A method, medium and device for analyzing slope infiltration and stability

Abstract

The application relates to the technical field of water and soil simulation analysis, and discloses a slope infiltration and stability analysis method, medium and equipment. The method improves a GA model by introducing seepage characteristics and fractal theory, a new slope rainfall infiltration model is proposed, the model establishes a slope body initial water content distribution model in combination with underground water distribution, and the runoff-seepage coupling effect is taken into account to dynamically analyze the influence of slope surface water on the infiltration rate; the Mohr-Coulomb strength criterion is optimized based on the saturated zone seepage action and fractal theory, the improved infiltration model is applied to finite slope stability analysis, and the limitation that the traditional model is only applicable to infinite long slopes is broken; by comprehensively considering factors such as soil particle size characteristics, slope surface runoff, slope, rainfall intensity and underground water level, the safety factors of each point in the slope body can be accurately calculated, and the accuracy of the description of the infiltration process under the condition of heavy rainfall and the reliability of the slope stability analysis are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of soil and water simulation analysis technology, and in particular to a method, medium and equipment for slope infiltration and stability analysis. Background Technology

[0002] Landslides are one of the most widespread natural disasters worldwide, causing enormous losses to engineering projects and the socio-economic landscape. Existing research indicates that rainfall is one of the main triggering factors for shallow landslides. On the one hand, rainwater infiltration increases the saturation of the slope soil, leading to an increase in soil weight and consequently, an increase in the slope's sliding force. On the other hand, under rainfall infiltration conditions, the matric suction in the unsaturated soil zone gradually decreases, weakening the slope's resistance to sliding. Furthermore, after the formation of a wetting front, seepage occurs in the saturated zone of the slope, and the resulting seepage force further reduces slope stability. Therefore, strengthening research on rainfall infiltration and slope stability analysis is of great significance for slope prevention and control.

[0003] The feasibility of applying numerical simulation to analyze rainfall infiltration in slopes has been increasingly supported by numerous scholars. However, numerical simulation studies require a large number of model calculation parameters, demand high parameter accuracy, and involve complex calculation principles and significant computational load. Furthermore, the model analysis results are easily affected by boundary conditions, element size, and mesh generation, leading to convergence difficulties. In theoretical and experimental research, common models for studying rainfall infiltration include the Philips model, the Mein-Larson model, the Green-Ampt model (hereinafter referred to as the GA model), and the Horton empirical model. Among these, the GA model, proposed by Green and Ampt in 1911, is widely used in the study of rainfall infiltration in unsaturated soils due to its easier-to-obtain calculation parameters and simpler principles compared to other methods.

[0004] However, because the GA model assumes that the soil is horizontal and has a uniform initial moisture content, it ignores the complex distribution of initial soil moisture content and the influence of saturated zone seepage on slope infiltration patterns. It is only applicable to infinitely long slopes and does not consider the influence of the elliptical transition layer in the infiltration zone. When performing rainfall infiltration analysis, it only considers the increase in wetting front depth caused by rainwater infiltration, ignoring the decrease in wetting front depth caused by saturated zone seepage. When performing slope stability analysis, it only considers the influence of rainfall on slope weight and matrix suction, ignoring the influence of rainfall-induced saturated zone seepage force on slope stability, and does not consider the influence of soil particle size distribution characteristics on shear strength. Therefore, it has certain limitations and is not suitable for practical application.

[0005] Therefore, a slope infiltration and stability analysis method is needed to solve the problems existing in the current slope rainfall infiltration and stability analysis. Summary of the Invention

[0006] The purpose of this invention is to provide a slope infiltration and stability analysis method that incorporates seepage characteristics and fractal theory, in order to improve the accuracy of describing the infiltration process under heavy rainfall conditions and the precision of fitting calculations of slope stability. The specific technical solution is as follows:

[0007] A method for analyzing slope infiltration and stability includes the following steps:

[0008] S1: Based on the soil gradation characteristics, establish a soil-water characteristic curve model and an unsaturated hydraulic conductivity curve model of the soil based on fractal theory, and establish a slope water content distribution model based on the influence of initial groundwater.

[0009] S2: Based on the soil infiltration characteristics during rainfall, the influence of the transition layer is considered between the saturated layer and the natural layer. An elliptical curve is used to describe the distribution law of the volumetric water content of the transition layer along the depth of the slope soil, and the slope water content distribution model after rainfall is obtained.

[0010] S3: Considering the seepage in the saturated zone above the wetting front of the slope, the slope length L is introduced, and the actual depth change rate of the wetting front is obtained according to the principle of rainfall conservation and Darcy's law.

[0011] S4: Based on the variation law of rainfall infiltration rate, the rainfall process is divided into two stages, and the expression of rainfall infiltration rate and the relationship between wet front depth and rainfall time are obtained.

[0012] S5: Based on seepage characteristics and fractal theory, the Mohr-Coulomb strength criterion is optimized. The improved infiltration model is applied to the stability analysis of finite slopes to obtain the stability coefficients of each point inside the slope. The minimum value of the stability coefficient is taken as the slope stability coefficient under the most unfavorable conditions.

[0013] Preferably, S1 includes:

[0014] The soil pore surface exhibits fractal characteristics, and is covered by spheres of equal radius; the number of spheres... With the radius of the gap The relationship between them is:

[0015] 1);

[0016] in: Represents the fractal dimension of the pores. Represents the proportionality coefficient. Indicates the pore radius;

[0017] Pore ​​volume With the radius of the gap The relationship is:

[0018] 2);

[0019] Define relative moisture content Volumetric water content of unsaturated soil With residual volumetric moisture content The difference; Equation 3) shows the change in relative water content of the soil due to the increase in pore size of the unsaturated soil:

[0020] 3);

[0021] in: Indicates the initial pore volume of the soil;

[0022] Combining equations 1) and 3), we get:

[0023] 4);

[0024] in: =4π / [ (3- When the soil is saturated, the relative volumetric water content is as follows:

[0025] 5);

[0026] in: This represents the relative volumetric water content when the soil is in a saturated state. This indicates the saturated volumetric water content of the slope soil; The maximum pore radius;

[0027] Combining equations 4)-5) with the Young-Laplace equation =(2Tcos ) / ,make =0, thus obtaining the SWCC model describing the soil particle size distribution:

[0028] 6);

[0029] Where: T represents surface tension; The contact angle is 0. Indicates the air intake suction head of the soil; This indicates the matrix suction head of the soil;

[0030] Based on the soil pore distribution pattern, the unsaturated hydraulic conductivity curve model is as follows:

[0031] 7);

[0032] in: A function representing the unsaturated permeability coefficient of soil; Represents the matrix suction function of the soil; Indicates the air intake suction head of the soil; The saturated permeability coefficient of the soil; Indicates saturation;

[0033] The pore fractal dimension of the soil was determined based on its gradation distribution characteristics. The calculation formula is as follows:

[0034] 8);

[0035] in: This indicates the total mass of soil particles; Indicates that the particle size is smaller than Soil quality; Indicates soil particle size; Indicates the maximum soil particle size;

[0036] Based on the soil matrix suction head With soil depth The relationship between the soil and water characteristics is such that, ignoring the influence of residual volumetric water content, the slope water content distribution model influenced by initial groundwater is obtained by combining the soil-water characteristic curve model. Its expression is:

[0037] 9);

[0038] in: This indicates the moisture content of the slope before rainfall; This indicates the distribution of moisture content on the slope before rainfall; This represents the soil's air intake value; b represents the height of the capillary water saturation zone, b= H represents the vertical distance between the slope surface and the groundwater level. Parameters representing the pore distribution characteristics of soil;

[0039] Soil matrix suction head With soil depth The relationship between them is:

[0040] 10).

[0041] Preferably, S2 specifically includes:

[0042] Using an elliptic curve to assume the distribution pattern of soil volumetric moisture content in the transition layer, and combining it with the slope moisture content distribution model influenced by initial groundwater, the modified slope moisture content distribution model after rainfall is obtained as follows:

[0043] 11);

[0044] in: This indicates the distribution of moisture content on the slope after rainfall. This indicates the moisture content at the location of the slope's peak wetting point before rainfall; Indicates the depth of the moistened front; Indicates the depth of the saturation layer; Indicates the depth of the transition layer;

[0045] As the infiltration process proceeds, the proportion of the transition layer to the wetting layer continuously decreases, and the proportion of the transition layer has a linear relationship with the depth of the wetting peak, as shown in the following formula:

[0046] 12);

[0047] in: This indicates the proportion of the transition layer to the total depth of the wetting front; and The correlation coefficient represents the linear relationship.

[0048] Preferably, S3 includes:

[0049] The change in the depth of the wetting front can be divided into two parts: one part is the increase in the depth of the wetting front due to the infiltration of rainwater, and the other part is the decrease in the depth of the wetting front due to the drainage of water from the slope by the seepage of the saturated zone.

[0050] The rate of change of the wetting front caused by rainwater infiltration was obtained based on the characteristics of rainwater infiltration on slopes. The expression is:

[0051] 13);

[0052] in: Indicates matrix suction; Indicates the angle of inclination;

[0053] exist The flow rate discharged from the slope by seepage from the saturated zone within a given time period. Equal to the decrease in cumulative infiltration ,Right now:

[0054] 14);

[0055] in: Indicates soil in The change in moisture content over time, when considering seepage in the saturated zone above the wetting front of the slope, incorporates the slope length. According to Darcy's law, the seepage rate in the saturated zone above the wetting front is obtained. for:

[0056] 15);

[0057] Combining equations 14) and 15), we obtain the rate of change of the wetting front depth caused by seepage in the saturated zone above the wetting front. for:

[0058] 16);

[0059] Wherein: the difference between equations 13) and 16) is the actual rate of change of the depth of the wetting front. ,Right now:

[0060] 17);

[0061] Matrix suction With the unsaturated permeability coefficient of the soil The relationship between them is:

[0062] 18);

[0063] in, i The soil moisture content is indicated by The matrix suction at that time; This represents the unsaturated permeability coefficient function of soil.

[0064] Preferably, S4 includes:

[0065] There is a critical moment during slope rainfall. When the rainfall lasts longer than At that time, rainwater cannot completely infiltrate, and runoff begins to occur on the slope surface;

[0066] Under heavy rainfall conditions, the slope rainfall infiltration rate was obtained by measuring the actual depth change rate of the wetting front. for:

[0067] 19);

[0068] in: Indicates rainfall intensity;

[0069] The critical moment is determined based on the principle of rainfall conservation. The corresponding critical wetting front depth and critical rainfall infiltration The expression is as follows:

[0070] 20);

[0071] twenty one);

[0072] When the time it takes for the slope soil to reach the critical wetting front depth during heavy rainfall is relatively short, the critical time can be approximated. Previous average infiltration rate = ( + ) / 2; where the infiltration rate at the initial time is 1 / 2. = cos ; Critical moment The corresponding infiltration rate at that time;

[0073] At the critical moment After and at what time Previously, the average rate of rainfall infiltration was approximated by the slope rainfall infiltration rate. for:

[0074] twenty two);

[0075] Finally, the cumulative infiltration amount at each stage was obtained. The relationship between the depth of the moist front and the duration of rainfall is as follows:

[0076] twenty three).

[0077] Preferably, S5 includes:

[0078] The cumulative infiltration volume at each stage was applied to the analysis of rainfall infiltration and stability of the roadbed slope. Based on seepage characteristics and fractal theory, the Mohr-Coulomb strength criterion was optimized. The improved infiltration model was applied to the stability analysis of finite slopes, and the expressions for the stability coefficients at various points inside the slope were obtained, as follows:

[0079] Effective stress of soil based on fractal theory for:

[0080] twenty four);

[0081] Shear strength τ caused by soil matrix suction s Represented as:

[0082] 25);

[0083] Corrected shear strength of unsaturated soil for:

[0084] 26);

[0085] in, It represents the cohesive force of the soil; Indicates the internal friction angle of the soil; This represents the normal stress at the bottom of the slope; This represents the net normal force at the bottom of the slope; Indicates the specific gravity of water;

[0086] The moist front of the slope moves continuously with rainfall, and the depth of the moist front at different rainfall times can be obtained using Equation 23). and saturation layer depth Furthermore, the changes in unit weight at various points on the slope caused by changes in slope moisture content during rainfall infiltration were derived. for:

[0087] 27);

[0088] In the formula: Indicates the dry unit weight of the soil; Indicates the saturated unit weight of soil

[0089] Saturated zone seepage will generate seepage force parallel to the slope surface. Its expression is:

[0090] 28);

[0091] Further, the weight of the soil above the sliding surface is obtained. for:

[0092] 29);

[0093] In the formula: Indicates the depth of the sliding surface at various points on the slope; This indicates the unit weight of the slope at various points after rainfall;

[0094] Normal stress at the bottom of the sliding surface and shear stress for:

[0095] 30);

[0096] 31);

[0097] Furthermore, the safety factor at each point within the slope is obtained. for:

[0098] 32);

[0099] Get included The expression for the slope safety factor at each point within the slope is:

[0100] 33).

[0101] Rainfall infiltration on slopes is a complex process controlled by factors such as soil particle size distribution, surface runoff, slope gradient, rainfall intensity, and groundwater level. Understanding the movement of water in the soil is crucial for slope disaster prevention. This invention provides a slope infiltration and stability analysis method that incorporates seepage characteristics and fractal theory. Based on the Green-Ampt model, it considers the influence of multiple factors to obtain a novel slope rainfall infiltration model. This model, combined with groundwater distribution, determines the initial moisture content distribution of the slope and considers the influence of runoff-seepage coupling effects to analyze the impact of dynamic changes in surface water caused by rainfall on the infiltration rate. Based on the effect of seepage in the saturated zone and fractal theory, the Mohr-Coulomb strength criterion was further optimized, and the improved rainfall infiltration model was applied to the rainfall infiltration and stability analysis of roadbed slopes. This model takes into account the influence of slope length, extending the model that was originally only applicable to infinitely long slopes to the stability analysis of finite slopes. In this way, the safety factor of each point inside the slope was obtained, which effectively improved the accuracy of describing the infiltration process under heavy rainfall conditions and the accuracy of fitting and calculating slope stability.

[0102] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the aforementioned method for slope infiltration and stability analysis.

[0103] The present invention also provides an electronic device, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to perform the aforementioned slope infiltration and stability analysis method by executing the executable instructions.

[0104] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0105] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0106] Figure 1 A flowchart of a method provided according to an exemplary embodiment of this application;

[0107] Figure 2 A schematic diagram of the initial moisture content distribution of the slope provided for the embodiment;

[0108] Figure 3 A schematic diagram of rainfall infiltration analysis using the improved GA model provided in the example;

[0109] Figure 4(a) is a schematic diagram of the stress analysis at various points on the slope in the embodiment;

[0110] Figure 4(b) is a schematic diagram of the stress analysis of the saturation zone in Figure 4(a);

[0111] Figure 4(c) is a schematic diagram of the force analysis of the transition zone in Figure 4(a);

[0112] Figure 4(d) is a schematic diagram of the stress analysis of natural soil layer 1 in Figure 4(a);

[0113] Figure 4(e) is a schematic diagram of the stress analysis of natural soil layer 2 in Figure 4(a);

[0114] Figure 5 This is an analysis model of a shallow silty clay slope under heavy rainfall in the embodiments;

[0115] Figure 6(a) shows the fractal dimension fitting and schematic diagram of silty clay;

[0116] Figure 6(b) is a schematic diagram of the soil-water characteristic curve of silty clay;

[0117] Figure 7(a) is a schematic diagram of the changes in the moist front;

[0118] Figure 7(b) shows the volumetric water content profile;

[0119] Figure 7(c) is a schematic diagram of the stability analysis at various points within the slope;

[0120] Figure 8(a) is a schematic diagram of the changes in the moist front;

[0121] Figure 8(b) shows the volumetric water content profile;

[0122] Figure 8(c) is a schematic diagram of the stability analysis at various points within the slope; Detailed Implementation

[0123] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0124] refer to Figure 1 A method for analyzing slope infiltration and stability includes the following steps:

[0125] S1: Based on the soil gradation characteristics, establish a soil-water characteristic curve model and an unsaturated hydraulic conductivity curve model of the soil based on fractal theory, and establish a slope water content distribution model based on the influence of initial groundwater.

[0126] S2: Based on the soil infiltration characteristics during rainfall, the influence of the transition layer is considered between the saturated layer and the natural layer. An elliptical curve is used to describe the distribution law of the volumetric water content of the transition layer along the depth of the slope soil, and the slope water content distribution model after rainfall is obtained.

[0127] S3: Considering seepage in the saturated zone above the wetting front of the slope, the slope length is introduced. L Based on the principle of conservation of rainfall and Darcy's law, the actual rate of change of the wet front depth is obtained.

[0128] S4: Based on the variation law of rainfall infiltration rate, the rainfall process is divided into two stages, and the expression of rainfall infiltration rate and the relationship between wet front depth and rainfall time are obtained.

[0129] S5: Based on seepage characteristics and fractal theory, the Mohr-Coulomb strength criterion is optimized. The improved infiltration model is applied to the stability analysis of finite slopes to obtain the stability coefficients of each point inside the slope. The minimum value of the stability coefficient is taken as the slope stability coefficient under the most unfavorable conditions.

[0130] The technical solution of this invention will be further explained below using a specific region as an example. In this region, the soil covering the roadbed slope is mostly silty clay, and there is stable initial groundwater. The thickness of the silty clay covering the slope is d=3m, and the lower part is an impermeable bedrock layer. The groundwater level is parallel to the bedrock and located 2.4m below the slope surface. The relevant parameters of the slope are shown in Table 1:

[0131] Table 1 Slope-related parameters

[0132]

[0133] Details are as follows:

[0134] S1: Based on the soil gradation characteristics, a soil-water characteristic curve model and an unsaturated hydraulic conductivity curve model are established using fractal theory. Furthermore, considering the influence of initial groundwater, a slope moisture content distribution model based on the initial groundwater influence is established. Details are as follows:

[0135] The soil pore surface exhibits fractal characteristics, and is covered by spheres of equal radius. The number of spheres... With the radius of the gap The relationship between them is:

[0136] 1);

[0137] in,: Represents the fractal dimension of the pores. Represents the proportionality coefficient. Indicates the pore radius.

[0138] Pore ​​volume With the radius of the gap The relationship is:

[0139] 2);

[0140] Define relative moisture content Volumetric water content of unsaturated soil With residual volumetric moisture content The difference; Equation 3) shows the change in relative water content of the soil due to the increase in pore size of the unsaturated soil:

[0141] 3);

[0142] Combining equations 1) and 3), we get:

[0143] 4);

[0144] in: =4π / [ (3- When the soil is saturated, the relative volumetric water content is as follows:

[0145] 5);

[0146] in: This represents the relative volumetric water content when the soil is in a saturated state. This indicates the saturated volumetric water content of the slope soil; This represents the maximum pore radius.

[0147] Combining equations 4)-5) with the Young-Laplace equation =(2Tcos ) / ,make =0, thus obtaining the SWCC model describing the soil particle size distribution:

[0148] 6);

[0149] Where T represents surface tension; The contact angle is 0. Indicates the air intake suction head of the soil; This indicates the soil matrix suction head.

[0150] Based on the soil pore distribution pattern, the unsaturated hydraulic conductivity curve model is obtained as follows:

[0151] 7);

[0152] in: A function representing the unsaturated permeability coefficient of soil; Represents the matrix suction function of the soil; Indicates the air intake suction head of the soil; The saturated permeability coefficient of the soil; Indicates saturation.

[0153] The pore fractal dimension of the soil was determined based on its gradation distribution characteristics. The calculation formula is as follows:

[0154] 8);

[0155] in: This indicates the total mass of soil particles; Indicates that the particle size is smaller than Soil quality; Indicates soil particle size; Indicates the maximum soil particle size;

[0156] This embodiment obtains the particle size and mass distribution of silty clay based on survey data from the literature, as shown in Table 2.

[0157] Table 2 Percentage content of silty clay within different particle size ranges

[0158]

[0159] Substituting the existing particle size distribution (PSD) fractal model (Equation 2) into the model and performing linear regression fitting with a slope of 3-D, the fractal dimension D of the tailings sand particle size distribution can be obtained. The results are shown in Figure 6(a). Fitting the particle size test results of the silty clay with a linear fitting slope of approximately 0.205 yields an unsaturated soil pore fractal dimension D = 2.795. Based on Equations 5) and 7), the complete soil-water characteristic curve of the silty clay can be obtained, as shown in Figure 6(b).

[0160] Further establish a slope water content distribution model influenced by initial groundwater; such as Figure 2 The diagram shown is a schematic representation of the initial moisture content distribution of the slope provided in this embodiment.

[0161] The specific steps are as follows:

[0162] Based on the soil matrix suction head With soil depth The relationship between the soil and water characteristics is such that, ignoring the influence of residual volumetric water content, the slope water content distribution model influenced by initial groundwater is obtained by combining the soil-water characteristic curve model. Its expression is:

[0163] 9);

[0164] in: This indicates the moisture content of the slope before rainfall; This indicates the distribution of moisture content on the slope before rainfall; Indicates the air intake value of the soil This indicates the vertical distance between the slope surface and the groundwater level; Parameters representing the pore distribution characteristics of soil;

[0165] Soil matrix suction head With soil depth The relationship between them is:

[0166] 10).

[0167] S2: Based on the soil infiltration characteristics during rainfall, the influence of the transition layer between the saturated and natural layers is considered. An elliptic curve is used to describe the distribution law of the volumetric water content of the transition layer along the depth of the slope soil, resulting in the slope water content distribution model after rainfall, as follows:

[0168] Using an elliptic curve to assume the distribution pattern of soil volumetric moisture content in the transition layer, and combining it with the slope moisture content distribution model influenced by initial groundwater, the modified slope moisture content distribution model after rainfall is obtained as follows:

[0169] 11);

[0170] in: This indicates the distribution of moisture content on the slope after rainfall. This indicates the moisture content at the location of the slope's peak wetting point before rainfall; Indicates the depth of the moistened front; Indicates the depth of the saturation layer; Indicates the depth of the transition layer.

[0171] As the infiltration process proceeds, the proportion of the transition layer to the wetting layer continuously decreases, and the proportion of the transition layer has a good linear relationship with the wetting peak depth, as shown in the following formula:

[0172] 12);

[0173] in: This indicates the proportion of the transition layer to the total depth of the wetting front; and The correlation coefficient represents the linear relationship.

[0174] S3: Considering seepage in the saturated zone above the wetting front on the slope, and introducing the slope length L, the actual depth change rate of the wetting front is obtained according to the principle of rainfall conservation and Darcy's law, as follows:

[0175] The change in the depth of the wetting front can be divided into two parts: one part is the increase in the depth of the wetting front due to the infiltration of rainwater, and the other part is the decrease in the depth of the wetting front due to the drainage of water from the slope by the seepage of the saturated zone.

[0176] The rate of change of the wetting front caused by rainwater infiltration was obtained based on the characteristics of rainwater infiltration on slopes. The expression is:

[0177] 13);

[0178] in: Indicates matrix suction; Indicates the angle of inclination;

[0179] exist The flow rate discharged from the slope by seepage from the saturated zone within a given time period. Equal to the decrease in cumulative infiltration ,Right now:

[0180] 14);

[0181] in: Indicates soil in The change in moisture content over time, when considering seepage in the saturated zone above the wetting front of the slope, incorporates the slope length. According to Darcy's law, the seepage rate in the saturated zone above the wetting front is obtained. for:

[0182] 15);

[0183] Combining equations 14) and 15), we obtain the rate of change of the wetting front depth caused by seepage in the saturated zone above the wetting front. for:

[0184] 16);

[0185] Wherein: the difference between equations 13) and 16) is the actual rate of change of the depth of the wetting front. ,Right now:

[0186] 17);

[0187] Matrix suction With the unsaturated permeability coefficient of the soil The relationship between them is:

[0188] 18);

[0189] in, i The soil moisture content is indicated by The matrix suction at that time; This represents the unsaturated permeability coefficient function of soil.

[0190] S4: Based on the variation law of rainfall infiltration rate, the rainfall process is divided into two stages, resulting in the expression for rainfall infiltration rate and the relationship between wetting front depth and rainfall time, specifically:

[0191] There is a critical moment during slope rainfall. When the rainfall lasts longer than At that time, rainwater cannot completely infiltrate, and runoff begins to occur on the slope surface;

[0192] Under heavy rainfall conditions, the slope rainfall infiltration rate was obtained by measuring the actual depth change rate of the wetting front. for:

[0193] 19);

[0194] in: Indicates rainfall intensity;

[0195] The critical moment is determined based on the principle of rainfall conservation. The corresponding critical wetting front depth and critical rainfall infiltration The expression is as follows:

[0196] 20);

[0197] twenty one);

[0198] When the time it takes for the slope soil to reach the critical wetting front depth during heavy rainfall is relatively short, the critical time can be approximated. Previous average infiltration rate = ( + ) / 2; where the infiltration rate at the initial time is 1 / 2. = cos ; Critical moment The corresponding infiltration rate at that time;

[0199] At the critical moment After and at what time Previously, the average rate of rainfall infiltration was approximated by the slope rainfall infiltration rate. for:

[0200] twenty two);

[0201] Finally, the cumulative infiltration amount at each stage was obtained. The relationship between the depth of the moist front and the duration of rainfall is as follows:

[0202] twenty three).

[0203] like Figure 3 As shown, this is a schematic diagram of the improved GA model for rainfall infiltration analysis provided in this embodiment. Based on the traditional Green-Ampt model, this embodiment considers the influence of various factors such as slope geometry, groundwater level, saturated zone seepage, and soil pore distribution characteristics, and derives a new slope rainfall infiltration model. See Figures 4(a)-(e), specifically: Figure 4(a) is a schematic diagram of the stress analysis at various points on the slope in this embodiment, Figure 4(b) is a schematic diagram of the stress analysis of the saturated zone in Figure 4(a), Figure 4(c) is a schematic diagram of the stress analysis of the transition zone in Figure 4(a), Figure 4(d) is a schematic diagram of the stress analysis of natural soil layer 1 in Figure 4(a), and Figure 4(e) is a schematic diagram of the stress analysis of natural soil layer 2 in Figure 4(a). Figure 5 An analysis model for shallow silty clay slopes under heavy rainfall was developed; further, the improved rainfall infiltration model was applied to the analysis of rainfall infiltration and stability of roadbed slopes.

[0204] This embodiment selects a rainfall intensity of 4 mm / h for analysis. As the soil type varies, the particle size distribution characteristics also differ, and the model parameter λ changes accordingly. This embodiment can be used for slope infiltration and stability analysis under different soil pore distribution characteristics (fractal dimension). Figure 7(a) is a schematic diagram of the wetting front change, showing the variation of the slope wetting front with rainfall time under different soil pore distribution characteristics (fractal dimension). This figure is derived from Equation 19 of this embodiment. It can be seen from the figure that the smaller the parameter λ, the better the soil's water conductivity, and the higher the initial water content of the slope soil, resulting in a greater wetting front depth under the same rainfall duration. Furthermore, the smaller λ, the lower the critical moment... The smaller the slope, the earlier runoff forms.

[0205] S5: Based on seepage characteristics and fractal theory, the Mohr-Coulomb strength criterion is optimized. The improved infiltration model is applied to the stability analysis of finite slopes to obtain the stability coefficients at various points within the slope. The minimum value of the stability coefficient is taken as the slope stability coefficient under the most unfavorable conditions. Specifically:

[0206] The cumulative infiltration volume at each stage was applied to the analysis of rainfall infiltration and stability of the roadbed slope. Based on seepage characteristics and fractal theory, the Mohr-Coulomb strength criterion was optimized. The improved infiltration model was applied to the stability analysis of finite slopes, and the expressions for the stability coefficients at various points inside the slope were obtained, as follows:

[0207] Effective stress of soil based on fractal theory for:

[0208] twenty four);

[0209] Shear strength τ caused by soil matrix suction s Represented as:

[0210] 25);

[0211] Corrected shear strength of unsaturated soil for:

[0212] 26);

[0213] in, It represents the cohesive force of the soil; Indicates the internal friction angle of the soil; This represents the normal stress at the bottom of the slope; This represents the net normal force at the bottom of the slope; Indicates the specific gravity of water;

[0214] The moist front of the slope moves continuously with rainfall, and the depth of the moist front at different rainfall times can be obtained using Equation 23). and saturation layer depth Furthermore, the changes in unit weight at various points on the slope caused by changes in slope moisture content during rainfall infiltration were derived. for:

[0215] 27);

[0216] In the formula: Indicates the dry unit weight of the soil; Indicates the saturated unit weight of the soil;

[0217] Saturated zone seepage will generate seepage force parallel to the slope surface. Its expression is:

[0218] 28);

[0219] Further, the weight of the soil above the sliding surface is obtained. for:

[0220] 29);

[0221] In the formula: Indicates the depth of the sliding surface at various points on the slope; This indicates the unit weight of the slope at various points after rainfall;

[0222] Normal stress at the bottom of the sliding surface and shear stress for:

[0223] 30);

[0224] 31);

[0225] Furthermore, the safety factor at each point within the slope is obtained as follows:

[0226] 32);

[0227] Get included The expression for the slope safety factor at each point within the slope is:

[0228] 33).

[0229] In this embodiment, the evaluation criteria are set as follows:

[0230] Table 3 Evaluation criteria set in this embodiment

[0231]

[0232] Figure 7(b) shows the volumetric water content profile, which is a schematic diagram of the volumetric water content profile of the slope under different rainfall times. This figure is derived from Figure 7(a) and combined with Equation 9). Further, considering the effect of seepage in the saturated zone and the Mohr-Coulomb strength criterion optimized by fractal theory, it is applied to the analysis of rainfall infiltration and stability of the roadbed slope. The safety factor of each point inside the slope is obtained, and the most dangerous point of the slope can be determined by combining Equation 29), as shown in Figure 7(c). For natural soil layers, due to the influence of the initial groundwater level, the initial water content of each point on the slope is different, resulting in different matric suction forces. τ needs to be considered. s While the impact of these factors is limited, the overall safety factor at various points within the natural soil layer is relatively high. It continues to decrease with the depth of the slope, and at a certain depth... The minimum value is reached at an impermeable bedrock layer of 4m. The slope angle has a significant impact on slope stability; the steeper the slope, the greater the slope safety factor under the same conditions, and the more prone the slope is to instability and failure.

[0233] The influence of slope angle on slope rainfall infiltration has always been a key research focus. This embodiment aims to provide an analytical method that can be used to study the influence of different slope angles on slope infiltration and stability. Figure 8(a) shows the variation of the slope wetting front with rainfall time under different slope angles. This figure is derived from Equation 19) of this embodiment. It can be seen from the figure that under the same rainfall conditions, the size of the slope angle has a significant impact on the rate of slope wetting front movement. The rate of slope wetting front movement decreases with the increase of slope angle. Figure 8(b) shows a schematic diagram of the slope volumetric water content profile under different rainfall times. This figure is derived from Figure 8(a) and combined with Equation 9). Based on this, the effect of saturated zone seepage and the Mohr-Coulomb strength criterion optimized by fractal theory are further considered and applied to the analysis of rainfall infiltration and stability of roadbed slopes. The safety factor of each point inside the slope is obtained, and the most dangerous point of the slope can be identified by combining Equation 29), as shown in Figure 8(c). For natural soil layers, due to the influence of the initial groundwater level, the initial water content varies at different points on the slope, resulting in different matric suction forces. Therefore, τ needs to be considered. s While the impact of these factors is limited, the overall safety factor at various points within the natural soil layer is relatively high. It continues to decrease with the depth of the slope, and at a certain depth... The minimum value is reached at an impermeable bedrock layer of 4m. The distribution of soil particle porosity has a relatively small impact on slope stability. The parameter λ mainly affects slope stability by influencing the infiltration rate of the slope, and is more likely to affect the stability of the slope in the soil layer of the wetting front transition zone.

[0234] In summary, this embodiment addresses the limitations of existing models due to neglecting factors such as the complex distribution of initial soil moisture content, seepage effects in the saturated zone, the transition layer in the infiltration zone, and soil particle size distribution. Based on the traditional Green-Ampt model, this embodiment improves the GA model by introducing seepage characteristics and fractal theory, proposing a new slope rainfall infiltration model. This model establishes an initial slope moisture content distribution model in conjunction with groundwater distribution and incorporates runoff-seepage coupling effects to dynamically analyze the impact of surface water on the infiltration rate. Furthermore, based on saturated zone seepage and fractal theory, the Mohr-Coulomb strength criterion is optimized, and the improved infiltration model is applied to finite slope stability analysis, overcoming the limitation of traditional models being only applicable to infinitely long slopes. By comprehensively considering factors such as soil particle size characteristics, slope surface runoff, slope gradient, rainfall intensity, and groundwater level, this invention can accurately calculate the safety factor at various points within the slope, significantly improving the accuracy of the infiltration process description and the reliability of slope stability analysis under heavy rainfall conditions, providing effective theoretical support for slope disaster prevention and control.

[0235] This embodiment also discloses a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the slope infiltration and stability analysis method described in this embodiment.

[0236] This embodiment also discloses an electronic device, including:

[0237] A processor; and a memory for storing executable instructions of the processor;

[0238] The processor is configured to execute the slope infiltration and stability analysis method as described in this embodiment by executing the executable instructions.

[0239] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for analyzing slope infiltration and stability, characterized in that, Includes the following steps: S1: Based on the soil gradation characteristics, a soil-water characteristic curve model and an unsaturated hydraulic conductivity curve model are established using fractal theory. Furthermore, considering the influence of initial groundwater, a slope moisture content distribution model under the influence of initial groundwater is established. The expression for the slope moisture content distribution model under the influence of initial groundwater is as follows: （9）； in: This indicates the moisture content of the slope before rainfall; This indicates the distribution of moisture content on the slope before rainfall; Indicates the height of the capillary water saturation zone. ; This indicates the vertical distance between the slope surface and the groundwater level; Parameters representing the porosity distribution characteristics of soil; This indicates the saturated volumetric water content of the slope soil. Indicates the residual volumetric moisture content; Indicates the air suction head of the soil; Indicates the depth of the soil; S2: Based on the soil infiltration characteristics during rainfall, the influence of the transition layer between the saturated and natural layers is considered. An elliptic curve is used to describe the distribution law of the volumetric water content of the transition layer along the depth of the slope soil, resulting in a slope water content distribution model after rainfall. This slope water content distribution model after rainfall is as follows: （11）； in: This indicates the distribution of moisture content on the slope after rainfall. This indicates the moisture content at the location of the slope's peak wetting point before rainfall; Indicates the depth of the moistened front; Indicates the depth of the saturation layer; Indicates the depth of the transition layer; S3: Considering seepage in the saturated zone above the wetting front of the slope, the slope length is introduced. L Based on the principle of conservation of rainfall and Darcy's law, the actual depth change rate of the moist front is obtained; this actual depth change rate of the moist front As shown in the following formula: （17）； in: This indicates the rate of change of the wetting front caused by rainwater infiltration. This indicates the rate of change of the wetting front depth caused by seepage from the saturated zone above the wetting front; The saturated permeability coefficient of the soil; Indicates the angle of inclination; Indicates matrix suction; This represents the volumetric water content of unsaturated soil. S4: Based on the variation pattern of rainfall infiltration rate, the rainfall process is divided into two stages, resulting in an expression for rainfall infiltration rate and the relationship between wetting front depth and rainfall time, specifically including: There is a critical moment during slope rainfall. When the rainfall lasts longer than At that time, rainwater cannot completely infiltrate, and runoff begins to occur on the slope surface; Under heavy rainfall conditions, the slope rainfall infiltration rate was obtained by measuring the actual depth change rate of the wetting front. for: （19）； in: Indicates rainfall intensity; The critical moment is determined based on the principle of rainfall conservation. The corresponding critical wetting front depth and critical rainfall infiltration The expression is as follows: （20）； （21）； When the time it takes for the slope soil to reach the critical wetting front depth during heavy rainfall is relatively short, the critical time can be approximated. Previous average infiltration rate =( + ) / 2; where the infiltration rate at the initial time is 1 / 2. = cos ; Critical moment The corresponding infiltration rate at that time; At the critical moment After and at what time Previously, the average rate of rainfall infiltration was approximated by the slope rainfall infiltration rate. for: （22）； Finally, the cumulative infiltration amount at each stage was obtained. The relationship between the depth of the moist front and the duration of rainfall is as follows: （23）； S5: Based on seepage characteristics and fractal theory, the Mohr-Coulomb strength criterion is optimized. The improved infiltration model is applied to the stability analysis of finite slopes to obtain the stability coefficients of each point inside the slope. The minimum value of the stability coefficient is taken as the slope stability coefficient under the most unfavorable conditions.

2. The method for slope infiltration and stability analysis according to claim 1, characterized in that, S1 includes: The soil pore surface exhibits fractal characteristics, and is covered by spheres of equal radius; the number of spheres... With pore radius The relationship between them is: （1）； in: Represents the fractal dimension of the pores. Represents the proportionality coefficient. Indicates the pore radius; Pore ​​volume With pore radius The relationship is: （2）； Define relative moisture content The volumetric water content of unsaturated soil With residual volumetric moisture content The difference; Equation (3) shows the change in relative water content of the soil due to the increase in pore size of unsaturated soil: （3）； in: Indicates the initial pore volume of the soil; Combining equations (1) and (3), we get: （4）； in: =4π / [ (3- When the soil is saturated, the relative volumetric water content is as follows: （5）； in: This represents the relative volumetric water content when the soil is in a saturated state. The maximum pore radius; Combining equations (4)-(5) with the Young-Laplace equation =(2Tcos ) / ,make =0, thus obtaining the SWCC model describing the soil particle size distribution: （6）； Where: T represents surface tension; The contact angle is 0. Indicates the matrix suction head of the soil; Based on the soil pore distribution pattern, the unsaturated hydraulic conductivity curve model is as follows: （7）； in: A function representing the unsaturated permeability coefficient of soil; The matrix suction function represents the soil mass. Indicates the air suction head of the soil; Indicates saturation The pore fractal dimension of the soil is determined based on its gradation distribution characteristics. The calculation formula is as follows: （8）； in: This represents the total mass of soil particles; Indicates that the particle size is smaller than The quality of the soil; Indicates the particle size of the soil; Indicates the maximum particle size of the soil. Based on the soil matrix suction head With soil depth The relationship between the soil and water characteristics curves is used to obtain the slope moisture content distribution model under the influence of initial groundwater, ignoring the influence of residual volumetric water content. Soil matrix suction head With soil depth The relationship between them is: （10）。 3. The method for slope infiltration and stability analysis according to claim 2, characterized in that, Specifically, S2 is: The distribution law of soil volumetric water content in the transition layer is assumed by using an elliptical curve. Combined with the slope water content distribution model under the influence of initial groundwater, the slope water content distribution model after rainfall is obtained by correction. As the infiltration process proceeds, the proportion of the transition layer to the wetting layer continuously decreases, and the proportion of the transition layer has a linear relationship with the depth of the wetting peak, as shown in the following formula: （12）； in: This indicates the proportion of the transition layer to the total depth of the wetting front; and The correlation coefficient represents the linear relationship.

4. The method for slope infiltration and stability analysis according to claim 3, characterized in that, S3 includes: The change in the depth of the wetting front can be divided into two parts: one part is the increase in the depth of the wetting front due to the infiltration of rainwater, and the other part is the decrease in the depth of the wetting front due to the drainage of water from the slope by the seepage of the saturated zone. The rate of change of the wetting front caused by rainwater infiltration was obtained based on the characteristics of rainwater infiltration on slopes. The expression is: （13）； Among them: The flow rate discharged from the slope by seepage from the saturated zone within a given time period. Equal to the decrease in cumulative infiltration ,Right now: （14）； in: Indicates the soil in The change in moisture content over time, when considering seepage in the saturated zone above the wetting front of the slope, incorporates the slope length. According to Darcy's law, the seepage rate in the saturated zone above the wetting front is obtained. for: （15）； Equations (14) and (15) are combined to obtain the rate of change of the wetting front depth caused by seepage in the saturated zone above the wetting front. for: （16）； The difference between equations (13) and (16) is the actual rate of change of the depth of the wetting front. ; Matrix suction The relationship between the unsaturated permeability coefficient of the soil and the soil is as follows: （18）； in, i The water content of the soil is indicated by The matrix suction at that time; The function representing the unsaturated permeability coefficient of soil.

5. The method for slope infiltration and stability analysis according to claim 1, characterized in that, S5 includes: The cumulative infiltration volume at each stage was applied to the analysis of rainfall infiltration and stability of the roadbed slope. Based on seepage characteristics and fractal theory, the Mohr-Coulomb strength criterion was optimized. The improved infiltration model was applied to the stability analysis of finite slopes, and the expressions for the stability coefficients at various points inside the slope were obtained, as follows: Effective stress of soil based on fractal theory for: （24）； Shear strength τ caused by matric suction of soil s Represented as: （25）； Corrected shear strength of unsaturated soil for: （26）； in, Indicates the cohesion of the soil; Indicates the internal friction angle of the soil; This indicates the normal stress at the bottom of the sliding surface; This represents the net normal force at the bottom of the slope; Indicates the specific gravity of water; Indicates pore gas pressure; This represents the correction factor for matrix suction. The moist front of the slope moves continuously with rainfall, and the depth of the moist front at different rainfall times can be obtained by equation (23). and saturation layer depth Furthermore, the changes in unit weight at various points on the slope caused by changes in slope moisture content during rainfall infiltration were derived. for: （27）； In the formula: Indicates the dry unit weight of the soil; Indicates the saturated unit weight of the soil; Saturated zone seepage will generate seepage force parallel to the slope surface. Its expression is: （28）； Further, the weight of the soil above the sliding surface is obtained. for: （29）； In the formula: Indicates the depth of the sliding surface at various points on the slope; This indicates the unit weight of the slope at various points after rainfall; Normal stress at the bottom of the sliding surface and shear stress for: （30）； （31）； Furthermore, the safety factor at each point within the slope is obtained. for: （32）； Get included The expression for the slope safety factor at each point within the slope is: （33）。 6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the slope infiltration and stability analysis method according to any one of claims 1-5.

7. An electronic device, characterized in that, include: processor; and memory for storing the executable instructions of the processor; The processor is configured to execute the slope infiltration and stability analysis method as described in any one of claims 1-5 by executing the executable instructions.

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