Method for calculating non-limit soil pressure of foundation pit support under barrier effect

Abstract

The invention discloses a foundation pit retaining non-limit soil pressure calculation method under a barrier effect, which comprises the following steps: obtaining foundation pit parameters including the width of a foundation pit, the rainfall depth and the calculation point depth of a target calculation point; calculating the distance between the target calculation point and the slip crack surface of the foundation pit based on the depth of the target calculation point and the rainfall depth; calculating the deformation of the support based on the distance between the target calculation point and the slip crack surface of the foundation pit; establishing a non-limit soil pressure calculation model considering the influence of retaining displacement under the precipitation condition before excavation; and active area non-limit soil pressure and passive area non-limit soil pressure are calculated based on the non-limit soil pressure calculation model, the active area is the soil body range outside the foundation pit support, and the passive area is the soil body range in the foundation pit in the foundation pit support.

Description

Technical Field

[0001] The invention relates to the technical field of soil pressure calculation of foundation pits, in particular to a method for calculating non-limit soil pressure of foundation pit support under a barrier effect. Background Art

[0002] In recent years, with the government's investment in urbanization, more and more underground spaces have been developed and utilized, including underground integrated pipe corridors, underground commercial buildings, subways, etc., resulting in a large number of foundation pit projects. However, foundation pit operations in an environment with increasingly dense buildings will have an impact on the surrounding environment, such as building tilts, ground cracks, etc., posing a threat to people's lives and property safety. Therefore, the many environmental problems caused by the foundation pit construction process should receive more extensive attention and research.

[0003] In fact, every process of foundation pit construction will have an impact on the deformation of the surrounding environment that cannot be underestimated, including the lateral displacement of the retaining structure and the surface settlement outside the pit. Especially in water-rich areas, precipitation before excavation is an indispensable part of the foundation pit construction process. Existing research and related engineering data show that precipitation before foundation pit excavation will cause centimeter-level lateral displacement of the retaining structure. At the same time, precipitation of the foundation pit will induce deformation of surrounding structures, and surrounding structures will also have a certain impact on the deformation of the surrounding environment caused by precipitation of the foundation pit. However, when reviewing existing studies, it was found that there are very few studies on precipitation before foundation pit excavation, and even fewer studies on the deformation of the surrounding environment caused by the influence of existing adjacent structures during the precipitation stage. Moreover, most studies are carried out by relying on three-dimensional numerical simulation and actual on-site testing, which have their own advantages and disadvantages: three-dimensional numerical simulation research needs to find constitutive models and related parameters that match the actual working conditions, and at the same time, a large number of numerical models need to be established to simulate the actual situation. The process is relatively complicated and has high requirements on objective conditions, such as computer configuration and software proficiency; the results of actual on-site testing often have certain empirical coefficients, and due to the influence of factors such as different geological conditions, their applicability is relatively low. Therefore, it is more important to more accurately and conveniently predict the deformation caused by precipitation before excavation under the influence of existing adjacent structures. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the technical problem to be solved by the present invention is how to more accurately and conveniently predict the deformation of the surrounding environment caused by precipitation before foundation pit excavation under the influence of existing adjacent structures.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: a method for calculating non-limit earth pressure of foundation pit support under barrier effect, which includes obtaining foundation pit parameters, the foundation pit parameters including foundation pit width, dewatering depth and calculation point depth of target calculation point; calculating the distance between the target calculation point and the foundation pit sliding surface based on the target calculation point depth and the dewatering depth; calculating the deformation of the support based on the distance between the target calculation point and the foundation pit sliding surface; establishing a non-limit earth pressure calculation model considering the influence of support displacement under dewatering conditions before excavation; calculating the non-limit earth pressure in the active zone and the non-limit earth pressure in the passive zone based on the non-limit earth pressure calculation model, wherein the active zone is the soil range outside the foundation pit support, and the passive zone is the soil range inside the foundation pit inside the foundation pit support.

[0008] As a preferred solution of the method for calculating the non-limit earth pressure of foundation pit support under the barrier effect described in the present invention, the obtaining of foundation pit parameters specifically includes: constructing a three-dimensional scene model of the foundation pit; creating a parametric component family library, the family library includes a family file of at least one type of foundation pit component, the family file includes structural attribute information and functional attribute information of the foundation pit component; processing the two-dimensional graphic element information of the foundation pit, importing the two-dimensional information of the foundation pit into the three-dimensional scene model of the foundation pit to construct a foundation pit data monitoring system, decomposing the two-dimensional information according to the classification of the foundation pit components to obtain the two-dimensional decomposition elements of the foundation pit components, and associating the two-dimensional decomposition elements with the family files of the foundation pit components; calling the family file of the foundation pit in the three-dimensional scene model of the foundation pit to obtain the foundation pit parameters.

[0009] As a preferred solution of the method for calculating the non-limit earth pressure of foundation pit support under the barrier effect of the present invention, the construction of the three-dimensional scene model of the foundation pit specifically includes:

[0010] Obtain relevant geographic parameter data packets required for constructing a foundation pit three-dimensional scene, wherein the geographic parameter data packets include scene longitude and latitude data and terrain data required for the scene;

[0011] Determine the spatial position of the on-site terrain of the foundation pit based on the scene latitude and longitude data of the foundation pit, and determine the collection point for on-site panoramic data collection through the relationship between the BIM model and the spatial position of the on-site terrain of the foundation pit;

[0012] Taking panoramic photos of the collection points in the on-site terrain area of ​​the target scene according to the viewing angle and height of the collection points;

[0013] The panoramic photos are stitched together to obtain a long panoramic image, and the long panoramic image is repaired to obtain a three-dimensional scene model of the foundation pit.

[0014] As a preferred solution of the method for calculating the non-limit earth pressure of foundation pit support under the barrier effect of the present invention, the calculation formula of the distance between the target calculation point and the foundation pit sliding surface is:

[0015]

[0016] Among them, H is the height of the foundation pit enclosure; is the effective friction angle of soil; z is the depth of the retaining structure.

[0017] As a preferred solution of the method for calculating the non-limit earth pressure of foundation pit support under the barrier effect of the present invention, the calculation formula δ(z) of the deformation of the support is:

[0018]

[0019] Where x is the distance from any point in the disturbed area of ​​the soil on both sides of the support to the support.

[0020] As a preferred solution of the method for calculating the non-limit earth pressure of foundation pit support under the barrier effect of the present invention, the establishment of the limit earth pressure calculation model specifically includes:

[0021] Based on the stress-strain relationship curve model of the triaxial shear test, the results of the triaxial shear test are linearly fitted according to the ε1 / σ1-σ3 relationship of ε1 to obtain the fitting relationship:

[0022]

[0023] The stress-strain relationship curve model is:

[0024]

[0025] Where: σ1 is the axial stress; σ3 is the radial stress; ε a is the axial strain; a and b are experimental constants; the fitting results are:

[0026]

[0027] Subtract the initial deviator stress σ from the deviator stress σ1-σ3 1c -σ 3c , and under the same loading and unloading conditions of the stress path, the stress-strain fitting relationship is replaced by the average consolidation pressure σ m After normalization, the normalized stress-strain relationship formula is obtained:

[0028]

[0029] Where: represents the intercept of the normalized straight line on the ordinate, represents the slope of the normalized straight line; σ m is the average consolidation pressure, K0 is the static earth pressure coefficient;

[0030] A non-limit earth pressure calculation model is obtained based on the normalized stress-strain relationship formula and the distance between the target calculation point and the foundation pit sliding surface.

[0031] As a preferred solution of the method for calculating the non-limit earth pressure of foundation pit support under the barrier effect of the present invention, the non-limit earth pressure calculation model includes the non-limit earth pressure calculation model of the active zone;

[0032] The calculation model of the non-limit earth pressure in the active zone is:

[0033]

[0034] Where: K0γ'z represents the horizontal earth pressure before foundation pit dewatering; γ'z represents the vertical earth pressure before dewatering; K0 represents the static earth pressure coefficient; γ' is the effective weight of the soil; λ represents the soil layer reduction coefficient,

[0035] As a preferred solution of the method for calculating the non-limit earth pressure of foundation pit support under the barrier effect of the present invention, the non-limit earth pressure calculation model also includes a passive zone non-limit earth pressure calculation model;

[0036] The calculation model of the non-limit earth pressure in the passive zone is:

[0037]

[0038] Where: K0 is the earth pressure coefficient under no deformation condition (or called static earth pressure coefficient), γ′ is the effective weight of soil, γ G is the weight of soil after precipitation, H is the depth of the enclosure structure, h1 is the distance between the ground and the initial water level, h2 is the precipitation depth outside the pit after the precipitation in the pit is completed; λ represents the soil layer reduction coefficient,

[0039] Beneficial effects of the present invention: By establishing a non-limit earth pressure calculation model that takes into account the influence of support displacement under dewatering conditions before excavation, the present invention can predict the lateral displacement of foundation pit supports during the dewatering stage before foundation pit excavation, thereby reflecting the impact on the surrounding environment; the calculation model is monotonic and meets the initial conditions. The monotonicity reflects the changing relationship between earth pressure and support displacement. When the initial conditions are met, that is, when the support displacement is zero, the earth pressure is static earth pressure, which provides great convenience for the selection and optimization of foundation pit engineering design. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0041] Figure 1 This is a flow chart of the calculation method for non-limit earth pressure of foundation pit support under barrier effect.

[0042] Figure 2 This is a schematic diagram of the soil strain state before and after support in the foundation pit settlement prediction method based on the non-limit earth pressure calculation model.

[0043] Figure 3 This is the force analysis diagram of the active zone unit in the foundation pit settlement prediction method based on the non-limit earth pressure calculation model.

[0044] Figure 4 This is the force analysis diagram of the passive zone unit in the foundation pit settlement prediction method based on the non-limit earth pressure calculation model. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0046] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0047] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0048] Water blocking effect: underground structures such as the outer walls of subway stations will block the natural flow of groundwater, change the flow path, and lead to the redistribution of groundwater levels. It can also be understood that the interaction between underground structures and the surrounding soil blocks the natural deformation or movement of the soil.

[0049] In this paper, the barrier effect specifically refers to the obstruction to groundwater flow and soil deformation caused by the presence of underground structures such as adjacent subway stations during foundation pit construction. This effect includes two aspects in this study: water blocking effect and soil blocking effect, and the two together affect the deformation and stability of the surrounding environment of the foundation pit.

[0050] In one embodiment, the present invention provides a method for calculating the non-limit earth pressure of foundation pit support under the barrier effect, such as Figure 1 As shown, the technical solution is as follows:

[0051] Step S1: Acquire foundation pit parameters, which include foundation pit width, precipitation depth, and calculation point depth of target calculation point.

[0052] Specifically, the foundation pit parameters are obtained based on a pre-built foundation pit data monitoring system.

[0053] The obtaining of foundation pit parameters specifically includes:

[0054] Construct a three-dimensional scene model of the foundation pit; the specific steps are as follows:

[0055] Obtain relevant geographic parameter data packets required for constructing a foundation pit three-dimensional scene, wherein the geographic parameter data packets include scene longitude and latitude data and terrain data required for the scene.

[0056] The spatial position of the on-site terrain of the foundation pit is determined based on the scene latitude and longitude data of the foundation pit, and the collection points for on-site panoramic data collection are determined through the relationship between the BIM model and the spatial position of the on-site terrain of the foundation pit; wherein the BIM model is a Building Information Modeling (Building Information Modeling).

[0057] According to the viewing angle and height of the collection point, a panoramic photo of the collection point is taken in the on-site terrain area of ​​the target scene.

[0058] The panoramic photos are stitched together to obtain a long panoramic image, and the long panoramic image is repaired to obtain a three-dimensional scene model of the foundation pit.

[0059] Creating a parametric component family library, the family library including family files of at least one type of foundation pit component, the family files including structural attribute information and functional attribute information of the foundation pit component;

[0060] Process the two-dimensional primitive information of the foundation pit, import the two-dimensional information of the foundation pit into the three-dimensional scene model of the foundation pit to build a foundation pit data monitoring system, decompose the two-dimensional information according to the classification of the foundation pit components, obtain the two-dimensional decomposition elements of the foundation pit components, and associate the two-dimensional decomposition elements with the family files of the foundation pit components; wherein the two-dimensional primitive information is CAD primitive information, and importing the two-dimensional information of the foundation pit into the three-dimensional scene model of the foundation pit is specifically importing the CAD drawing of the foundation pit into the three-dimensional scene model of the foundation pit, decomposing the two-dimensional information according to the classification of the foundation pit components is decomposing the CAD drawing content according to the classification of the foundation pit components, and the two-dimensional decomposition elements are CAD decomposition elements.

[0061] The family file of the foundation pit is called in the foundation pit three-dimensional scene model to obtain the foundation pit parameters.

[0062] Step S2: Calculate the distance between the target calculation point and the foundation pit sliding surface based on the target calculation point depth and the precipitation depth.

[0063] The foundation pit sliding surface refers to the crack surface caused by sliding phenomenon that occurs during deep foundation pit or excavation process.

[0064] The main reasons for the formation of foundation pit sliding surface are geomechanical factors and the influence of human engineering activities. For example, the original soil balance state is destroyed during the foundation pit excavation process, resulting in soil slippage and deformation.

[0065] Step S3: Calculate the deformation of the support based on the distance between the target calculation point and the foundation pit sliding surface.

[0066] The calculation formula for the distance between the target calculation point and the foundation pit sliding surface is:

[0067]

[0068] Among them, H is the height of the foundation pit enclosure; is the effective friction angle of soil; z is the depth of the retaining structure.

[0069] The distance L between the target calculation point and the foundation pit slip surface is the distance from the enclosure structure at the buried depth z to the boundary line of the disturbance / non-disturbance zone. The disturbance zone refers to the area where the foundation pit enclosure structure contacts the soil. The lateral displacement of the enclosure or the change in the force on the soil will directly affect the deformation of the soil in this area. During the precipitation stage before excavation, the displacement of the enclosure structure will cause the soil to shift in the horizontal and vertical directions, and the soil in the disturbance zone will undergo a large deformation. For details, please follow the following instructions: Figure 2 shown.

[0070] The non-disturbance zone refers to the area that is not directly affected by the lateral displacement of the retaining structure or the force on the soil during the foundation pit construction or precipitation process. The soil in this area basically remains in its original state, with little deformation, and is almost not directly disturbed by the foundation pit construction or precipitation.

[0071] It should be noted that during the dewatering stage before foundation pit excavation, the soil outside the foundation pit underwent horizontal and vertical displacements. The deformation mechanism of the soil in the pit was that the lateral displacement of the support squeezed the soil in the pit, causing it to undergo horizontal displacement. Dewatering operations were carried out in the pit, the pore water pressure dissipated, and the effective stress of the soil increased, resulting in vertical deformation of the soil in the pit. As for the outside of the pit, the support moved toward the inside of the pit, thereby pulling the soil outside the pit and causing it to deform. The deformation δ(z) of the support was caused by the deformation of the soil between the support and the sliding surface. The soil strain between the support and the sliding surface decreased nonlinearly. The strain of each point on the compressed side of the soil can be approximately expressed according to the fitting curve as follows: Where x is the distance from any point in the disturbance zone of the soil on both sides of the support to the support. The strain is integrated within the deformation zone to obtain

[0072] The calculation formula δ(z) of the deformation of the support is:

[0073] Step S4: Establish a non-limit earth pressure calculation model considering the influence of support displacement under the dewatering condition before excavation.

[0074] The establishment of the ultimate earth pressure calculation model specifically includes:

[0075] Based on the stress-strain relationship curve model of triaxial shear test, the results of triaxial shear test are converted into The relationship is fitted by a straight line to obtain the fitting relationship:

[0076]

[0077] The stress-strain relationship curve model is:

[0078]

[0079] Where: σ1 is the axial stress; σ3 is the radial stress; ε a is the axial strain; a and b are experimental constants; the fitting results are:

[0080]

[0081] Subtract the initial deviator stress σ from the deviator stress σ1-σ3 1c -σ 3c , and under the same loading and unloading conditions of the stress path, the stress-strain fitting relationship is replaced by the average consolidation pressure σ m After normalization, the normalized stress-strain relationship formula is obtained:

[0082]

[0083] Where: represents the intercept of the normalized straight line on the ordinate, represents the slope of the normalized straight line; σ m is the average consolidation pressure, K0 is the static earth pressure coefficient;

[0084] A non-limit earth pressure calculation model is obtained based on the normalized stress-strain relationship formula and the distance between the target calculation point and the foundation pit sliding surface.

[0085] It should be noted that the triaxial shear test is one of the main methods for determining the shear strength of soil. The triaxial shear test is based on the Mohr-Coulomb strength theory. It uses 3 to 4 specimens to apply axial pressure under different constant ambient pressures and shear until failure, thereby determining the shear strength parameters of the soil.

[0086] The non-limit earth pressure calculation model includes the non-limit earth pressure calculation model of the active zone;

[0087] The calculation model of the non-limit earth pressure in the active zone is:

[0088]

[0089] Where: K0γ'z represents the horizontal earth pressure before foundation pit dewatering; γ'z represents the vertical earth pressure before dewatering; K0 represents the static earth pressure coefficient; γ' is the effective weight of the soil; λ is the coefficient,

[0090] Furthermore, the calculation model of non-limit earth pressure in the active zone can be simplified to:

[0091]

[0092] The calculation model of the non-limit earth pressure in the passive zone is:

[0093]

[0094] Where: K0 is the earth pressure coefficient under no deformation condition (or called static earth pressure coefficient), γ′ is the effective weight of soil, γ G is the weight of soil after precipitation, H is the depth of the enclosure structure, h1 is the distance between the ground and the initial water level, h2 is the precipitation depth outside the pit after the precipitation in the pit is completed; λ is the soil layer reduction coefficient,

[0095] For soils with good permeability, such as sand, the reduction coefficient is 0.8; for soils with poor permeability, such as clay, the reduction coefficient is 0.5.

[0096] Furthermore, the calculation model of non-limit earth pressure in the passive zone can be simplified to:

[0097]

[0098] Where A and B are coefficients,

[0099] See also Figure 3 , Figure 3 It is a diagram of the stress state of the soil unit closely connected to the enclosure structure at any given depth z. K0 is the earth pressure coefficient under the condition of no deformation (or called static earth pressure coefficient), γ′ is the effective weight of the soil, γ G is the weight of the soil after precipitation, H is the depth of the enclosure structure, h1 is the distance between the ground and the initial water level, and h2 is the precipitation depth outside the pit after the precipitation in the pit is completed. It is assumed that when no precipitation operation is carried out, the enclosure structure has sufficient stability and will not move laterally, and the unit is in a static state. When precipitation operations are carried out in the pit, the water pressure in the pit decreases, breaking the pressure balance on both sides of the original enclosure structure. At this time, the enclosure structure will shift to seek a new equilibrium state. Through analysis, it can be obtained that: when the depth z is less than the distance between the ground and the initial water level (that is, z < h1), before precipitation: δ 1c =γz,δ 3c =K0γz, after precipitation: δ1=γz, δ3=P a ; When the depth z is between the depth of precipitation outside the pit after the precipitation in the pit ends (i.e., when h1<z 1c =γh1+γ′(z-h1),δ 3c =K0(γh1+γ′(z-h1)), after precipitation: δ1=γh1+γ G (z-h1), δ3=P a ; When the depth z is below the depth of precipitation outside the pit after the precipitation in the pit ends (i.e. z>h1+h2), before precipitation: δ 1c =γh1+γ′(z-h1),δ 3c =K0(γh1+γ′(z-h1)), after precipitation: δ1=γh1+γ G h2+γ′(z-h1-h2),δ3=P a .

[0100] See also Figure 4 , Figure 4 ​It is a diagram of the stress state of the soil unit closely connected to the foundation pit support at any given depth z. It is assumed that when no precipitation operation is carried out, the support has sufficient stability and will not move laterally, and the unit is in a static state. When precipitation is carried out in the pit, the water pressure in the pit decreases, breaking the pressure balance on both sides of the original enclosure structure. At this time, the support will shift to seek a new equilibrium state. Through analysis, it can be obtained that: when the depth z is less than the distance between the ground and the initial water level (that is, z≤h1), before precipitation: δ 1c =γz,δ 3c =K0γz, after precipitation: δ1=γz, δ3=P p ; When the depth z is between the depth of precipitation in the pit after the precipitation in the pit ends (i.e. h1<z≤h1+H d Hours), before precipitation: δ 1c =γh1+γ′(z-h1),δ 3c =K0(γh1+γ′(z-h1)), after precipitation: δ1=γh1+γ G (z-h1), δ3=P p ; When the depth z is below the pit precipitation depth after the pit precipitation ends (i.e. z>h1+H d Hours), before precipitation: δ 1c =γh1+γ′(z-h1),δ 3c =K0(γh1+γ′(z-h1)), after precipitation: δ1=γh1+γ G H d +γ′(z-h1-H d ),δ3=P p .

[0101] Step S5: Calculating the non-limit earth pressure in the active area and the non-limit earth pressure in the passive area based on the non-limit earth pressure calculation model.

[0102] Among them, the active area is the soil range outside the foundation pit support, and the passive area is the soil range inside the foundation pit inside the foundation pit support. Specifically, the retaining wall is the soil outside the foundation pit as the active area, and the soil inside the pit is the passive area. According to the force of the retaining wall, the soil pressure acting on the retaining wall from the outside of the foundation pit is the active soil pressure, and the soil pressure acting on the retaining wall after the retaining wall is deformed is the passive soil pressure. Therefore, the retaining wall is the active area outside the foundation pit, and the pit is the passive area.

[0103] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to several modifications still falling within the scope of the appended claims.

[0104] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0105] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0106] 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 preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for calculating the non-limit earth pressure of foundation pit support under the barrier effect, characterized by: include, Acquire foundation pit parameters, wherein the foundation pit parameters include foundation pit width, precipitation depth, and calculation point depth of target calculation point; Calculating the distance between the target calculation point and the foundation pit sliding surface based on the target calculation point depth and the precipitation depth; Calculate the deformation of the support based on the distance between the target calculation point and the foundation pit sliding surface; Establish a non-limit earth pressure calculation model considering the influence of support displacement under the condition of water reduction before excavation; Based on the non-limit earth pressure calculation model, the non-limit earth pressure in the active zone and the non-limit earth pressure in the passive zone are calculated, wherein the active zone is the soil range outside the foundation pit support, and the passive zone is the soil range inside the foundation pit inside the foundation pit support.

2. The method for calculating the non-limit earth pressure of foundation pit support under the barrier effect according to claim 1 is characterized in that: The obtaining of foundation pit parameters specifically includes: Construct a three-dimensional scene model of the foundation pit; Creating a parametric component family library, the family library including family files of at least one type of foundation pit component, the family files including structural attribute information and functional attribute information of the foundation pit component; Processing the two-dimensional primitive information of the foundation pit, importing the two-dimensional information of the foundation pit into the three-dimensional scene model of the foundation pit to build a foundation pit data monitoring system, decomposing the two-dimensional information according to the classification of the foundation pit components, obtaining the two-dimensional decomposition elements of the foundation pit components, and associating the two-dimensional decomposition elements with the family files of the foundation pit components; The family file of the foundation pit is called in the foundation pit three-dimensional scene model to obtain the foundation pit parameters.

3. The method for calculating the non-limit earth pressure of foundation pit support under the barrier effect according to claim 2 is characterized in that: The construction of the foundation pit three-dimensional scene model specifically includes: Obtain relevant geographic parameter data packets required for constructing a foundation pit three-dimensional scene, wherein the geographic parameter data packets include scene longitude and latitude data and terrain data required for the scene; Determine the spatial position of the on-site terrain of the foundation pit based on the scene latitude and longitude data of the foundation pit, and determine the collection point for on-site panoramic data collection through the relationship between the BIM model and the spatial position of the on-site terrain of the foundation pit; Taking panoramic photos of the collection points in the on-site terrain area of ​​the target scene according to the viewing angle and height of the collection points; The panoramic photos are stitched together to obtain a long panoramic image, and the long panoramic image is repaired to obtain a three-dimensional scene model of the foundation pit.

4. The method for calculating the non-limit earth pressure of foundation pit support under the barrier effect according to claim 1 is characterized in that: The calculation formula for the distance between the target calculation point and the foundation pit sliding surface is: Among them, H is the height of the foundation pit enclosure; is the effective friction angle of soil; z is the depth of the retaining structure.

5. The method for calculating the non-limit earth pressure of foundation pit support under the barrier effect according to claim 1 is characterized in that: The calculation formula δ(z) of the deformation of the support is: Where x is the distance from any point in the disturbed area of ​​the soil on both sides of the support to the support.

6. The method for calculating the non-limit earth pressure of foundation pit support under the barrier effect according to claim 1 is characterized in that: The establishment of the ultimate earth pressure calculation model specifically includes: Based on the stress-strain relationship curve model of the triaxial shear test, the results of the triaxial shear test are linearly fitted according to the ε1σ1-σ3 relationship of ε1 to obtain the fitting relationship: The stress-strain relationship curve model is: Where: σ1 is the axial stress; σ3 is the radial stress; ε a is the axial strain; a and b are experimental constants; the fitting results are: Subtract the initial deviator stress σ from the deviator stress σ1-σ3 1c -σ 3c , and under the same loading and unloading conditions of the stress path, the stress-strain fitting relationship is replaced by the average consolidation pressure σ m After normalization, the normalized stress-strain relationship formula is obtained: Where: represents the intercept of the normalized straight line on the ordinate, represents the slope of the normalized straight line; σ m is the average consolidation pressure, K0 is the static earth pressure coefficient; A non-limit earth pressure calculation model is obtained based on the normalized stress-strain relationship formula and the distance between the target calculation point and the foundation pit sliding surface.

7. The method for calculating the non-limit earth pressure of foundation pit support under the barrier effect according to claim 1 is characterized in that: The non-limit earth pressure calculation model includes the non-limit earth pressure calculation model of the active zone; The calculation model of the non-limit earth pressure in the active zone is: Where: K0γ'z represents the horizontal earth pressure before foundation pit dewatering; γ'z represents the vertical earth pressure before dewatering; K0 represents the static earth pressure coefficient; γ' is the effective weight of the soil; λ represents the soil layer reduction coefficient, 8. The method for calculating the non-limit earth pressure of foundation pit support under the barrier effect according to claim 7 is characterized in that: The non-limit earth pressure calculation model also includes the passive zone non-limit earth pressure calculation model; The calculation model of the non-limit earth pressure in the passive zone is: Where: K0 is the earth pressure coefficient under no deformation condition (or called static earth pressure coefficient), γ′ is the effective weight of soil, γ G is the weight of soil after precipitation, H is the depth of the enclosure structure, h1 is the distance between the ground and the initial water level, h2 is the precipitation depth outside the pit after the precipitation in the pit is completed; λ represents the soil layer reduction coefficient,

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