A design method for slope cutting in rural house construction

Abstract

The present invention provides a method for designing slope cutting for rural house construction. The method obtains rock and soil parameters by conducting indoor tests after field soil sampling, takes different values ​​for multiple parameters in the slope cutting parameters, combines the parameters of the slope cutting parameters, and calculates the slope cutting stability coefficient and potential sliding area under each parameter combination based on Geostudio simulation according to the rock and soil parameters; obtains the fitting formula of the slope cutting stability coefficient and the slope cutting parameters, and the fitting formula of the potential sliding area and the slope cutting parameters through multivariate fitting; obtains the design safety distance of the house based on the potential sliding area and the movement distance formula of the slope cutting type landslide disaster. The technical scheme proposed by the present invention has the beneficial effects of: determining the physical and mechanical parameters of the rock and soil in the study area by indoor tests, calculating the slope cutting stability coefficient and potential sliding area under different parameter combinations based on Geostudio simulation and multivariate nonlinear fitting, and proposing a method for designing slope cutting scheme for rural house construction in combination with the movement distance of the slope cutting type landslide.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical technology, and in particular to a slope cutting design method for rural house construction. Background Art

[0002] Slope is one of the common natural geological environments in engineering construction activities and human survival. The geological disasters such as collapse and landslide caused by the instability of slope rock and soil will bring inestimable losses.

[0003] At present, the research methods mainly evaluate the stability of the existing slopes, with the help of qualitative methods and quantitative analysis methods. Qualitative methods include geological analysis (historical cause analysis), engineering geological analogy, and graphical methods; quantitative analysis methods include limit equilibrium method and numerical analysis methods. Common limit equilibrium methods include strip method, arc method, Bishop method, Janbu method, etc. However, most studies have not analyzed the influence of different slope excavation conditions on the stability of the slope from the comprehensive relationship between the characteristics of the disaster body itself and the disaster-causing factors, nor have they given slope engineering excavation construction plans from a quantitative perspective. No general conclusions have been proposed to guide the design of slope cutting plans for rural house construction. Effective scheme design in the early stage of house construction can reduce disaster risks and improve government management efficiency.

[0004] The existing design of slope cutting scheme for building houses has the following problems: ① The accurate physical and mechanical parameters of rock and soil suitable for the study area are not adopted. ② The influencing factors such as slope height, slope angle, slope cutting angle, and cover thickness are not considered when studying the stability of the slope. ③ No formula suitable for promotion and application is proposed. ④ The safe distance of the design house is not considered. Summary of the invention

[0005] In view of this, in order to solve the above problems, an embodiment of the present invention provides a slope cutting design method for rural house construction.

[0006] An embodiment of the present invention provides a method for designing a slope cut for building a rural house, comprising the following steps:

[0007] S1: Obtain rock and soil parameters by conducting indoor tests after taking soil on site, wherein the rock and soil parameters include rock and soil cohesion, internal friction angle, and gravity;

[0008] S2: Different values ​​are taken for multiple parameters in the slope cutting parameters, and the parameters of the slope cutting parameters are combined. According to the rock and soil parameters, the slope cutting stability coefficient and potential sliding area under each parameter combination are simulated and calculated based on Geostudio;

[0009] S3: Through multivariate fitting, the fitting formulas of the slope stability coefficient and slope parameters, and the fitting formulas of the potential sliding area and slope parameters are obtained;

[0010] S4: Based on the potential sliding area and the movement distance formula of slope-cutting landslide disaster, the design safety distance of the house is obtained.

[0011] Furthermore, the slope cutting is divided into soil slope cutting and rock-soil mixed slope cutting. The slope cutting parameters of the soil slope cutting include natural slope angle, slope cutting height and slope cutting angle, and the slope cutting parameters of the rock-soil mixed slope cutting include natural slope angle, slope cutting height and covering layer thickness.

[0012] Furthermore, in step S2, the slope stability coefficient calculation method in Geostudio is:

[0013] According to the limit equilibrium method, a differential equation that satisfies the force balance and moment balance conditions is established, and the solution to the problem is obtained according to the boundary conditions of the entire sliding soil:

[0014] E n (F s ,λ)=0;

[0015]

[0016] y=A x +B;

[0017] In the formula, E n is the normal inter-stripe force; M n is the lateral moment of the bar, F s is the stability coefficient; X is the tangential inter-bar force; E is the normal force; n is the number of bars; λ, A, and B are all arbitrary constants.

[0018] Furthermore, in step S3, by multivariate nonlinear fitting, the fitting formula of the slope cutting stability coefficient and the slope cutting parameter is:

[0019]

[0020] The fitting formula of potential sliding area and cutting slope parameters is:

[0021]

[0022] In the formula, are the slope stability coefficients of rock-soil mixed cutting slope and soil cutting slope, y D sr and D s are the potential sliding areas of rock-soil mixed cutting slope and soil cutting slope respectively; x1 sr , x2 sr , x3 sr They are the natural slope angle, slope height and cover thickness of the rock-soil mixed cut slope; x1 s , x2 s , x3 sThey are the cutting height, natural slope and cutting slope of the soil cutting slope respectively; a1~a4, b1~b4, c1~c4, d1~d4 are empirical parameters.

[0023] Furthermore, in the rock-soil mixed cutting slope, the fitting formula of the cutting slope stability coefficient and the cutting slope parameters is:

[0024]

[0025] The fitting formula of potential sliding area and cutting slope parameters is:

[0026]

[0027] Furthermore, in soil slope cutting, the fitting formula of slope stability coefficient and slope cutting parameter is:

[0028]

[0029] The fitting formula of potential sliding area and cutting slope parameters is:

[0030]

[0031] Furthermore, in step S4, the calculation formula for the house design safety distance is:

[0032] d=m*(V*tanθ) n ;

[0033] V = S × l;

[0034] Where d is the horizontal distance from the front edge of the landslide to the front edge of the accumulation; θ is the natural slope angle of the landslide; m and n are empirical parameters, V is the volume of the sliding body; S is the potential sliding area calculated using Geostudio; l is the length of the cut slope, which depends on the artificial design length.

[0035] Furthermore, in step S4, the calculation formula of the house design safety distance is: d = 0.37298*(V*tanθ) 0.53192 .

[0036] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows: indoor experiments are used to determine the physical and mechanical parameters of the rock and soil in the study area, the slope stability coefficient and potential sliding area under different parameter combinations are calculated based on Geostudio simulation and multivariate nonlinear fitting, and a design method for slope cutting schemes for rural house construction is proposed in combination with the movement distance of slope cutting type landslides.

[0037] The combination of different slope cutting types and slope cutting methods was considered, and the research results were formulated using multivariate nonlinear fitting, which can facilitate professionals to carry out slope cutting hazard assessment efficiently. The potential sliding distance of the slope can be obtained by combining the potential sliding area with the empirical formula of landslide movement distance obtained from field surveys, providing a basis for the design of housing safety distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of soil cut slope;

[0039] Figure 2 is a schematic diagram of the potential sliding area;

[0040] Figure 3 It is the calculation result of soil slope stability coefficient and potential area;

[0041] Figure 4 It is a schematic diagram of rock-soil mixed slope cutting;

[0042] Figure 5 It is the calculation result of the stability coefficient and potential area of ​​rock-soil mixed cutting slope;

[0043] Figure 6 It is a comparison chart between the multivariate nonlinear fitting results and the numerical simulation calculation results;

[0044] Figure 7 It is a statistical model of the movement distance, volume and slope of landslide hazards;

[0045] Figure 8 It is the housing safety distance model. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0047] An embodiment of the present invention provides a method for designing a slope cut for building a rural house, comprising the following steps:

[0048] S1: The rock and soil parameters are obtained by conducting indoor tests after taking soil on site, and the rock and soil parameters include rock and soil cohesion, internal friction angle, and gravity.

[0049] Artificial slopes are controlled by geological environmental factors and human engineering activities, and are mostly soil slopes and rock-soil mixed slopes. The main instability factor of soil slopes is that the soil itself is loose, and if the soil layer is thick, it is easy to form arc sliding. Rock-soil mixed slopes are mainly found in artificial slopes of low height. The thickness of the rock slope and the soil slope is roughly the same. The soil layer covers the upper part of the rock layer, and the lower rock layer is mostly fully weathered, which can easily cause slope instability. The overall sliding caused by the bedrock as a non-sliding layer in the rock-soil mixed slope is not common in the study area. Through field investigations, it was found that most of the landslides in the study area occurred in the fully weathered bedrock, and all landslides occurred at the front edge of the slope. Therefore, the lower bedrock was considered as a fully-weathered layer that may slide in the calculation. The soil and granite fully weathered layer were obtained in the field, and the indoor direct shear test showed that the soil cohesion in the saturated state was 13.51 kPa, the internal friction angle was 27°, and the specific gravity was 19.8 kN / m 3 The cohesion of the whole weathering layer is 16.58 kPa, the internal friction angle is 35°, and the gravity is 21.5 kN / m 3 .

[0050] S2: Different values ​​are taken for multiple parameters in the slope cutting parameters, and the parameters of the slope cutting parameters are combined. According to the rock and soil parameters, the slope cutting stability coefficient and potential sliding area under each parameter combination are simulated and calculated based on Geostudio.

[0051] The calculation method of slope stability coefficient in Geostudio is:

[0052] According to the limit equilibrium method, a differential equation that satisfies the force balance and moment balance conditions is established, and the solution to the problem is obtained according to the boundary conditions of the entire sliding soil:

[0053] E n (F s ,λ)=0;

[0054]

[0055] y=A x +B;

[0056] In the formula, E n is the normal inter-stripe force; M n is the lateral moment of the bar, F s is the stability coefficient; X is the tangential inter-bar force; E is the normal force; n is the number of bars; λ, A, and B are all arbitrary constants.

[0057] The slope cutting is divided into soil slope cutting and rock-soil mixed slope cutting. The slope cutting parameters of the soil slope cutting include natural slope angle, slope cutting height and slope cutting angle, and the slope cutting parameters of the rock-soil mixed slope cutting include natural slope angle, slope cutting height and cover layer thickness.

[0058] For example, please refer to Figure 1 , the soil cutting slope was studied, the first slope height was controlled to be 25m, the natural slope angle β (20°, 30°, 40°), the cutting slope height H (2m, 4m, 6m, 8m) and the cutting slope angle α (60°, 70°, 80°, 90°) were changed, and 48 kinds of cutting slope schemes were composed for simulation calculation. Figure 2 For example, if you design a slope with a natural slope angle of 40°, a slope angle of 80°, and a slope height of 6m, Geostudio will automatically search for the most unfavorable sliding surface (such as Figure 2 The stability coefficient is 0.885, and the potential sliding area is about 23.54m 2 , the shear outlet of the sliding surface is located at the foot of the slope. All calculation results are obtained in this way, refer to Figure 3 . As the natural slope angle and the height of the slope increase, the stability of the slope gradually decreases. Reducing the slope angle can improve the stability of the slope. When the natural slope angle is 20°, the stability is good. When the slope height is greater than 6m, the slope stability is in an unstable to unstable stage. When the natural slope angle is 30°, the stability is general. When the slope angle is 90°, the slope height may become unstable when it is greater than 4m. When the natural slope angle is 40°, the stability is poor, and the slope height is greater than 4m, instability is likely to occur.

[0059] Please refer to Figure 4 , the rock-soil mixed cutting slope was studied, the first slope height was controlled to be 25m, the natural slope angle β (20°, 30°, 40°), the cover layer thickness h (1m, 2m, 3m, 4m) and the cutting slope height H (2m, 4m, 6m, 8m) were changed, and 48 cutting slope schemes were composed for simulation calculation. In order to reduce the amount of calculation, the default cutting slope angle of 90° is the most unfavorable working condition. All calculation results were obtained in this way, refer to Figure 5 The increase of natural slope angle, slope height and cover thickness will cause the stability coefficient of rock-soil mixed slope to decrease. The slope height has the greatest impact on stability. When the slope height reaches 8m, the stability is under-stable-unstable.

[0060] S3: Combining the above calculation results, through multivariate fitting, the fitting formula of the slope stability coefficient and the slope parameters, and the fitting formula of the potential sliding area and the slope parameters are obtained.

[0061] Specifically, through multivariate nonlinear fitting, the fitting formula of slope stability coefficient and slope parameters is: The fitting formula of potential sliding area and cutting slope parameters is:

[0062] In this embodiment, the fitting formula of the slope cutting stability coefficient and the slope cutting parameter is:

[0063]

[0064] The fitting formula of potential sliding area and cutting slope parameters is:

[0065]

[0066] In the formula, are the slope stability coefficients of rock-soil mixed cutting slope and soil cutting slope, y D sr and D s are the potential sliding areas of rock-soil mixed cutting slope and soil cutting slope respectively; x1 sr , x2 sr , x3 sr They are the natural slope angle, slope height and cover thickness of the rock-soil mixed cut slope; x1 s , x2 s , x3 s are the cutting height, natural slope and cutting slope of soil cutting slope respectively; a1~a4, b1~b4, c1~c4, d1~d4 are empirical parameters. Figure 6 ,The results calculated by numerical simulation are compared with the formula fitting results, and it is found that the formula has a good fitting degree.

[0067] S4: The movement distance analysis of the slope-cutting landslide is to construct the safe distance of the house. Figure 7 Based on the potential sliding area and the movement distance formula of slope-cutting landslide disaster, the design safety distance of the house is obtained.

[0068] Specifically, the calculation formula for the house design safety distance is: d = m*(V*tanθ) n ; V = S × l; where d is the horizontal distance from the front edge of the landslide to the front edge of the accumulation; θ is the natural slope angle of the landslide; m, n are empirical parameters, V is the volume of the sliding body; S is the potential sliding area calculated using Geostudio; l is the length of the cut slope, which depends on the artificial design length.

[0069] In this embodiment, the calculation formula for the house design safety distance is:

[0070] d=0.37298*(V*tanθ) 0.53192 .

[0071] The house safety distance model can be constructed based on the sliding distance of this area. Figure 8 Residents can choose to cut slopes according to their own needs and calculate the reserved safety distance for houses. Farmland or roads can be built within the safety distance. If the land cannot meet the reserved safety distance, the slope can be cut to support the rear edge to reduce the risk of slope cutting landslides.

[0072] In this document, the directional words such as front, back, top, and bottom are defined by the positions of the components in the drawings and the positions of the components relative to each other, and are only for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the directional words should not limit the scope of protection claimed in this application.

[0073] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing slope cutting for rural house construction, characterized in that: The following steps are involved: S1: Obtain rock and soil parameters by conducting indoor tests after taking soil on site, wherein the rock and soil parameters include rock and soil cohesion, internal friction angle, and gravity; S2: The slope cutting is divided into soil slope cutting and rock-soil mixed slope cutting. The slope cutting parameters of the soil slope cutting include natural slope angle, slope cutting height and slope cutting angle, and the slope cutting parameters of the rock-soil mixed slope cutting include natural slope angle, slope cutting height and cover layer thickness. Different values ​​are taken for multiple parameters in the slope cutting parameters, and the parameters of the slope cutting parameters are combined. According to the rock and soil parameters, the slope stability coefficient and potential sliding area under each parameter combination are simulated and calculated based on Geostudio. S3: Through multivariate fitting, the fitting formulas of the slope stability coefficient and slope parameters, and the fitting formulas of the potential sliding area and slope parameters are obtained; Through multivariate nonlinear fitting, the fitting formula of slope stability coefficient and slope parameters is: The fitting formula of potential sliding area and cutting slope parameters is: In the formula, are the slope stability coefficients of rock-soil mixed cutting slope and soil cutting slope, y D sr and D s are the potential sliding areas of rock-soil mixed cutting slope and soil cutting slope respectively; x1 sr , x2 sr , x3 sr They are the natural slope angle, slope height and cover thickness of the rock-soil mixed cut slope; x1 s , x2 s , x3 s are the cutting height, natural slope and cutting slope of soil cutting slope respectively; a1~a4, b1~b4, c1~c4, d1~d4 are empirical parameters; In rock-soil mixed slope cutting, the fitting formula of slope stability coefficient and slope cutting parameters is: The fitting formula of potential sliding area and cutting slope parameters is: S4: Based on the potential sliding area and the movement distance formula of slope-cutting landslide disaster, the design safety distance of the house is obtained.

2. The rural house cutting slope design method according to claim 1, characterized in that: In step S2, the slope stability coefficient calculation method in Geostudio is: According to the limit equilibrium method, a differential equation that satisfies the force balance and moment balance conditions is established, and the solution to the problem is obtained according to the boundary conditions of the entire sliding soil: E n (F s ,λ)=0; and=A x +B; In the formula, E n is the normal inter-stripe force; M n is the lateral moment of the bar, F s is the stability coefficient; X is the tangential inter-bar force; E is the normal force; n is the number of bars; λ, A, and B are all arbitrary constants.

3. The rural house cutting slope design method according to claim 1, characterized in that: In soil slope cutting, the fitting formula of slope stability coefficient and slope cutting parameters is: The fitting formula of potential sliding area and cutting slope parameters is:

4. The rural house cutting slope design method according to claim 1, characterized in that: In step S4, the calculation formula for the house design safety distance is: d=m*(V*tanθ) n ; V = S × l; Where, d is the horizontal distance from the front edge of the landslide to the front edge of the accumulation; θ is the natural slope angle of the landslide; m and n are empirical parameters, V is the volume of the sliding body; S is the potential sliding area calculated using Geostudio; l is the length of the cut slope, which depends on the artificially designed length.

5. The rural house cutting slope design method according to claim 4, characterized in that: In step S4, the calculation formula of the house design safety distance is: d = 0.37298*(V*tanθ) 0.53192 .

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