Method for evaluating stability of waterside cohesive soil slope

Abstract

The invention discloses a waterside cohesive soil slope stability evaluation method which comprises the following steps: S1, selecting a cohesive soil slope affected by waterside as a to-be-evaluated slope, and measuring the terrain of the to-be-evaluated slope; s2, determining various stability evaluation indexes of the slope to be evaluated; s3, assigning each stability evaluation index of the slope to be evaluated; s4, calculating the stability U of the slope to be evaluated; and S5, evaluating the stability of the waterside cohesive soil slope according to the stability U. According to the method for evaluating the stability of the waterside cohesive soil slope, the problem that the dispersity, collapsibility, water sensitivity and the form of the waterside face of the slope are insufficiently considered when an existing method for evaluating the stability of the waterside cohesive soil slope is used for evaluating the stability is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil and water conservation engineering for ecological protection and high-quality development of the Yellow River Basin, and specifically relates to a method for evaluating the stability of clay soil slopes near water. Background Art

[0002] With the advancement of the Yellow River Basin ecological protection and high-quality development strategy and the implementation of major projects such as the national major water network construction, a large number of soil and water conservation projects and water conservancy engineering facilities have been planned and constructed in the Northwest clay soil plateau area, which play an important role in the regional ecological environment regulation and water resource utilization. In particular, reservoirs and silt dam projects not only have the functions of regulation, flood control, and sand interception, but also have the advantages of using local materials and being green and environmentally friendly. However, with the occurrence of floods in the river channel or the impoundment of reservoirs, the instability and destruction of the clay soil slopes near the water will have an adverse impact on the social and economic development of the river and reservoir area, leading to the retreat of the reservoir shoreline and the damage to farmland on both sides, the destruction of transportation facilities, etc., resulting in river diversion and the reduction of the effective storage capacity of the reservoir. In severe cases, it may cause disasters such as surges, resulting in serious consequences. However, these clay soil slopes near the water are usually large in scale, and comprehensive engineering management is not feasible. The response measures are mainly preventive.

[0003] The soil of clayey soil slopes near water often has certain dispersion, collapsibility and water sensitivity. The current stability assessment and calculation of clayey soil slopes near water mostly adopts empirical methods or static pure theoretical formulas, which do not take into account the shortcomings of dispersion, water sensitivity, collapsibility and the shape of the slope surface near water, and cannot guarantee the accuracy of the calculation results. Summary of the invention

[0004] The purpose of the present invention is to provide a method for evaluating the stability of a clay soil slope near water, which solves the problem that the existing method for evaluating the stability of clay soil slope near water does not take into account the dispersion, collapsibility, water sensitivity and the morphology of the slope near water surface when evaluating the stability.

[0005] The technical solution adopted by the present invention is a method for evaluating the stability of a clayey soil slope near water, comprising the following steps: S1: Select the clay slope affected by water as the slope to be evaluated and measure the topography of the slope to be evaluated; S2: Determine various stability evaluation indicators of the slope to be evaluated; S3: Assign values ​​to various stability assessment indicators of the slope to be assessed; S4: Calculate the stability U of the slope to be evaluated; S5: Evaluate the stability of clayey soil slopes near water based on the stability U.

[0006] The present invention is also characterized in that: In step S1, when the clay slope is located on the concave bank of the river channel, a clay slope with a slope greater than twice the underwater natural repose angle of the clay soil on the surface of the clay slope, or a designated slope, is selected as the slope to be evaluated; When the clay slope is located on the convex bank of the river channel, a clay slope with a slope greater than 1.8 times the underwater natural angle of repose of the clay soil on the surface of the clay slope, or a designated slope, is selected as the slope to be evaluated; For each slope to be evaluated, a representative profile is determined, and the total number p of slopes to be evaluated, the water surface elevation H1 on the water side of the slope to be evaluated, the slope foot elevation H2, and the height H of the slope to be evaluated are measured and determined.

[0007] In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0008] The water sensitivity of slope clay soil u1 is the average water sensitivity of the useful layer of the slope to be evaluated; The calculation formula (1) of slope clay soil water sensitivity is: (1) Where n is the average water sensitivity of all sampling points on the slope to be evaluated, n u is the water sensitivity of the u-th sampling point on the slope to be evaluated, and v is the total number of sampling points on the slope to be evaluated; The rainfall intensity coefficient u2 is the product of the average annual precipitation of the slope to be evaluated and the coefficient of variation of the average monthly precipitation. The calculation formula (2) of the rainfall intensity coefficient is: Kh=h×Cvh(2) Among them, Kh is the rainfall intensity coefficient, h is the average annual precipitation of the slope to be evaluated, and Cvh is the coefficient of variation of the average monthly precipitation.

[0009] The dispersion of the clay soil of the slope, u3, is the average value of the dispersion of the sampling points on the representative section of the slope to be evaluated multiplied by the treatment coefficient. The number and location of the sampling points are the same as the water sensitivity of the clay soil of the slope, u1; The calculation formula for the dispersion of slope clay is: (3) Where D is the dispersion of slope clay, D u is the dispersion of the u-th sampling point of the slope to be evaluated, K u is the treatment coefficient of the u-th sampling point of the slope to be evaluated, and v is the total number of sampling points of the slope to be evaluated; The collapsibility of clay soil on the slope, u4, is the average collapsibility of each measuring point of the slope to be evaluated. The calculation formula (4) of the average collapsibility of each measuring point of the slope to be evaluated is: (4) Where K is the average collapsibility of each measuring point on the slope to be evaluated, Δs u is the self-weight wetting collapsibility of the u-th sampling point of the slope to be evaluated; Δzs u is the wetting collapse amount of the u-th sampling point on the slope to be evaluated; Slope flatness u5 is the number, size and distribution of sinkholes within the range L on both sides of the representative section of the slope to be evaluated, where L=2H; The calculation formula (5) for slope flatness is: D L =D1×D2×D3×D4 (5) Among them, D L is the flatness of the slope, D1 is the instability score of the number of sinkholes, D2 is the instability score of the location of the sinkholes, D3 is the instability score of the average volume of the sinkholes, and D4 is the instability score of the average spacing of the sinkholes; The catchment area u6 is the product of the straight-line distance from the watershed above the top of the slope to the foot of the slope in the representative section of the slope to be evaluated and the unit width, where gentle slopes with a slope of less than 3 degrees are not included; The calculation formula (6) for the rainwater collection area is: s=d×w(6) Where d is the straight-line distance from the watershed above the top of the slope to the foot of the slope, w is the unit width, and w is taken as 1m; The chemical dispersion of slope soil, u7, is the percentage value of exchangeable sodium ions of the slope to be evaluated. The calculation formula (7) of the chemical dispersion of slope soil is: (7) Among them, P ES is the percentage value of exchangeable sodium ions of the slope to be evaluated, b(Na,exch) is the exchangeable sodium ion content, and CEC is the cation exchange capacity; The slope stability coefficient u8 is the stability coefficient of the slope to be evaluated calculated by the Bishop method. The calculation adopts the saturated quick shear index of the direct shear test, and the profile adopts the representative profile of the slope to be evaluated obtained by measurement. The water flow velocity u9 is the measured water flow velocity at the intersection of the representative profile of the slope to be evaluated and the water surface.

[0010] The sampling locations of the slope sampling points to be evaluated include the toe of the slope and the water surface. There are two initial sampling points at each location, which are 0.5m and 1.0m deep perpendicular to the slope. When the difference between the water surface elevation H1 and the toe elevation H2 of the slope is greater than 20m, one sampling location is added at the toe elevation H2 and the water surface elevation H1. All sampling locations divide the toe elevation H2 and the water surface elevation H1 equally, and the sampling point depth is the same as other locations.

[0011] The dispersion D of the uth sampling point of the slope to be evaluated u The calculation formula is: (8) Among them, D u is the dispersion of the u-th sampling point of the slope to be evaluated, Ps1 is the content of particles smaller than 0.05 mm when no dispersant is added, and Ps2 is the content of particles smaller than 0.05 mm when no dispersant is added; When the sampling point of the slope to be evaluated is non-dispersed soil, the treatment coefficient Ku=1; when the sampling point of the slope to be evaluated is transitional soil, the treatment coefficient Ku=1.5; when the sampling point of the slope to be evaluated is physically dispersed soil, the treatment coefficient Ku=2.0; when the sampling point of the slope to be evaluated is chemically dispersed soil, the treatment coefficient Ku=2.5; when the sampling point of the slope to be evaluated is physically-chemically dispersed soil, the treatment coefficient Ku=3.0.

[0012] The number of sinkholes is W, the location of the sinkholes is A, the average volume of the sinkholes is V, and the average distance between the sinkholes is S, then: When W≤3, D1 takes the value of 3; When 3<W≤7, D1 takes the value of 5; When 7<W≤15, D1 takes the value of 7; When W>15, D1 takes the value of 10; When the sinkhole position A is below the water surface, D2 takes the value of 10; When the sinkhole position A is above the water surface, D2 takes the value of 5; When V≤3, D3 takes the value of 3; When 3<V≤7, D3 takes the value of 5; When 7<V≤15, D3 takes the value of 7; When V>15, D3 takes the value of 10; When S≤5, D4 takes the value of 3; When 5<S≤10, D4 takes the value of 5; When 10<S≤20, D4 takes the value of 7; When S>20, D4 takes the value of 10.

[0013] In step S3, the slope clay soil water sensitivity u1 is assigned: When u1≤0.25, the score value Ui1 of slope clay soil water sensitivity is 1; When 0.25<u1≤0.5, the score value Ui1 of slope cohesive soil water sensitivity is 2; When 0.5<u1≤0.75, the score value Ui1 of slope cohesive soil water sensitivity is 3; When u1>0.75, the score value Ui1 of slope cohesive soil water sensitivity is 4; Assign a value to the rainfall intensity coefficient u2: When u2≤200, the score value Ui2 of the rainfall intensity coefficient is 1; When 200<u2≤300, the score value Ui2 of the rainfall intensity coefficient is 2; When 300<u2≤400, the score value Ui2 of the rainfall intensity coefficient is 3; When u2>400, the score value Ui2 of the rainfall intensity coefficient is 4; Assign a value to the dispersion u3 of the slope clay soil: When u3≤0.5, the score value Ui3 of the dispersion of slope clay soil is 1; When 0.5<u3≤1.25, the score value Ui3 of the dispersion of slope clay soil is 2; When 1.25<u3≤2, the score value Ui3 of the dispersion of slope clay soil is 3; When u3>2, the score value Ui3 of the dispersion of slope clay soil is 4; Assign the collapsibility u4 of the slope clay soil: When u4≤50, the score value Ui4 of the collapsibility of the clayey soil of the slope is 1; When 50<u4≤100, the score value Ui4 of the collapsibility of the clayey soil of the slope is 2; When 100<u4≤200, the score value Ui4 of the collapsibility of the clayey soil of the slope is 3; When u4>200, the score value Ui4 of the collapsibility of the slope clay soil is 4; Assign a value to the slope flatness u5: When u5≤500, the slope flatness score Ui5 is 1; When 500<u5≤1500, the slope flatness score Ui5 is 2; When 1500<u5≤5000, the slope flatness score Ui5 is 3; When u5>5000, the slope flatness score Ui5 is 4; Assign a value to the rainwater collection area u6: When u6≤20, the score value Ui6 of the catchment area is 1; When 20<u6≤50, the score value Ui6 of the catchment area is 2; When 50<u6≤100, the score value Ui6 of the catchment area is 3; When u6>100, the score value Ui6 of the catchment area is 4; Assign value to the chemical dispersion of slope soil u7: When u7≤7, the score value Ui7 of the chemical dispersion of the slope soil is 1; When 7<u7≤11, the score value Ui7 of the chemical dispersion of the slope soil is 2; When 11<u7≤15, the score value Ui7 of the chemical dispersion of the slope soil is 3; When u7>15, the score value Ui7 of the chemical dispersion of the slope soil is 4; Assign a value to the slope stability coefficient u8: When u8>1.2, the score value Ui8 of the slope stability coefficient is 1; When 1.0<u8≤1.2, the score value Ui8 of the slope stability coefficient is 2; When 0.8<u8≤1.0, the score value Ui8 of the slope stability coefficient is 3; When u8≤15, the score value Ui8 of the slope stability coefficient is 4; Assign a value to the water flow rate u9: When u9≤3, the water flow rate score Ui9 takes the value of 1; When 3<u9≤8, the water flow rate score Ui9 is 2; When 8<u9≤15, the water flow rate score Ui9 is 3; When u9>15, the water flow rate score Ui9 is 4.

[0014] In step S4, the calculation formula (9) of the stability U of the water-bound clay slope to be evaluated is: U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9 (9).

[0015] In step S5, the stability of the water-bearing clay slope is evaluated according to the score of the stability U, including: When U≤12, the stability assessment result of the clay soil slope near water is low risk; When 12<U≤20, the stability assessment result of the clay soil slope near water is medium risk; When 20<U≤28, the stability assessment result of the clay soil slope near water is medium-high risk; When U>28, the stability assessment result of the clayey soil slope near water is high risk.

[0016] The beneficial effects of the present invention are: The method for assessing the stability of water-facing clayey soil slopes provided by the present invention solves the defect that the existing stability assessment of water-facing clayey soil slopes does not take into account the dispersion of soil, collapsibility, water sensitivity and the morphology of the water-facing surface of the slope inadequately, based on simple measurements and surface soil test results, accurately realizes the stability assessment of unsupported, large-scale water-facing clayey soil slopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of the method for assessing the stability of a clayey soil slope near water. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] The present invention provides a method for evaluating the stability of a clayey soil slope near water, such as Figure 1 As shown, the following steps are included: S1: Select the clay slope affected by water as the slope to be evaluated and measure the topography of the slope to be evaluated; S2: Determine various stability evaluation indicators of the slope to be evaluated; S3: Assign values ​​to various stability assessment indicators of the slope to be assessed; S4: Calculate the stability U of the slope to be evaluated; S5: Evaluate the stability of clayey soil slopes near water based on the stability U.

[0020] In step S1, when the clay slope is located on the concave bank of the river channel, a clay slope with a slope greater than twice the underwater natural repose angle of the clay soil on the surface of the clay slope, or a designated slope, is selected as the slope to be evaluated; When the clay slope is located on the convex bank of the river channel, a clay slope with a slope greater than 1.8 times the underwater natural angle of repose of the clay soil on the surface of the clay slope, or a designated slope, is selected as the slope to be evaluated; For each slope to be evaluated, a representative profile is determined, and the total number p of slopes to be evaluated, the water surface elevation H1 on the water side of the slope to be evaluated, the slope foot elevation H2, and the height H of the slope to be evaluated are measured and determined.

[0021] In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0022] The water sensitivity of slope clay soil u1 is the average water sensitivity of the useful layer of the slope to be evaluated; The calculation formula (1) of slope clay soil water sensitivity is: (1) Where n is the average water sensitivity of all sampling points on the slope to be evaluated, n u is the water sensitivity of the u-th sampling point on the slope to be evaluated, and v is the total number of sampling points on the slope to be evaluated; The sampling locations of the slope sampling points to be evaluated include the toe of the slope and the water surface. There are two initial sampling points at each location, which are 0.5m and 1.0m deep perpendicular to the slope. When the difference between the water surface elevation H1 and the toe elevation H2 of the slope is greater than 20m, one sampling location is added at the toe elevation H2 and the water surface elevation H1. All sampling locations divide the toe elevation H2 and the water surface elevation H1 equally, and the sampling point depth is the same as other locations.

[0023] The rainfall intensity coefficient u2 is the product of the average annual precipitation of the slope to be evaluated and the coefficient of variation of the average monthly precipitation. The calculation formula (2) of the rainfall intensity coefficient is: Kh=h×Cvh(2) Among them, Kh is the rainfall intensity coefficient, h is the average annual precipitation of the slope to be evaluated, and Cvh is the coefficient of variation of the average monthly precipitation.

[0024] The dispersion of the clay soil of the slope, u3, is the average value of the dispersion of the sampling points on the representative section of the slope to be evaluated multiplied by the treatment coefficient. The number and location of the sampling points are the same as the water sensitivity of the clay soil of the slope, u1; The calculation formula for the dispersion of slope clay is: (3) Where D is the dispersion of slope clay, D u is the dispersion of the u-th sampling point of the slope to be evaluated, K u is the treatment coefficient of the u-th sampling point of the slope to be evaluated, and v is the total number of sampling points of the slope to be evaluated; The dispersion D of the uth sampling point of the slope to be evaluated u The calculation formula is: (8) Among them, D uis the dispersion of the u-th sampling point of the slope to be evaluated, Ps1 is the content of particles smaller than 0.05 mm when no dispersant is added, and Ps2 is the content of particles smaller than 0.05 mm when no dispersant is added; When the sampling point of the slope to be evaluated is non-dispersed soil, the treatment coefficient Ku=1; when the sampling point of the slope to be evaluated is transitional soil, the treatment coefficient Ku=1.5; when the sampling point of the slope to be evaluated is physically dispersed soil, the treatment coefficient Ku=2.0; when the sampling point of the slope to be evaluated is chemically dispersed soil, the treatment coefficient Ku=2.5; when the sampling point of the slope to be evaluated is physically-chemically dispersed soil, the treatment coefficient Ku=3.0.

[0025] The collapsibility of clay soil on the slope, u4, is the average collapsibility of each measuring point on the slope to be evaluated. The calculation formula (4) for the average collapsibility of each measuring point on the slope to be evaluated is: (4) Where K is the average collapsibility of each measuring point on the slope to be evaluated, Δs u is the self-weight wetting collapsibility of the u-th sampling point of the slope to be evaluated; Δzs u is the wetting collapse amount of the u-th sampling point on the slope to be evaluated; Slope flatness u5 is the number, size and distribution of sinkholes within the range L on both sides of the representative section of the slope to be evaluated, where L = 2H; The calculation formula (5) for slope flatness is: D L =D1×D2×D3×D4 (5) Among them, D L is the flatness of the slope, D1 is the instability score of the number of sinkholes, D2 is the instability score of the location of the sinkholes, D3 is the instability score of the average volume of the sinkholes, and D4 is the instability score of the average spacing of the sinkholes; The number of sinkholes is W, the location of the sinkholes is A, the average volume of the sinkholes is V, the average distance between the sinkholes is S, and the scoring table for D1, D2, D3 and D4 is shown in Table 1: When W≤3, D1 takes the value of 3; When 3<W≤7, D1 takes the value of 5; When 7<W≤15, D1 takes the value of 7; When W>15, D1 takes the value of 10; When the sinkhole position A is below the water surface, D2 takes the value of 10; When the sinkhole position A is above the water surface, D2 takes the value of 5; When V≤3, D3 takes the value of 3; When 3<V≤7, D3 takes the value of 5; When 7<V≤15, D3 takes the value of 7; When V>15, D3 takes the value of 10; When S≤5, D4 takes the value of 3; When 5<S≤10, D4 takes the value of 5; When 10<S≤20, D4 takes the value of 7; When S>20, D4 takes the value of 10.

[0026] Table 1 Slope flatness evaluation index scoring table

[0027] The catchment area u6 is the product of the straight-line distance from the watershed above the top of the slope to the foot of the slope in the representative section of the slope to be evaluated and the unit width, where gentle slopes with a slope of less than 3 degrees are not included; The calculation formula (6) for the rainwater collection area is: s=d×w(6) Where d is the straight-line distance from the watershed above the top of the slope to the foot of the slope, w is the unit width, and w is taken as 1m; The chemical dispersion of slope soil, u7, is the percentage value of exchangeable sodium ions of the slope to be evaluated. The calculation formula (7) of the chemical dispersion of slope soil is: (7) Among them, P ES is the percentage value of exchangeable sodium ions of the slope to be evaluated, b(Na,exch) is the exchangeable sodium ion content, and CEC is the cation exchange capacity; The slope stability coefficient u8 is the stability coefficient of the slope to be evaluated calculated by the Bishop method. The calculation adopts the saturated quick shear index of the direct shear test, and the profile adopts the representative profile of the slope to be evaluated obtained by measurement. The water flow velocity u9 is the measured water flow velocity at the intersection of the representative profile of the slope to be evaluated and the water surface.

[0028] In step S3, the slope clay soil water sensitivity u1 is assigned: When u1≤0.25, the score value Ui1 of slope clay soil water sensitivity is 1; When 0.25<u1≤0.5, the score value Ui1 of slope cohesive soil water sensitivity is 2; When 0.5<u1≤0.75, the score value Ui1 of slope cohesive soil water sensitivity is 3; When u1>0.75, the score value Ui1 of slope cohesive soil water sensitivity is 4; Assign a value to the rainfall intensity coefficient u2: When u2≤200, the score value Ui2 of the rainfall intensity coefficient is 1; When 200<u2≤300, the score value Ui2 of the rainfall intensity coefficient is 2; When 300<u2≤400, the score value Ui2 of the rainfall intensity coefficient is 3; When u2>400, the score value Ui2 of the rainfall intensity coefficient is 4; Assign a value to the dispersion u3 of the slope clay soil: When u3≤0.5, the score value Ui3 of the dispersion of slope clay soil is 1; When 0.5<u3≤1.25, the score value Ui3 of the dispersion of slope clay soil is 2; When 1.25<u3≤2, the score value Ui3 of the dispersion of slope clay soil is 3; When u3>2, the score value Ui3 of the dispersion of slope clay soil is 4; Assign the collapsibility u4 of the slope clay soil: When u4≤50, the score value Ui4 of the collapsibility of the clayey soil of the slope is 1; When 50<u4≤100, the score value Ui4 of the collapsibility of the clayey soil of the slope is 2; When 100<u4≤200, the score value Ui4 of the collapsibility of the clayey soil of the slope is 3; When u4>200, the score value Ui4 of the collapsibility of the slope clay soil is 4; Assign a value to the slope flatness u5: When u5≤500, the slope flatness score Ui5 is 1; When 500<u5≤1500, the slope flatness score Ui5 is 2; When 1500<u5≤5000, the slope flatness score Ui5 is 3; When u5>5000, the slope flatness score Ui5 is 4; Assign a value to the rainwater collection area u6: When u6≤20, the score value Ui6 of the catchment area is 1; When 20<u6≤50, the score value Ui6 of the catchment area is 2; When 50<u6≤100, the score value Ui6 of the catchment area is 3; When u6>100, the score value Ui6 of the catchment area is 4; Assign value to the chemical dispersion of slope soil u7: When u7≤7, the score value Ui7 of the chemical dispersion of the slope soil is 1; When 7<u7≤11, the score value Ui7 of the chemical dispersion of the slope soil is 2; When 11<u7≤15, the score value Ui7 of the chemical dispersion of the slope soil is 3; When u7>15, the score value Ui7 of the chemical dispersion of the slope soil is 4; Assign a value to the slope stability coefficient u8: When u8>1.2, the score value Ui8 of the slope stability coefficient is 1; When 1.0<u8≤1.2, the score value Ui8 of the slope stability coefficient is 2; When 0.8<u8≤1.0, the score value Ui8 of the slope stability coefficient is 3; When u8≤15, the score value Ui8 of the slope stability coefficient is 4; Assign a value to the water flow rate u9: When u9≤3, the water flow rate score Ui9 takes the value of 1; When 3<u9≤8, the water flow rate score Ui9 is 2; When 8<u9≤15, the water flow rate score Ui9 is 3; When u9>15, the water flow rate score Ui9 is 4.

[0029] In step S4, the calculation formula (9) of the stability U of the water-bound clay slope to be evaluated is: U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9 (9).

[0030] In step S5, the stability of the water-bearing clay slope is evaluated according to the score of the stability U, including: When U≤12, the stability assessment result of the clay soil slope near water is low risk; When 12<U≤20, the stability assessment result of the clay soil slope near water is medium risk; When 20<U≤28, the stability assessment result of the clay soil slope near water is medium-high risk; When U>28, the stability assessment result of the clayey soil slope near water is high risk.

[0031] Example 1 The method for evaluating the stability of a clayey soil slope near water proposed in this embodiment includes the following steps: S1: Select a clay slope affected by water as the slope to be evaluated. Measure the topography of the slope to be evaluated. The height of the slope to be evaluated is H=27m. The difference between the water surface elevation H1 and the slope foot elevation H2 is 18m. The number of sampling points v is 2.

[0032] S2: Determine the stability evaluation indicators of the slope to be evaluated: In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0033] Determine the average monthly precipitation of the slope to be evaluated, as shown in Table 2: Table 2 Example 1 - Monthly average precipitation values ​​of the slope to be evaluated

[0034] The average annual precipitation h of the slope to be evaluated is calculated, and the rainfall intensity coefficient u2 is calculated based on Kh=h×Cvh with the monthly average precipitation variation coefficient Cvh. The results are shown in Table 3: Table 3 Example 1 - Rainfall intensity coefficient calculation results

[0035] The rainfall intensity coefficient u2 is 293.

[0036] The relevant parameters of the dispersion of the clayey soil of the slope are determined. The parameters include the dispersion Du of the u-th sampling point of the slope to be evaluated, the treatment coefficient Ku of the u-th sampling point of the slope to be evaluated, and the dispersion of each sampling point is calculated. The results are shown in Table 4: Table 4 Example 1 - Dispersion results of each sampling point

[0037] According to the calculation formula , it is calculated that D=1.1 and the dispersion of slope clay soil u3=1.1.

[0038] Determine the relevant parameters of the collapsibility of the clayey soil on the slope, including the self-weight collapsibility of the u-th sampling point on the slope to be evaluated, Δs u , the wetting amount of the u-th sampling point of the slope to be evaluated Δzs u , the collapsibility of each sampling point was calculated, and the results are shown in Table 5: Table 5 Example 1 - Collapsibility results for each sampling point

[0039] According to the calculation formula , it is calculated that K=65, and the collapsibility of slope clay soil u4=65.

[0040] The relevant parameters for determining the slope flatness are the number, size and distribution of sinkholes within the range L on the left and right sides of the representative section of the slope to be evaluated. The parameters include the number of sinkholes W=6, the location of the sinkholes A below the water surface, the average volume of the sinkholes V=6, and the average spacing of the sinkholes S=12; When W is 6, the instability score D1 of the number of sinkholes is 5; when the sinkhole position A is below the water surface, the instability score D2 of the sinkhole position is 10; when V is 6, the instability score D3 of the average volume of the sinkholes is 5; when S is 12, the instability score D4 of the average spacing of the sinkholes is 5; According to the calculation formula D L =D1×D2×D3×D4, calculated D L =1250, slope flatness u5=1250.

[0041] In summary, the other required parameters of the stability evaluation indicators of the slope to be evaluated are determined, and the calculation results are shown in Table 6: Table 6 Example 1 - Calculation results of various stability evaluation indicators

[0042] S3: Assign values ​​to various stability evaluation indicators of the slope to be evaluated. The results are shown in Table 7: Table 7 Example 1 - Results of various stability evaluation index assignments

[0043] S4: Calculate the stability U of the slope to be evaluated; According to the calculation formula U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9, we get U=18.

[0044] S5: Evaluate the stability of clay slopes near water according to the stability U; When U=18, the stability assessment result of the water-adjacent clay slope in this embodiment is medium risk.

[0045] Example 2 The method for evaluating the stability of a clayey soil slope near water proposed in this embodiment includes the following steps: S1: Select a clay slope affected by water as the slope to be evaluated. Measure the topography of the slope to be evaluated. The height of the slope to be evaluated is H=19m. The difference between the water surface elevation H1 and the slope foot elevation H2 is 16m. The number of sampling points v is 2.

[0046] S2: Determine the stability evaluation indicators of the slope to be evaluated: In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0047] Determine the average monthly precipitation of the slope to be evaluated, as shown in Table 8 below: Table 8 Example 2 - Monthly average precipitation values ​​of the slope to be evaluated

[0048] The average annual precipitation h of the slope to be evaluated is calculated, and the rainfall intensity coefficient u2 is calculated based on Kh=h×Cvh with the monthly average precipitation variation coefficient Cvh. The results are shown in Table 9: Table 9 Example 2-Rainfall intensity coefficient calculation results

[0049] The rainfall intensity coefficient u2 is 293.

[0050] The relevant parameters of the dispersion of the clayey soil of the slope are determined. The parameters include the dispersion Du of the u-th sampling point of the slope to be evaluated, the treatment coefficient Ku of the u-th sampling point of the slope to be evaluated, and the dispersion of each sampling point is calculated. The results are shown in Table 10: Table 10 Example 2 - Dispersion results of each sampling point

[0051] According to the calculation formula , it is calculated that D=0.8 and the dispersion of slope clay soil u3=0.8.

[0052] Determine the relevant parameters of the collapsibility of the clayey soil on the slope, including the self-weight collapsibility of the u-th sampling point on the slope to be evaluated, Δs u , the wetting amount of the u-th sampling point of the slope to be evaluated Δzs u , the collapsibility of each sampling point was calculated, and the results are shown in Table 11: Table 11 Example 2 - Collapsibility results for each sampling point

[0053] According to the calculation formula , it is calculated that K=85, and the collapsibility of slope clay soil u4=85.

[0054] The relevant parameters for determining the slope flatness are the number, size and distribution of sinkholes within the range L on the left and right sides of the representative section of the slope to be evaluated. The parameters include the number of sinkholes W=5, the location of the sinkhole A below the water surface, the average volume of the sinkholes V=7, and the average spacing between the sinkholes S=13; When W is 5, the instability score D1 of the number of sinkholes is 5; when the sinkhole position A is below the water surface, the instability score D2 of the sinkhole position is 10; when V is 7, the instability score D3 of the average volume of the sinkholes is 5; when S is 12, the instability score D4 of the average spacing between sinkholes is 7.

[0055] According to the calculation formula D L =D1×D2×D3×D4, calculated D L =1750, slope flatness u5=1750.

[0056] In summary, the other required parameters of the stability evaluation indicators of the slope to be evaluated are determined, and the calculation results are as shown in Table 12: Table 12 Example 2 - Calculation results of various stability evaluation indicators

[0057] S3: Assign values ​​to various stability evaluation indicators of the slope to be evaluated. The results are shown in Table 13: Table 13 Example 2 - Results of various stability evaluation index assignments

[0058] S4: Calculate the stability U of the slope to be evaluated; According to the calculation formula U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9, we get U=20.

[0059] S5: Evaluate the stability of clay slopes near water according to the stability U; When U=20, the stability assessment result of the water-adjacent clay slope in this embodiment is medium risk.

[0060] Example 3 The method for evaluating the stability of a clayey soil slope near water proposed in this embodiment includes the following steps: S1: Select a clay slope affected by water as the slope to be evaluated. Measure the topography of the slope to be evaluated. The height of the slope to be evaluated is H=29m. The difference between the water surface elevation H1 and the slope foot elevation H2 is 18m. The number of sampling points v is 2.

[0061] S2: Determine the stability evaluation indicators of the slope to be evaluated: In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0062] Determine the average monthly precipitation of the slope to be evaluated, as shown in Table 14: Table 14 Example 3 - Monthly average precipitation values ​​of the slope to be evaluated

[0063] The average annual precipitation h of the slope to be evaluated is calculated, and the rainfall intensity coefficient u2 is calculated based on Kh=h×Cvh with the monthly average precipitation variation coefficient Cvh. The results are shown in Table 15: Table 15 Example 3 - Rainfall intensity coefficient calculation results

[0064] The rainfall intensity coefficient u2 is 293.

[0065] The relevant parameters of the dispersion of the clayey soil of the slope are determined. The parameters include the dispersion Du of the u-th sampling point of the slope to be evaluated, the treatment coefficient Ku of the u-th sampling point of the slope to be evaluated, and the dispersion of each sampling point is calculated. The results are shown in Table 16: Table 16 Example 3 - Dispersion results of each sampling point

[0066] According to the calculation formula , it is calculated that D=0.45, and the dispersion of slope clay soil u3=0.45.

[0067] Determine the relevant parameters of the collapsibility of the clayey soil on the slope, including the self-weight collapsibility of the u-th sampling point on the slope to be evaluated, Δs u , the wetting amount of the u-th sampling point of the slope to be evaluated Δzs u , the collapsibility of each sampling point was calculated, and the results are shown in Table 17: Table 17 Example 3 - Collapsibility results for each sampling point

[0068] According to the calculation formula , it is calculated that K=112, and the collapsibility of slope clay soil u4=112.

[0069] The relevant parameters for determining the slope flatness are the number, size and distribution of sinkholes within the range L on the left and right sides of the representative section of the slope to be evaluated. The parameters include the number of sinkholes W=8, the location of the sinkholes A below the water surface, the average volume of the sinkholes V=2, and the average spacing of the sinkholes S=4; When W is 8, the instability score D1 of the number of sinkholes is 7; when the sinkhole position A is below the water surface, the instability score D2 of the sinkhole position is 10; when V is 2, the instability score D3 of the average volume of the sinkholes is 3; when S is 4, the instability score D4 of the average spacing between sinkholes is 3.

[0070] According to the calculation formula D L =D1×D2×D3×D4, calculated D L =630, slope flatness u5=630.

[0071] In summary, the other required parameters of the stability evaluation indicators of the slope to be evaluated are determined, and the calculation results are as shown in Table 18: Table 18 Example 3 - Calculation results of various stability evaluation indicators

[0072] S3: Assign values ​​to various stability evaluation indicators of the slope to be evaluated. The results are shown in Table 19: Table 19 Example 3 - Results of various stability evaluation index assignments

[0073] S4: Calculate the stability U of the slope to be evaluated; According to the calculation formula U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9, we get U=16.

[0074] S5: Evaluate the stability of clay slopes near water according to the stability U; When U=16, the stability assessment result of the water-adjacent clay slope in this embodiment is medium risk.

[0075] Example 4 The method for evaluating the stability of a clayey soil slope near water proposed in this embodiment includes the following steps: S1: Select a clay slope affected by water as the slope to be evaluated. Measure the topography of the slope to be evaluated. The height of the slope to be evaluated is H=25m. The difference between the water surface elevation H1 and the slope foot elevation H2 is 17m. The number of sampling points v is 2.

[0076] S2: Determine the stability evaluation indicators of the slope to be evaluated: In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0077] Determine the average monthly precipitation of the slope to be evaluated, as shown in Table 20 below: Table 20 Example 4 - Monthly average precipitation values ​​of the slope to be evaluated

[0078] The average annual precipitation h of the slope to be evaluated is calculated, and the rainfall intensity coefficient u2 is calculated based on Kh=h×Cvh with the monthly average precipitation variation coefficient Cvh. The results are shown in Table 21: Table 21 Example 4 - Rainfall intensity coefficient calculation results

[0079] The rainfall intensity coefficient u2 is 293.

[0080] The relevant parameters of the dispersion of the clayey soil of the slope are determined. The parameters include the dispersion Du of the u-th sampling point of the slope to be evaluated, the treatment coefficient Ku of the u-th sampling point of the slope to be evaluated, and the dispersion of each sampling point is calculated. The results are shown in Table 22: Table 22 Example 4 - Dispersion results of each sampling point

[0081] According to the calculation formula , it is calculated that D=0.65, and the dispersion of slope clay soil u3=0.65.

[0082] Determine the relevant parameters of the collapsibility of the clayey soil on the slope, including the self-weight collapsibility of the u-th sampling point on the slope to be evaluated, Δs u , the wetting amount of the u-th sampling point of the slope to be evaluated Δzs u , the collapsibility of each sampling point was calculated, and the results are shown in Table 23: Table 23 Example 4 - Collapsibility results for each sampling point

[0083] According to the calculation formula , it is calculated that K=125, and the collapsibility of slope clay soil u4=125.

[0084] The relevant parameters for determining the slope flatness are the number, size and distribution of sinkholes within the range L on the left and right sides of the representative section of the slope to be evaluated. The parameters include the number of sinkholes W=9, the location of the sinkholes A below the water surface, the average volume of the sinkholes V=9, and the average spacing between the sinkholes S=8; When W is 9, the instability score D1 of the number of sinkholes is 7; when the sinkhole position A is below the water surface, the instability score D2 of the sinkhole position is 10; when V is 9, the instability score D3 of the average volume of the sinkholes is 7; when S is 8, the instability score D4 of the average spacing between sinkholes is 5.

[0085] According to the calculation formula D L =D1×D2×D3×D4, calculated D L =2450, slope flatness u5=2450.

[0086] In summary, the other required parameters of the stability evaluation indicators of the slope to be evaluated are determined, and the calculation results are as shown in Table 24: Table 24 Example 4 - Calculation results of various stability evaluation indicators

[0087] S3: Assign values ​​to various stability evaluation indicators of the slope to be evaluated. The results are shown in Table 25: Table 25 Example 4 - Results of various stability evaluation index assignments

[0088] S4: Calculate the stability U of the slope to be evaluated; According to the calculation formula U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9, we get U=22.

[0089] S5: Evaluate the stability of clay slopes near water according to the stability U; When U=22, the stability assessment result of the water-adjacent clay slope in this embodiment is medium-high risk.

[0090] Example 5 The method for evaluating the stability of a clayey soil slope near water proposed in this embodiment includes the following steps: S1: A clay slope affected by water is selected as the slope to be evaluated. The topography of the slope to be evaluated is measured. The height of the slope to be evaluated is H=32m, and the difference between the water surface elevation H1 and the slope foot elevation H2 is 19m; the number of sampling points v is 2.

[0091] S2: Determine the stability evaluation indicators of the slope to be evaluated: In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0092] Determine the average monthly precipitation of the slope to be evaluated, as shown in Table 26 below: Table 26 Example 5 - Monthly average precipitation values ​​of the slope to be evaluated

[0093] The average annual precipitation h of the slope to be evaluated is calculated, and the rainfall intensity coefficient u2 is calculated based on Kh=h×Cvh with the monthly average precipitation variation coefficient Cvh. The results are shown in Table 27: Table 27 Example 5 - Rainfall intensity coefficient calculation results

[0094] The rainfall intensity coefficient u2 is 293.

[0095] The relevant parameters of the dispersion of the clayey soil of the slope are determined. The parameters include the dispersion Du of the u-th sampling point of the slope to be evaluated, the treatment coefficient Ku of the u-th sampling point of the slope to be evaluated, and the dispersion of each sampling point is calculated. The results are shown in Table 28: Table 28 Example 5 - Dispersion results of each sampling point

[0096] According to the calculation formula , it is calculated that D=1.46, and the dispersion of slope clay soil u3=1.46.

[0097] Determine the relevant parameters of the collapsibility of the clayey soil on the slope, including the self-weight collapsibility of the u-th sampling point on the slope to be evaluated, Δs u , the wetting amount of the u-th sampling point of the slope to be evaluated Δzs u , the collapsibility of each sampling point was calculated, and the results are shown in Table 29: Table 29 Example 5 - Collapsibility results for each sampling point

[0098] According to the calculation formula , it is calculated that K=59, and the collapsibility of slope clay soil u4=59.

[0099] The relevant parameters for determining the flatness of the slope are the number, size and distribution of sinkholes within the range L on the left and right sides of the representative section of the slope to be evaluated. The parameters include the number of sinkholes W=10, the location of the sinkholes A above the water surface, the average volume of the sinkholes V=10, and the average spacing of the sinkholes S=9; When W is 10, the instability score D1 of the number of sinkholes is 7; when the sinkhole position A is above the water surface, the instability score D2 of the sinkhole position is 5; when V is 10, the instability score D3 of the average volume of the sinkholes is 7; when S is 9, the instability score D4 of the average spacing between sinkholes is 5.

[0100] According to the calculation formula D L =D1×D2×D3×D4, calculated D L =1225, slope flatness u5=1225.

[0101] In summary, the other required parameters of the stability evaluation indicators of the slope to be evaluated are determined, and the calculation results are shown in Table 30: Table 30 Example 5 - Calculation results of various stability evaluation indicators

[0102] S3: Assign values ​​to various stability evaluation indicators of the slope to be evaluated. The results are shown in Table 31: Table 31 Example 5 - Results of various stability evaluation index assignments

[0103] S4: Calculate the stability U of the slope to be evaluated; According to the calculation formula U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9, we get U=23.

[0104] S5: Evaluate the stability of clay slopes near water according to the stability U; When U=23, the stability assessment result of the water-adjacent clay slope in this embodiment is medium-high risk.

[0105] Example 6 The method for evaluating the stability of a clayey soil slope near water proposed in this embodiment includes the following steps: S1: Select a clay slope affected by water as the slope to be evaluated. Measure the topography of the slope to be evaluated. The height of the slope to be evaluated is H=35m. The difference between the water surface elevation H1 and the slope foot elevation H2 is 22m. The number of sampling points v is 3.

[0106] S2: Determine the stability evaluation indicators of the slope to be evaluated: In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

[0107] Determine the average monthly precipitation of the slope to be evaluated, as shown in Table 32 below: Table 32 Example 6 - Monthly average precipitation values ​​of the slope to be evaluated

[0108] The average annual precipitation h of the slope to be evaluated is calculated, and the rainfall intensity coefficient u2 is calculated based on Kh=h×Cvh with the monthly average precipitation variation coefficient Cvh. The results are shown in Table 33: Table 33 Example 6 - Rainfall intensity coefficient calculation results

[0109] The rainfall intensity coefficient u2 is 293.

[0110] The relevant parameters of the dispersion of the clayey soil of the slope are determined. The parameters include the dispersion Du of the u-th sampling point of the slope to be evaluated, the treatment coefficient Ku of the u-th sampling point of the slope to be evaluated, and the dispersion of each sampling point is calculated. The results are shown in Table 34: Table 34 Example 6 - Dispersion results of each sampling point

[0111] According to the calculation formula , it is calculated that D=1.56, and the dispersion of slope clay soil u3=1.56.

[0112] Determine the relevant parameters of the collapsibility of the clayey soil on the slope, including the self-weight collapsibility of the u-th sampling point on the slope to be evaluated, Δs u , the wetting amount of the u-th sampling point of the slope to be evaluated Δzs u , the collapsibility of each sampling point was calculated, and the results are shown in Table 35: Table 35 Example 6 - Collapsibility results for each sampling point

[0113] According to the calculation formula , it is calculated that K=156, and the collapsibility of slope clay soil u4=156.

[0114] The relevant parameters for determining the slope flatness are the number, size and distribution of sinkholes within the range L on the left and right sides of the representative section of the slope to be evaluated. The parameters include the number of sinkholes W = 10, the location of the sinkhole A below the water surface, the average volume of the sinkholes V = 8, and the average spacing of the sinkholes S = 13; When W is 10, the instability score D1 of the number of sinkholes is 7; when the sinkhole position A is below the water surface, the instability score D2 of the sinkhole position is 10; when V is 8, the instability score D3 of the average volume of the sinkholes is 7; when S is 13, the instability score D4 of the average spacing between sinkholes is 7.

[0115] According to the calculation formula D L =D1×D2×D3×D4, calculated D L =3430, slope flatness u5=3430.

[0116] In summary, the other required parameters of the stability evaluation indicators of the slope to be evaluated are determined, and the calculation results are shown in Table 36: Table 36 Example 6 - Calculation results of various stability evaluation indicators

[0117] S3: Assign values ​​to various stability evaluation indicators of the slope to be evaluated. The results are shown in Table 37: Table 37 Example 6 - Results of various stability evaluation index assignments

[0118] S4: Calculate the stability U of the slope to be evaluated; According to the calculation formula U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9, we get U=25.

[0119] S5: Evaluate the stability of clay slopes near water according to the stability U; When U=25, the stability assessment result of the water-adjacent clay slope in this embodiment is medium-high risk.

Claims

1. A method for assessing the stability of a clayey soil slope near water, characterized in that: The following steps are involved: S1: Select the clay slope affected by water as the slope to be evaluated and measure the topography of the slope to be evaluated; S2: Determine various stability evaluation indicators of the slope to be evaluated; S3: Assign values ​​to various stability assessment indicators of the slope to be assessed; S4: Calculate the stability U of the slope to be evaluated; S5: Evaluate the stability of clayey soil slopes near water based on the stability U.

2. The method for evaluating the stability of water-bearing clayey soil slope according to claim 1, characterized in that: In step S1, when the clay slope is located on the concave bank of the river channel, a clay slope with a slope greater than twice the underwater natural repose angle of the clay soil on the surface of the clay slope, or a designated slope, is selected as the slope to be evaluated; When the clay slope is located on the convex bank of the river channel, a clay slope with a slope greater than 1.8 times the underwater natural angle of repose of the clay soil on the surface of the clay slope, or a designated slope, is selected as the slope to be evaluated; For each slope to be evaluated, a representative profile is determined, and the total number p of slopes to be evaluated, the water surface elevation H1 on the water side of the slope to be evaluated, the slope foot elevation H2, and the height H of the slope to be evaluated are measured and determined.

3. The method for evaluating the stability of water-bearing clay slope according to claim 2, characterized in that: In step S2, the stability evaluation indicators of the slope to be evaluated include slope clay water sensitivity u1, rainfall intensity coefficient u2, slope clay dispersion u3, slope clay collapsibility u4, slope flatness u5, rainwater collection area u6, slope soil chemical dispersion u7, slope stability coefficient u8 and water flow rate u9.

4. The method for evaluating the stability of water-bearing clayey soil slope according to claim 3, characterized in that: The slope clay soil water sensitivity u1 is the average water sensitivity of the useful layer of the slope to be evaluated; The calculation formula (1) of the slope clay water sensitivity is: （1） Where n is the average water sensitivity of all sampling points on the slope to be evaluated, n u is the water sensitivity of the u-th sampling point on the slope to be evaluated, and v is the total number of sampling points on the slope to be evaluated; The rainfall intensity coefficient u2 is the product of the average annual precipitation of the slope to be evaluated and the coefficient of variation of the average monthly precipitation. The calculation formula (2) of the rainfall intensity coefficient is: Kh=h×Cvh(2) Among them, Kh is the rainfall intensity coefficient, h is the average annual precipitation of the slope to be evaluated, and Cvh is the coefficient of variation of the average monthly precipitation; The dispersion of the clay soil of the slope u3 is the average value of the dispersion of the sampling points on the representative section of the slope to be evaluated multiplied by the treatment coefficient. The number and location of the sampling points are the same as the water sensitivity of the clay soil of the slope u1; The calculation formula for the dispersion of the slope clay is: （3） Where D is the dispersion of slope clay, D u is the dispersion of the u-th sampling point of the slope to be evaluated, K u is the treatment coefficient of the u-th sampling point of the slope to be evaluated, and v is the total number of sampling points of the slope to be evaluated; The collapsibility of the clay soil of the slope u4 is the average collapsibility of each measuring point of the slope to be evaluated. The calculation formula (4) of the average collapsibility of each measuring point of the slope to be evaluated is: （4） Where K is the average collapsibility of each measuring point on the slope to be evaluated, Δs u is the self-weight wetting collapsibility of the u-th sampling point of the slope to be evaluated; Δzs u is the wetting collapse amount of the u-th sampling point on the slope to be evaluated; The slope flatness u5 is the number, size and distribution of sinkholes within the range L on the left and right sides of the representative section of the slope to be evaluated, where L=2H; The calculation formula (5) for the slope flatness is: D L =D1×D2×D3×D4(5) Among them, D L is the flatness of the slope, D1 is the instability score of the number of sinkholes, D2 is the instability score of the location of the sinkholes, D3 is the instability score of the average volume of the sinkholes, and D4 is the instability score of the average spacing of the sinkholes; The catchment area u6 is the product of the straight-line distance from the watershed above the top of the slope to the foot of the slope in the representative section of the slope to be evaluated and the unit width, wherein gentle slopes with a slope of less than 3 degrees are not included; The calculation formula (6) for the rainwater collection area is: s=d×w(6) Where d is the straight-line distance from the watershed above the top of the slope to the foot of the slope, w is the unit width, and w is taken as 1m; The chemical dispersion of the slope soil, u7, is the percentage value of the exchangeable sodium ions of the slope to be evaluated. The calculation formula (7) of the chemical dispersion of the slope soil is: （7） Among them, P ES is the percentage value of exchangeable sodium ions of the slope to be evaluated, b(Na,exch) is the exchangeable sodium ion content, and CEC is the cation exchange capacity; The slope stability coefficient u8 is the stability coefficient of the slope to be evaluated calculated by the Bishop method, the calculation adopts the saturated quick shear index of the direct shear test, and the profile adopts the representative profile of the slope to be evaluated obtained by measurement; The water flow velocity u9 is the measured water flow velocity at the intersection of the representative profile of the slope to be evaluated and the water surface.

5. The method for evaluating the stability of water-bearing clayey soil slope according to claim 4, characterized in that: The sampling locations of the slope sampling points to be evaluated include the toe of the slope and the water surface. There are two initial sampling points at each location, which are 0.5m and 1.0m deep perpendicular to the slope. When the difference between the water surface elevation H1 and the toe elevation H2 of the slope is greater than 20m, one sampling location is added at the toe elevation H2 and the water surface elevation H1. All sampling locations divide the toe elevation H2 and the water surface elevation H1 equally, and the sampling point depth is the same as other locations.

6. The method for evaluating the stability of a clayey soil slope near water according to claim 4, characterized in that: The dispersion D of the u-th sampling point of the slope to be evaluated u The calculation formula is: （8） Among them, D u is the dispersion of the u-th sampling point of the slope to be evaluated, Ps1 is the content of particles smaller than 0.05 mm when no dispersant is added, and Ps2 is the content of particles smaller than 0.05 mm when no dispersant is added; When the sampling point of the slope to be evaluated is non-dispersed soil, the treatment coefficient Ku=1; when the sampling point of the slope to be evaluated is transitional soil, the treatment coefficient Ku=1.5; when the sampling point of the slope to be evaluated is physically dispersed soil, the treatment coefficient Ku=2.0; when the sampling point of the slope to be evaluated is chemically dispersed soil, the treatment coefficient Ku=2.5; when the sampling point of the slope to be evaluated is physically-chemically dispersed soil, the treatment coefficient Ku=3.

0.

7. The method for evaluating the stability of water-bearing clayey soil slope according to claim 4, characterized in that: The number of sinkholes is W, the location of the sinkholes is A, the average volume of the sinkholes is V, and the average distance between the sinkholes is S, then: When W≤3, D1 takes the value of 3; When 3<W≤7, D1 takes the value of 5; When 7<W≤15, D1 takes the value of 7; When W>15, D1 takes the value of 10; When the sinkhole position A is below the water surface, D2 takes the value of 10; When the sinkhole position A is above the water surface, D2 takes the value of 5; When V≤3, D3 takes the value of 3; When 3<V≤7, D3 takes the value of 5; When 7<V≤15, D3 takes the value of 7; When V>15, D3 takes the value of 10; When S≤5, D4 takes the value of 3; When 5<S≤10, D4 takes the value of 5; When 10<S≤20, D4 takes the value of 7; When S>20, D4 takes the value of 10.

8. The method for evaluating the stability of a clayey soil slope near water according to claim 4, characterized in that: In step S3, the slope clay soil water sensitivity u1 is assigned: When u1≤0.25, the score value Ui1 of slope clay soil water sensitivity is 1; When 0.25<u1≤0.5, the score value Ui1 of slope cohesive soil water sensitivity is 2; When 0.5<u1≤0.75, the score value Ui1 of slope cohesive soil water sensitivity is 3; When u1>0.75, the score value Ui1 of slope cohesive soil water sensitivity is 4; Assign a value to the rainfall intensity coefficient u2: When u2≤200, the score value Ui2 of the rainfall intensity coefficient is 1; When 200<u2≤300, the score value Ui2 of the rainfall intensity coefficient is 2; When 300<u2≤400, the score value Ui2 of the rainfall intensity coefficient is 3; When u2>400, the score value Ui2 of the rainfall intensity coefficient is 4; Assign a value to the dispersion u3 of the slope clay soil: When u3≤0.5, the score value Ui3 of the dispersion of slope clay soil is 1; When 0.5<u3≤1.25, the score value Ui3 of the dispersion of slope clay soil is 2; When 1.25<u3≤2, the score value Ui3 of the dispersion of slope clay soil is 3; When u3>2, the score value Ui3 of the dispersion of slope clay soil is 4; Assign a value to the collapsibility u4 of the clay soil of the slope: When u4≤50, the score value Ui4 of the collapsibility of the clayey soil of the slope is 1; When 50<u4≤100, the score value Ui4 of the collapsibility of the clayey soil of the slope is 2; When 100<u4≤200, the score value Ui4 of the collapsibility of the clayey soil of the slope is 3; When u4>200, the score value Ui4 of the collapsibility of the slope clay soil is 4; Assign a value to the slope flatness u5: When u5≤500, the slope flatness score Ui5 is 1; When 500<u5≤1500, the slope flatness score Ui5 is 2; When 1500<u5≤5000, the slope flatness score Ui5 is 3; When u5>5000, the slope flatness score Ui5 is 4; Assign a value to the rainwater collection area u6: When u6≤20, the score value Ui6 of the catchment area is 1; When 20<u6≤50, the score value Ui6 of the catchment area is 2; When 50<u6≤100, the score value Ui6 of the catchment area is 3; When u6>100, the score value Ui6 of the catchment area is 4; Assign a value to the chemical dispersion u7 of the slope soil: When u7≤7, the score value Ui7 of the chemical dispersion of the slope soil is 1; When 7<u7≤11, the score value Ui7 of the chemical dispersion of the slope soil is 2; When 11<u7≤15, the score value Ui7 of the chemical dispersion of the slope soil is 3; When u7>15, the score value Ui7 of the chemical dispersion of the slope soil is 4; Assign a value to the slope stability coefficient u8: When u8>1.2, the score value Ui8 of the slope stability coefficient is 1; When 1.0<u8≤1.2, the score value Ui8 of the slope stability coefficient is 2; When 0.8<u8≤1.0, the score value Ui8 of the slope stability coefficient is 3; When u8≤15, the score value Ui8 of the slope stability coefficient is 4; Assign a value to the water flow rate u9: When u9≤3, the water flow rate score Ui9 takes the value of 1; When 3<u9≤8, the water flow rate score Ui9 is 2; When 8<u9≤15, the water flow rate score Ui9 is 3; When u9>15, the water flow rate score Ui9 is 4.

9. The method for evaluating the stability of water-bearing clayey soil slope according to claim 8, characterized in that: In step S4, the calculation formula (9) of the stability U of the water-bound clay slope to be evaluated is: U=Ui1+Ui2+Ui3+Ui4+Ui5+Ui6+Ui7+Ui8+Ui9 (9).

10. The method for evaluating the stability of clay soil slope near water according to claim 1, characterized in that: In step S5, the stability of the water-bearing clay slope is evaluated according to the score of the stability U, including: When U≤12, the stability assessment result of the clay soil slope near water is low risk; When 12<U≤20, the stability assessment result of the clay soil slope near water is medium risk; When 20<U≤28, the stability assessment result of the clay soil slope near water is medium-high risk; When U>28, the stability assessment result of the clayey soil slope near water is high risk.

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