Waste slag storage yard slope stability evaluation and analysis method considering material static liquefaction instability

Abstract

The invention discloses a waste slag storage yard slope stability evaluation and analysis method considering material static liquefaction instability, and the method comprises the steps: obtaining related mechanical parameters of a waste slag storage yard slope with a potential liquefaction region; constructing an elastic-plastic constitutive model, and carrying out iterative calculation on the elastic-plastic constitutive model into which the related mechanical parameters are substituted through an optimization algorithm to obtain optimal simulation parameters; determining a critical state line and an unstable line in a stress space according to the optimal simulation parameters and related mechanical parameters; analyzing the side slope of the waste slag storage yard through a strip division method and an effective stress analysis method to obtain effective stress states of related points on different slip planes; according to the critical state line and the unstable line in the stress space, the effective stress state of each point in the side slope is used for static liquefaction instability possibility judgment, and then the potential liquefaction instability area of the side slope is obtained; and according to the potential liquefaction instability area of the side slope, the waste slag storage yard side slope with the potential liquefaction area is evaluated, so that the safety coefficient of the waste slag storage yard side slope considering the static liquefaction instability characteristic of the material is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of slope stability assessment and analysis, and in particular relates to a method for assessing and analyzing the stability of a slag dump slope taking into account static liquefaction instability of materials. Background Art

[0002] The terrain in my country is undulating, especially at the intersection of the second and third steps. Due to the undulating terrain, it is inevitable to transform the terrain during engineering construction. The transformation of the terrain results in a huge amount of earth and stone excavation, and the huge amount of earth and stone backfill will form a waste dump for the project. Affected by the complex changes in hydraulic conditions, the loose backfill may undergo static liquefaction, which will not only reduce the stability of the slope of the waste dump, but also cause its overall instability. The damage of the slope of the waste dump is highly concealed and may cause large-scale deformation, which will have a great impact on engineering safety and personal safety. The previous slope stability analysis method ignored the static liquefaction instability that may occur before the damage of the slope of the waste dump, resulting in a high safety factor in the slope stability analysis. Part of the soil of the slope of the waste dump may produce static liquefaction under the action of static loads such as self-weight load and overburden pressure. Therefore, when analyzing the slope of the waste dump, its potential liquefaction area must be considered. Static liquefaction will cause the soil in this area to become unstable before reaching the ultimate strength. Therefore, it is necessary to consider the static liquefaction of slag when analyzing the stability of the slag dump slope. The strength parameters in the potential static liquefaction area should adopt the mechanical parameters corresponding to its unstable state. However, in the existing technology, the influence of static liquefaction of slag on the stability of the slag dump slope is not considered, resulting in inaccurate assessment and analysis of the slag dump slope stability. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a method for evaluating and analyzing the slope stability of a slag dump taking into account the static liquefaction instability of materials, so as to solve the problems existing in the above prior art.

[0004] To achieve the above object, the present invention provides a method for evaluating and analyzing the slope stability of a slag dump considering static liquefaction instability of materials, comprising:

[0005] Obtain relevant mechanical parameters of the spoil dump slopes in potential liquefaction areas;

[0006] Constructing an elastic-plastic constitutive model, bringing the relevant mechanical parameters into the elastic-plastic constitutive model, and iteratively calculating the elastic-plastic constitutive model with the relevant mechanical parameters through an optimization algorithm to obtain optimal simulation parameters;

[0007] According to the optimal simulation parameters and related mechanical parameters, the critical state line and the instability line are constructed;

[0008] The slope of the waste dump is analyzed by the strip method and the effective stress analysis method to obtain the stress state of the effective stress points on different sliding surfaces;

[0009] According to the critical state line and the unstable line, the potential unstable area is obtained. According to the potential unstable area, the stress state of the effective stress point is judged, and based on the judgment result, the potential liquefaction area of ​​the slope is obtained;

[0010] According to the potential liquefaction area of ​​the slope, the slope of the waste dump with potential liquefaction area is evaluated to obtain the safety factor of the slope of the waste dump.

[0011] Optionally, the elastic-plastic constitutive model adopts an improved Mohr-Coulomb elastic-plastic hardening model, and the improved Mohr-Coulomb elastic-plastic hardening model is obtained by adding an equivalent particle state parameter of an equivalent porosity ratio to the Mohr-Coulomb elastic-plastic hardening model.

[0012] Optional, equivalent particle state parameters are:

[0013]

[0014] in, is the equivalent particle porosity ratio of the current state of the spoil heap; is the critical state equivalent particle porosity ratio.

[0015] Optionally, the optimization algorithm adopts a particle swarm optimization algorithm.

[0016] Optionally, the process of judging the stress state of the effective stress point includes:

[0017] Perform inequality judgment on the effective stress points in the potential unstable area, obtain all the effective stress points that meet the inequality judgment, and mark them in the cross-sectional diagram corresponding to the slope of the waste dump, and draw the potential liquefaction area of ​​the slope based on the marking results;

[0018] The inequality is where τ is the shear stress, σ i is the normal stress on the slip surface of soil strip i, c i ' is the cohesion on the slip surface of soil strip i, is the angle of internal friction.

[0019] Optionally, the process of evaluating the potential liquefaction area of ​​the slope includes:

[0020] The safety factor of the slope of the waste dump in the potential liquefaction area is calculated by the safety factor calculation model, and the safety factor of the slope of the waste dump is obtained;

[0021] The safety factor calculation model is:

[0022]

[0023] Among them, F represents the safety factor, i represents the soil strip number, n represents the total amount of soil strips, and c i is the cohesion on the slip surface of soil strip i. When the soil strip is in the potential liquefaction area, the strength parameter corresponding to the unstable line is used; is the internal friction angle on the sliding surface of soil strip i. When the soil strip is in the potential liquefaction area, the strength parameter corresponding to the unstable line is used. p i represents the thrust on the side of soil strip i, θ represents the angle between soil strip i and the horizontal direction, α i represents the bottom inclination angle of soil strip i, W i represents the gravity of soil strip i, l i Represents the bottom length of soil strip i.

[0024] Optionally, for the waste dump slope where there is no potential liquefaction area of ​​the slope, a conventional safety factor calculation formula is used for calculation.

[0025] Optionally, before obtaining the relevant mechanical parameters of the spoil dump slope with potential liquefaction area, the following steps are also included:

[0026] Conduct geological surveys on the slopes of the waste dump and judge the slopes of the waste dump based on the results of the geological survey to obtain the slopes of the waste dump with potential liquefaction areas.

[0027] Compared with the prior art, the present invention has the following advantages and technical effects:

[0028] 1) First, conduct a geological survey on site and use general knowledge to exclude soil layers that are unlikely to undergo static liquefaction, thereby reducing the search scope of potential unstable areas, reducing the workload, and finding potential unstable areas efficiently and quickly;

[0029] 2) Static liquefaction is considered when analyzing the stability of the slope. By considering static liquefaction, the problem of high safety factor caused by the existing landslide stability analysis method can be avoided, and a slope safety factor closer to the actual engineering situation can be obtained. When considering the unstable area, the present invention adopts the Mohr-Coulomb elastic-plastic hardening model, which is more suitable for the analysis of the slope of the waste dump, and the model is based on the equivalent particle porosity e * The equivalent particle state parameter ψ * Improvements to the general constitutive model. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0031] Figure 1 is a flow chart of an embodiment of the present invention;

[0032] Figure 2 A slope diagram of a waste dump according to an embodiment of the present invention;

[0033] Figure 3 A potential unstable area map of the soil mass on the slope of the waste dump according to an embodiment of the present invention;

[0034] Figure 4 A relationship diagram between the stress state of soil on each sliding surface of the waste dump slope and the potential unstable area according to an embodiment of the present invention;

[0035] Figure 5 A detailed diagram showing the relationship between the stress state and the instability line of the soil on each sliding surface of the waste dump slope according to an embodiment of the present invention;

[0036] Figure 6 A potential liquefaction area map of a slope according to an embodiment of the present invention;

[0037] Figure 7 This is a slope safety factor diagram considering static liquefaction according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0040] The present invention provides a method for evaluating and analyzing the stability of a slag dump slope taking into account the static liquefaction instability of materials. Through on-site geological surveys and tests on the mechanical properties of slag, the relevant mechanical parameters of the soil of the slag dump slope are obtained, and the optimal solution of other mechanical parameters of the slag is obtained by inverse calculation using a particle swarm optimization algorithm combined with a material state-related critical state constitutive model based on the Mohr-Coulomb criterion. The above parameters are used for analysis to obtain the critical state line and the instability line of the soil of the slag dump slope. According to the critical state line and the instability line, the stress state of the slag dump slope is compared to determine the potential liquefaction area in the slope, and then the slope safety factor considering the potential liquefaction area of ​​the slope is calculated, and compared with the ordinary safety factor to achieve a reasonable assessment of the stability of the slope. The advantage of the present invention is that the static liquefaction characteristics of the slag are taken into account, and a safety factor that is closer to the actual situation can be obtained for the slag dump slope under the conditions of complex changes in the hydraulic environment.

[0041] The technical problem to be solved by the present invention is how to provide a method for evaluating and analyzing the stability of a storage yard slope taking into account the influence of the static liquefaction instability characteristics of engineering waste slag.

[0042] In order to solve the above technical problems, the present invention provides a method for evaluating and analyzing the stability of a slag dump slope considering the static liquefaction instability of materials. The relevant mechanical parameters of the soil of the slag dump slope are obtained through on-site geological survey and slag mechanical property test. The optimal solution of other parameters of the slag material is obtained by back-calculating through a particle swarm optimization algorithm combined with a material state-related critical state elastoplastic constitutive model based on the Mohr-Coulomb criterion, and the critical state line and instability line of the slag are obtained through the above parameters. According to the critical state line and the instability line, the potential liquefaction area inside the slope is determined by comparing the stress state of the slope, and then the safety factor considering the potential liquefaction area of ​​the slope is calculated. The specific steps are as follows:

[0043] Step S1: Determine whether there is a potential liquefaction area through on-site geological survey; if a potential liquefaction area is found, a slope stability assessment and analysis method for the abandoned slag dump considering the static liquefaction instability characteristics is adopted; if there is no potential liquefaction area, a conventional analysis method is adopted;

[0044] Step S2: Through the mechanical property test of the spoil, combined with the results of geological survey and on-site scientific investigation, the relevant mechanical parameters of the spoil dump slope soil, including internal friction angle, cohesion, etc., are obtained; then the relevant mechanical parameters of the spoil dump slope soil are substituted into the elastic-plastic constitutive model that is more suitable for the spoil dump slope analysis, and the particle swarm optimization algorithm is used to iteratively calculate the elastic-plastic constitutive model with the mechanical parameters substituted into the mechanical parameters to obtain the optimal solution of other parameters, that is, the optimal simulation parameters, that is, the particle swarm optimization algorithm is used to calculate the analytical solution of other parameters. If the analytical solution of other parameters is not the optimal solution, the particle swarm optimization algorithm is performed again until the optimal solution of other parameters is obtained; Table 1 shows the coordinate range of the optimal solution of the model parameters.

[0045] Table 1

[0046] parameter <![CDATA[G0]]> v <![CDATA[n b ]]> <![CDATA[n d ]]> <![CDATA[d0]]> A scope 50-150 0.01-0.20 1.0-2.0 1.0-5.0 0.5-1.0 0-0.005

[0047] Step S3: Determine the critical state line and instability line of the soil of the spoil dump slope by using the above-mentioned soil-related mechanical parameters and optimal simulation parameters, and use the strip method and effective stress analysis method to analyze different sliding surfaces of the spoil dump slope, so as to determine the stress state of the effective stress points in different sliding surfaces of the spoil dump slope;

[0048] Step S4: Based on the critical state line and the unstable line, a potential unstable area is divided. In the potential unstable area, the stress state of the potential instability is compared with the stress state of the effective stress point in the soil of the slope of the waste dump to determine the potential liquefaction area of ​​the slope;

[0049] Step S5: Based on the potential liquefaction area, different mechanical parameters are respectively introduced into the slope safety factor calculation formula to calculate, and the safety factor of the waste dump slope is obtained, and then compared with the slope safety factor without considering static liquefaction, so as to evaluate the slope stability.

[0050] The step S1 is specifically as follows: when conducting geological survey, a detailed analysis is conducted on the soil parameters of the slope of the waste dump, which requires understanding the type and thickness of the overburden layer under the project, and excluding soil layers that are unlikely to undergo static liquefaction through general knowledge, thereby reducing the search range of potential unstable areas, thereby achieving the goal of reducing the workload while efficiently finding potential unstable areas.

[0051] The constitutive model of step S2 is an improvement on the Mohr-Coulomb elastic-plastic hardening model and is more suitable for the analysis of the slope of the waste dump. * The equivalent particle state parameter ψ * Add what you get;

[0052] When the fine particle content in the waste dump increases, the particle size distribution and inter-particle contact of the soil sample change. The void ratio e based on the equivalent particle pore size is used. * Equivalent material state parameter ψ * is a better choice.

[0053] Equivalent particle state parameter ψ * The calculation formula is:

[0054] in: is the equivalent particle porosity ratio of the waste slag pile in the current state; is the critical state equivalent particle porosity ratio.

[0055] For different particle characteristics, e * Obtained through the following formula:

[0056]

[0057] Where: is the equivalent particle porosity ratio; is the equivalent fine particle porosity ratio; m is determined by the particle characteristics and is between 0 and 1; f c represents the particle content, b represents the proportion of fine particles participating in the structural strength effect, e represents the porosity of the clay itself, and R d represents the adsorption retardation factor, f thre Indicates the critical fine particle content.

[0058]

[0059] Where: k = 1-r 0.25 ; b is the proportion of fine particles participating in the structural strength effect, n b is the fitting parameter; r = 1 / χ, r is the particle size ratio, χ is the particle size ratio, χ = D 10 / d 50 ;D 10 is the effective particle size of sand; d 50 is the average particle size of fine particles. ; μ is the fitting parameter, which is taken as 0.30; n b is the fitting parameter and takes 1.

[0060] You can use e c You can also use e * -(p' / p a ) ξ The equivalent particle critical state line in the plane is determined. p' represents the average normal stress, p a is the standard atmospheric pressure, ξ * is a dimensionless material constant, different fine particle contents f cThe samples have the same equivalent particle critical state line.

[0061]

[0062] in, is the slope of the critical state line, p' represents the average normal stress, and p a is the standard atmospheric pressure, ξ * is the dimensionless material constant,

[0063] The yield function F is proposed based on the widely used Mohr-Coulomb elastoplastic constitutive model, and its yield function is:

[0064] F=q-Mp'=0

[0065] Where: p' = σ ij / 3-u; s' ij =σ' ij -δ ij p';σ' ij =σ ij -u; u is the pore water pressure; δ ij is the Knerok symbol, σ ij represents the stress in the i-th direction corresponding to the j-th direction, s' ij represents the strain in the i-th direction corresponding to the j-th direction, the superscript ' represents the parameter after removing the pore water pressure, q represents the shear stress, and p' represents the effective average normal stress.

[0066] Pietruszczak and Stolle assumed that M obeys the hyperbolic law to describe the hardening phenomenon of the specimen more accurately:

[0067]

[0068] Where: M represents the pressure ratio, M P represents the pressure ratio coefficient, e ij =ε ij -δ ij ε ii / 3; A is the fitting parameter.

[0069] Assume M p is related to the equivalent state (Bouferra, 2004), and its expression is:

[0070] M P =M CS exp(-n b ψ * )

[0071] Where: M CSis the stress ratio under critical state; n b is the material parameter describing the dilatancy.

[0072] The plastic potential function is a description of the dilatancy of the soil. The rationality of the dilatancy description is related to the accuracy of the model. The expression of the dilatancy D of the soil sample is:

[0073]

[0074] Where:

[0075] Usually, there is a unique functional relationship between stress ratio and dilatancy. However, for loose specimens and compact specimens made of the same type of sand, when the same stress ratio load is applied to them, it is found that the loose specimen shrinks while the compact specimen expands. Subsequent studies have found that the dilatancy of sand is closely related to the state parameters in addition to the stress ratio. In order to reflect the influence of the material state, Li, Dafalias, Gajo, etc. added the state parameters to the stress-dilatancy function. In order to reflect the influence of fine particles, the state parameters were replaced by equivalent material state parameters, that is:

[0076] D=A d [M d -M]=A d [M CS exp(n d ψ * )-M]

[0077] Where: A d =d0 / M cs is the fitting parameter; d0 is the material parameter; n d Peak stress ratio material parameter.

[0078] Assumption A d = 1 to simplify the formula, it is not difficult to find that the simplified formula is the same as the dilatancy function in the Cambridge model, and the formula can be expressed by the plastic potential function equivalent to Q, that is:

[0079]

[0080] Based on the above theory, the elastic-plastic constitutive equation in rate form can be obtained:

[0081]

[0082] Where: is the stress rate, is the strain rate, ε is the elastic-plastic modulus tensor.

[0083] The bulk modulus K and shear modulus G are:

[0084]

[0085] Where v represents Poisson’s ratio, P at Indicates standard atmospheric pressure.

[0086] There are eleven mechanical parameters of the spoil dump slope soil in the constitutive model, namely: critical fine particle content f thre , the proportion of fine particles participating in the structural strength effect b, material constant G0; Poisson's ratio v; for The slope of the critical state line on the plane; Critical state line intercept on the plane; dimensionless material constant ξ * ; Fitting parameter n b , usually 1; fitting parameter n d ; Average pore diameter d0 of soil; Fitting parameter A; Where: f thre a (critical fine particle content) and b (proportion of fine particles participating in the structural strength effect) are calculated based on the particle size ratio of the soil samples.

[0087] Through the mechanical property test of the indoor waste slag, that is, the CU test of the waste slag, the average effective normal stress and porosity of the waste slag are fitted to obtain the critical state line of the equivalent particles, and then the slope of the critical state line is obtained. Critical state line intercept Dimensionless material constant ξ * For material constant G0, Poisson's ratio v, fitting parameter n b , fitting parameter n d The five parameters of the average pore diameter d0 of the soil are obtained by fitting the improved Mohr-Coulomb elastic-plastic hardening model through iterative calculation by optimization algorithm. The fitting parameter A can be obtained by fitting the fitting results of the above five parameters.

[0088] Critical state equivalent particle porosity The calculation formula is:

[0089] Where: p a is the standard atmospheric pressure, and p' is the mean normal stress.

[0090] Step S3 specifically involves drawing a critical state line of the waste slag based on relevant test results. The instability line of the spoil is often difficult to obtain directly. Based on the mechanical characteristic parameters of the spoil, the constitutive model and particle swarm optimization algorithm can be used to reversely analyze the model simulation parameters of the spoil pile slope soil, thereby determining the slope of the instability line in stress space. By using the strip method and effective stress analysis method, the sliding surfaces of the spoil pile slope are analyzed to determine the stress state in the spoil pile slope.

[0091] Step S4 specifically includes marking the effective stress state points on each slip surface in the potential unstable area map, and obtaining a relationship diagram between the stress state of the soil on the slip surface of the spoil dump slope and the potential unstable area. According to the relationship diagram between the stress state of the soil on the slip surface of the spoil dump slope and the potential unstable area, when the soil on the spoil dump slope is in the potential unstable area, the points on the slip surface satisfy Where τ is the shear stress, σ i is the normal stress on the slip surface of soil strip i, c i ' is the cohesion on the sliding surface of soil strip i, is the internal friction angle.

[0092] The inequality is used to draw a detailed diagram of the relationship between the stress state and the instability line at different points on the slip surface of the spoil dump slope. According to the relationship between the stress state and the instability line of the spoil dump slope soil at each point on the slip surface in the diagram, all points that satisfy the above equation are found and marked on the spoil dump slope soil diagram. Then, the potential liquefaction area map of the slope is obtained by drawing the approximate location of the potential liquefaction area in the slope.

[0093] The step S5 specifically includes bringing different soil mechanical parameters into the overall safety factor calculation formula considering the static liquefaction of the slope to obtain the slope safety factor.

[0094] The safety factor of the slope is calculated as:

[0095]

[0096] Where: c i is the cohesion on the slip surface of soil strip i. When the soil strip is in the potential liquefaction zone, the strength parameter corresponding to the unstable line is used; is the internal friction angle on the sliding surface of soil strip i. When the soil strip is in the potential liquefaction zone, the strength parameter corresponding to the unstable line is used. p i represents the thrust on the side of soil strip i, θ represents the angle between soil strip i and the horizontal direction, α i represents the inclination angle of the bottom surface of soil strip i (i.e. the angle between the bottom surface of soil strip and the horizontal direction), W i represents the gravity of soil strip i, l i represents the bottom length of soil strip i;

[0097] The safety factor of the slag dump slope obtained by considering static liquefaction instability is then compared with the corresponding safety factor without considering static liquefaction instability, thereby evaluating the stability of the slope.

[0098] The relevant technical solutions of the present invention are described in detail with reference to the relevant drawings:

[0099] like Figure 1-Figure 7As shown, the present invention provides a method for evaluating and analyzing the stability of a storage yard slope considering the static liquefaction instability of engineering waste slag, and the specific steps are as follows:

[0100] Step S1: Conduct geological survey on site, first exclude the parts that are unlikely to undergo static liquefaction: attachments on the slope are not considered to undergo static liquefaction; part of the soil is a silt layer, which also does not need to be considered to undergo static liquefaction.

[0101] The static liquefaction considered in this invention is only for non-cohesive soil. For areas without potential liquefaction, conventional slope stability analysis methods are used for analysis, that is, conventional safety factor calculation formula is used. Perform calculations.

[0102] The slope of the embodiment of the present invention is as follows Figure 2 As shown, the slope angle α = 26.6° and the height h = 45.7m. For the spoil dump slope soil with potential liquefaction area, the spoil dump slope stability assessment and analysis method considering the static liquefaction instability characteristics is used for analysis, that is, when calculating the safety factor for the slope stability analysis of the soil strip in the potential liquefaction area, the soil mechanical parameters corresponding to the instability line are used.

[0103] Step S2: Through the mechanical property test of the waste slag, the relevant mechanical parameters of the soil body on the slope of the waste slag dump are obtained, including the effective internal friction angle and the effective cohesion; the effective cohesion of the soil body on the slope of the waste slag in the embodiment of the present invention is c'=0kPa, the effective internal friction angle is Other parameters are porosity e = 0.89, dry weight γ d =13.75kN / m 3 , saturation S r =97%, soil weight γ t =18.22kN / m 3 The safety factor of the slope of the waste dump without considering static liquefaction is

[0104] Step S3: Draw the critical state line of the soil layer according to the effective mechanical parameters. The instability line of the waste material cannot be directly obtained. Based on the material state-related critical state elastoplastic constitutive model established based on the Mohr-Coulomb criterion, the model parameters of the waste are back-calculated by the particle swarm optimization algorithm, and the instability line of the waste is obtained after the model parameters are back-calculated. The instability line and critical state line of the waste are shown in Figure 3 As shown. Figure 2 The various sliding surfaces of the waste dump slope in the calculation are analyzed and the following are obtained: Figure 4 The relationship between the stress state of the soil mass on the slope of the waste dump and the unstable area on the sliding surface is shown in Figure 4It can be seen that when the stress point in the slope of the waste dump is in the potential unstable area, the stress state of the soil at this location satisfies

[0105] Step S4: Draw the stress state and instability line relationship details of different points on the slope sliding surface of the waste dump through the inequality of step S3, such as Figure 5 As shown in the figure, according to the detailed relationship between the stress state of the soil mass of the spoil dump slope at each point on the slip surface and the instability line, all points that satisfy the above formula are found and marked on the spoil dump slope soil map. Then, by drawing the position of the potential liquefaction area in the slope, the potential liquefaction area map of the slope is obtained, as shown in Figure 6 shown.

[0106] Step S5: Calculate the overall safety factor of the spoil dump slope as follows:

[0107]

[0108] For the waste slag in the potential liquefaction area, it should be noted that the mechanical parameters of the plastic limit state of the waste slag should not be used. The mechanical parameters corresponding to their instability lines should be substituted into the overall safety factor calculation formula, because this part of the waste slag cannot reach its ultimate strength, and it is very likely that static liquefaction will occur before reaching the ultimate strength, resulting in a decrease in the strength of the waste slag. Therefore, conventional mechanical parameters different from the plastic limit state should be used for calculation. The waste slag that is not in the potential liquefaction area is calculated using conventional mechanical parameters, and the final safety factor is 1.039. When the ratio is greater than 1, the slope is stable; when it is equal to 1, the slope is in a limit equilibrium state; when it is less than 1, the slope is damaged.

[0109] The comparison shows that after considering the influence of static liquefaction, the overall stability safety factor of the slope has decreased significantly compared with the previous situation, and the most dangerous sliding surface of the analysis method considering static liquefaction has also moved downward compared with the analysis method without considering static liquefaction. Figure 7 ,It can be seen from the figure that the potential liquefaction area of ​​the slope contains most of the most dangerous sliding surface.

[0110] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for evaluating and analyzing the slope stability of a slag dump considering the static liquefaction instability of materials, characterized in that: include: Obtain relevant mechanical parameters of the spoil dump slopes in potential liquefaction areas; Constructing an elastic-plastic constitutive model, bringing the relevant mechanical parameters into the elastic-plastic constitutive model, and iteratively calculating the elastic-plastic constitutive model with the relevant mechanical parameters through an optimization algorithm to obtain optimal simulation parameters; According to the optimal simulation parameters and related mechanical parameters, the critical state line and the instability line are constructed; The slope of the waste dump is analyzed by the strip method and the effective stress analysis method to obtain the stress state of the effective stress points on different sliding surfaces; According to the critical state line and the unstable line, the potential unstable area is obtained. According to the potential unstable area, the stress state of the effective stress point is judged, and based on the judgment result, the potential liquefaction area of ​​the slope is obtained; According to the potential liquefaction area of ​​the slope, the slope of the waste dump with potential liquefaction area is evaluated to obtain the safety factor of the slope of the waste dump.

2. The method according to claim 1, characterized in that The elastic-plastic constitutive model adopts an improved Mohr-Coulomb elastic-plastic hardening model, and the improved Mohr-Coulomb elastic-plastic hardening model is obtained by adding an equivalent particle state parameter of an equivalent porosity ratio to the Mohr-Coulomb elastic-plastic hardening model.

3. The method according to claim 1, characterized in that The equivalent particle state parameters are: in, is the equivalent particle porosity ratio of the current state of the spoil heap; is the critical state equivalent particle porosity ratio.

4. The method according to claim 1, characterized in that: The optimization algorithm adopts particle swarm optimization algorithm.

5. The method according to claim 1, characterized in that The process of judging the stress state of the effective stress point includes: Perform inequality judgment on the effective stress points in the potential unstable area, obtain all the effective stress points that meet the inequality judgment, and mark them in the cross-sectional diagram corresponding to the slope of the waste dump, and draw the potential liquefaction area of ​​the slope based on the marking results; The inequality is where τ is the shear stress, σ i is the normal stress on the slip surface of soil strip i, c i ' is the cohesion on the slip surface of soil strip i, is the angle of internal friction.

6. The method according to claim 1, characterized in that The process of assessing the potential liquefaction area of ​​the slope includes: The safety factor of the slope of the waste dump in the potential liquefaction area is calculated by the safety factor calculation model, and the safety factor of the slope of the waste dump is obtained; The safety factor calculation model is: Among them, F represents the safety factor, i represents the soil strip number, n represents the total amount of soil strips, and c i is the cohesion on the slip surface of soil strip i. When the soil strip is in the potential liquefaction area, the strength parameter corresponding to the unstable line is used; is the internal friction angle on the sliding surface of soil strip i. When the soil strip is in the potential liquefaction area, the strength parameter corresponding to the unstable line is used. p i represents the thrust on the side of soil strip i, θ represents the angle between soil strip i and the horizontal direction, α i represents the bottom inclination angle of soil strip i, W i represents the gravity of soil strip i, l i Represents the bottom length of soil strip i.

7. The method according to claim 1, characterized in that For the waste dump slope where there is no potential liquefaction area, the conventional safety factor calculation formula is used for calculation.

8. The method according to claim 1, characterized in that Before obtaining the relevant mechanical parameters of the spoil dump slope with potential liquefaction area, the following are also included: Conduct geological surveys on the slopes of the waste dump and judge the slopes of the waste dump based on the results of the geological survey to obtain the slopes of the waste dump with potential liquefaction areas.

Images