Method, system and device for calculating internal force deformation of circular shaft structure and medium

Abstract

This invention provides a method, system, equipment, and medium for calculating the internal forces and deformations of a circular shaft structure. The method includes: establishing a three-dimensional model of the foundation pit support structure; using plate elements to simulate the diaphragm wall, solid elements to simulate the inner lining wall and concrete ring beam, soil spring elements to simulate the resistance of the soil inside the foundation pit, and compression-only resistance spring elements to simulate the constraint of the soil outside the circular shaft on the diaphragm wall; wherein the constitutive model of the diaphragm wall is a 2D orthotropic material; the constitutive models of the inner lining wall and concrete ring beam adopt isotropic elastic models; determining the horizontal stiffness of the soil spring elements, the stiffness coefficient of the resistance spring elements, the stiffness of the soil spring elements located at the bottom of the diaphragm wall, and the static earth pressure outside the circular shaft; and using the three-dimensional model of the foundation pit support structure to simulate and analyze the foundation pit construction process, obtaining the internal forces and deformations of the diaphragm wall and the inner lining wall. This invention can determine the internal forces and deformations of a circular shaft structure, and the calculation results better reflect the actual working conditions.

Description

Technical Field

[0001] This invention belongs to the field of foundation pit diaphragm wall support technology, and particularly relates to a method, system, equipment and medium for calculating internal forces and deformations of a circular vertical shaft structure. Background Technology

[0002] The design and calculation methods for circular diaphragm walls differ significantly from those for traditional straight diaphragm walls. Due to the significant spatial effects of circular diaphragm walls, especially double-layered circular shaft structures such as diaphragm walls and inner lining walls, their design calculations must fully consider both circumferential and vertical stress characteristics. Currently, commonly used design and calculation methods mainly include the following:

[0003] The first method is the planar vertical elastic foundation beam method. Based on this method, it considers the arch effect, treating the circular diaphragm wall as an axisymmetric structure and selecting a unit width of wall as the vertical elastic foundation beam. By replacing the circular diaphragm wall and its attached circumferential supports with springs of equivalent stiffness, the axial force is derived from the deformation calculations. However, when applying the planar elastic foundation beam method to deep foundation pit projects with significant spatial effects, the model is overly simplified and cannot reflect the actual spatial deformation characteristics of the structure, nor can it obtain the circumferential internal forces of the diaphragm wall.

[0004] The second method is the spatial elastic foundation plate method. For deep foundation pit projects with significant spatial effects, the spatial elastic foundation plate method is used to calculate the internal forces and deformations of the diaphragm wall. This method first establishes a three-dimensional finite element model based on the actual support structure design scheme. The model includes the retaining structure, horizontal support system, vertical support system, and soil spring elements. For retaining structures using diaphragm walls, three-dimensional plate elements can be used for simulation; for retaining structures using cast-in-place piles, beam elements or plate elements can be used for approximate simulation. In cases where temporary horizontal supports are used, the horizontal support system only includes beams, and beam elements can be used for simulation; for cases where the horizontal support system uses the main structural beams and slabs, beam and plate elements are used to simulate the horizontal support components, while also considering the combined action of the beams and slabs. The vertical support system includes columns and column piles, and can generally also be simulated using beam elements. The soil and water pressure loads exerted by the external soil on the retaining structure are determined based on the construction conditions and engineering geological conditions, and the internal forces and deformations of the support structure are analyzed accordingly. The spatial elastic foundation plate method is still based on the assumption of elastic foundation, which has limited adaptability to soil nonlinearity and complex boundary conditions. It cannot fully simulate the fine interaction between three-dimensional soil and structure, and does not take into account the stress characteristics of circular shaft structure, especially the weakening effect of diaphragm wall groove joint on the circumferential stiffness of diaphragm wall.

[0005] The third method is the three-dimensional continuum finite element method. Based on continuum mechanics, this method can finely simulate complex factors such as the interaction between soil and structure, seepage, and nonlinear materials. It considers three-dimensional spatial effects and is suitable for complex foundation pits that are ultra-deep, ultra-large, or located near sensitive buildings. The three-dimensional continuum finite element method requires fine mesh generation, large model size, high hardware requirements, and is time-consuming. The accuracy of the soil constitutive model and model parameters directly affects the results, making parameter determination difficult. Modeling, boundary condition setting, and result analysis require professional knowledge and are prone to non-convergence or errors. Summary of the Invention

[0006] The purpose of this invention is to provide a method, system, equipment, and medium for calculating the internal forces and deformations of a circular shaft structure. This method can determine the internal forces and deformations of the circular shaft structure, and the determined internal forces and deformations of the circular shaft structure can better reflect the actual working conditions. The calculation results are more consistent with the actual situation and can better ensure the safety of the project.

[0007] This invention is achieved through the following technical solution: A method for calculating the internal forces and deformations of a circular vertical shaft structure is provided. The circular vertical shaft includes a diaphragm wall and an inner lining wall located inside the diaphragm wall. The method includes the following steps: Based on actual engineering projects, a three-dimensional load-bearing structural model of the foundation pit support structure was established. Plate elements were used to simulate the diaphragm wall, solid elements were used to simulate the inner lining wall and concrete ring beam, soil spring elements were used to simulate the resistance of the soil inside the circular shaft, and compression-only resistance spring elements were used to simulate the constraint of the soil outside the circular shaft on the diaphragm wall. The constitutive model of the diaphragm wall is a 2D orthotropic material, while the constitutive models of the inner lining wall and concrete ring beam are isotropic elastic models. The parameters of the 2D orthotropic material are obtained by the following formula: (1); (2); (3); (4); (5); (6); In the formula, It is the transverse elastic modulus. Here, E represents the calculated elastic modulus of concrete. For longitudinal elastic modulus, , This is the reduction factor. , and Both are shear modulus. Compared to pine and cypress; Determine the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element; Determine the stiffness of the soil spring element located at the bottom of the diaphragm wall; Determine the at-rest earth pressure outside the circular shaft; The construction process of the foundation pit was simulated and analyzed using a three-dimensional model of the foundation pit support structure, and the internal forces and deformations of the diaphragm wall and the inner lining wall were obtained.

[0008] Furthermore, the step of determining the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element includes: The horizontal stiffness of the soil spring element is calculated using the following formula: (7); (8); In the formula, For the compressive stiffness of the soil spring, This is the horizontal reaction force coefficient of the soil inside the circular shaft. The horizontal spacing of the spring is calculated. The vertical calculation spacing of the spring is given by m, where m is the proportionality coefficient of the soil's horizontal reaction force. To calculate the depth of the point from the ground, For the first Calculate the excavation depth of the foundation pit under the following working conditions; The preset percentage of the horizontal stiffness of the soil spring element is used as the stiffness coefficient of the resistance spring element.

[0009] Furthermore, the step of calculating the horizontal stiffness of the soil spring element according to the following formula includes: The proportionality coefficient of the soil's horizontal reaction force coefficient is calculated according to formula (9): (9); In the formula, To represent the cohesion of soil, Let be the internal friction angle of the soil. This represents the horizontal displacement of the retaining structure at the bottom of the pit.

[0010] Furthermore, the step of simulating the constraint of the diaphragm wall on the outer soil of the circular shaft using only compressed resistance spring units includes: For the strata surrounding the circular shaft, stress zones at 90-degree angles to each other are delineated along the circumference of the circular shaft. It is assumed that the difference in friction angle between the two stress zones at 90-degree angles to each other is [value missing]. 4°, at the internal friction angle +4 0 The corresponding stress area is set with only compression-resistant spring units to simulate the constraint of the soil outside the circular shaft on the diaphragm wall; For a stress-bearing region consisting of soil layers, assuming an effective internal friction angle of 90 degrees between two stress-bearing regions... The difference is 4°, for a stress-bearing area consisting of strongly weathered rock, assuming the difference in the static earth pressure coefficient K0 between two stress-bearing areas at 90 degrees to each other is 4°, 0.05, for a stress-bearing area consisting of weakly weathered rock, assuming the difference in the coefficient of static earth pressure K0 between two stress-bearing areas at 90 degrees to each other is 0.05. 0.03.

[0011] This invention also provides a system for calculating the internal forces and deformations of a circular shaft structure, used in a circular shaft, the circular shaft including a diaphragm wall and an inner lining wall disposed inside the diaphragm wall, the system comprising: A module is established to create a 3D model of the foundation pit support structure based on actual engineering projects. Plate elements are used to simulate the diaphragm wall, solid elements to simulate the inner lining wall and concrete ring beam, soil spring elements to simulate the resistance of the soil inside the circular shaft, and compression-only resistance spring elements to simulate the constraint of the soil outside the circular shaft on the diaphragm wall. The constitutive model of the diaphragm wall is a 2D orthotropic material, while the constitutive models of the inner lining wall and concrete ring beam are isotropic elastic models. The parameters of the 2D orthotropic material are obtained from the following formulas: (1); (2); (3); (4); (5); (6); In the formula, It is the transverse elastic modulus. Here, E represents the calculated elastic modulus of concrete. For longitudinal elastic modulus, , This is the reduction factor. , and Both are shear modulus. Compared to pine and cypress; The first determining module is used to determine the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element; The second determining module is used to determine the stiffness of the soil spring unit located at the bottom of the diaphragm wall; The third determining module is used to determine the at-rest earth pressure outside the circular shaft; The analysis module is used to simulate and analyze the construction process of the foundation pit using a three-dimensional model of the foundation pit support structure, and to obtain the internal forces and deformations of the diaphragm wall and the inner lining wall.

[0012] The present invention also discloses an electronic device, which includes: processor; Memory is used to store executable computer programs; Among them, the steps of implementing the method for calculating the internal force and deformation of a circular vertical shaft structure when the processor executes the computer program.

[0013] The present invention also discloses a computer-readable storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of a method for calculating the internal force and deformation of a circular vertical shaft structure.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the diaphragm wall adopts orthotropic concrete material, and the circumferential modulus parameter takes into account the reduction factor, which can determine the internal force and deformation of the circular shaft structure, better reflect the actual working conditions, and the calculation results are more in line with the actual situation, thus better ensuring the safety of the project. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the steps of the method for calculating the internal forces and deformations of a circular vertical shaft structure according to the present invention. Figure 2 This is a schematic diagram of the calculation model for the internal force and deformation calculation method of the circular vertical shaft structure of the present invention; Figure 3 Schematic diagram for the uneven distribution of water and soil pressure during excavation. Figure 4 This is a schematic diagram of the simulation calculation process for excavating soil to 0.5m below the bottom elevation of the capping beam during construction; Figure 5 This is a schematic diagram of the simulation calculation process for excavating soil to 0.5m below the bottom elevation of the first section of the concrete inner lining wall during construction. Figure 6 Plan view of the working shaft of GS01# shield tunnel; Figure 7 This is a cross-sectional view of the working shaft of the GS01# shield tunnel. Figure 8 This is a schematic diagram of the load calculation model; Figure 9 A diagram showing the parameter settings for the modulus of a 2D orthotropic material in a diaphragm wall in Midas / GTS software; Figure 10 Plan view of the deformation monitoring layout for the GS01# shaft continuous wall foundation pit; Figure 11 For GS01#-IN2-1, see the cumulative displacement curve. Figure 12 For GS01#-IN3-1, see the cumulative displacement curve. Figure 13 For GS01#-IN4-1, see the cumulative displacement curve. Figure 14 For GS01#-IN5-1, see the cumulative displacement curve. Figure 15 For GS01#-IN6-1, see the cumulative displacement curve. Figure 16 The cumulative displacement envelope curves for each inclinometer tube are shown. Figure 17 Plan view of the stress monitoring layout for the continuous wall of the GS01# working well foundation pit; Figure 18 A displacement envelope diagram comparing calculated and measured values; Figure 19 A bending moment envelope diagram comparing the calculated and measured values; Figure 20 This is a schematic diagram of the module of the circular vertical shaft structure internal force and deformation calculation system of the present invention; Figure 21 This is a hardware structure diagram of the electronic device of the present invention.

[0016] In the diagram, 1-diaphragm wall, 2-lining wall, 3-excavation face, 4-soil spring unit, 5-resistance spring unit, 6-first horizontal displacement measuring point, 7-second horizontal displacement measuring point, 8-third horizontal displacement measuring point, 9-fourth horizontal displacement measuring point, 10-fifth horizontal displacement measuring point, 11-sixth horizontal displacement measuring point, 12-first vertical displacement measuring point, 13-second vertical displacement measuring point, 14-third vertical displacement measuring point, 15-fourth vertical displacement measuring point, 16-fifth vertical displacement measuring point, 17-sixth vertical displacement measuring point, 18-first inclinometer tube, 19-second inclinometer tube, 20-third inclinometer tube, 21-fourth inclinometer tube, 22-fifth inclinometer tube, 23-sixth inclinometer tube, 24-first reinforcement gauge, 25-second reinforcement gauge, 26-third reinforcement gauge, 27-fourth reinforcement gauge, 28-fifth reinforcement gauge, 29-sixth reinforcement gauge, 30-seventh reinforcement gauge, 31-eighth reinforcement gauge. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0019] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0021] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0022] Please see Figure 1 and Figure 2 , Figure 1 This is a flowchart illustrating the steps of the method for calculating the internal forces and deformations of a circular vertical shaft structure according to the present invention. Figure 2 This is a schematic diagram of the calculation model for the internal force and deformation calculation method of a circular shaft structure according to the present invention. The present invention provides a method for calculating the internal force and deformation of a circular shaft structure, applicable to a circular shaft, which includes a diaphragm wall and an inner lining wall disposed inside the diaphragm wall; the method includes the following steps: S1. Based on actual engineering, a three-dimensional load structure model of the foundation pit support structure is established. Plate elements are used to simulate the diaphragm wall, solid elements are used to simulate the inner lining wall and concrete ring beam, soil spring elements are used to simulate the resistance of the soil inside the circular shaft, and compression-only resistance spring elements are used to simulate the constraint of the soil outside the circular shaft on the diaphragm wall. Among them, the constitutive model of the diaphragm wall is a 2D orthotropic material, and the constitutive models of the inner lining wall and concrete ring beam are isotropic elastic models. The parameters of the 2D orthotropic material are obtained by the following formula: (1); (2); (3); (4); (5); (6); In the formula, It is the transverse elastic modulus. Here, E represents the calculated elastic modulus of concrete. For longitudinal elastic modulus, , This is the reduction factor. , and Both are shear modulus. Compared to pine and cypress; S2. Determine the horizontal stiffness of the soil spring unit inside the foundation pit and the stiffness of the resistance spring unit of the soil outside the foundation pit under each excavation condition. S3. Determine the stiffness of the soil spring unit located at the bottom of the diaphragm wall; S4. Determine the at-rest earth pressure outside the circular shaft under each excavation condition; S5. The three-dimensional load structure model of the foundation pit support structure is used to simulate and analyze the foundation pit construction process, and the internal forces and deformations of the diaphragm wall and inner lining wall under various excavation conditions are obtained.

[0023] In step S1 above, a three-dimensional load-bearing structural model of the foundation pit support structure is established based on the actual project. The established model is as follows: Figure 2 As shown, the diaphragm wall is arranged in a polygonal plan according to the actual structure and is simulated using plate elements. The inner lining wall and concrete ring beam are simulated using solid elements. The water and soil pressure load of the soil outside the foundation pit on the diaphragm wall is determined according to the construction conditions and engineering geological conditions. The resistance of the soil inside the foundation pit is simulated using soil springs. Figure 2 of Additionally, a soil-resistance spring with only compression is applied to the outside of the diaphragm wall to simulate the constraint effect of the soil in the deformation zone outside the diaphragm wall on the diaphragm wall, such as... Figure 2of The constitutive model of the diaphragm wall is a 2D orthotropic material, with key parameters including unit weight. transverse elastic modulus Longitudinal elastic modulus Poisson's ratio shear modulus shear modulus and shear modulus When considering 85% of the strength of the diaphragm wall during earthwork excavation, the elastic modulus of the diaphragm wall is typically taken as... The diaphragm wall uses orthotropic plate elements to simulate the effect of the groove joint on the circumferential stiffness. To account for the reduction in circumferential stiffness, the circumferential modulus parameter is multiplied by... The reduction can be taken according to the "Specifications for Design of Highway Bridge and Culvert Foundations" (JTG3363-2019). =0.4~0.7, when When the value is large, or when there are many trench segments, a smaller value is used; this invention takes into account the large depth of the diaphragm wall and the difficulty in controlling the verticality of the trench holes; the need for secondary connection of the diaphragm wall reinforcement cage into the trench increases the possibility of mud inclusion in the joints between trench segments; the stiffness reduction caused by the construction error of the diaphragm wall's roundness, this invention considers the construction influence coefficient based on the back analysis of the circumferential stiffness monitoring of the diaphragm wall in actual projects. Regarding the reduction of the circumferential stiffness of the wall, it is proposed that, in addition to the reduction method specified in the code, a reduction factor should also be considered. It is acceptable =0.7~1.0; therefore, formulas (1) to (6) are used to calculate the 2D orthotropic material parameters. The constitutive models of the inner lining wall and the concrete ring beam adopt isotropic concrete material, and the elastic modulus of the inner lining wall and the bottom slab concrete is taken as 0.8. This is mainly because the formwork will be removed and excavation will begin when the concrete strength of each compartment reaches 80%.

[0024] To account for the uneven earth pressure caused by differences in the strata surrounding the working shaft, the steps of simulating the constraint of the diaphragm wall by the soil outside the circular shaft using only compression-bearing resistance spring elements include: S11. For the strata surrounding the circular shaft, delineate stress zones at 90-degree angles to each other along the circumference of the circular shaft. Assume the difference in friction angle between the two stress zones at 90-degree angles to each other is... 4°, at the internal friction angle +4 0 The corresponding stress area is set with only compression-resistant spring units to simulate the constraint of the soil outside the circular shaft on the diaphragm wall; S12. For stress-bearing regions consisting of soil layers, assume the effective internal friction angle of the soil layers in two stress-bearing regions that are 90 degrees apart. The difference is 4°, for a stress-bearing area consisting of strongly weathered rock, assuming the difference in the static earth pressure coefficient K0 between two stress-bearing areas at 90 degrees to each other is 4°, 0.05, for a stress-bearing area consisting of weakly weathered rock, assuming the difference in the coefficient of static earth pressure K0 between two stress-bearing areas at 90 degrees to each other is 0.05. 0.03.

[0025] In steps S11 to S12 above, it is assumed that the two sides are 90 degrees apart. 0 The difference in the internal friction angle between the two soil layers is ±4. 0 .exist +4 0 An external set of springs is applied to the outer side of the area to simulate the constraint effect of the soil on the wall in the outward deformation zone of the circular well. For the soil layers: it is assumed that they are at an interval of 90 degrees. 0 Effective internal friction angle of soil layers in two zones The difference is ±4 0 The diagram is as follows Figure 3 As shown; for rock strata: strongly weathered rock, assuming they are at an interval of 90 degrees... 0 The difference in the static earth pressure coefficient K0 between the two zones is ±0.05; for the weakly weathered rock layer, the difference in the static earth pressure coefficient K0 is ±0.03.

[0026] In step S2 above, the steps for determining the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element include: S21. Calculate the horizontal stiffness of the soil spring element according to the following formula: (7); (8); In the formula, For the compressive stiffness of the soil spring, This is the horizontal reaction force coefficient of the soil inside the circular shaft. The horizontal spacing of the spring is calculated. The vertical calculation spacing of the spring is given by m, where m is the proportionality coefficient of the soil's horizontal reaction force. To calculate the depth of the point from the ground, For the first Calculate the excavation depth of the foundation pit under the following working conditions; S22. Use the preset percentage of the horizontal stiffness of the soil spring as the stiffness coefficient of the resistance spring unit.

[0027] In steps S21 and S22 above, the horizontal stiffness of the soil spring element inside the foundation pit below the excavation surface can be calculated according to formulas (7) and (8), where and The width and height of the retaining structure unit (plate unit) connected to the soil spring unit in the three-dimensional model are respectively taken as the width and height. In the process of calculating the horizontal reaction coefficient of the soil inside the circular shaft, the proportionality coefficient m of the horizontal reaction coefficient of the soil can be determined according to Article 4.1.6 of the Technical Specification for Foundation Pit Support of Buildings, or the proportionality coefficient of the horizontal reaction coefficient of the soil can be calculated according to formula (9): (9); In the formula, To represent the cohesion of soil, Let be the internal friction angle of the soil. This represents the horizontal displacement of the retaining member (diaphragm wall) at the bottom of the pit, where cohesion... and internal friction angle The value shall be determined in accordance with the provisions of Article 3.1.14 of this specification; for multi-layered soil, the value shall be taken separately for each soil layer.

[0028] The stiffness of the resistance spring unit on the outside of the foundation pit can be taken as a preset percentage of the horizontal stiffness of the soil spring unit on the inside of the pit. In this embodiment, the preset percentage is set to 10%. That is, 10% of the horizontal stiffness of the soil spring unit on the inside of the pit is taken as the stiffness of the resistance spring unit.

[0029] In step S3 above, the stiffness of the soil spring element located at the bottom of the diaphragm wall... According to Articles 4.1.5 and 4.1.6 of the "Technical Specification for Foundation Pit Support" JGJ 120-2012, for ease of modeling, the stiffness of the soil spring element located at the bottom of the diaphragm wall is calculated. Greater than the maximum horizontal subgrade coefficient At that time, the horizontal subgrade coefficient The stiffness of the soil spring unit located at the bottom of the diaphragm wall .

[0030] In step S4 above, the method for calculating the static earth pressure outside the circular shaft is the same as that for the planar vertical elastic foundation beam. The only difference is that in the planar vertical elastic foundation beam, the earth pressure acts as a line load on the retaining structure, while in the spatial elastic foundation plate method, the earth pressure is a surface load acting on the retaining structure.

[0031] In step S5 above, the parameters obtained from steps S2 to S5 are substituted into the three-dimensional model of the foundation pit support structure to simulate the foundation pit construction process. An incremental calculation method is used, and finite element software is employed to analyze the construction process of the foundation pit support structure, obtaining the internal forces and deformations of the diaphragm wall and the inner lining wall. Specifically, in the engineering design calculations, for a support structure assuming n layers of inner lining (including capping beams) or supporting ring beams, the principle of simultaneous excavation and construction of the inner lining or ring beams is adopted. The specific analysis process is as follows: First, excavate to 0.5m below the bottom elevation of the capping beam layer (or including part of the inner lining wall). A simplified calculation diagram is shown below. Figure 4 As shown, the internal forces and deformations of the support structure are calculated when the soil and water pressure on the outside is applied. Second, after the first section of the capping beam is completed and the concrete strength reaches 80% of the design value, excavate to 0.5m below the bottom elevation of the first section of the concrete lining wall. A simplified calculation diagram is shown below. Figure 5 As shown, an increment of soil and water pressure is applied, and the deformation and internal forces of the support structure under the new soil and water pressure are calculated. Third, in sequence, apply the (n-1)th concrete inner lining wall (or concrete ring beam) and excavate the nth layer of soil until the foundation pit is excavated to the base position; Fourth, construct the concrete base slab. After the concrete strength reaches 80% of the design value, remove the concrete ring beam and construct the portal wall and inner lining wall. Fifth, the shield tunneling machine is hoisted. At this time, the ground overload in the hoisting area is calculated as 70 kPa.

[0032] The finite element method can be used in this process to obtain the internal forces and deformations of the diaphragm wall and the inner lining wall.

[0033] The following specific engineering examples illustrate the feasibility of the method for calculating internal forces and deformations in the circular vertical shaft structure of this invention: The project involves the GS01# working shaft, a shield tunneling launch shaft. The working shaft is a circular vertical shaft with an outer diameter of 39m. The excavation depth is 39.10m, the diaphragm wall depth is 43.10m, and the embedment depth is 4m. A diaphragm wall with reinforced concrete lining is used for support. The diaphragm wall is 1.2m thick, and four 1.5m thick lining walls are constructed using a reverse method. Additionally, there are two ring beams, each 2.5m wide and 1.5m high. The plan view is shown below. Figure 6 As shown, Figure 6 AA sectional view as follows Figure 7 As shown.

[0034] The geological conditions of the working well are as follows: the upper and middle parts of the site consist of fill and alluvial layers, with a relatively thick alluvial layer including silty soil, silty fine sand, clay, and medium-fine argillaceous sand; the lower part consists of thin layers of completely weathered and strongly weathered coarse sandstone, which is soft and broken; below that is a relatively intact weakly weathered argillaceous conglomerate. The alluvial layer, completely weathered soil layer, and strongly weathered rock have poor self-stabilizing capacity. The silty fine sand layer and medium-fine argillaceous sand are aquifers with moderate to strong permeability. The strongly weathered rock is broken and has moderate permeability. The engineering geological conditions are poor, and seepage prevention measures should be taken during well excavation to avoid seepage damage such as water inrush, sand inrush, and well wall collapse. Attention should be paid to well wall support and drainage measures. The calculated borehole for the GS01# working well is ZKCB01. The recommended values ​​of physical and mechanical properties for each soil layer in the site are detailed in Table 1.

[0035] Table 1 Recommended values ​​for physical and mechanical properties of soil layers

[0036] According to the Technical Specification for Foundation Pit Support of Buildings (JGJ 120-2012) and the Design Specification for Foundations and Substructures of Highway Bridges and Culverts (JTG D63-2019), the following earth pressure calculation model should be adopted for diaphragm walls: the retaining side uses static earth pressure; the soil reaction on the foundation pit side consists of the initial soil reaction and a set of elastic supports (soil resistance) on the passive side (foundation pit side). The initial soil reaction is calculated according to Rankine's active earth pressure formula, but the effect of soil cohesion is not considered.

[0037] For the soil layer, the coefficient of earth pressure at rest, K0 = 1 - sin , This is the effective internal friction angle.

[0038] For rock strata where soil and water are compatible, considering the effect of certain bedrock fissure water pressure, the static earth pressure coefficient K0 of strongly weathered silty mudstone is taken as 0.50, and the static earth pressure coefficient K0 of weakly weathered silty mudstone is taken as 0.30.

[0039] The groundwater level is calculated based on the actual groundwater level and the water pressure is not reduced.

[0040] Below the groundwater level, for sandy soils with high permeability, calculations are based on separate water and soil measurements; for other soil layers, calculations are based on a combined water and soil measurement. For rock strata, strongly weathered sandstone, gravelly sandstone, conglomerate, and granite have high permeability and are classified as medium to strong permeable layers, calculated separately for water and soil measurements; strongly weathered mudstone and silty mudstone have medium to weak permeability and are calculated based on a combined water and soil measurement; weakly weathered rock generally has low permeability and is classified as a weakly permeable layer, calculated based on a combined water and soil measurement.

[0041] Overload during construction around the launch shaft pit is controlled at 35 kPa, and overload during shield machine hoisting on the ground is considered at 70 kPa.

[0042] In the modeling and calculation, the top of the foundation pit is taken as the depth z=0m, and the calculation model is as follows: Figure 8 As shown.

[0043] Excavation of the foundation pit proceeds in layers from top to bottom. Each time excavation reaches 0.5m below the concrete lining section elevation or 0.5m below the bottom surface of the concrete ring beam structure, the concrete lining or ring beam construction for that section must be carried out. The foundation pit can only be further excavated after the concrete strength of the lining or ring beam reaches 80% of the design value. This process is repeated until the design elevation of the pit bottom is reached. After the bottom slab is poured and the concrete strength reaches 80% of the design value, the concrete ring beam supports are removed, and the portal wall is constructed. According to Guangdong Provincial Standards "Technical Specification for Building Foundation Pit Engineering," "Design Specification for Highway Bridge and Culvert Foundations," and "Design and Construction Specification for Underground Continuous Wall Structures in Port Engineering," circular working shafts should be calculated as spatial structures.

[0044] The circular working shaft of this project adopts the internal force and deformation calculation method of the circular vertical shaft structure of this invention during the construction drawing stage, and is calculated using MIDAS\GTS software. The specific calculation conditions are shown in Table 2.

[0045] Table 2 Calculation Condition Table

[0046] The diaphragm wall design uses C30 concrete. The well shaft has a large diameter and many trench sections, so a correction factor of a=0.4 is taken. Since the actual layout of the diaphragm wall is polygonal, and the construction error of the verticality of the trench section causes misalignment between the trench sections, resulting in a reduction in the wall thickness, the effective thickness of the diaphragm wall is taken as d=0.75b, where b is the thickness of the diaphragm wall. In order to facilitate modeling and calculation, the coefficient 0.75 is converted into the modulus for consideration.

[0047] In addition, considering the large depth of the diaphragm wall in this project, the verticality of the trench is difficult to control; the reinforcement cage of the diaphragm wall needs to be reconnected twice when entering the trench, which increases the possibility of mud getting into the joints between trench sections; the reduction in stiffness caused by the construction error of the circularity of the continuous wall, the construction influence coefficient β on the reduction of the circumferential stiffness of the wall was also considered in the construction drawing stage of this project. In this project, β=0.7 is taken.

[0048] The modulus of the 2D orthotropic material of the diaphragm wall is calculated as follows: ; ; ; Right now = ; ; ; ; In this calculation, only one decimal place is used according to the standard. Therefore, the parameter settings for the modulus of the 2D orthotropic material of the diaphragm wall in the Midas / GTS software are as follows: Figure 9 As shown.

[0049] During the actual excavation of the working shaft foundation pit, the layout plan for monitoring the deformation of the working shaft continuous wall foundation pit is shown below. Figure 10To monitor the horizontal displacement of the top of the diaphragm wall, six horizontal displacement measuring points were installed on the top of the diaphragm wall in sections 3, 9, 13, 16, 22, and 25 around the foundation pit. These points are designated as the first, second, third, fourth, fifth, and sixth horizontal displacement measuring points, and are numbered GS01#-TP1-1, GS01#-TP2-1, GS01#-TP3-1, GS01#-TP4-1, GS01#-TP5-1, and GS01#-TP6-1, respectively. The horizontal displacement of the top of the diaphragm wall in the GS01# working shaft was between -8.89 mm and 11.75 mm in the radial direction and between -4.43 mm and 14.33 mm in the tangential direction. The deformation at each measuring point was within the allowable range. To monitor the vertical displacement of the working shaft, six vertical displacement measuring points were cast in the same pier as the horizontal displacement measuring points. These are the first, second, third, fourth, fifth, and sixth vertical displacement measuring points, with design numbers GS01#-LD1-1, GS01#-LD2-1, GS01#-LD3-1, GS01#-LD4-1, GS01#-LD5-1, and GS01#-LD6-1, respectively. The vertical displacement settlement of the diaphragm wall of the GS01# working shaft ranged from 0.28 mm to 5.18 mm, showing a relatively small rate of change. The observation results of the horizontal and vertical displacement measuring points at the top of the diaphragm wall of the GS01# working shaft are shown in Table 3.

[0050] Table 3: Observation Results of Horizontal and Vertical Displacement at the Top of the Diaphragm Wall in Shaft GS01#

[0051] To monitor the deep horizontal displacement of the diaphragm wall in the working shaft, a total of six inclinometer tubes were installed in the working shaft, namely the first inclinometer tube, the second inclinometer tube, the third inclinometer tube, the fourth inclinometer tube, the fifth inclinometer tube, and the sixth inclinometer tube, numbered GS01#-IN1-1, GS01#-IN2-1, GS01#-IN3-1, GS01#-IN4-1, GS01#-IN5-1, and GS01#-IN6-1 respectively. The six inclinometer tubes were installed in sections 3#, 9#, 13#, 16#, 22#, and 25# respectively. The installation time of the inclinometer tubes was consistent with the installation time of the diaphragm wall reinforcement cage in the corresponding section. However, the instrument at measuring point GS01#-IN1-1 was damaged and could not be monitored. The maximum displacement of GS01 was 11.125 mm towards the working well, located at a depth of -31 m from the GS01#IN2-1 measuring point. Since obtaining the initial value, this borehole has shown a slow deformation trend, and the deformation trend of all measured values ​​remained stable during the excavation of the foundation pit. As can be seen from the monitoring deformation diagram, in the early stage of foundation pit excavation, the deformation rate of the borehole was small and the deformation trend was stable. After the foundation pit was fully excavated, all boreholes showed deformation towards the foundation pit. The overall trend of change was that the deformation moved towards the bottom of the foundation pit as the excavation depth increased. The cumulative displacement of the deep horizontal displacement was small, and the measured values ​​of all boreholes in the working well did not exceed the design warning values. The displacement process line is shown below. Figures 11 to 15 The envelope diagrams for each measuring point are shown below. Figure 16 The results of the maximum and minimum displacement values ​​are summarized in Table 4. Displacement towards the working well is positive, and displacement away from it is negative.

[0052] Table 4 Summary of Maximum Displacement of Each Inclinometer Pipe in GS01# Working Well

[0053] The monitoring data above shows that during construction, the horizontal displacement of the top of the diaphragm wall of the GS01# working well was controlled within 15mm, with the largest displacement occurring at measuring points TP4-1 and TP-5. The vertical displacement of the diaphragm wall was smaller, controlled within 6mm. The main horizontal displacement occurred in the lower and middle parts of the diaphragm wall. The deformation along the depth obtained from the inclinometer measuring points was basically consistent. As the excavation depth increased, the elevation of the maximum horizontal deformation also gradually increased, with the maximum horizontal displacement occurring in the range of 27–31m depth, and the maximum displacement within 12mm. Although the embedment depth of the diaphragm wall was only 4m, its height within the rock strata was approximately 15m, and the deep soil provided good embedment, resulting in relatively small deformation at the bottom of the diaphragm wall.

[0054] The diaphragm wall of the GS01# working shaft uses vibrating wire rebar gauges to measure rebar stress. Eight rebar gauges are used for vertical stress measurement, numbered GS01#-R1-1 to GS01#-R1-4 and GS01#-R5-1 to GS01#-R5-4 respectively. The layout plan for stress monitoring of the diaphragm wall in the foundation pit is shown below. Figure 17 The vertical stress measurement results ranged from -16.87 MPa to 65.84 MPa. The specific measurement results are shown in Table 5. Table 5 Reinforcement Measurement Results

[0055] The maximum design positive bending moment of the GS01# working well was calculated to be 1289.78 kN. m / m, the maximum design negative bending moment is -1390.13kN m / m. The measured results were compared with the design values; the displacement results are shown below. Figure 18 The bending moment results at each measuring point are shown in the figure. Figure 19 It can be seen that the design value and the measured result are in good agreement, which verifies the feasibility of the method.

[0056] Please refer to the following: Figure 20 , Figure 20 This is a schematic diagram of the module of the circular shaft structure internal force and deformation calculation system of the present invention. Corresponding to the aforementioned embodiment of the circular shaft structure internal force and deformation calculation method of the present invention, the present invention also discloses a circular shaft structure internal force and deformation calculation system for a circular shaft, the circular shaft including a diaphragm wall and an inner lining wall disposed inside the diaphragm wall, the system including: Module 1 is established to create a 3D model of the foundation pit support structure based on actual engineering projects. Plate elements are used to simulate the diaphragm wall, solid elements to simulate the inner lining wall and concrete ring beam, soil spring elements to simulate the resistance of the soil inside the circular shaft, and compression-only resistance spring elements to simulate the constraint of the soil outside the circular shaft on the diaphragm wall. The constitutive model of the diaphragm wall is a 2D orthotropic material, while the constitutive models of the inner lining wall and concrete ring beam are isotropic elastic models. The parameters of the 2D orthotropic material are obtained from the following formulas: (1); (2); (3); (4); (5); (6); In the formula, For longitudinal elastic modulus, Here, E represents the calculated elastic modulus of concrete. It is the transverse elastic modulus. , This is the reduction factor. , and Both are shear modulus. Compared to pine and cypress; The first determining module 2 is used to determine the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element; The second determining module 3 is used to determine the stiffness of the soil spring unit located at the bottom of the diaphragm wall; The third determining module 4 is used to determine the at-rest earth pressure outside the circular shaft; Analysis module 5 is used to simulate and analyze the construction process of the foundation pit using a three-dimensional model of the foundation pit support structure, and to obtain the internal forces and deformations of the diaphragm wall and the inner lining wall.

[0057] Furthermore, the first determining module 2 includes: The calculation submodule is used to calculate the horizontal stiffness of the soil spring element according to the following formula: (7); (8); In the formula, For the compressive stiffness of the soil spring, This is the horizontal reaction force coefficient of the soil inside the circular shaft. The horizontal spacing of the spring is calculated. The vertical calculation spacing of the spring is given by m, where m is the proportionality coefficient of the soil's horizontal reaction force. To calculate the depth of the point from the ground, For the first Calculate the excavation depth of the foundation pit under the following working conditions; As a submodule, it is used to use a preset percentage of the horizontal stiffness of the soil spring unit as the stiffness of the resistance spring unit.

[0058] Furthermore, the first computational submodule includes: The calculation unit is used to calculate the proportionality coefficient of the soil's horizontal reaction force coefficient according to formula (9): (9); In the formula, To represent the cohesion of soil, Let be the internal friction angle of the soil. This represents the horizontal displacement of the retaining structure at the bottom of the pit.

[0059] Furthermore, the module setup includes: The delineation submodule is used to delineate stress-bearing zones at 90-degree angles to each other along the circumference of the circular shaft in the surrounding strata, assuming that the difference in friction angle between the two stress-bearing zones at 90-degree angles is... 4°, at the internal friction angle +4 0 The corresponding stress area is set with only compression-resistant spring units to simulate the constraint of the soil outside the circular shaft on the diaphragm wall; Assuming a submodule, for stress regions consisting of soil layers, the effective internal friction angle of the soil layers in two stress regions at 90 degrees to each other is assumed. The difference is 4°, for a stress-bearing area consisting of strongly weathered rock, assuming the difference in the static earth pressure coefficient K0 between two stress-bearing areas at 90 degrees to each other is 4°, 0.05, for a stress-bearing area consisting of weakly weathered rock, assuming the difference in the coefficient of static earth pressure K0 between two stress-bearing areas at 90 degrees to each other is 0.05. 0.03.

[0060] The implementation process of the functions and roles of each module, submodule, and unit in the above system is detailed in the implementation process of the corresponding steps in the above method, and will not be repeated here. For the system embodiment, since it basically corresponds to the method embodiment, relevant parts can be referred to in the description of the method embodiment. The system embodiment described above is merely illustrative; the units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units.

[0061] Corresponding to the aforementioned embodiments of the method for calculating the internal force and deformation of a circular shaft structure, this invention also provides an electronic device. The electronic device may include: a processor; and a memory for storing an executable computer program. When the processor executes the computer program, it implements the method for calculating the internal force and deformation of a circular shaft structure as described in any of the aforementioned method embodiments. All embodiments of the circular shaft structure internal force and deformation calculation system provided by this invention can be applied to electronic devices. Taking software implementation as an example, as a logical device, it is formed by the processor of the electronic device reading the corresponding computer program instructions from the non-volatile memory into the memory for execution. From a hardware perspective, as shown in Figure 21, in addition to the processor, memory, network interface, and non-volatile memory shown in Figure 21, the electronic device may also include other hardware, such as a camera module; or, depending on the actual function of the electronic device, it may also include other hardware, which will not be elaborated further.

[0062] Corresponding to the aforementioned embodiment of the method for calculating the internal force and deformation of a circular shaft structure, this embodiment of the invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the method for calculating the internal force and deformation of a circular shaft structure.

[0063] Embodiments of the present invention may take the form of a computer program product implemented on one or more storage media containing program code (including but not limited to disk storage, CD-ROM, optical storage, etc.). The computer-readable storage medium may include: permanent or non-permanent removable or non-removable media. The information storage function of the computer-readable storage medium can be implemented by any feasible method or technology. The information may be computer-readable instructions, data structures, program models, or other data.

[0064] In addition, computer-readable storage media include, but are not limited to: phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or other non-transfer media that can be used to store information accessible by a computing device.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for calculating the internal forces and deformations of a circular vertical shaft structure, used for a circular vertical shaft, the circular vertical shaft comprising a diaphragm wall and an inner lining wall disposed inside the diaphragm wall, characterized in that, The method includes the following steps: Based on actual engineering projects, a three-dimensional load-bearing structural model of the foundation pit support structure was established. Plate elements were used to simulate the diaphragm wall, solid elements were used to simulate the inner lining wall and concrete ring beam, soil spring elements were used to simulate the resistance of the soil inside the circular shaft, and compression-only resistance spring elements were used to simulate the constraint of the soil outside the circular shaft on the diaphragm wall. The constitutive model of the diaphragm wall is a 2D orthotropic material, while the constitutive models of the inner lining wall and concrete ring beam are isotropic elastic models. The parameters of the 2D orthotropic material are obtained by the following formula: （1）； （2）； （3）； （4）； （5）； （6）； In the formula, It is the transverse elastic modulus. Here, E represents the calculated elastic modulus of concrete. For longitudinal elastic modulus, , This is the reduction factor. , and Both are shear modulus. Compared to pine and cypress; Determine the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element; Determine the stiffness of the soil spring element located at the bottom of the diaphragm wall; Determine the at-rest earth pressure outside the circular shaft; The construction process of the foundation pit was simulated and analyzed using a three-dimensional load structure model of the foundation pit support structure, and the internal forces and deformations of the diaphragm wall and inner lining wall under various excavation conditions were obtained.

2. The method for calculating the internal forces and deformations of a circular vertical shaft structure according to claim 1, characterized in that, The steps for determining the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element include: Calculate the horizontal stiffness of the soil spring element using the following formula: （7）； （8）； In the formula, For the compressive stiffness of the soil spring, This is the horizontal reaction force coefficient of the soil inside the circular shaft. The horizontal spacing of the spring is calculated. The vertical calculation spacing of the spring is given by m, where m is the proportionality coefficient of the soil's horizontal reaction force. To calculate the depth of the point from the ground, For the first Calculate the excavation depth of the foundation pit under the following working conditions; The preset percentage of the horizontal stiffness of the soil spring element is used as the stiffness of the resistance spring element.

3. The method for calculating the internal forces and deformations of a circular vertical shaft structure according to claim 2, characterized in that, The step of calculating the horizontal stiffness of the soil spring element according to the following formula includes: The proportionality coefficient of the soil's horizontal reaction force coefficient is calculated according to formula (9): （9）； In the formula, To represent the cohesion of soil, Let be the internal friction angle of the soil. This represents the horizontal displacement of the retaining structure at the bottom of the pit.

4. The method for calculating the internal forces and deformations of a circular vertical shaft structure according to claim 1, characterized in that, The steps for simulating the constraint of the diaphragm wall on the outer soil of a circular shaft using only compression-resistant spring units include: For the strata surrounding the circular shaft, stress zones at 90-degree angles to each other are delineated along the circumference of the circular shaft. It is assumed that the difference in friction angle between the two stress zones at 90-degree angles to each other is [value missing]. 4°, at the internal friction angle +4 0 The corresponding stress area is set with only compression-resistant spring units to simulate the constraint of the soil outside the circular shaft on the diaphragm wall; For a stress-bearing region consisting of soil layers, assuming an effective internal friction angle of 90 degrees between two stress-bearing regions... The difference is 4°, for a stress-bearing area consisting of strongly weathered rock, assuming the difference in the static earth pressure coefficient K0 between two stress-bearing areas at 90 degrees to each other is 4°, 0.05, for a stress-bearing area consisting of weakly weathered rock, assuming the difference in the coefficient of static earth pressure K0 between two stress-bearing areas at 90 degrees to each other is 0.

05. 0.

03.

5. A system for calculating the internal force and deformation of a circular shaft structure, used for a circular shaft, the circular shaft comprising a diaphragm wall and an inner lining wall disposed inside the diaphragm wall, characterized in that, The system includes: A module is established to create a three-dimensional load-bearing structural model of the foundation pit support structure based on actual engineering projects. Plate elements are used to simulate the diaphragm wall, solid elements to simulate the inner lining wall and concrete ring beam, soil spring elements to simulate the resistance of the soil inside the circular shaft, and compression-only resistance spring elements to simulate the constraint of the soil outside the circular shaft on the diaphragm wall. The constitutive model of the diaphragm wall is a 2D orthotropic material, while the constitutive models of the inner lining wall and concrete ring beam are isotropic elastic models. The parameters of the 2D orthotropic material are obtained from the following formulas: （1）； （2）； （3）； （4）； （5）； （6）； In the formula, It is the transverse elastic modulus. Here, E represents the calculated elastic modulus of concrete. For longitudinal elastic modulus, , This is the reduction factor. , and Both are shear modulus. Compared to pine and cypress; The first determining module is used to determine the horizontal stiffness of the soil spring element and the stiffness of the resistance spring element; The second determining module is used to determine the stiffness of the soil spring unit located at the bottom of the diaphragm wall; The third determining module is used to determine the at-rest earth pressure outside the circular shaft; The analysis module is used to simulate and analyze the construction process of the foundation pit using a three-dimensional model of the foundation pit support structure, and to obtain the internal forces and deformations of the diaphragm wall and the inner lining wall.

6. An electronic device, characterized in that, include: processor; Memory is used to store executable computer programs; Wherein, when the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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