A method and system for designing adjacent foundation pits based on mobilization strength theory

Abstract

The present invention relates to the technical field of foundation pit engineering, and discloses a method and system for designing adjacent foundation pits based on mobilization strength theory, the method comprising: calculating the passive zone soil shear strain of adjacent foundation pits according to the respective wall displacements of adjacent foundation pits; calculating the soil shear strain between pits of adjacent foundation pits according to the influence range of the soil shear strain between pits of adjacent foundation pits; calculating the passive zone and the soil mobilization shear stress between pits according to the passive zone and the soil shear strain between pits, combined with mobilization strength theory; calculating the passive zone horizontal earth pressure and the horizontal earth pressure between pits on the walls of adjacent foundation pits; and then calculating the first wall bending moment of adjacent foundation pits that meets the stability requirement; calculating the second wall bending moment of adjacent foundation pits that meets the deformation requirement; calculating the wall bending moment difference of adjacent foundation pits, and judging whether the wall bending moment difference meets the threshold requirement. The present invention can realize the synchronous calculation of deformation and stability of adjacent foundation pits, and realize the overall design of adjacent foundation pits through the synchronous solution of adjacent foundation pits.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit engineering, and in particular to a method and system for designing adjacent foundation pits based on mobilization strength theory. Background Art

[0002] With the acceleration of the development of urban underground space, the construction scale of foundation pits has developed from single pits to multiple pits, and the construction mode has changed from independent to integrated. The excavation of adjacent foundation pits is common. Compared with single foundation pits, the deformation and stability mechanism of adjacent foundation pits are special. The soil deformation area caused by the excavation of adjacent foundation pits is affected by the excavation of two foundation pits, resulting in the superposition of soil deformation of adjacent foundation pits. In addition, the soil unloading caused by unilateral foundation pit excavation and the balance of the support system will affect the stability of adjacent foundation pits. Therefore, the stability of the support system of adjacent foundation pits is related.

[0003] At present, the current design specification "Technical Code for Building Foundation Pit Support" (JGJ120-2012) cannot design adjacent foundation pits as a whole, and can only design them as two single foundation pits independently, ignoring the mutual influence between deformation and stability of adjacent foundation pits, resulting in frequent collapse accidents. The existing technology has made scheme improvements for the design method of adjacent foundation pits. For example, the non-limiting earth pressure model is used to consider the influence of the limited width of the soil between adjacent foundation pits on the soil pressure, but the deformation superposition characteristics of the soil between pits caused by the excavation of adjacent foundation pits are ignored; by establishing a parametric family library of foundation pits and combining finite element analysis and simulation technology, BIM forward design is performed on adjacent foundation pits, but each change in the design scheme requires reconstruction and prediction simulation of the numerical model, resulting in high calculation cost and low design efficiency.

[0004] Therefore, there is an urgent need for a design method and system for adjacent foundation pits based on the mobilization strength theory, which can realize the synchronous calculation of foundation pit deformation and stability, and then consider the characteristics of the superposition of deformation and stability association of adjacent foundation pits, and realize the overall design of adjacent foundation pits through the synchronous solution of adjacent foundation pits. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method and system for designing adjacent foundation pits based on the mobilized strength theory, which can realize the synchronous calculation of foundation pit deformation and stability, and then consider the characteristics of the superposition of deformation and stability association of adjacent foundation pits, and realize the overall design of adjacent foundation pits through the synchronous solution of adjacent foundation pits.

[0006] The present invention provides a method for designing adjacent foundation pits based on mobilization strength theory, comprising the following steps:

[0007] S1. synchronously calculating the soil shear strains in the passive zones of the adjacent foundation pits according to the wall displacements of the adjacent foundation pits; wherein the adjacent foundation pits include foundation pit A and foundation pit B;

[0008] S2. Calculate the shear strain of the soil between the adjacent foundation pits according to the zoning conditions of the shear strain influence range of the soil between the adjacent foundation pits;

[0009] S3. According to the shear strain of the soil in the passive zones of the adjacent foundation pits and the shear strain of the soil between the pits, combined with the mobilization strength theory, the mobilization shear stress of the soil in the passive zones of the adjacent foundation pits and the mobilization shear stress of the soil between the pits are calculated;

[0010] S4. Calculate the passive zone horizontal earth pressure on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits according to the mobilized shear stress of the passive zone soil of the adjacent foundation pits and the mobilized shear stress of the soil between the pits;

[0011] S5. Based on the horizontal earth pressure in the passive zone and the horizontal earth pressure between the pits on the walls of the adjacent foundation pits, combined with the bending moment caused by the axial force of the internal support, the first wall bending moment of the adjacent foundation pits that meets the stability requirements is calculated synchronously;

[0012] S6. According to the wall displacements of the adjacent foundation pits, the second wall bending moments of the adjacent foundation pits that meet the deformation requirements are calculated synchronously;

[0013] S7, calculating the wall bending moment difference of each adjacent foundation pit according to the first wall bending moment and the second wall bending moment of each adjacent foundation pit, and determining whether the wall bending moment difference meets the threshold requirement;

[0014] If the bending moment differences of the walls of adjacent foundation pits are all less than or equal to the preset threshold, the real structural displacements of the walls of the adjacent foundation pits are output;

[0015] If the wall bending moment difference of adjacent foundation pits is greater than the preset threshold, the wall displacement of the foundation pit corresponding to the wall bending moment difference greater than the preset threshold is adjusted, and the iterative calculation is returned to S1 until the wall bending moment difference of the foundation pit is less than or equal to the preset threshold, and the true structural displacement of the walls of the adjacent foundation pits is output.

[0016] Furthermore, the shear strain of the soil in the passive zone of each adjacent foundation pit is calculated synchronously according to the wall displacement of each adjacent foundation pit, including:

[0017] S11. Preset the wall structure displacements of adjacent foundation pits;

[0018] S12, according to the preset structural displacements of the walls of the adjacent foundation pits, decomposing the preset structural displacements of the walls of the adjacent foundation pits into a superposition of several wall displacement modes; wherein the wall displacement mode includes a wall rotation displacement mode around the bottom, a wall translation displacement mode and a wall articulation displacement mode;

[0019] S13. Calculate the soil shear strain increment caused by different wall displacement modes;

[0020] Specifically include:

[0021] The calculation formula for the soil shear strain increment caused by the wall rotation displacement mode around the bottom is as follows:

[0022] ;

[0023] in, represents the shear strain increment caused by the wall rotation around the bottom, Indicates the angular increment of the wall's rotation around the bottom;

[0024] The calculation formula for the soil shear strain increment caused by the wall translation displacement mode is as follows:

[0025] ;

[0026] in, represents the shear strain increment caused by wall translation, represents the horizontal translation displacement increment of the wall, Indicates the height of the wall;

[0027] The wall articulated displacement mode is achieved by superimposing two displacements of the wall rotating around the bottom in different directions:

[0028] The first displacement is the rotation of the wall as a whole around the bottom toward the inside of the pit;

[0029] The second displacement is that the wall is divided into two parts with the hinge as the boundary, the lower part remains vertical, and the upper part rotates around the bottom toward the outside of the pit;

[0030] S14, calculating the soil shear strain in the passive zones of adjacent foundation pits according to the soil shear strain increment caused by different wall displacement modes;

[0031] The calculation formula is as follows:

[0032] ;

[0033] in, represents the shear strain of soil in the passive zone; represents the shear strain caused by the wall rotation; represents the shear strain caused by wall translation.

[0034] Furthermore, according to the zoning conditions of the shear strain influence range of the soil between the adjacent foundation pits, the calculation of the shear strain of the soil between the adjacent foundation pits includes:

[0035] S21. Calculate the shear strain of soil between adjacent foundation pits without considering the superposition effect;

[0036] S22, determining the shear strain correction amount of the soil between the adjacent foundation pits according to the partitioning conditions of the shear strain influence range of the soil between the adjacent foundation pits;

[0037] S23. The shear strain of the soil between the adjacent foundation pits is calculated based on the sum of the shear strain of the soil between the adjacent foundation pits without considering the superposition effect and the correction amount of the shear strain of the soil between the adjacent foundation pits.

[0038] Furthermore, the zoning conditions of the shear strain influence range of the soil between adjacent foundation pits include:

[0039] According to the wall depths of adjacent foundation pits and the distances between adjacent foundation pits, the partition conditions of the shear strain influence range of the soil between adjacent foundation pits are determined;

[0040] Specifically include:

[0041] When the wall depths of adjacent pits are greater than the distance between adjacent pits, the working conditions are mutually affected;

[0042] When the wall depth of foundation pit A is greater than the spacing between adjacent foundation pits, and the spacing between adjacent foundation pits is greater than or equal to the wall depth of foundation pit B, it is the condition where foundation pit A affects foundation pit B;

[0043] When the wall depth of foundation pit B is greater than the distance between adjacent foundation pits, and the distance between adjacent foundation pits is greater than or equal to the wall depth of foundation pit A, it is the condition that foundation pit B affects foundation pit A;

[0044] When the distance between adjacent foundation pits is greater than or equal to the wall depth of each adjacent foundation pit, the working conditions will not affect each other.

[0045] Furthermore, according to the partitioning conditions of the shear strain influence range of the soil between the adjacent foundation pits, the shear strain correction amount of the soil between the adjacent foundation pits is determined, including:

[0046] When the shear strain influence range of the soil between adjacent foundation pits is divided into mutually influencing conditions, the shear strain correction of the soil between pits A is the shear strain of the soil between pits in the depth interval of the influence range of foundation pit B without considering the superposition effect, and the shear strain correction of the soil between pits B is the shear strain of the soil between pits in the depth interval of the influence range of foundation pit A without considering the superposition effect;

[0047] When the shear strain influence range of the soil between adjacent foundation pits is divided into the condition that foundation pit A affects foundation pit B, the shear strain correction of the soil between pits of foundation pit A is 0, and the shear strain correction of the soil between pits of foundation pit B is the shear strain of the soil between pits in the depth range of the influence range of foundation pit A without considering the superposition effect;

[0048] When the partitioning condition of the shear strain influence range of the soil between adjacent foundation pits is the condition where the foundation pit B affects the foundation pit A, the shear strain correction amount of the soil between the pits of foundation pit A is the shear strain of the soil between the pits in the depth interval of the influence range of foundation pit B without considering the superposition effect, and the shear strain correction amount of the soil between the pits of foundation pit B is 0;

[0049] When the shear strain influence range partitioning condition of the soil between adjacent foundation pits is a condition of no mutual influence, the shear strain correction amount of the soil between pits A is 0, and the shear strain correction amount of the soil between pits B is 0.

[0050] Furthermore, in S3, according to the shear strain of the soil in the passive zone of each adjacent foundation pit and the shear strain of the soil between each pit, combined with the mobilization strength theory, the mobilization shear stress of the soil in the passive zone of each adjacent foundation pit and the mobilization shear stress of the soil between the pits are calculated, and the calculation formula is as follows:

[0051] ;

[0052] in, Mobilize shear stress for soil, is an index derived from experiments, is the mobilization coefficient, represents the soil shear strain, is the undrained shear strength of soil, Indicates that the soil has mobilized half of its undrained shear strength The corresponding shear strain.

[0053] Furthermore, according to the mobilized shear stress of the passive zone soil of each adjacent foundation pit and the mobilized shear stress of the soil between the pits, the passive zone horizontal earth pressure on the walls of each adjacent foundation pit and the horizontal earth pressure between the pits are calculated. The calculation formula is as follows:

[0054] ;

[0055] in, is the horizontal earth pressure; is the vertical earth pressure, Mobilize shear stress for the soil.

[0056] Furthermore, in S5, based on the horizontal earth pressure in the passive zone on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits, combined with the bending moment caused by the internal support axial force, the first wall bending moment of the adjacent foundation pits that meets the stability requirements is calculated synchronously. The calculation formula is as follows:

[0057] ;

[0058] in, It indicates the first wall bending moment of adjacent foundation pits that meets the stability requirements. represents the internal support axial force, Indicates the height of the wall.

[0059] Furthermore, in S6, according to the wall displacements of the adjacent foundation pits, the second wall bending moments of the adjacent foundation pits that meet the deformation requirements are calculated synchronously, and the calculation formula is as follows:

[0060] ;

[0061] in, It indicates the bending moment of the second wall of adjacent foundation pits that meets the deformation requirements. is the bending stiffness of the wall, Represents the wall deflection.

[0062] The present invention also provides an adjacent foundation pit design system based on the mobilization strength theory, which is used to implement any of the adjacent foundation pit design methods based on the mobilization strength theory described above, and the system includes:

[0063] A soil shear strain calculation module is used to synchronously calculate the soil shear strains in the passive zones of the adjacent foundation pits according to the respective wall displacements of the adjacent foundation pits; wherein the adjacent foundation pits include foundation pit A and foundation pit B; and to calculate the soil shear strains between the adjacent foundation pits according to the partition of the soil shear strain influence range between the adjacent foundation pits;

[0064] The soil mobilization shear stress calculation module is connected to the soil shear strain calculation module and is used to calculate the soil mobilization shear stress in the passive zones of the adjacent foundation pits and the soil mobilization shear stress between the pits according to the soil shear strain in the passive zones of the adjacent foundation pits and the soil shear strain between the pits, combined with the mobilization strength theory;

[0065] The horizontal earth pressure calculation module is connected to the soil mobilization shear stress calculation module and is used to calculate the passive zone horizontal earth pressure on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits according to the passive zone soil mobilization shear stress of the adjacent foundation pits and the soil mobilization shear stress between the pits;

[0066] The wall bending moment calculation module is connected to the horizontal earth pressure calculation module, and is used to synchronously calculate the first wall bending moment of each adjacent foundation pit that meets the stability requirement according to the passive zone horizontal earth pressure and the inter-pit horizontal earth pressure on the walls of each adjacent foundation pit, combined with the bending moment caused by the internal support axial force; and synchronously calculate the second wall bending moment of each adjacent foundation pit that meets the deformation requirement according to the wall displacement of each adjacent foundation pit;

[0067] The wall structure displacement output module is connected to the wall bending moment calculation module, and is used to calculate the wall bending moment difference of each adjacent foundation pit according to the first wall bending moment and the second wall bending moment of each wall of the adjacent foundation pit, and judge whether the wall bending moment difference meets the threshold requirement; if the wall bending moment difference of each adjacent foundation pit is less than or equal to the preset threshold, the real structural displacement of each wall of the adjacent foundation pit is output; if the wall bending moment difference of each adjacent foundation pit is greater than the preset threshold, the wall displacement of the foundation pit corresponding to the wall bending moment difference greater than the preset threshold is adjusted, and the iterative calculation is returned to S1 until the wall bending moment difference of the foundation pit is less than or equal to the preset threshold, and the real structural displacement of each wall of the adjacent foundation pit is output.

[0068] The present invention has the following technical effects:

[0069] The present application realizes the synchronous calculation of the shear strain of the soil in the passive zone of adjacent foundation pits by decomposing the displacement of the walls of adjacent foundation pits into several wall displacement modes and combining the soil deformation mechanism under different wall displacement modes; for the soil between adjacent foundation pits, according to the relationship between the depth of the walls of adjacent foundation pits and the distance between adjacent foundation pits, different working conditions are distinguished by the mutual influence range of the shear strain of the soil between the pits, and the superposition effect of soil deformation is further considered to obtain the shear strain of the soil between adjacent foundation pits, and further calculate the soil pressure between the pits based on the superimposed shear strain, which reflects the characteristics of the stable association of adjacent foundation pits. Improve the design accuracy; perform two numerical integrations according to the horizontal soil pressure, and superimpose the bending moment caused by the internal support axial force to obtain the wall bending moment of each adjacent foundation pit that meets the stability requirements. At the same time, perform two numerical differentiations on the displacement of the adjacent foundation pit walls and multiply it by the wall bending stiffness to obtain the wall bending moment of the adjacent foundation pit that meets the deformation requirements. It is determined whether the bending moment error of the adjacent foundation pit walls that meets the stability and deformation requirements meets the threshold requirements, and the structural bending moment is repeatedly iterated until the bending moment difference of the adjacent foundation pit walls meets the threshold requirements at the same time, and the real structural displacement of the adjacent foundation pit walls is obtained. This application realizes the overall design of adjacent foundation pits by synchronously solving adjacent foundation pits, solves the deficiency that the current design specifications can only design adjacent foundation pits as two single pits, and further improves the design accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0071] Figure 1 is a flow chart of a method for designing adjacent foundation pits based on mobilization strength theory provided by an embodiment of the present invention;

[0072] Figure 2 It is a logic diagram of a method for designing adjacent foundation pits based on mobilization strength theory provided by an embodiment of the present invention;

[0073] Figure 3 It is a schematic diagram of the shear strain influence range of foundation pit A on foundation pit B under a mutually influencing working condition provided by an embodiment of the present invention;

[0074] Figure 4 It is a schematic diagram of the shear strain influence range of foundation pit B on foundation pit A under a mutually influencing working condition provided by an embodiment of the present invention;

[0075] Figure 5 It is a schematic diagram of the shear strain influence range of foundation pit A on foundation pit B under the condition that foundation pit A affects foundation pit B provided by an embodiment of the present invention;

[0076] Figure 6 It is a schematic diagram of the shear strain generation range of the active zone of the foundation pit B under the condition that the foundation pit A affects the foundation pit B provided by an embodiment of the present invention;

[0077] Figure 7 It is a schematic diagram of the shear strain generation range of the soil in the active areas of the foundation pit A and the foundation pit B under the working condition that they do not affect each other provided by an embodiment of the present invention;

[0078] Figure 8 is a curve diagram showing the horizontal displacement of the wall of a foundation pit A as a function of the excavation depth provided by an embodiment of the present invention;

[0079] Fig. 9 is a curve diagram showing the change of horizontal displacement of the wall of a foundation pit B with the excavation depth provided by an embodiment of the present invention;

[0080] Fig.10 It is a structural schematic diagram of an adjacent foundation pit design system based on mobilization strength theory provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0081] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0082] This paper proposes a design method for adjacent foundation pits based on the mobilization strength theory. Figure 1 is a flow chart of a method for designing adjacent foundation pits based on mobilization strength theory provided by an embodiment of the present invention. Figure 2is a logic diagram of a method for designing adjacent foundation pits based on mobilization strength theory provided by an embodiment of the present invention, see Figure 1 and Figure 2 , specifically including the following steps:

[0083] S1. The shear strain of the soil in the passive zone of each adjacent foundation pit is calculated synchronously according to the wall displacement of each adjacent foundation pit.

[0084] Among them, the adjacent foundation pits include foundation pit A and foundation pit B.

[0085] First, determine the adjacent foundation pit section support structure parameters and soil physical and mechanical parameters based on the engineering survey report, building structure construction drawings, etc. The adjacent foundation pit support structure parameters include: adjacent foundation pit wall height, wall bending stiffness , whether the bottom of the wall is embedded in the rock mass, the installation depth of the internal support, and the compressive stiffness of the internal support , the excavation sequence of adjacent foundation pits and the distance between adjacent foundation pits; the physical and mechanical parameters of the soil in the adjacent foundation pits include: the thickness, weight, undrained shear strength of each soil layer and the soil mobilizes half of its undrained shear strength The corresponding shear strain ;in It can be determined by triaxial testing or calculated by the following formula:

[0086] ;

[0087] In the formula, is the plasticity index, is the initial mean effective stress, is the atmospheric pressure, usually 101.3 kPa;

[0088] It should be noted that since adjacent foundation pits often appear in complex urban environments, they have strict deformation control requirements, large excavation depths, and wide excavation areas. Therefore, reinforcement measures such as cement soil mixing piles and high-pressure rotary jet piles must be carried out in the passive areas of the foundation pits. Based on this method, separate soil parameters can be input for the passive areas of adjacent foundation pits and the soil between pits. The shear strength of the composite soil in the composite foundation reinforcement area is The calculation is done using the following formula:

[0089] ;

[0090] In the formula, is the composite foundation replacement rate, is the undrained shear strength of soil, is the shear strength of the pile.

[0091] S11. Preset the wall structure displacements of adjacent foundation pits.

[0092] S12. According to the preset structural displacements of the walls of the adjacent foundation pits, the preset structural displacements of the walls of the adjacent foundation pits are decomposed into the superposition of several wall displacement modes.

[0093] Among them, the wall displacement mode includes the wall rotation displacement mode around the bottom, the wall translation displacement mode and the wall hinge displacement mode. It should be noted that since the adjacent foundation pit walls are deep and can be inserted into the foundation rock layer or the bearing layer to a large depth, it is generally believed that the adjacent foundation pit walls do not have a translation displacement mode.

[0094] S13. Calculate the soil shear strain increment caused by different wall displacement modes.

[0095] Specifically, in the wall rotation displacement mode around the bottom, assuming that the soil deformation range is a wedge-shaped body with an angle of 45° with the wall, and the shear strain increment in the strain field is uniform, the calculation formula for the soil shear strain increment caused by the wall rotation displacement mode around the bottom is as follows:

[0096] ;

[0097] in, represents the shear strain increment caused by the wall rotation around the bottom, Indicates the angular increment of the wall's rotation around the bottom;

[0098] In the wall translation displacement mode, assuming that the shear strain increment in the deformation range of the rectangular soil behind the wall is uniform, the calculation formula for the soil shear strain increment caused by the wall translation displacement mode is as follows:

[0099] ;

[0100] in, represents the shear strain increment caused by wall translation, represents the horizontal translation displacement increment of the wall, Indicates the height of the wall.

[0101] The wall hinge displacement mode is achieved by superimposing two displacements of the wall rotating around the bottom in different directions. The first displacement is that the wall as a whole rotates around the bottom toward the inside of the pit; the second displacement is that the wall is divided into two parts, upper and lower, with the hinge as the boundary, the lower part remains vertical, and the upper part rotates around the bottom toward the outside of the pit.

[0102] S14. Calculate the soil shear strain in the passive zones of adjacent foundation pits based on the soil shear strain increment caused by different wall displacement modes.

[0103] Specifically, the calculation formula is as follows:

[0104] ;

[0105] in, represents the shear strain of soil in the passive zone, represents the shear strain caused by the wall rotation, represents the shear strain caused by wall translation.

[0106] S2. Calculate the shear strain of the soil between the adjacent foundation pits according to the zoning conditions of the shear strain influence range of the soil between the adjacent foundation pits.

[0107] S21. Calculate the shear strain of the soil between adjacent foundation pits without considering the superposition effect.

[0108] Specifically, the calculation formula for the shear strain of soil between adjacent foundation pits without considering the superposition effect is the same as the calculation formula for the shear strain of soil in the passive zone in S14.

[0109] S22. Determine the shear strain correction amount of the soil between the adjacent foundation pits according to the zoning conditions of the shear strain influence range of the soil between the adjacent foundation pits.

[0110] Specifically, the zoning conditions of the shear strain influence range of the soil between adjacent foundation pits are determined according to the wall depths of the adjacent foundation pits and the distance between them. It is assumed that the walls of the adjacent foundation pits will not translate, and combined with the wall rotation displacement mode around the bottom, the shear strain generation range of the soil is 45° to the wall. For the soil between adjacent foundation pits, the shear strain influence range is also distributed upward at an angle of 45°, and in the overlap range of the wedge and the opposite wall, it is considered that the shear strain of the soil behind the wall produces linear superposition.

[0111] Specifically include:

[0112] Figure 3 is a schematic diagram of the shear strain influence range of foundation pit A on foundation pit B under a mutually influencing working condition provided by an embodiment of the present invention, Figure 4 FIG. 1 is a schematic diagram of the shear strain influence range of foundation pit B on foundation pit A under a mutually influencing working condition provided by an embodiment of the present invention, see Figure 3 and Figure 4 In the figure, 1 is foundation pit A, 2 is foundation pit B, 3 is the wall of foundation pit A, 4 is the wall of foundation pit B, 5 is the soil between adjacent foundation pits, and also serves as the soil in the active zone of foundation pits A and B, 6 is the support in the foundation pit, 7 is the influence range of foundation pit A on the shear strain of the soil behind the wall of foundation pit B, and 8 is the influence range of foundation pit B on the shear strain of the soil behind the wall of foundation pit A. is the wall depth of foundation pit A, is the depth of foundation pit B wall, is the distance between adjacent foundation pits, is the depth interval of the wall of pit A that affects the shear strain of pit B, is the depth interval of the wall of pit B that affects the shear strain of pit A. When the wall depths of adjacent pits are greater than the distance between adjacent pits, that is, , which is a mutually influencing working condition. Under this working condition, affected by the limited width of the soil between adjacent foundation pits, the shear strains of the soil in the active zone of the adjacent foundation pit walls have a mutual influence.

[0113] Figure 5 is a schematic diagram of the shear strain influence range of foundation pit A on foundation pit B under the condition that foundation pit A affects foundation pit B provided by an embodiment of the present invention, Figure 6 FIG. 1 is a schematic diagram of the shear strain generation range of the active zone of the foundation pit B under the condition that the foundation pit A affects the foundation pit B provided by an embodiment of the present invention. Figure 5 and Figure 6 , when the wall depth of foundation pit A is greater than the distance between adjacent foundation pits, and the distance between adjacent foundation pits is greater than or equal to the wall depth of foundation pit B, that is , is the condition where A affects B. Under this condition, the limited width of the soil between adjacent foundation pits only affects the shear strain of the soil behind the single-side wall, that is, the shear strain of the soil in the depth interval of the foundation pit A wall is inclined at 45°, which affects the shear strain of the soil behind the foundation pit B wall. However, the shear strain generation range of the active zone of foundation pit B does not overlap with the wall of foundation pit A, so it will not affect the shear strain of the soil behind the wall of foundation pit A.

[0114] When the wall depth of foundation pit B is greater than the spacing between adjacent foundation pits, and the spacing between adjacent foundation pits is greater than or equal to the wall depth of foundation pit A, it is the condition where foundation pit B affects foundation pit A; the same is true for the condition where foundation pit A affects foundation pit B.

[0115] Figure 7 FIG. 1 is a schematic diagram of the shear strain generation range of the soil in the active areas of the foundation pit A and the foundation pit B under the condition that they do not affect each other, provided by an embodiment of the present invention. Figure 7 , when the distance between adjacent foundation pits is greater than or equal to the wall depth of each adjacent foundation pit, that is, , is the working condition of no mutual influence. Under this working condition, the shear strain of the soil between adjacent foundation pits does not affect each other, and there is no need to consider the superposition effect of soil deformation.

[0116] Furthermore, when the shear strain influence range zoning condition of the soil between the adjacent foundation pits is a mutual influence condition, the shear strain correction amount of the soil between the pits of foundation pit A is the shear strain of the soil between the pits in the depth interval of the influence range of foundation pit B without considering the superposition effect, and the shear strain correction amount of the soil between the pits of foundation pit B is the shear strain of the soil between the pits in the depth interval of the influence range of foundation pit A without considering the superposition effect;

[0117] When the shear strain influence range of the soil between adjacent foundation pits is divided into the condition that foundation pit A affects foundation pit B, the shear strain correction of the soil between pits of foundation pit A is 0, and the shear strain correction of the soil between pits of foundation pit B is the shear strain of the soil between pits in the depth range of the influence range of foundation pit A without considering the superposition effect;

[0118] When the partitioning condition of the shear strain influence range of the soil between adjacent foundation pits is the condition where the foundation pit B affects the foundation pit A, the shear strain correction amount of the soil between the pits of foundation pit A is the shear strain of the soil between the pits in the depth interval of the influence range of foundation pit B without considering the superposition effect, and the shear strain correction amount of the soil between the pits of foundation pit B is 0;

[0119] When the shear strain influence range partitioning condition of the soil between adjacent foundation pits is a condition of no mutual influence, the shear strain correction amount of the soil between pits A is 0, and the shear strain correction amount of the soil between pits B is 0.

[0120] S23. The shear strain of the soil between the adjacent foundation pits is calculated based on the sum of the shear strain of the soil between the adjacent foundation pits without considering the superposition effect and the correction amount of the shear strain of the soil between the adjacent foundation pits.

[0121] S3. According to the shear strain of the soil in the passive zones of the adjacent foundation pits and the shear strain of the soil between the pits, combined with the mobilization strength theory, the mobilized shear stress of the soil in the passive zones of the adjacent foundation pits and the mobilized shear stress of the soil between the pits are calculated.

[0122] Specifically, the calculation formula is as follows:

[0123] ;

[0124] in, is the mobilized shear stress of soil (mobilized shear stress of soil in passive zone or mobilized shear stress of soil between pits), It is an index derived from experiments, usually taken as 0.6. is the mobilization coefficient, and its value range is , represents the soil shear strain (soil shear strain in the passive zone or soil shear strain between pits), is the undrained shear strength of soil, Indicates that the soil has mobilized half of its undrained shear strength The corresponding shear strain.

[0125] S4. Calculate the passive zone horizontal earth pressure on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits based on the mobilized shear stress of the passive zone soil of the adjacent foundation pits and the mobilized shear stress of the soil between the pits.

[0126] Specifically, the calculation formula is as follows:

[0127] ;

[0128] in, is the horizontal earth pressure; is the vertical earth pressure, It is important to note that the influence of soil deformation superposition effect is taken into account in the calculation of soil shear strain between pits, and the soil mobilized shear stress and horizontal earth pressure are calculated in sequence based on the superimposed shear strain, which leads to changes in the earth pressure on adjacent walls, further reflecting the characteristics of the stability association of adjacent foundation pits.

[0129] S5. Based on the horizontal earth pressure in the passive zone on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits, combined with the bending moment caused by the axial force of the internal support, the first wall bending moment of the adjacent foundation pits that meets the stability requirements is calculated synchronously.

[0130] Specifically, the calculation formula is as follows:

[0131] ;

[0132] in, It indicates the first wall bending moment of adjacent foundation pits that meets the stability requirements. represents the internal support axial force, represents the wall height; where the internal support axial force The calculation is based on the axial shortening value of the wall due to horizontal deflection. It should be noted that the support defined in this method can only withstand compressive stress and not tensile stress.

[0133] S6. According to the wall displacements of the adjacent foundation pits, the second wall bending moments of the adjacent foundation pits that meet the deformation requirements are calculated synchronously.

[0134] Specifically, the calculation formula is as follows:

[0135] ;

[0136] in, It indicates the bending moment of the second wall of adjacent foundation pits that meets the deformation requirements. is the bending stiffness of the wall, Represents the wall deflection.

[0137] S7. Calculate the wall bending moment difference of each adjacent foundation pit according to the first wall bending moment and the second wall bending moment of each adjacent foundation pit wall, and determine whether the wall bending moment difference meets the threshold requirement.

[0138] Specifically, if the bending moment differences of the walls of the adjacent foundation pits are both less than or equal to a preset threshold, the real structural displacements of the walls of the adjacent foundation pits are output;

[0139] If the bending moment difference of the walls of adjacent foundation pits is greater than the preset threshold, a displacement increment is added to each node of the wall of the foundation pit corresponding to the wall bending moment difference greater than the preset threshold, and the calculation is returned to S1 for iterative calculation until the bending moment difference of the wall of the foundation pit is less than or equal to the preset threshold, and the true structural displacement of each wall of the adjacent foundation pits is output.

[0140] Next, a hypothetical model of adjacent foundation pits is established in conjunction with a certain tunnel foundation pit, and the horizontal displacement of the adjacent foundation pit walls is predicted to further describe the method in this application. First, the physical and mechanical parameters of the adjacent foundation pit soil and the profile support structure parameters are determined based on the geological survey report, building structure construction drawings, etc., as shown in Tables 1 and 2. Among them, the distance between adjacent foundation pits is 12m, foundation pit A is excavated in three layers, and foundation pit B is excavated in two layers. The excavation depth of each layer is 4m, and internal support is applied after the excavation of the first layer of soil is completed. The horizontal displacement of the adjacent foundation pit walls predicted by the adjacent foundation pit design method based on the mobilization strength theory in this application is as shown in Tables 1 and 2. Figure 8 , Fig. 9 As shown, Figure 8 is a curve diagram showing the change of the horizontal displacement of the wall of a foundation pit A with the excavation depth provided by an embodiment of the present invention. Fig. 9 It is a curve diagram of the horizontal displacement of the wall of a foundation pit B as the excavation depth changes, provided by an embodiment of the present invention, wherein a positive value of the horizontal displacement of the wall represents deformation into the pit, and a negative value represents deformation out of the pit.

[0141] Table 1 Physical and mechanical parameters of soil in adjacent foundation pit engineering

[0142]

[0143] Table 2 Parameters of adjacent foundation pit excavation and support structure layout

[0144]

[0145] See also Figure 8 and Fig. 9 With the increase of the excavation depth of adjacent foundation pits and the construction of internal supports, the deformation of the adjacent foundation pit walls tends to bend inward. The maximum horizontal displacement values ​​of the wall corresponding to the three-layer excavation of foundation pit A are 1.39, 2.55, and 4.79 mm, respectively, and the maximum horizontal displacement values ​​of the wall corresponding to the two-layer excavation of foundation pit B are 1.06 and 2.85 mm, respectively. In addition, affected by the superposition effect of soil deformation between adjacent foundation pits and the lower wall depth, the horizontal displacement of the wall of foundation pit B increases by 12% when excavated to 8m compared with that of foundation pit A, which is consistent with the deformation trend of the adjacent foundation pit walls in actual projects, further illustrating the rationality of the design method in this application.

[0146] The present application realizes the synchronous calculation of the shear strain of the soil in the passive zone of adjacent foundation pits by decomposing the displacement of the walls of adjacent foundation pits into several wall displacement modes and combining the soil deformation mechanism under different wall displacement modes; for the soil between adjacent foundation pits, according to the relationship between the depth of the walls of adjacent foundation pits and the distance between adjacent foundation pits, different working conditions are distinguished by the mutual influence range of the shear strain of the soil between the pits, and the superposition effect of soil deformation is further considered to obtain the shear strain of the soil between adjacent foundation pits, and further calculate the soil pressure between the pits based on the superimposed shear strain, which reflects the characteristics of the stable association of adjacent foundation pits. Improve the design accuracy; perform two numerical integrations according to the horizontal soil pressure, and superimpose the bending moment caused by the internal support axial force to obtain the wall bending moment of each adjacent foundation pit that meets the stability requirements. At the same time, perform two numerical differentiations on the displacement of the adjacent foundation pit walls and multiply it by the wall bending stiffness to obtain the wall bending moment of the adjacent foundation pit that meets the deformation requirements. It is determined whether the bending moment error of the adjacent foundation pit walls that meets the stability and deformation requirements meets the threshold requirements, and the structural bending moment is repeatedly iterated until the bending moment difference of the adjacent foundation pit walls meets the threshold requirements at the same time, and the real structural displacement of the adjacent foundation pit walls is obtained. This application realizes the overall design of adjacent foundation pits by synchronously solving adjacent foundation pits, solves the deficiency that the current design specifications can only design adjacent foundation pits as two single pits, and further improves the design accuracy.

[0147] Fig.10 is a structural schematic diagram of an adjacent foundation pit design system based on mobilization strength theory provided by an embodiment of the present invention, see Fig.10 The embodiment of the present invention further provides an adjacent foundation pit design system based on the mobilization strength theory, which is used to implement the adjacent foundation pit design method based on the mobilization strength theory described in the above embodiment. The system includes:

[0148] A soil shear strain calculation module is used to synchronously calculate the soil shear strains in the passive zones of the adjacent foundation pits according to the respective wall displacements of the adjacent foundation pits; wherein the adjacent foundation pits include foundation pit A and foundation pit B; and to calculate the soil shear strains between the adjacent foundation pits according to the partitioning conditions of the soil shear strain influence range between the adjacent foundation pits;

[0149] The soil mobilization shear stress calculation module is connected to the soil shear strain calculation module and is used to calculate the soil mobilization shear stress in the passive zones of the adjacent foundation pits and the soil mobilization shear stress between the pits according to the soil shear strain in the passive zones of the adjacent foundation pits and the soil shear strain between the pits, combined with the mobilization strength theory;

[0150] The horizontal earth pressure calculation module is connected to the soil mobilization shear stress calculation module and is used to calculate the passive zone horizontal earth pressure on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits according to the passive zone soil mobilization shear stress of the adjacent foundation pits and the soil mobilization shear stress between the pits;

[0151] The wall bending moment calculation module is connected to the horizontal earth pressure calculation module, and is used to synchronously calculate the first wall bending moment of each adjacent foundation pit that meets the stability requirement according to the passive zone horizontal earth pressure and the inter-pit horizontal earth pressure on the walls of each adjacent foundation pit, combined with the bending moment caused by the internal support axial force; and synchronously calculate the second wall bending moment of each adjacent foundation pit that meets the deformation requirement according to the wall displacement of each adjacent foundation pit;

[0152] The wall structure displacement output module is connected to the wall bending moment calculation module, and is used to calculate the wall bending moment difference of each adjacent foundation pit according to the first wall bending moment and the second wall bending moment of each wall of the adjacent foundation pit, and judge whether the wall bending moment difference meets the threshold requirement; if the wall bending moment difference of each adjacent foundation pit is less than or equal to the preset threshold, the real structural displacement of each wall of the adjacent foundation pit is output; if the wall bending moment difference of each adjacent foundation pit is greater than the preset threshold, the wall displacement of the foundation pit corresponding to the wall bending moment difference greater than the preset threshold is adjusted, and the iterative calculation is returned to S1 until the wall bending moment difference of the foundation pit is less than or equal to the preset threshold, and the real structural displacement of each wall of the adjacent foundation pit is output.

[0153] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0154] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing adjacent foundation pits based on mobilization strength theory, characterized in that: The steps include: S1. synchronously calculating the soil shear strains in the passive zones of the adjacent foundation pits according to the wall displacements of the adjacent foundation pits; wherein the adjacent foundation pits include foundation pit A and foundation pit B; S2. Calculate the shear strain of the soil between the adjacent foundation pits according to the zoning conditions of the shear strain influence range of the soil between the adjacent foundation pits; Specifically include: S21. Calculate the shear strain of soil between adjacent foundation pits without considering the superposition effect; S22, determining the shear strain correction amount of the soil between the adjacent foundation pits according to the partitioning conditions of the shear strain influence range of the soil between the adjacent foundation pits; S23, calculating the shear strain of the soil between the adjacent foundation pits according to the sum of the shear strain of the soil between the adjacent foundation pits without considering the superposition effect and the correction amount of the shear strain of the soil between the adjacent foundation pits; S3. According to the shear strain of the soil in the passive zones of the adjacent foundation pits and the shear strain of the soil between the pits, combined with the mobilization strength theory, the mobilization shear stress of the soil in the passive zones of the adjacent foundation pits and the mobilization shear stress of the soil between the pits are calculated; S4. Calculate the passive zone horizontal earth pressure on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits according to the mobilized shear stress of the passive zone soil of the adjacent foundation pits and the mobilized shear stress of the soil between the pits; S5. Based on the horizontal earth pressure in the passive zone and the horizontal earth pressure between the pits on the walls of the adjacent foundation pits, combined with the bending moment caused by the axial force of the internal support, the first wall bending moment of the adjacent foundation pits that meets the stability requirements is calculated synchronously; S6. According to the wall displacements of the adjacent foundation pits, the second wall bending moments of the adjacent foundation pits that meet the deformation requirements are calculated synchronously; S7, calculating the wall bending moment difference of each adjacent foundation pit according to the first wall bending moment and the second wall bending moment of each wall of the adjacent foundation pit, and judging whether the wall bending moment difference meets the threshold requirement; If the bending moment differences of the walls of adjacent foundation pits are all less than or equal to the preset threshold, the real structural displacements of the walls of the adjacent foundation pits are output; If the wall bending moment difference of adjacent foundation pits is greater than a preset threshold, the wall displacement of the foundation pit corresponding to the wall bending moment difference greater than the preset threshold is adjusted, and the iterative calculation is returned to S1 until the wall bending moment difference of the foundation pit is less than or equal to the preset threshold, and the true structural displacement of each wall of the adjacent foundation pits is output.

2. The adjacent foundation pit design method based on mobilization strength theory according to claim 1 is characterized in that: In S1, synchronously calculating the soil shear strains in the passive zones of the adjacent foundation pits according to the wall displacements of the adjacent foundation pits includes: S11. Preset the wall structure displacements of adjacent foundation pits; S12, according to the preset structural displacements of the walls of the adjacent foundation pits, decomposing the preset structural displacements of the walls of the adjacent foundation pits into a superposition of several wall displacement modes; wherein the wall displacement mode includes a wall rotation displacement mode around the bottom, a wall translation displacement mode and a wall articulation displacement mode; S13. Calculate the soil shear strain increment caused by different wall displacement modes; Specifically include: The calculation formula for the soil shear strain increment caused by the wall rotation displacement mode around the bottom is as follows: ； in, represents the shear strain increment caused by the wall rotation around the bottom, Indicates the angular increment of the wall's rotation around the bottom; The calculation formula for the soil shear strain increment caused by the wall translation displacement mode is as follows: ； in, represents the shear strain increment caused by wall translation, represents the horizontal translation displacement increment of the wall, Indicates the height of the wall; The wall articulated displacement mode is achieved by superposition of two displacements of the wall rotating around the bottom in different directions: The first displacement is the rotation of the wall as a whole around the bottom toward the inside of the pit; The second displacement is that the wall is divided into two parts with the hinge as the boundary, the lower part remains vertical, and the upper part rotates around the bottom toward the outside of the pit; S14, calculating the soil shear strain in the passive zones of adjacent foundation pits according to the soil shear strain increment caused by different wall displacement modes; The calculation formula is as follows: ； in, represents the shear strain of soil in the passive zone; represents the shear strain caused by the wall rotation; represents the shear strain caused by wall translation.

3. The adjacent foundation pit design method based on mobilization strength theory according to claim 1 is characterized in that: In S22, the partitioning conditions of the shear strain influence range of the soil between adjacent foundation pits include: According to the wall depths of adjacent foundation pits and the distances between adjacent foundation pits, the partition conditions of the shear strain influence range of the soil between adjacent foundation pits are determined; Specifically include: When the wall depths of adjacent pits are greater than the distance between adjacent pits, the working conditions are mutually affected; When the wall depth of foundation pit A is greater than the spacing between adjacent foundation pits, and the spacing between adjacent foundation pits is greater than or equal to the wall depth of foundation pit B, it is the condition where foundation pit A affects foundation pit B; When the wall depth of foundation pit B is greater than the distance between adjacent foundation pits, and the distance between adjacent foundation pits is greater than or equal to the wall depth of foundation pit A, it is the condition that foundation pit B affects foundation pit A; When the distance between adjacent foundation pits is greater than or equal to the wall depth of each adjacent foundation pit, the working conditions will not affect each other.

4. The adjacent foundation pit design method based on mobilization strength theory according to claim 3 is characterized in that: In the step S22, according to the partitioning conditions of the shear strain influence range of the soil bodies between the adjacent foundation pits, determining the shear strain correction amount of the soil bodies between the adjacent foundation pits includes: When the shear strain influence range of the soil between adjacent foundation pits is divided into mutually influencing conditions, the shear strain correction of the soil between pits A is the shear strain of the soil between pits in the depth interval of the influence range of foundation pit B without considering the superposition effect, and the shear strain correction of the soil between pits B is the shear strain of the soil between pits in the depth interval of the influence range of foundation pit A without considering the superposition effect; When the shear strain influence range of the soil between adjacent foundation pits is divided into the condition that foundation pit A affects foundation pit B, the shear strain correction of the soil between pits of foundation pit A is 0, and the shear strain correction of the soil between pits of foundation pit B is the shear strain of the soil between pits in the depth range of the influence range of foundation pit A without considering the superposition effect; When the partitioning condition of the shear strain influence range of the soil between adjacent foundation pits is the condition where the foundation pit B affects the foundation pit A, the shear strain correction amount of the soil between the pits of foundation pit A is the shear strain of the soil between the pits in the depth interval of the influence range of foundation pit B without considering the superposition effect, and the shear strain correction amount of the soil between the pits of foundation pit B is 0; When the shear strain influence range partitioning condition of the soil between adjacent foundation pits is a condition of no mutual influence, the shear strain correction amount of the soil between pits A is 0, and the shear strain correction amount of the soil between pits B is 0.

5. The adjacent foundation pit design method based on mobilization strength theory according to claim 4 is characterized in that: In S3, according to the shear strain of the soil in the passive zones of the adjacent foundation pits and the shear strain of the soil between the pits, combined with the mobilization strength theory, the mobilization shear stress of the soil in the passive zones of the adjacent foundation pits and the mobilization shear stress of the soil between the pits are calculated, and the calculation formula is as follows: ； in, Mobilize shear stress for soil, is an index derived from experiments, is the mobilization coefficient, represents the soil shear strain, is the undrained shear strength of soil, Indicates that the soil has mobilized half of its undrained shear strength The corresponding shear strain.

6. The adjacent foundation pit design method based on mobilization strength theory according to claim 5 is characterized in that: In S4, the passive zone horizontal earth pressure on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits are calculated according to the mobilized shear stress of the soil in the passive zone of each adjacent foundation pit and the mobilized shear stress of the soil between the pits. The calculation formula is as follows: ； in, is the horizontal earth pressure; is the vertical earth pressure, Mobilize shear stress for the soil.

7. The adjacent foundation pit design method based on mobilization strength theory according to claim 6 is characterized in that: In S5, the first wall bending moment of each adjacent foundation pit that meets the stability requirement is calculated synchronously based on the horizontal earth pressure in the passive zone of each wall of the adjacent foundation pits and the horizontal earth pressure between the pits, combined with the bending moment caused by the internal support axial force. The calculation formula is as follows: ； in, It indicates the first wall bending moment of adjacent foundation pits that meets the stability requirements. represents the internal support axial force, Indicates the height of the wall.

8. The adjacent foundation pit design method based on mobilization strength theory according to claim 1 is characterized in that: In S6, according to the respective wall displacements of the adjacent foundation pits, the second wall bending moments of the adjacent foundation pits that meet the deformation requirements are calculated synchronously, and the calculation formula is as follows: ； in, It indicates the bending moment of the second wall of adjacent foundation pits that meets the deformation requirements. is the bending stiffness of the wall, Represents the wall deflection.

9. A system for designing adjacent foundation pits based on mobilization strength theory, used to implement a method for designing adjacent foundation pits based on mobilization strength theory as described in any one of claims 1 to 8, characterized in that: The system includes: A soil shear strain calculation module is used to synchronously calculate the soil shear strains in the passive zones of the adjacent foundation pits according to the respective wall displacements of the adjacent foundation pits; wherein the adjacent foundation pits include foundation pit A and foundation pit B; and to calculate the soil shear strains between the adjacent foundation pits according to the partitioning conditions of the soil shear strain influence range between the adjacent foundation pits; A soil mobilization shear stress calculation module is connected to the soil shear strain calculation module and is used to calculate the soil mobilization shear stress in the passive zones of the adjacent foundation pits and the soil mobilization shear stress between the pits according to the soil shear strain in the passive zones of the adjacent foundation pits and the soil shear strain between the pits, in combination with the mobilization strength theory; A horizontal earth pressure calculation module is connected to the soil mobilization shear stress calculation module and is used to calculate the passive zone horizontal earth pressure on the walls of the adjacent foundation pits and the horizontal earth pressure between the pits according to the passive zone soil mobilization shear stress of the adjacent foundation pits and the soil mobilization shear stress between the pits; A wall bending moment calculation module is connected to the horizontal earth pressure calculation module, and is used to synchronously calculate the first wall bending moment of each adjacent foundation pit that meets the stability requirement according to the horizontal earth pressure in the passive zone and the horizontal earth pressure between the pits on the walls of each adjacent foundation pit, combined with the bending moment caused by the internal support axial force; and synchronously calculate the second wall bending moment of each adjacent foundation pit that meets the deformation requirement according to the wall displacement of each adjacent foundation pit; The wall structure displacement output module is connected to the wall bending moment calculation module, and is used to calculate the wall bending moment difference of each adjacent foundation pit according to the first wall bending moment and the second wall bending moment of each wall of the adjacent foundation pits, and judge whether the wall bending moment difference meets the threshold requirement; if the wall bending moment difference of each adjacent foundation pit is less than or equal to the preset threshold, the real structural displacement of each wall of the adjacent foundation pit is output; if the wall bending moment difference of each adjacent foundation pit is greater than the preset threshold, the wall displacement of the foundation pit corresponding to the wall bending moment difference greater than the preset threshold is adjusted, and return to S1 for iterative calculation until the wall bending moment difference of the foundation pit is less than or equal to the preset threshold, and the real structural displacement of each wall of the adjacent foundation pit is output.

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