Method for calculating slope dynamic stability coefficient

Abstract

The invention discloses a method for calculating a dynamic stability coefficient of a slope, and belongs to the technical field of slope prevention and control engineering, and the method comprises the following steps: S1, obtaining landform, rock-soil body structure and parameter data of a research area; s2, acquiring amplification coefficient distribution rule characteristics of the slope under the dynamic conditions of different frequencies; s3, dividing a potential slip surface and performing strip block division on a potential slip mass of the side slope; s4, determining the position of the slope, and designing a basic seismic oscillation peak acceleration and a characteristic period; s5, determining and calculating seismic oscillation peak acceleration correction values of the section division in the outstanding periods of different strips and blocks; s6, calculating the horizontal earthquake acting force and the vertical earthquake acting force of the section; and S7, calculating the slope stability coefficient to obtain the slope stability coefficient. According to the method, the influence of the predominant period of the site and the local dynamic response rule on the slope stability under the earthquake action is considered, and the accuracy of the calculation result can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of slope protection engineering, and in particular to a method for calculating a slope dynamic stability coefficient. Background Art

[0002] Earthquakes, as a highly destructive natural geological phenomenon, have always attracted the attention of geologists around the world. The instability and deformation of slopes, especially steep rock slopes, caused by earthquakes can cause great damage. There are many methods for analyzing slope stability and deformation instability, but for rock slopes alone, the most commonly used methods are still the quasi-static method and numerical simulation method.

[0003] The quasi-static method is a fast and convenient method for calculating the slope stability coefficient by converting the earthquake action into a certain force by determining the position of the slope sliding zone. Currently, there is no unified standard for determining the potential sliding surface of the slope and comprehensively evaluating its stability. However, many studies have shown that the results of calculating the slope stability coefficient using the quasi-static method have shown good applicability in engineering practice.

[0004] Under the action of earthquakes, the influence of terrain on the stability coefficient of steep slopes calculated by the pseudo-static method has also received some attention. At the same time, in the study of slope dynamic response and deformation failure, complex and steep terrain factors often cause uneven distribution of slope dynamic amplification effect, which shows that it is obviously inappropriate to simply substitute a seismic peak acceleration parameter to calculate the seismic force in these types of slopes, and considering the site's predominant frequency is of great significance for slope stability calculation. In summary, in the previous calculation of slope stability coefficients using the pseudo-static method, the selection of seismic parameters rarely considered the influence of slope site complexity and site predominant frequency on stability, which makes the use of the pseudo-static method to calculate the slope stability coefficient less applicable to the calculation of the stability coefficient of steep slopes.

[0005] A Chinese patent document with publication number CN117929686A and publication date April 26, 2024 discloses a method for calculating the stability of a slope containing faults under dynamic loads. First, through the geological report of the mining area, supplementary survey data, on-site observations and stratigraphic profiles, the factors affecting the stability of the slope, such as the properties of the rock and soil mass, geological structure, type and state of the structural surface, blasting vibration, slope shape and cross-sectional morphology, are mastered; based on the engineering geological data of the mining area, it is concluded that the potential landslide mode of the slope is a combined sliding of the layer-arc with the fault as the side interface based on the rock strata characteristics, fault occurrence and stress conditions of the working slope of the open-pit mine, and the stability of the slope is determined. The stability calculation formula of the slope containing faults under dynamic loads is derived to determine the stability of the slope.

[0006] The patent document discloses a method for calculating the stability of a slope with faults under dynamic loads, which takes into account the influence of damage on slope stability and provides a damage calculation process under dynamic loads, which is of great significance to the safe production and normal operation of open-pit mines. However, since the influence of the site's dominant period and local dynamic response law on the stability of the slope under earthquake action is not taken into account, the accuracy of the calculation results is affected. Summary of the invention

[0007] In order to overcome the defects of the above-mentioned prior art, the present invention provides a method for calculating the dynamic stability coefficient of the slope. The present invention takes into account the influence of the site dominant period and the local dynamic response law on the stability of the slope under earthquake action, and can effectively improve the accuracy of the calculation results.

[0008] The present invention is achieved through the following technical solutions: A method for calculating a slope dynamic stability coefficient, characterized in that it comprises the following steps: S1. Obtain the topography, geomorphology, rock and soil structure and parameter data of the study area; S2. Calculate the seismic amplification factor within the slope area to obtain the distribution characteristics of the amplification factor of the slope under dynamic conditions of different frequencies; S3, select the calculation section, divide the potential sliding surface and divide the potential sliding body of the slope into strips and blocks; S4. Determine the slope location and design the basic ground motion peak acceleration and characteristic period , as the calculation parameter of ground motion for slope stability coefficient calculation; S5. Combine the distribution characteristics of the slope amplification coefficient under dynamic conditions of different frequencies to determine the outstanding periods of different strips and blocks divided into the calculation section Corrected value of peak acceleration of ground motion under ; S6, horizontal seismic forces on the sections and vertical earthquake force Perform calculations; S7. Calculate the slope stability coefficient to obtain the slope stability coefficient.

[0009] In step S2, the earthquake amplification factor is calculated by formula 1; Formula 1 in, is the earthquake amplification factor, For the The height of the soil strip, is the slope height.

[0010] In the step S3, dividing the potential sliding surface specifically refers to dividing the sliding area at the turning point of the sliding surface inclination.

[0011] In step S3, dividing the potential sliding body of the slope into strips and blocks specifically refers to dividing the potential sliding body of the slope into strips and blocks at the turning points of the surface morphology, the boundaries of buildings, and the boundaries of the slope soil layer, rock layer and groundwater, and the number of strips and blocks is not less than 8.

[0012] In step S5, the earthquake peak acceleration correction value is calculated by formula 2; Formula 2 in, is the basic ground motion peak acceleration, is the earthquake amplification factor, is the characteristic period, For the cycle of excellence.

[0013] In step S6, the horizontal earthquake force and vertical earthquake force Calculated by formula 3; Formula 3 in, is the earthquake effect reduction factor, Take 0.25; To calculate the block weight; is the acceleration due to gravity; is the horizontally corrected peak ground acceleration; is the vertical corrected peak acceleration of the earthquake.

[0014] In step S7, the slope stability coefficient is calculated by formula 4; Formula 4 in, is the slope stability coefficient, To act on The anti-sliding force on the sliding surface of the block segment, To act on The sliding force on the block sliding surface, To act on The anti-sliding force on the sliding surface of the block segment, To act on The sliding force on the block sliding surface, is the transfer coefficient.

[0015] The basic principles of the present invention are as follows: In the process of using the quasi-static method to calculate the slope stability coefficient under earthquake action, the selection of seismic motion parameters is a major factor affecting the calculation results. The high and steep slopes with complex terrain are affected by topographic factors, and the seismic dynamic response characteristics often present complex rules. Therefore, when using the quasi-static method to calculate the stability coefficient of such slopes, it is of great significance to reasonably consider the dynamic response characteristics of the slope during the earthquake process for the accuracy of the calculation results. Based on the above considerations, the present invention optimizes the method of calculating the slope stability coefficient using the quasi-static method based on the following calculation principles: A mapping seismic response simulator based on a hybrid model is used to calculate the seismic dynamic response characteristics of the slope area, and the distribution of the acceleration amplitude amplification coefficient of the slope area under different characteristic period dynamic conditions is obtained. In this way, the dynamic response characteristics of the slope in the characteristic period of its seismic acceleration response spectrum are obtained, and then the selection of seismic motion parameters in the quasi-static method calculation is optimized.

[0016] The beneficial effects of the present invention are mainly manifested in the following aspects: 1. The present invention obtains the distribution law of the acceleration amplitude magnification coefficient of the slope site under different predominant periods, and then optimizes the parameters in the pseudo-static method calculation process, taking into account the influence of the predominant period of the site and the local dynamic response law on the stability of the slope under earthquake action, and effectively improves the accuracy of the calculation results.

[0017] 2. In the present invention, in step S3, the strip division of the potential sliding body of the slope specifically refers to dividing the strips at the turning points of the surface morphology, the boundaries of buildings, the boundaries of the slope soil layer, the rock layer and the groundwater, and the number of strips is not less than 8. This specific division can ensure the accuracy of the calculation results and the convenience of the calculation process.

[0018] 3. The present invention improves the applicability of the calculation of the stability coefficient of high and steep slopes in complex terrain by optimizing the selection of earthquake motion parameters in the calculation of the stability coefficient of the slope using the quasi-static method.

[0019] 4. The present invention optimizes the seismic parameter values ​​for calculating the stability coefficient of high and steep slopes in complex terrain using the pseudo-static method. Based on the enriched theoretical basis of slope seismic stability calculation, it can guide the engineering construction and stability evaluation of slope sites.

[0020] 5. The calculation results of the present invention are more accurate than those of the traditional pseudo-static method and have better universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 It is a flowchart of the present invention; Figure 2This is a characteristic diagram of the acceleration amplification coefficient distribution under the outstanding period of the left bank slope site of the valley in the specific example of the present invention; Figure 3 This is the calculation section and strip division diagram of the left bank slope II-II′ of the river valley of the specific example of the present invention. DETAILED DESCRIPTION

[0022] Example 1 A method for calculating a slope dynamic stability coefficient comprises the following steps: S1. Obtain the topography, geomorphology, rock and soil structure and parameter data of the study area; S2. Calculate the seismic amplification factor within the slope area to obtain the distribution characteristics of the amplification factor of the slope under dynamic conditions of different frequencies; S3, select the calculation section, divide the potential sliding surface and divide the potential sliding body of the slope into strips and blocks; S4. Determine the slope location and design the basic ground motion peak acceleration and characteristic period , as the calculation parameter of ground motion for slope stability coefficient calculation; S5. Combine the distribution characteristics of the slope amplification coefficient under dynamic conditions of different frequencies to determine the outstanding periods of different strips and blocks divided into the calculation section Corrected value of peak acceleration of ground motion under ; S6, horizontal seismic forces on the sections and vertical earthquake force Perform calculations; S7. Calculate the slope stability coefficient to obtain the slope stability coefficient.

[0023] This embodiment is the most basic implementation method. By obtaining the distribution law of the acceleration amplitude amplification coefficient of the slope site under different predominant periods, the parameters in the quasi-static method calculation process are optimized. The influence of the predominant period of the site and the local dynamic response law on the stability of the slope under earthquake action is taken into account, thereby effectively improving the accuracy of the calculation results.

[0024] Example 2 A method for calculating a slope dynamic stability coefficient comprises the following steps: S1. Obtain the topography, geomorphology, rock and soil structure and parameter data of the study area; S2. Calculate the seismic amplification factor within the slope area to obtain the distribution characteristics of the amplification factor of the slope under dynamic conditions of different frequencies; S3, select the calculation section, divide the potential sliding surface and divide the potential sliding body of the slope into strips and blocks; S4. Determine the slope location and design the basic ground motion peak acceleration and characteristic period , as the calculation parameter of ground motion for slope stability coefficient calculation; S5. Combine the distribution characteristics of the slope amplification coefficient under dynamic conditions of different frequencies to determine the outstanding periods of different strips and blocks divided into the calculation section Corrected value of peak acceleration of ground motion under ; S6, horizontal seismic forces on the sections and vertical earthquake force Perform calculations; S7. Calculate the slope stability coefficient to obtain the slope stability coefficient.

[0025] In step S2, the earthquake amplification factor is calculated by formula 1; Formula 1 in, is the earthquake amplification factor, For the The height of the soil strip, is the slope height.

[0026] In the step S3, dividing the potential sliding surface specifically refers to dividing the sliding area at the turning point of the sliding surface inclination.

[0027] In step S3, dividing the potential sliding body of the slope into strips and blocks specifically refers to dividing the potential sliding body of the slope into strips and blocks at the turning points of the surface morphology, the boundaries of buildings, and the boundaries of the slope soil layer, rock layer and groundwater, and the number of strips and blocks is not less than 8.

[0028] In step S5, the earthquake peak acceleration correction value is calculated by formula 2; Formula 2 in, is the basic ground motion peak acceleration, is the earthquake amplification factor, is the characteristic period, For the cycle of excellence.

[0029] This embodiment is a preferred implementation method. In step S3, the potential sliding body of the slope is divided into strips and blocks, specifically referring to the division of strips and blocks at the turning points of the surface morphology, the boundaries of buildings, the boundaries of the slope soil layer, the rock layer and the groundwater. The number of strips and blocks is not less than 8. This specific division can ensure the accuracy of the calculation results and the convenience of the calculation process.

[0030] Example 3 A method for calculating a slope dynamic stability coefficient comprises the following steps: S1. Obtain the topography, geomorphology, rock and soil structure and parameter data of the study area; S2. Calculate the seismic amplification factor within the slope area to obtain the distribution characteristics of the amplification factor of the slope under dynamic conditions of different frequencies; S3, selecting a calculation section, dividing the potential sliding surface and dividing the potential sliding body of the slope into strips and blocks; S4. Determine the slope location and design the basic ground motion peak acceleration and characteristic period , as the calculation parameter of ground motion for slope stability coefficient calculation; S5. Combine the distribution characteristics of the slope amplification coefficient under dynamic conditions of different frequencies to determine the outstanding periods of different strips and blocks divided into the calculation section Corrected value of peak acceleration of ground motion under ; S6, horizontal seismic forces on the sections and vertical earthquake force Perform calculations; S7. Calculate the slope stability coefficient to obtain the slope stability coefficient.

[0031] In step S2, the earthquake amplification factor is calculated by formula 1; Formula 1 in, is the earthquake amplification factor, For the The height of the soil strip, is the slope height.

[0032] In the step S3, dividing the potential sliding surface specifically refers to dividing the sliding area at the turning point of the sliding surface inclination.

[0033] In step S3, dividing the potential sliding body of the slope into strips and blocks specifically refers to dividing the potential sliding body of the slope into strips and blocks at the turning points of the surface morphology, the boundaries of buildings, and the boundaries of the slope soil layer, rock layer and groundwater, and the number of strips and blocks is not less than 8.

[0034] In step S5, the earthquake peak acceleration correction value is calculated by formula 2; Formula 2 in, is the basic ground motion peak acceleration, is the earthquake amplification factor, is the characteristic period, For the cycle of excellence.

[0035] In step S6, the horizontal earthquake force and vertical earthquake force Calculated by formula 3; Formula 3 in, is the earthquake effect reduction factor, Take 0.25; To calculate the block weight; is the acceleration due to gravity; is the horizontally corrected peak ground acceleration; is the vertical corrected peak acceleration of the earthquake.

[0036] This embodiment is another preferred implementation method. In the calculation of the slope stability coefficient by the quasi-static method, the selection of earthquake motion parameters is optimized, thereby improving the applicability in the calculation of the stability coefficient of high and steep slopes in complex terrain.

[0037] Example 4 A method for calculating a slope dynamic stability coefficient comprises the following steps: S1. Obtain the topography, geomorphology, rock and soil structure and parameter data of the study area; S2. Calculate the seismic amplification factor within the slope area to obtain the distribution characteristics of the amplification factor of the slope under dynamic conditions of different frequencies; S3, select the calculation section, divide the potential sliding surface and divide the potential sliding body of the slope into strips and blocks; S4. Determine the slope location and design the basic ground motion peak acceleration and characteristic period , as the calculation parameter of ground motion for slope stability coefficient calculation; S5. Combine the distribution characteristics of the slope amplification coefficient under dynamic conditions of different frequencies to determine the outstanding periods of different strips and blocks divided into the calculation section Corrected value of peak acceleration of ground motion under ; S6, horizontal seismic forces on the sections and vertical earthquake force Perform calculations; S7. Calculate the slope stability coefficient to obtain the slope stability coefficient.

[0038] In step S2, the earthquake amplification factor is calculated by formula 1; Formula 1 in, is the earthquake amplification factor, For the The height of the soil strip, is the slope height.

[0039] In the step S3, dividing the potential sliding surface specifically refers to dividing the sliding area at the turning point of the sliding surface inclination.

[0040] In step S3, dividing the potential sliding body of the slope into strips and blocks specifically refers to dividing the potential sliding body of the slope into strips and blocks at the turning points of the surface morphology, the boundaries of buildings, and the boundaries of the slope soil layer, rock layer and groundwater, and the number of strips and blocks is not less than 8.

[0041] In step S5, the earthquake peak acceleration correction value is calculated by formula 2; Formula 2 in, is the basic ground motion peak acceleration, is the earthquake amplification factor, is the characteristic period, For the cycle of excellence.

[0042] In step S6, the horizontal earthquake force and vertical earthquake force Calculated by formula 3; Formula 3 in, is the earthquake effect reduction factor, Take 0.25; To calculate the block weight; is the acceleration due to gravity; is the horizontally corrected peak ground acceleration; is the vertical corrected peak acceleration of the earthquake.

[0043] In step S7, the slope stability coefficient is calculated by formula 4; Formula 4 in, is the slope stability coefficient, To act on The anti-sliding force on the sliding surface of the block segment, To act on The sliding force on the block sliding surface, To act on The anti-sliding force on the sliding surface of the block segment, To act on The sliding force on the block sliding surface, is the transfer coefficient.

[0044] This embodiment is the best implementation method, which optimizes the seismic parameter values ​​for calculating the stability coefficient of high and steep slopes in complex terrain using the quasi-static method. On the basis of enriching the theoretical basis for slope seismic stability calculation, it can guide engineering construction and stability evaluation of slope sites.

[0045] The calculation results are more accurate than the traditional quasi-static method and have better universality. The present invention is described below by taking a specific example of a high and steep slope on the left bank of a river valley: Obtain the topographic and geomorphological conditions and engineering geological conditions to determine the horizontal corrected peak acceleration of the slope =0.4g, vertical corrected peak acceleration of slope =0.25g, excellent cycle = 0.25s, the distribution of acceleration amplification factor of the slope area under the design value is calculated using a mapping earthquake response simulator based on a hybrid model, see Figure 2 ; Select the calculation section, divide the potential sliding surface and use the transfer coefficient method to divide the potential sliding body of the slope into strips and blocks, see Figure 3 ; and determine the values ​​of slope rock and soil parameters. The parameters of each strip are shown in Table 1.

[0046] Table 1 Based on the Code for Slope Design of Water Conservancy and Hydropower Projects (SL 386-2007), the seismic force of each block under the design basic ground motion peak acceleration is calculated using Formula 3, and the seismic force of each strip block in the section is calculated. The results are shown in Table 2.

[0047] Table 2 The above formula is used to determine the The anti-sliding force on the sliding surface of the block acts on the The sliding force and transfer coefficient on the block sliding surface are shown in Table 3.

[0048] Table 3 The slope stability coefficient is calculated using Formula 4, and the slope stability coefficient is 2.20. The slope is relatively stable under its design basic ground motion peak acceleration.

Claims

1. A method for calculating the dynamic stability coefficient of a slope, characterized in that: The following steps are involved: S1. Obtain the topography, geomorphology, rock and soil structure and parameter data of the study area; S2. Calculate the seismic amplification factor within the slope area to obtain the distribution characteristics of the amplification factor of the slope under dynamic conditions of different frequencies; S3, select the calculation section, divide the potential sliding surface and divide the potential sliding body of the slope into strips and blocks; S4. Determine the slope location and design the basic ground motion peak acceleration and characteristic period , as the calculation parameter of ground motion for slope stability coefficient calculation; S5. Combine the distribution characteristics of the slope amplification coefficient under dynamic conditions of different frequencies to determine the outstanding periods of different strips and blocks divided into the calculation section Corrected value of peak acceleration of ground motion under ; S6, horizontal seismic forces on the sections and vertical earthquake force Perform calculations; S7. Calculate the slope stability coefficient to obtain the slope stability coefficient.

2. The method for calculating the dynamic stability coefficient of a slope according to claim 1, characterized in that: In step S2, the earthquake amplification factor is calculated by formula 1; Formula 1 in, is the earthquake amplification factor, For the The height of the soil strip, is the slope height.

3. The method for calculating the dynamic stability coefficient of a slope according to claim 1, characterized in that: In the step S3, dividing the potential sliding surface specifically refers to dividing the sliding area at the turning point of the sliding surface inclination.

4. The method for calculating the dynamic stability coefficient of a slope according to claim 1, characterized in that: In step S3, dividing the potential sliding body of the slope into strips and blocks specifically refers to dividing the potential sliding body of the slope into strips and blocks at the turning points of the surface morphology, the boundaries of buildings, and the boundaries of the slope soil layer, rock layer and groundwater, and the number of strips and blocks is not less than 8.

5. The method for calculating the dynamic stability coefficient of a slope according to claim 1, characterized in that: In step S5, the earthquake peak acceleration correction value is calculated by formula 2; Formula 2 in, is the basic ground motion peak acceleration, is the earthquake amplification factor, is the characteristic period, For the cycle of excellence.

6. A method for calculating the dynamic stability coefficient of a slope according to claim 1, characterized in that: In step S6, the horizontal earthquake force and vertical earthquake force Calculated by formula 3; Formula 3 in, is the earthquake effect reduction factor, Take 0.25; To calculate the block weight; is the acceleration due to gravity; is the horizontally corrected peak ground acceleration; is the vertical corrected peak acceleration of the earthquake.

7. A method for calculating the dynamic stability coefficient of a slope according to claim 1, characterized in that: In step S7, the slope stability coefficient is calculated by formula 4; Formula 4 in, is the slope stability coefficient, To act on The anti-sliding force on the sliding surface of the block segment, To act on The sliding force on the block sliding surface, To act on The anti-sliding force on the sliding surface of the block segment, To act on The sliding force on the block sliding surface, is the transfer coefficient.

Images