A method and apparatus for calculating ultimate support force, electronic equipment, and storage medium.

Abstract

This invention discloses a method, device, electronic equipment, and storage medium for calculating ultimate support force. The method first establishes a wedge-prism model based on the soil arching effect and determines the height and width of the prism. Then, it determines the ground liquefaction index based on actual construction conditions and determines the soil parameter reduction coefficient based on the ground liquefaction index. Next, it reduces the lateral pressure coefficient of the prism using the soil parameter reduction coefficient. Finally, it solves for the ultimate support force based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model. This method considers the ground liquefaction phenomenon that occurs in loose liquefied strata during actual shield tunnel construction. After determining the soil parameter reduction coefficient based on the ground liquefaction index, the soil shear strength index is reduced. It simultaneously takes into account the influence of soil arching effect and ground liquefaction, greatly improving the calculation accuracy of the ultimate support force at the excavation face of shield tunnels in loose liquefied strata and ensuring construction safety.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, and in particular to a method and apparatus for calculating support force, an electronic device, and a computer-readable storage medium. Background Technology

[0002] Shield tunneling boasts advantages such as safety, reliability, rapid excavation, and high construction quality, making it the primary method for constructing underground linear infrastructure like urban rail transit and municipal tunnels. Ensuring the stability of the excavation face and controlling ground deformation are key technical issues in shield tunnel construction. Ultimate support force, the minimum support force required to maintain excavation face stability, is a crucial parameter in tunnel excavation. When the support force of the shield's sealed chamber is less than the ultimate support force of the excavation face, the ground will experience active instability and failure, leading to excessive deformation of the ground and adjacent structures. For example, instability at the excavation face of a section of Metro Line 1 in a certain city caused surface subsidence, resulting in a serious traffic accident; and excessive surface subsidence occurred when Metro Line 4 passed under a river in another city.

[0003] Currently, the main theoretical methods for calculating the ultimate support force of the excavation face of a shield tunnel are: (1) the limit analysis model based on the upper and lower limit principle; and (2) the classic "wedge-prism" limit equilibrium model. The former is complex to calculate and difficult to apply directly to engineering. For the latter, patent CN202010534607.3 proposes a method for calculating the ultimate support force of the circumferential excavation face of a shield tunnel without considering the surface overload condition, and patent CN201810700027.X proposes a method for calculating the minimum support force of the excavation face of a shield tunnel in sandy gravel strata. During shield tunneling, the lateral pressure coefficient of the soil in front of the excavation face changes, the particles become tightly bound and the horizontal stress increases, transferring the self-weight stress to the soil in the stable side zone. This stress transfer phenomenon is caused by the soil arching effect, which significantly affects the distribution of the stress state of the strata. However, both of the above patents treat the soil in front of the excavation face as a rigid slider and do not consider the influence of the soil arching effect during the tunneling process, which may result in an overestimation of the calculated ultimate support force. Furthermore, patent CN201910224817.X proposes a method for calculating the ultimate support force of the excavation face of a deep-buried shield tunnel in sandy soil strata, considering the soil arching effect. However, its derivation assumes that the soil arching zone satisfies Protodyakonov's arch theory, making it mainly applicable to deep-buried tunnels in rock strata and not suitable for loose sandy soil strata commonly encountered by shield tunnels. In addition, the cutting action of the cutterhead, excavation unloading, and mechanical vibration during the shield tunneling process can cause strong disturbances to the strata, easily leading to foundation liquefaction in sandy soil strata with high liquefaction levels, increasing strata deformation and the ultimate support force of the excavation face. Moreover, depending on the level of liquefaction, the mechanical properties of the soil will decrease to varying degrees. Foundation liquefaction is detrimental to the soil arching effect and can lead to theoretical calculations that are biased towards dangerous levels, easily causing engineering accidents. Currently, there is no method for determining the ultimate support force of the shield tunnel excavation face that considers the influence of sand liquefaction. In summary, it is necessary to consider both the soil arching effect and the foundation liquefaction simultaneously, and propose a method for calculating the ultimate support force of the shield tunnel excavation face applicable to loose liquefied strata. Summary of the Invention

[0004] This invention provides a method and apparatus for calculating support force, an electronic device, and a computer-readable storage medium to solve the technical problem that existing methods for calculating the ultimate support force of shield tunnel excavation faces are not applicable to loose liquefied strata.

[0005] According to one aspect of the present invention, a method for calculating ultimate support force is provided for calculating the ultimate support force of a shield tunnel excavation face in loose liquefied strata, comprising the following:

[0006] Based on the soil arching effect, a wedge-prism model of the front of the shield tunnel excavation face is established, and the height and width of the prism are determined.

[0007] The liquefaction index of the foundation is determined based on the actual construction conditions, and the soil parameter reduction factor is determined based on the liquefaction index of the foundation.

[0008] The lateral pressure coefficient of the prism is calculated based on the soil parameter reduction factor and the soil arching effect.

[0009] The ultimate support force is solved based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model.

[0010] Furthermore, the height and width of the prism are calculated based on the following formula:

[0011] H = min{C, 2L}

[0012] L=D / tanβ

[0013] Where H represents the height of the prism, L represents the width of the prism, C represents the burial depth of the tunnel arch, D represents the tunnel diameter, and β represents the wedge angle of the wedge.

[0014] Furthermore, the soil parameter reduction factor is calculated based on the following formula:

[0015]

[0016] Where α represents the soil parameter reduction factor, I le This indicates the liquefaction index of the foundation.

[0017] Furthermore, the lateral pressure coefficient of the prism is calculated based on the following formula:

[0018]

[0019] Among them, K s This represents the lateral pressure coefficient of the prism. α represents the soil parameter reduction factor. Indicates the effective internal friction angle of the soil. K represents the reduced effective internal friction angle of the soil. a Indicates the active earth pressure coefficient.

[0020] Furthermore, the ultimate support force is calculated based on the following formula:

[0021]

[0022] Among them, S lim σ represents the ultimate support force at the excavation face. av This represents the average stress acting on the wedge, while f0, f1, and ε represent coefficients related to the physical properties of the soil. γ′ represents the buoyant unit weight of the soil, and λ represents the lateral pressure coefficient of the wedge. c represents soil cohesion, γ w Δh represents the specific gravity of water, and Δh represents the head difference between the shield tunnel's sealed chamber and the far field.

[0023] Furthermore, the average stress acting on the wedge is calculated based on the following formula:

[0024]

[0025] Where γ′ represents the buoyant unit weight of the soil, and A represents the cross-sectional area of ​​the prism. U represents the perimeter of the cross-section of the prism. β represents the wedge angle of the wedge, L represents the width of the prism, B represents the length of the prism, H represents the height of the prism, D represents the tunnel diameter, and q0 represents the overload acting on the top surface of the prism. γ represents the unit weight of the soil, and C represents the depth of the tunnel arch.

[0026] Furthermore, the specific process for solving the ultimate support force is as follows:

[0027] By changing the wedge angle β and obtaining the excavation face support force values ​​under different wedge angles β, the maximum value is selected as the ultimate support force of the excavation face.

[0028] In addition, the present invention also provides an ultimate support force calculation device for calculating the ultimate support force of a shield tunnel excavation face in loose liquefied strata, comprising:

[0029] The model building module is used to establish a wedge-prism model in front of the excavation face of the shield tunnel based on the soil arching effect, and to determine the height and width of the prism.

[0030] The first calculation module is used to determine the liquefaction index of the foundation based on the actual construction conditions, and to determine the soil parameter reduction factor based on the liquefaction index of the foundation.

[0031] The second calculation module is used to calculate the lateral pressure coefficient of the prism based on the soil parameter reduction factor and the soil arching effect.

[0032] The third calculation module is used to solve for the ultimate support force based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model.

[0033] In addition, the present invention also provides an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method described above by calling the computer program stored in the memory.

[0034] In addition, the present invention provides a computer-readable storage medium for storing a computer program for calculating the ultimate support force, wherein the computer program executes the steps of the method described above when running on a computer.

[0035] The present invention has the following effects:

[0036] The ultimate support force calculation method of the present invention first establishes a wedge-prism model in front of the shield tunnel excavation face based on the soil arching effect, and determines the height and width of the prism. Then, the liquefaction index of the foundation is determined according to the actual construction conditions, and the soil parameter reduction coefficient is determined based on the foundation liquefaction index. Then, the lateral pressure coefficient of the prism is calculated based on the soil parameter reduction coefficient and the soil arching effect. The lateral pressure coefficient of the prism is reduced by the soil parameter reduction coefficient. Finally, the ultimate support force is solved based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model. The ultimate support force calculation method of this invention takes into account the liquefaction phenomenon of the foundation in loose liquefied strata during actual shield tunnel construction. After determining the soil parameter reduction coefficient based on the foundation liquefaction index, the soil shear strength index is reduced. At the same time, it takes into account the influence of soil arching effect and foundation liquefaction on the ultimate support force of the shield tunnel excavation face in loose liquefied strata, which greatly improves the calculation accuracy of the ultimate support force of the shield tunnel excavation face in loose liquefied strata and ensures construction safety.

[0037] In addition, the ultimate support force calculation device of the present invention also has the above-mentioned advantages.

[0038] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0039] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0040] Figure 1 This is a flowchart illustrating the method for calculating the ultimate support force according to a preferred embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of a wedge-prism model in front of the shield tunnel excavation face based on the soil arching effect in a preferred embodiment of the present invention.

[0042] Figure 3 This is a schematic diagram of a principal stress arch considering the soil arching effect within a prism in a preferred embodiment of the present invention.

[0043] Figure 4This is a schematic diagram of the force analysis of the wedge in the wedge-prism model of a preferred embodiment of the present invention.

[0044] Figure 5 This is a schematic diagram of the force analysis of the internal micro-element of a prism.

[0045] Figure 6 This is a simplified diagram showing the soil layer distribution in a section of Hangzhou Metro Line 1.

[0046] Figure 7 This is a schematic diagram of the module structure of the ultimate support force calculation device according to a preferred embodiment of the present invention. Detailed Implementation

[0047] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0048] like Figure 1 As shown, a preferred embodiment of the present invention provides a method for calculating the ultimate support force of a shield tunnel excavation face in loose liquefied strata, comprising the following:

[0049] Step S1: Based on the soil arching effect, establish a wedge-prism model in front of the shield tunnel excavation face, and determine the height and width of the prism;

[0050] Step S2: Determine the liquefaction index of the foundation based on the actual construction conditions, and determine the soil parameter reduction factor based on the liquefaction index;

[0051] Step S3: Calculate the lateral pressure coefficient of the prism based on the soil parameter reduction factor and the soil arching effect;

[0052] Step S4: Solve for the ultimate support force based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model.

[0053] It is understood that the ultimate support force calculation method in this embodiment first establishes a wedge-prism model in front of the shield tunnel excavation face based on the soil arching effect, and determines the height and width of the prism. Then, the liquefaction index of the foundation is determined according to the actual construction conditions, and the soil parameter reduction coefficient is determined based on the foundation liquefaction index. Then, the lateral pressure coefficient of the prism is calculated based on the soil parameter reduction coefficient and the soil arching effect. The lateral pressure coefficient of the prism is reduced by the soil parameter reduction coefficient. Finally, the ultimate support force is solved based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model. The ultimate support force calculation method of this invention takes into account the liquefaction phenomenon of the foundation in loose liquefied strata during actual shield tunnel construction. After determining the soil parameter reduction coefficient based on the foundation liquefaction index, the soil shear strength index is reduced. At the same time, it takes into account the influence of soil arching effect and foundation liquefaction on the ultimate support force of the shield tunnel excavation face in loose liquefied strata, which greatly improves the calculation accuracy of the ultimate support force of the shield tunnel excavation face in loose liquefied strata and ensures construction safety.

[0054] It can be understood that in step S1, the wedge-prism model in front of the shield tunnel excavation face established based on the soil arching effect is as follows: Figure 2 As shown. The width L of the prism can be obtained through a simple geometric conversion of triangle Ade, specifically: L = D / tanβ, where L represents the width of the prism and β represents the wedge angle of the wedge. When the tunnel depth ratio is relatively small, for example, C / D = 0.5, where C represents the tunnel crown depth and D represents the tunnel diameter, the prism in the ultimate state has extended to the ground surface, and its height H is equal to the tunnel crown depth C. However, when the tunnel depth ratio is relatively large, for example, C / D = 1 or C / D = 2, the prism height H is less than the tunnel crown depth C. Numerous experimental measurements show that in such cases, the prism's height-to-width ratio H / L ≈ 1.52–2.36, with an average value of approximately 2. Therefore, the formula for calculating the prism height H is as follows: H = min{C, 2L}.

[0055] It is understood that in step S2, the liquefaction index I of the foundation is determined based on the disturbance of the surrounding strata under actual construction conditions. le For specific calculation methods, please refer to the "Standard for Geotechnical Testing Methods". The specific calculation process for the foundation liquefaction index is existing technology and will not be elaborated here. Based on the foundation liquefaction index I... le Soil liquefaction levels can be classified into three levels: slight, moderate, and severe. Then, the soil parameter reduction factor is calculated based on the following formula:

[0056]

[0057] Where α represents the soil parameter reduction factor, I leThis represents the foundation liquefaction index. When the foundation liquefaction index I... le When the liquefaction index is 0, the liquefaction level of the foundation soil is slight liquefaction, and the soil parameter reduction factor α is 1; when the foundation liquefaction index I... le When the index is 4, the liquefaction level of the foundation soil is slight liquefaction, and the soil parameter reduction factor α is 0.8; when the foundation liquefaction index I... le When the index is 10, the liquefaction level of the foundation soil is moderate, and the soil parameter reduction factor α is 0.5; when the foundation liquefaction index I... le When the index is 16, the liquefaction level of the foundation soil is moderate, and the soil parameter reduction factor α is 0.2; when the foundation liquefaction index I... le When the value is greater than or equal to 18, 18 is used for calculation. The liquefaction level of the foundation soil is severe liquefaction, and the soil parameter reduction factor α is 0.1.

[0058] It is understood that in step S3, the schematic diagram of the major principal stress arch considering the soil arching effect within the prism is as follows: Figure 3 As shown, the soil arching effect is based on the following basic assumptions: 1) Cohesionless sand follows the Mohr-Coulomb failure criterion and the unstable prism moves vertically downwards; 2) The major principal stress traces within and around the prism form a series of major principal stress arches, with the geometric shape of the arches being upward-convex circular arcs; 3) The magnitudes of the principal stresses within any specific major principal stress arch are constant, and their ratio σ3 / σ1 is equal to the active earth pressure coefficient K. a Therefore, for any infinitesimal element in a major principal stress arch, its lateral pressure coefficient K s The calculation formula is:

[0059]

[0060] Among them, K s This represents the lateral pressure coefficient of the prism. α represents the soil parameter reduction factor. Indicates the effective internal friction angle of the soil. K represents the reduced effective internal friction angle of the soil. a Indicates the active earth pressure coefficient.

[0061] It is understood that in step S4, within the wedge-prism model, it is necessary to ensure the force balance of the wedge during the shield tunnel excavation process. For example... Figure 4 As shown, the forces acting on the wedge mainly include: 1) the self-weight G of the wedge abcdef; 2) the vertically distributed force σ acting on the top surface cdef of the wedge. av ;3) The reaction force Q1 acting on the inclined sliding surface abfe of the wedge;4) The two normal forces 2Q acting on the two vertical sliding surfaces ade and bcf of the wedge. 2N (Not shown in the figure) and two tangential forces 2Q2t Among them, the tangential force 2Q 2t 5) The direction is parallel to the inclined sliding surface abfe; 6) The support force S acting on the excavation face abcd. It should be noted that this model does not consider the friction force acting on the top surface cdef of the wedge for safety reasons. The force balance of the wedge is analyzed by the wedge-prism model equilibrium equation to obtain the expression of the excavation face support force. Then, by changing the wedge angle β of the wedge block, the excavation face support force value under different wedge angles β is obtained, and the maximum value is selected as the ultimate support force of the excavation face. The formula for calculating the ultimate support force is:

[0062]

[0063] Among them, S lim σ represents the ultimate support force at the excavation face. av This represents the average stress acting on the wedge, while f0, f1, and ε represent coefficients related to the physical properties of the soil. γ′ represents the buoyant unit weight of the soil, and λ represents the lateral pressure coefficient of the wedge. c represents soil cohesion, γ w Let Δh represent the specific weight of water, and Δh represent the head difference between the shield-sealed chamber and the far field. The specific derivation process of the support force formula is as follows: Figure 4 As shown, the weight of the wedge abcdef can be easily calculated. The vertical uniformly distributed force on the top surface cdef of the wedge is σ av Assuming the vertical stress within the tunnel is linearly distributed along the depth, and the buoyant unit weight of the soil is γ′, it is easy to calculate... Based on the force balance of the wedge, the support force S acting on the excavation face can be obtained. By changing the wedge angle β of the wedge block, the support force value of the excavation face under different wedge angles β is obtained, and the maximum value is selected as the ultimate support force of the excavation face.

[0064] It is understandable that the average stress acting on the wedge is calculated based on the following formula:

[0065]

[0066] Where γ′ represents the buoyant unit weight of the soil, and A represents the cross-sectional area of ​​the prism. U represents the perimeter of the cross-section of the prism. β represents the wedge angle of the wedge, L represents the width of the prism, B represents the length of the prism, H represents the height of the prism, D represents the tunnel diameter, and q0 represents the overload acting on the top surface of the prism. γ represents the soil weight, and C represents the tunnel arch depth. The detailed derivation of the average stress acting on the wedge is as follows: Figure 5Force analysis of a small element soil strip inside the prism shown. Based on the force equilibrium condition in the vertical direction, the following equation can be established:

[0067]

[0068] Among them, K s The coefficient of lateral pressure inside the prism. The prism has a width of 2d, and the infinitesimal element has a width of dz. Integrating this equation and substituting the upper boundary condition (i.e., when z = 0), σ... av =q0, from which we can obtain the expression for the average stress acting on the wedge.

[0069] It is understood that this invention also calculates the ultimate support force of a shield tunnel section of Hangzhou Metro Line 1 based on the ultimate support force calculation method of this embodiment. The specific process is as follows:

[0070] The tunnel section is approximately 3km long longitudinally and was constructed using a Komatsu earth pressure balance tunnel boring machine (TBM) from Japan. The TBM is 8.4m long and 6.34m in diameter, with a tunnel axis burial depth of 19m. Above the tunnel bottom, the majority of the soil consists of sandy silt and silty sand layers with relatively similar soil properties. Figure 6 To illustrate the simplified soil layer distribution in this section, the groundwater level is 4m below the surface. First, a wedge-prism model is established, determining the prism's height and width. The tunnel diameter D = 6.34m, the tunnel arch depth C = 15.84m, the prism height H = min{C, 2L}, and the width L = D / tanβ. Then, the actual foundation liquefaction index I is calculated according to the "Standard for Geotechnical Testing Methods". le The soil parameter reduction factor α was calculated. Then, based on the soil parameter reduction factor α, the soil shear strength index was reduced, and the ultimate support force calculation equation was solved. After repeatedly changing the wedge angle β to calculate the support force, it was finally found that when the wedge angle β was 65°, the calculated ultimate support force of the excavation face was the largest, indicating the most dangerous state. The specific results are as follows:

[0071] When the foundation liquefaction index is 0, the foundation is slightly liquefied, and at this time S lim The pressure is 145.4 kPa.

[0072] When the foundation liquefaction index is 4, the foundation is slightly liquefied, and at this time S lim The pressure is 150.0 kPa.

[0073] When the foundation liquefaction index is 10, the foundation is moderately liquefied, and at this time S lim The Pa is 168.7 kPa.

[0074] When the foundation liquefaction index is 16, the foundation is moderately liquefied, and at this time S lim The Pa is 245.1 kPa.

[0075] When the liquefaction index of the foundation is greater than or equal to 18, the foundation is severely liquefied, and at this time S lim The value is 308.5 kPa.

[0076] In addition, such as Figure 7 As shown, another embodiment of the present invention also provides an ultimate support force calculation device for calculating the ultimate support force of a shield tunnel excavation face in loose liquefied strata, preferably employing the calculation method described above, including:

[0077] The model building module is used to establish a wedge-prism model in front of the excavation face of the shield tunnel based on the soil arching effect, and to determine the height and width of the prism.

[0078] The first calculation module is used to determine the liquefaction index of the foundation based on the actual construction conditions, and to determine the soil parameter reduction factor based on the liquefaction index of the foundation.

[0079] The second calculation module is used to calculate the lateral pressure coefficient of the prism based on the soil parameter reduction factor and the soil arching effect.

[0080] The third calculation module is used to solve for the ultimate support force based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model.

[0081] It is understood that the ultimate support force calculation device in this embodiment first establishes a wedge-prism model in front of the shield tunnel excavation face based on the soil arching effect, and determines the height and width of the prism. Then, it determines the foundation liquefaction index based on the actual construction conditions, and determines the soil parameter reduction coefficient based on the foundation liquefaction index. Then, it calculates the lateral pressure coefficient of the prism based on the soil parameter reduction coefficient and the soil arching effect, and reduces the lateral pressure coefficient of the prism by the soil parameter reduction coefficient. Finally, it solves for the ultimate support force based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model. The ultimate support force calculation device of the present invention takes into account the liquefaction phenomenon of the foundation in loose liquefied strata during actual shield tunnel construction. After determining the soil parameter reduction coefficient based on the foundation liquefaction index, the soil shear strength index is reduced. At the same time, it takes into account the influence of soil arching effect and foundation liquefaction on the ultimate support force of the shield tunnel excavation face in loose liquefied strata, which greatly improves the calculation accuracy of the ultimate support force of the shield tunnel excavation face in loose liquefied strata and ensures construction safety.

[0082] It is understood that the model building module calculates the height and width of the prism based on the following formula:

[0083] H = min{C, 2L}

[0084] L=D / tanβ

[0085] Where H represents the height of the prism, L represents the width of the prism, C represents the burial depth of the tunnel arch, D represents the tunnel diameter, and β represents the wedge angle of the wedge.

[0086] It is understood that the first calculation module calculates the soil parameter reduction factor based on the following formula:

[0087]

[0088] Where α represents the soil parameter reduction factor, I le This indicates the liquefaction index of the foundation.

[0089] It can be understood that the second calculation module calculates the lateral pressure coefficient of the prism based on the following formula:

[0090]

[0091] Among them, K s This represents the lateral pressure coefficient of the prism. α represents the soil parameter reduction factor. Indicates the effective internal friction angle of the soil. K represents the reduced effective internal friction angle of the soil. a Indicates the active earth pressure coefficient.

[0092] It is understood that the third calculation module calculates the ultimate support force based on the following formula:

[0093]

[0094] Among them, S lim σ represents the ultimate support force at the excavation face. av This represents the average stress acting on the wedge, while f0, f1, and ε represent coefficients related to the physical properties of the soil. γ′ represents the buoyant unit weight of the soil, and λ represents the lateral pressure coefficient of the wedge. c represents soil cohesion, γ w Δh represents the specific gravity of water, and Δh represents the head difference between the shield tunnel's sealed chamber and the far field.

[0095] It is understood that the third calculation module calculates the average stress acting on the wedge based on the following formula:

[0096]

[0097] Where γ′ represents the buoyant unit weight of the soil, and A represents the cross-sectional area of ​​the prism. U represents the perimeter of the cross-section of the prism. β represents the wedge angle of the wedge, L represents the width of the prism, B represents the length of the prism, H represents the height of the prism, D represents the tunnel diameter, and q0 represents the overload acting on the top surface of the prism. γ represents the soil weight, and C represents the tunnel arch depth.

[0098] It can be understood that the process of the third calculation module solving for the ultimate support force is as follows:

[0099] By changing the wedge angle β and obtaining the excavation face support force values ​​under different wedge angles β, the maximum value is selected as the ultimate support force of the excavation face.

[0100] It is understood that each module in the device of this embodiment corresponds to each step of the above method embodiment. Therefore, the specific calculation process and calculation principle of each module will not be described in detail here. Please refer to the above method embodiment.

[0101] In addition, another embodiment of the present invention provides an electronic device including a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method described above by calling the computer program stored in the memory.

[0102] In addition, another embodiment of the present invention provides a computer-readable storage medium for storing a computer program for calculating the ultimate support force, wherein the computer program executes the steps of the method described above when run on a computer.

[0103] Common computer-readable storage media include: floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tape, any other physical media with perforated patterns, random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), flash erasable programmable read-only memory (FLASH-EPROM), any other memory chips or cartridges, or any other media readable by a computer. Instructions may further be transmitted or received by a transmission medium. The term transmission medium can include any tangible or intangible medium used to store, encode, or carry instructions for machine execution, and includes digital or analog communication signals or intangible media that facilitate communication of such instructions. Transmission media include coaxial cables, copper wires, and optical fibers, which contain conductors for transmitting a bus of computer data signals.

[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0105] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0106] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0107] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0108] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0109] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0110] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for calculating ultimate support force, used to calculate the ultimate support force of the excavation face of a shield tunnel in loose liquefied strata, characterized in that, Includes the following: Based on the soil arching effect, a wedge-prism model of the front of the shield tunnel excavation face is established, and the height and width of the prism are determined. The liquefaction index of the foundation is determined based on the actual construction conditions, and the soil parameter reduction factor is determined based on the liquefaction index of the foundation. The lateral pressure coefficient of the prism is calculated based on the soil parameter reduction factor and the soil arching effect. The lateral pressure coefficient of a prism is calculated using the following formula: ； in, This represents the lateral pressure coefficient of the prism. , , This represents the soil parameter reduction factor. Indicates the effective internal friction angle of the soil. This represents the reduced effective internal friction angle of the soil. Indicates the active earth pressure coefficient. ; The ultimate support force is solved based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model; specifically, the ultimate support force is calculated based on the following formula: ； in, Indicates the ultimate support force of the excavation face. This represents the average stress acting on the wedge. , and Represented as coefficients related to the physical properties of the soil. , , , Indicates the buoyant unit weight of soil. This represents the lateral pressure coefficient of the wedge. , Indicates soil cohesion. Indicates the specific gravity of water. This indicates the head difference between the shield tunnel's sealed chamber and the far field. β Indicates the wedge angle of the wedge; The specific process for solving the ultimate support force is as follows: Change the wedge angle β And obtain different wedge angles β The maximum value of the excavation face support force is selected as the ultimate support force of the excavation face.

2. The method for calculating the ultimate support force as described in claim 1, characterized in that, Calculate the height and width of the prism using the following formula: ； in, H Indicates the height of the prism. L Indicates the width of the prism. C Indicates the depth of the tunnel arch. D Indicates the tunnel diameter. β This indicates the wedge angle of the wedge.

3. The method for calculating the ultimate support force as described in claim 1, characterized in that, The soil parameter reduction factor is calculated based on the following formula: ； in, α This represents the soil parameter reduction factor. This indicates the liquefaction index of the foundation.

4. The method for calculating the ultimate support force as described in claim 1, characterized in that, The average stress acting on the wedge is calculated using the following formula: ； in, Indicates the buoyant unit weight of soil. This represents the cross-sectional area of ​​the prism. , U This represents the perimeter of the cross section of the prism. , β The wedge angle represents the wedge shape. L Indicates the width of the prism. B Indicates the length of the prism. H Indicates the height of the prism. D Indicates the tunnel diameter. This indicates an overload acting on the top surface of the prism. , Indicates soil weight. C This indicates the depth of the tunnel arch.

5. A device for calculating ultimate support force, used to calculate the ultimate support force at the excavation face of a shield tunnel in loose liquefied strata, employing the ultimate support force calculation method as described in any one of claims 1 to 4, characterized in that, include: The model building module is used to establish a wedge-prism model in front of the excavation face of the shield tunnel based on the soil arching effect, and to determine the height and width of the prism. The first calculation module is used to determine the liquefaction index of the foundation based on the actual construction conditions, and to determine the soil parameter reduction factor based on the liquefaction index of the foundation. The second calculation module is used to calculate the lateral pressure coefficient of the prism based on the soil parameter reduction factor and the soil arching effect. The third calculation module is used to solve for the ultimate support force based on the lateral pressure coefficient of the prism and the equilibrium equation of the wedge-prism model.

6. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method as described in any one of claims 1 to 4 by calling the computer program stored in the memory.

7. A computer-readable storage medium for storing a computer program for calculating the ultimate support force, characterized in that, The computer program, when run on a computer, performs the steps of the method as described in any one of claims 1 to 4.

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