The numerical model is based on the established geological model and mechanical model to construct corresponding two-dimensional and three-dimensional numerical models for analyzing the disaster mechanism of fault-controlled slopes. It describes the response of the slope displacement field, stress field and damage zone under the single factor or the coupled action of multiple factors such as gravity, engineering disturbance, earthquake and rainfall, and reveals the disaster mechanism of deformation and sliding of fault-controlled slopes outside steep slopes. The response law refers to the quantifiable displacement, stress and plastic damage zone evolution characteristics presented by the deformation and sliding failure process of the slope rock mass under the single factor or the coupled action of multiple factors such as gravity, rainfall, earthquake and engineering disturbance. The physical model is based on a geological model, a mechanical model, and a numerical model to establish a physical model for analyzing and testing a steep slope with an external fault-controlled slope under earthquake dynamics. The physical model simulates the entire process of deformation and rupture, instability and sliding, and movement evolution of a steep slope with an external fault-controlled slope under strong earthquake conditions, revealing the dynamic characteristics and disaster mechanism of fault-controlled landslides from the perspective of physical model testing. The dynamic characteristics refer to the quantifiable kinematic and energy evolution laws exhibited by a fault-controlled slope in the entire process from deformation to instability under strong earthquakes. The dynamic characteristics include vibration response, motion trajectory, motion speed, and energy conversion. Carry out consistency test between the results of physical model test and geological model, mechanical model and numerical model analysis test to reveal the disaster mechanism of external fault-controlled landslides on steep slopes under static and dynamic action in tectonic active mountainous areas.

2. The method for analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes according to claim 1, characterized in that: The technical means of the geological model include data collection, geological survey, profile measurement, engineering investigation, remote sensing interpretation, in-situ testing and geophysical exploration, which determine the planar and spatial distribution characteristics and activity of the fault zone extension length, direction, dip, inclination, and find out the planar and profile morphological characteristics and material structure composition of fault-controlled landslides.

3. The method for analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes according to claim 1, characterized in that: The earthquake conditions in the numerical model take into account the peak acceleration of seismic motion. In order to analyze the disaster mechanism of steep slope external fault-controlled slopes under extreme earthquake conditions, on the basis of the specified peak acceleration of seismic motion, the maximum value of the peak acceleration of seismic motion suffered by the slope is increased by 50-100% taking into account the high-level amplification effect of seismic waves. The strength reduction method is used to calculate the stress field, displacement field, plastic zone distribution, disaster evolution characteristics and overall stability of the steep slope external fault-controlled slope.

4. The method for analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes according to claim 3, characterized in that: The calculation steps of the strength reduction method are as follows: f / SRF 、 c / SRF replace f 、 c The value is calculated, f is the actual internal friction coefficient of the material in the numerical model, c is the actual cohesion of the material in the numerical model, SRF is the strength reduction factor and SRF The value of is greater than 1; SRF Gradually increase, when the calculation results do not converge, SRF This is the overall safety factor of the slope, and the calculated maximum shear strain distribution area inside the slope is the potential sliding surface.

5. The method for analyzing and testing the mechanism of landslide disasters controlled by external faults on steep slopes according to claim 1, characterized in that: The rainfall conditions in the numerical model are calculated by bringing the saturation parameters of each material into the numerical model.

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