A method and system for determining additional stress of a lining after back grouting of a shield tunnel wall

Abstract

The application discloses a method, system and device for determining lining additional stress after shield tunnel wall grouting and a storage medium, and the method comprises the following steps: determining the construction condition of a to-be-tested shield tunnel and the geological condition thereof; determining the slurry condition applied to the to-be-tested shield tunnel; combining the construction condition, the geological condition and the slurry condition to construct a tunnel construction three-dimensional fluid-solid coupling model associated with the to-be-tested shield tunnel; setting multiple wall grouting working conditions under different grouting conditions, controlling the tunnel construction three-dimensional fluid-solid coupling model to run for a period of time under each wall grouting working condition to monitor and obtain lining stress, and then combining the stress of the lining when the lining is just installed to determine the lining additional stress generated under each wall grouting working condition. The tunnel construction three-dimensional fluid-solid coupling model considering the lining wall grouting slurry diffusion and solidification working condition is built, the lining additional stress change condition caused by tunnel construction can be simulated, and the operation is simple and easy to implement.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel engineering technology, specifically to a method, system, equipment, and storage medium for determining the additional stress of the lining after grouting behind the shield tunnel wall. Background Technology

[0002] In tunnel construction, the lining serves as a crucial support measure, and the synergistic interaction between the rock strata and the lining is a key issue in the safety control of urban rail transit. Due to the support at the tunnel face and the spatial constraint effect of the surrounding rock, the pressure on the surrounding rock causes deformation and exerts forces on the lining, leading to excessive deformation and instability, resulting in damage phenomena such as large-scale collapse of the tunnel lining. This poses a significant threat to tunnel construction safety. When the theoretical analysis of lining stress and deformation cannot fully reflect the actual stress and deformation of tunnel segments in actual engineering projects, further optimization of existing methods is necessary. Therefore, in addressing the problem of unreasonable stress on tunnel lining segments, determining the stress and deformation of the lining has a profound impact on ensuring the safety and efficiency of tunnel construction. Summary of the Invention

[0003] This invention provides a method, system, equipment, and storage medium for determining the additional stress of the lining after grouting behind the shield tunnel wall, in order to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0004] In a first aspect, a method for determining the additional stress in the lining after grouting behind the wall of a shield tunnel is provided, the method comprising:

[0005] Determine the construction conditions of the shield tunnel to be tested and the geological conditions of its location;

[0006] Determine the slurry conditions to be applied to the shield tunnel under test;

[0007] Based on the construction conditions, geological conditions, and grout conditions, a three-dimensional fluid-structure interaction model of tunnel construction associated with the shield tunnel to be tested is constructed.

[0008] Multiple back-wall grouting conditions are set under different grouting conditions. The three-dimensional fluid-structure interaction model of tunnel construction is controlled to run for a period of time under each back-wall grouting condition to monitor the lining stress. The additional lining stress generated under each back-wall grouting condition is then determined by combining the stress when the lining is just installed.

[0009] Furthermore, the construction conditions of the shield tunnel to be tested include construction information, earth pressure balance shield machine information, and lining information;

[0010] The construction information includes the depth of the construction layer and the center of the tunnel; the earth pressure balance shield machine information includes the outer diameter, body length, shield tail void thickness, unit weight, minimum construction thickness and Young's modulus; and the lining information includes the inner and outer diameters, width, unit weight, Young's modulus and Poisson's ratio.

[0011] Furthermore, the geological conditions of the shield tunnel to be tested include stratum information, basic soil information, and soil stiffness information;

[0012] The stratigraphic information includes each soil layer and the soil stiffness dependence index and failure ratio of each soil layer on stress level. The basic soil information includes unit weight, effective cohesion, effective internal friction angle, at-rest earth pressure coefficient, and permeability coefficient. The soil stiffness information includes soil shear modulus under reference pressure, shear strain when soil shear modulus drops to 0.7 times, tangent modulus obtained from three-dimensional consolidation test under reference pressure, secant modulus obtained from triaxial consolidation drained shear test under reference pressure, and unloading-reloading modulus obtained from triaxial consolidation drained unloading-reloading test under reference pressure.

[0013] Furthermore, the slurry conditions include slurry diffusion parameters, slurry consolidation parameters, and the penetration distance of the slurry when applied to the shield tunnel under test;

[0014] The grout diffusion parameters include grout density, grout yield stress, grout kinematic viscosity, and the permeability coefficient of the grout in the formation. The grout consolidation parameters include the time corresponding to grout solidification shrinkage to 50%, and the ratio of the Young's modulus of the concrete stable on day 1 to the Young's modulus of the concrete stable on day 28. Combining the grout diffusion parameters and the grout consolidation parameters, the penetration distance of the grout when applied to the shield tunnel under test is determined as follows:

[0015]

[0016] Where y is the grout penetration distance, λ is the empirical diffusion coefficient, r is the soil pore radius, t is the diffusion time, ρ is the grout density, f1, f2, and f3 are all descriptive variables, and P G γ is the slurry permeation and diffusion pressure. w Let be the unit weight of water, h1 be the distance from the initial water level to the tunnel center, R be the radius from the outer boundary of the tunnel void to the tunnel center, θ be the given seepage angle inside the tunnel, τ0 be the grout yield stress, Q be the grouting volume, μ be the kinematic viscosity of the grout, n be the soil porosity, L be the lining width, and K be the density of water. g denoted as the permeability coefficient of the slurry as it diffuses through the formation, and g is the acceleration due to gravity.

[0017] Furthermore, the construction process of the three-dimensional fluid-structure interaction model for tunnel construction includes:

[0018] Based on the construction conditions, geological conditions, and slurry conditions, the scope of model analysis is determined;

[0019] The initial water level and boundary conditions of the three-dimensional fluid-structure interaction model for tunnel construction are set, wherein the boundary conditions include the soil in the model moving freely in the vertical direction, the normal displacement of the four sides of the model being zero, and the displacement of the bottom surface of the model being zero in three directions.

[0020] Based on the geological conditions of the shield tunnel to be tested, a constitutive model of small-strain hardened soil is constructed.

[0021] Modulus decay curves were constructed by performing direct shear tests on soil at the center depth of each soil layer.

[0022] Based on the actual situation of tunnel construction, the simulation implementation procedures in the three-dimensional fluid-structure interaction model of tunnel construction are proposed, which include setting various working parameters of the earth pressure balance shield machine, activating the earth pressure balance shield machine and the excavated part of the tunnel after the ground stress is balanced, activating the grouting slurry in the tunnel lining and the shield tail gap, and the soil-grout mixture.

[0023] Furthermore, the setting of multiple back-wall grouting conditions under different grouting conditions includes:

[0024] When the grouting rate is 100%, the stress-strain relationship of the grout in the three-dimensional fluid-structure interaction model of the tunnel construction is defined by the linear elastic model. At the same time, the Young's modulus of the grout is set to the Young's modulus on the 28th day to form a back-wall grouting condition without diffusion or consolidation.

[0025] When the grouting rate is 100%, the grout stress-strain relationship in the three-dimensional fluid-structure interaction model of the tunnel construction is defined by the concrete model to form a back-wall grouting condition with no diffusion but with consolidation.

[0026] When the grouting rate is 200%, the stress-strain relationship of the soil-grout mixture in the three-dimensional fluid-structure interaction model of the tunnel construction is defined by the linear elastic model to form a back-wall grouting condition with diffusion and consolidation.

[0027] Furthermore, the three-dimensional fluid-structure interaction model for tunnel construction is controlled to run for a period of time under any backfill grouting condition to monitor the lining stress. This stress is then combined with the stress at the time of lining installation to determine the additional lining stress generated under that backfill grouting condition, including:

[0028] When the three-dimensional fluid-structure interaction model for tunnel construction is running under any backfill grouting condition, the grout gradually transmits pressure to the lining. The soil in the model changes from a static earth pressure state to an active earth pressure state. The soil around the lining is subjected to changes in stress in the vertical direction and a predetermined horizontal direction. After the three-dimensional fluid-structure interaction model for tunnel construction runs in this way for a period of time, the lining stress is monitored. Then, the difference between the lining stress and the stress when the lining is just installed is calculated to obtain the additional stress of the lining.

[0029] Secondly, a system for determining the additional stress in the lining after grouting behind the shield tunnel wall is provided, the system comprising:

[0030] The first determination module is used to determine the construction conditions of the shield tunnel to be tested and the geological conditions of its location;

[0031] The second determining module is used to determine the slurry conditions applied to the shield tunnel under test;

[0032] A construction module is used to construct a three-dimensional fluid-structure interaction model of tunnel construction associated with the shield tunnel to be tested, by combining the construction conditions, the geological conditions and the slurry conditions.

[0033] The output module is used to set multiple back-wall grouting conditions under different grouting conditions, control the three-dimensional fluid-structure interaction model of tunnel construction to run for a period of time under each back-wall grouting condition to monitor the lining stress, and then combine the stress when the lining is just installed to determine the additional lining stress generated under each back-wall grouting condition.

[0034] Thirdly, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the method for determining the additional stress of the lining after grouting behind the shield tunnel wall as described in the first aspect.

[0035] Fourthly, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method for determining the additional stress of the lining after grouting behind the shield tunnel wall as described in the first aspect.

[0036] The present invention has at least the following beneficial effects: by building a three-dimensional fluid-structure interaction model for tunnel construction that takes into account the diffusion and consolidation of grout behind the lining wall, the changes in additional stress of the lining caused by tunnel construction can be simulated. The whole operation process is simple and easy to implement, and can effectively assist technicians in judging the safety issues of shield tunneling. Attached Figure Description

[0037] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0038] Figure 1 This is a flowchart illustrating a method for determining the additional stress of the lining after grouting behind the shield tunnel wall, according to an embodiment of the present invention.

[0039] Figure 2 This is a simplified schematic diagram of a three-dimensional fluid-structure interaction model for tunnel construction in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the lining stress fed back by the three-dimensional fluid-structure interaction model of tunnel construction in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the composition of a system for determining the additional stress of the lining after grouting behind the shield tunnel wall in an embodiment of the present invention.

[0042] Figure 5 This is a schematic diagram of the hardware structure of the computer device in an embodiment of this disclosure. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] It should be noted that although functional modules are divided in the system diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first," "second," "third," "fourth," etc., used in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed and are inherent to these processes, methods, products, or apparatuses.

[0045] Please refer to Figure 1 , Figure 1This is a flowchart illustrating a method for determining the additional stress in the lining after grouting behind the shield tunnel wall, provided by an embodiment of the present invention. The method includes the following steps:

[0046] S110. Determine the construction conditions of the shield tunnel to be tested and the geological conditions of its location;

[0047] S120. Determine the slurry conditions applied to the shield tunnel to be tested;

[0048] S130. Combining the construction conditions, geological conditions, and grout conditions, construct a three-dimensional fluid-structure interaction model of the tunnel construction associated with the shield tunnel to be tested;

[0049] S140. Set multiple grouting conditions behind the wall under different grouting conditions, and control the three-dimensional fluid-structure interaction model of tunnel construction to run for a period of time under each grouting condition behind the wall to monitor the lining stress. Then, combine the stress when the lining is just installed to determine the additional stress of the lining generated under each grouting condition behind the wall. The additional stress of the lining refers to the stress generated by grouting behind the wall during the shield tunnel construction process.

[0050] In this embodiment of the invention, the construction conditions of the shield tunnel to be tested mentioned in step S110 specifically include information on the earth pressure balance shield machine, construction information, and lining information; wherein, the information on the earth pressure balance shield machine actually includes the basic dimensional information and construction parameters of the earth pressure balance shield machine, the basic dimensional information includes the outer diameter and the length of the machine body, the construction parameters include the thickness of the tail gap, the minimum construction thickness, the unit weight, and the Young's modulus; the construction information includes the pressure at the construction layer and the pressure at the bottom and top of the arch, the tunnel center depth when the shield tunnel to be tested is in the construction layer, and the lining information includes the inner diameter, outer diameter, unit weight, width, Poisson's ratio, and Young's modulus corresponding to each ring of lining.

[0051] In this embodiment of the invention, the geological conditions of the shield tunnel to be tested mentioned in step S110 specifically include stratum information, soil stiffness information, and basic soil information; wherein, the stratum information includes each soil layer and the failure ratio and stress level dependence index associated with each soil layer; the soil stiffness information includes a first type of soil stiffness information obtained by numerical simulation correction after collection from engineering geological reports and a second type of soil stiffness information obtained by numerical simulation correction after performing different test operations indoors; the basic soil information includes effective cohesion, soil weight, effective internal friction angle, permeability coefficient, and static earth pressure coefficient.

[0052] More specifically, the first type of soil stiffness information includes the soil shear modulus under reference pressure and the shear strain corresponding to the soil shear modulus decaying to 0.7 times. The second type of soil stiffness information includes the secant modulus obtained based on the triaxial consolidated drained shear test under reference pressure, the tangent modulus obtained based on the standard three-dimensional consolidated test under reference pressure, and the unloading-reloading modulus obtained based on the triaxial consolidated drained unloading-reloading test under reference pressure.

[0053] In this embodiment of the invention, the grout conditions mentioned in step S120 specifically include grout consolidation parameters, grout diffusion parameters, and the permeation distance allowed when the grout is applied to the shield tunnel under test. The grout consolidation parameters include the time required for the grout shrinkage to reach half of the total shrinkage, the ratio between the Young's modulus of concrete stability on day 1 and day 28, and the present invention uses a concrete model to simulate the stress-strain relationship of the grout based on the consolidation parameters. The grout diffusion parameters include the grout yield stress, the permeability coefficient required for the grout to diffuse into the formation, the grout density, the grout kinematic viscosity, the grout cake porosity, and the initial porosity of the grout. Combining the force balance theorem, the law of conservation of momentum, and Darcy's law, the grout permeation and diffusion pressure at the soil-grout interface can be derived. Further combining the grout consolidation parameters and the grout diffusion parameters, the permeation distance allowed when the grout is applied to the shield tunnel under test can be derived as follows:

[0054]

[0055] In the formula, y represents the grout penetration distance, specifically the distance the grout diffuses into the soil pores; λ is the diffusion empirical coefficient, which is specified by technicians for different grouts such as inert grout, single-component grout, and two-component grout with a slow initial setting time; r is the soil pore radius; t is the diffusion time; ρ is the grout density; f1, f2, and f3 are actually three variables proposed by technicians, each with its own corresponding calculation formula; P G To derive the slurry permeation and diffusion pressure, γ w Let be the unit weight of water, h1 be the distance from the initial water level to the tunnel center, R be the radius from the outer boundary of the tunnel void to the tunnel center, θ be the given permeation angle inside the tunnel, and the above formula is mainly used to calculate the grout permeation distance at the given permeation angle θ. τ0 is the grout yield stress, Q is the grouting volume, μ is the kinematic viscosity of the grout, n is the soil porosity, L is the width of each lining ring, and K... g denoted as ρ, where ρ is the permeability coefficient that the slurry should achieve to penetrate and diffuse into the formation, and g is the acceleration due to gravity.

[0056] In this embodiment of the invention, the three-dimensional fluid-structure interaction model for tunnel construction is actually constructed using the finite element analysis method to simulate the backfill grouting simulation experiment of a shield tunnel. The specific implementation process of the above step S130 includes the following:

[0057] Step S131: Combining the slurry conditions, geological conditions, and construction conditions, set the model analysis range, which includes the stratum information of the tunnel construction area, the tunnel lining parameters, and the specific dimensions of the model (i.e., the length, width, and height of the model). At the same time, the depth Z direction of the model analysis range needs to ensure that the plastic zone and elastic zone generated by the tunnel construction coexist, while the boundary effect needs to be eliminated in the length X and length Y directions.

[0058] Step S132: Taking into account the hydraulic connection between various soil layers in the geological information of the tunnel construction area and the fact that groundwater seepage recharge is allowed on the four sides and bottom of the model, the boundary conditions and initial water level of the three-dimensional fluid-structure coupling model for tunnel construction are set. The boundary conditions include that the soil in the model can move freely in the vertical direction, the normal movement of the four sides of the model is restricted (i.e., the normal displacement is set to zero), and the movement of the bottom of the model in three directions is restricted (i.e., the corresponding displacement is also set to zero).

[0059] Step S133: Based on the soil stiffness information involved in the geological conditions, construct a constitutive model of small-strain hardening soil, as follows:

[0060]

[0061] Where G0 is the shear modulus of soil under small strain. This refers to the shear modulus of soil under small strain at a reference pressure, which is assumed to be 100 kPa. ′ The effective cohesion of the soil, σ3 is the effective internal friction angle of the soil. ′ p is the effective stress of the soil. ref For reference shear stress, m is the soil stiffness dependence index of the construction layer on stress level, and G d γ is the secant modulus, also known as the secant shear modulus, where γ is the shear strain corresponding to the small-strain soil shear modulus G0. 0. G represents the shear strain corresponding to the shear modulus G0 of the low-strain soil decreasing to 0.7 times, α is the proportionality coefficient of the shear strain of the low-strain hardened soil, and G... t It is the tangential modulus, also known as the tangential shear modulus.

[0062] Step S134: First, perform direct shear tests on the soil at the center depth of each soil layer to obtain several sets of test data. Then, perform numerical fitting on the several sets of test data to construct the modulus decay curve, and then calculate the relationship between shear modulus and shear strain.

[0063] Step S135: Set the simulation implementation process in the three-dimensional fluid-structure interaction model of the tunnel construction to keep it the same as the actual tunnel construction process. The simulation implementation process is specifically manifested as follows: First, set several working parameters of the earth pressure balance shield machine, that is, set the initial construction position and the final construction position of the tunnel construction layer to be determined by the Y-axis direction of the model, set the surface shrinkage rate of the shield machine construction face, set the surface shrinkage rate of the shield machine tail, and set the surface progressive shrinkage rate of the shield machine per unit distance; Second, perform ground stress balance, then activate the excavated part of the tunnel and the earth pressure balance shield machine, and set a large time step to eliminate the influence of this activation action on the surrounding soil; Finally, freeze each ring of soil unit, and activate the tunnel lining, the grouting slurry in the shield tail gap and the soil slurry mixture to perform tunnel construction simulation. The grouting pressure generated during the simulated grouting acts on the outer boundary of the soil slurry mixture.

[0064] In this embodiment of the invention, the multiple back-wall grouting conditions mentioned in step S140 above are mainly determined based on different grouting pressure gradient distributions, specifically including the following:

[0065] (1) When the grouting rate is 100% (i.e. no grout permeates and diffuses into the soil pores and the grouting pressure acts on the outer boundary of the tunnel), the stress-strain relationship of the grout in the three-dimensional fluid-structure coupling model of the tunnel construction is set as a linear elastic relationship, and the Young's modulus of the grout is set as the Young's modulus on the 28th day. Thus, the three-dimensional fluid-structure coupling model of the tunnel construction simulates the back wall grouting condition without consolidation and without diffusion.

[0066] (2) When the grouting rate is 100%, the stress-strain relationship of the grout in the three-dimensional fluid-structure interaction model of the tunnel construction is set as that of the concrete model, thereby enabling the three-dimensional fluid-structure interaction model of the tunnel construction to simulate the backfill grouting condition with consolidation but no diffusion; wherein, the concrete model mainly uses the viscoelastic creep method to express the creep characteristics of concrete, and the time-related creep strain and stress are assumed to have a linear relationship, satisfying the following formula:

[0067]

[0068] In the formula, ε cr Let σ be the creep strain, t be time, σ be the unreleased soil stress, and D be the creep strain. e Let φ be the elastic-plastic matrix. crLet t0 be the creep stress, and t0 be the time corresponding to the instantaneous action, which is usually taken as 0. This is the time corresponding to when the creep strain of the slurry reaches 50%.

[0069] (3) When the grouting rate is 200%, the stress-strain relationship of the soil-grout mixture in the three-dimensional fluid-structure interaction model of the tunnel construction is set as a linear elastic relationship. The role of grout particles and soil particles in the soil-grout mixture is fully considered. The Young's modulus of the soil-grout mixture is determined by weighted average method. Thus, the three-dimensional fluid-structure interaction model of the tunnel construction simulates the back wall grouting condition with consolidation and diffusion.

[0070] In this embodiment of the invention, the three-dimensional fluid-structure interaction model for tunnel construction mentioned in step S140 above is used to monitor the required lining stress under any backfill grouting condition for a period of time. Then, based on the lining stress and the stress at the time of lining installation, the additional lining stress generated under the backfill grouting condition can be obtained, specifically as follows:

[0071] When the tunnel lining is first installed, first ensure that the vertical pressure at the arch crown and arch bottom of the lining is minimized but the horizontal pressure is maximized, and ensure that the vertical pressure at the left and right arch waists of the lining is maximized but the horizontal pressure is minimized.

[0072] The three-dimensional fluid-structure interaction model for tunnel construction is controlled to run under any backfill grouting condition. The soil in the model changes from the original static earth pressure state to the active earth pressure state. The backfill grout will gradually transmit pressure to the lining as time increases. The lining is subjected to predetermined horizontal (i.e., the X-axis direction of the model) and vertical (i.e., the Z-axis direction of the model) soil stress changes. After the three-dimensional fluid-structure interaction model for tunnel construction runs in this way for a period of time (preferably 5 days in this invention), the required lining stress can be monitored. Finally, the difference between the lining stress and the stress when the lining is just installed is used as the additional stress of the lining output.

[0073] To better illustrate the technical solution proposed in this application, a more specific application example is provided below. Taking a section of a shield tunnel in a certain city as an example, the following steps are specifically used to determine the additional stress of the lining after grouting behind the shield tunnel wall.

[0074] Step 1: Determine the construction conditions of the shield tunnel and the geological conditions of the location of the shield tunnel.

[0075] (1) The geological conditions specifically include stratigraphic information, soil stiffness information and basic soil information.

[0076] A1. The stratigraphic information includes each soil layer and the associated failure ratio and stress level dependence index of each soil layer. The soil layers, layered from top to bottom, include: first clay layer ①, second clay layer ②, silty clay layer ③, silty clay layer ④, third clay layer ⑤, fourth clay layer ⑥, and fine silt layer ⑦. See details... Figure 2 As shown; the failure ratios associated with the silty clay layer ③ and the silty clay layer ④ are both 0.6, and the failure ratios associated with the first clay layer ①, the second clay layer ②, the third clay layer ⑤, the fourth clay layer ⑥, and the fine silt layer ⑦ are all 0.9; the soil stiffness dependence index on stress level associated with the first clay layer ①, the second clay layer ②, the silty clay layer ③, the silty clay layer ④, the third clay layer ⑤, and the fourth clay layer ⑥ is all 0.8, and the soil stiffness dependence index on stress level associated with the fine silt layer ⑦ is 0.5.

[0077] A2. The soil stiffness information includes a first type of soil stiffness information obtained by numerical simulation correction after collection from engineering geological reports and a second type of soil stiffness information obtained by numerical simulation correction after performing different test operations indoors; wherein, the first type of soil stiffness information includes the soil shear modulus under reference pressure and the shear strain corresponding to the soil shear modulus decaying to 0.7 times, and the second type of soil stiffness information includes the secant modulus obtained based on triaxial consolidated drained shear test under reference pressure, the tangent modulus obtained based on standard three-dimensional consolidated test under reference pressure, and the unloading-reloading modulus obtained based on triaxial consolidated drained unloading-reloading test under reference pressure.

[0078] A3. The basic information of the soil includes effective cohesion, soil weight, effective internal friction angle, permeability coefficient, and static earth pressure coefficient.

[0079] (2) The construction conditions specifically include information on earth pressure balance shield tunneling machines, construction information and lining information.

[0080] B1. The information regarding the earth pressure balance tunnel boring machine actually includes the basic dimensions and construction parameters of the earth pressure balance tunnel boring machine. The basic dimensions include an outer diameter of 6.34m and a body length of 8.4m. The construction parameters include a tail gap thickness of 7cm, a minimum construction thickness of 0.17m, and a unit weight of 247kN / m³. 3 The Young's modulus is 200 GPa.

[0081] B2. The construction information includes selecting the third clay layer ⑤ as the construction layer, the pressure at the crown of the construction layer is 230 kPa, the pressure at the bottom of the construction layer is 312 kPa, and the tunnel center depth when the shield tunnel is in the construction layer is 22 m below the ground surface.

[0082] B3. The lining information includes an inner diameter of 5.5m, an outer diameter of 6.2m, and a unit weight of 27kN / m for each ring of lining. 3 It has a width of 1.2m, a Poisson's ratio of 0.10, and a Young's modulus of 2600MPa.

[0083] Step two: Determine the grout conditions required for the shield tunnel to be tested during the back wall grouting process. Specifically, this includes grout consolidation parameters, grout diffusion parameters, and the permeation distance allowed when the grout is applied to the shield tunnel to be tested.

[0084] C1. The grout consolidation parameters include at least the following: the time required for the grout shrinkage to reach half of the total shrinkage at a grouting pressure of 250 kPa is 10.46 days; and the ratio between the Young's modulus of concrete stability on day 1 and the Young's modulus of concrete stability on day 28 is 0.44.

[0085] C2, The slurry diffusion parameters include a slurry yield stress of 4×10⁻⁶. -3 The permeability coefficient that the grout should achieve when it diffuses into the formation at kPa is 1.22 × 10⁻⁶. -8 m / s, slurry density is 1850 kg / m 3 The kinematic viscosity of the slurry is 1.46 × 10⁻⁶. - 4 The slurry porosity was 0.24 kPa·s, the cake porosity was 0.31, and the initial porosity of the slurry was 0.31.

[0086] C3. Based on the calculation formula for the penetration distance provided above, the grout penetration and diffusion distance at seven locations behind the lining wall is obtained through simulation analysis. The grout penetration and diffusion time is 10 minutes, and the grout thickness distribution behind the lining wall is recorded. The seven locations behind the lining wall include the 90° direction (i.e., the tunnel arch), the 60° direction, the 30° direction, the 0° direction (i.e., the right arch waist of the tunnel), the 330° direction, the 300° direction, and the 270° direction (i.e., the tunnel arch bottom).

[0087] Step 3: Combining the geological conditions, construction conditions, and grout conditions, a three-dimensional fluid-structure interaction model of the tunnel construction corresponding to the shield tunnel to be tested is built using the finite element analysis method. The total number of elements in the three-dimensional fluid-structure interaction model of the tunnel construction is set to 95,503, and the total number of nodes is set to 143,783. The mesh at the tunnel lining is densified, and the mesh at a distance from the tunnel lining is sparsed.

[0088] (1) Based on the grout conditions, geological conditions, and construction conditions, the model analysis scope is set, which includes the stratigraphic information of the tunnel construction area, the tunnel lining parameters, and the specific dimensions of the model being 100m × 90m × 60m (i.e., the length, width, and height of the model). See details... Figure 2 As shown; at the same time, it is necessary to ensure that the plastic zone and elastic zone generated by tunnel construction coexist in the depth Z direction of the model analysis range, while the boundary effect needs to be eliminated in the length X and length Y directions.

[0089] (2) Set the boundary conditions and initial water level of the three-dimensional fluid-structure interaction model for tunnel construction. The boundary conditions include that the soil in the model can move freely in the vertical direction, the normal movement of the four sides of the model is restricted (i.e., the normal displacement is set to zero), and the movement of the bottom surface of the model in three directions is restricted (i.e., the corresponding displacement is also set to zero). The initial water level is set to 1 meter below the ground surface.

[0090] (3) Based on the soil stiffness information involved in the geological conditions, the constitutive model of the low-strain hardening soil provided above was constructed to observe the seven soil layers in the shear strain range of 10. -6 <γ<10 -3 Changes in the soil within the area.

[0091] (4) First, direct shear tests are performed on the soil at the center depth of each soil layer to obtain several sets of test data. Then, numerical fitting is performed on the several sets of test data to construct the modulus decay curve, and then the relationship between shear modulus and shear strain can be calculated.

[0092] Combination Figure 2 It can be seen that the center depth of the first clay layer ① is 2m, the center depth of the second clay layer ② is 5m, the center depth of the silty clay layer ③ is 12m, the center depth of the silty clay layer ④ is 32m, the center depth of the third clay layer ⑤ is 50m, the center depth of the fourth clay layer ⑥ is 50m, and the center depth of the fine silt layer ⑦ is 55m.

[0093] (5) Set the simulation implementation process in the three-dimensional fluid-structure interaction model of the tunnel construction to keep it the same as the actual tunnel construction process. The simulation implementation process is specifically manifested as follows: First, set several working parameters of the earth pressure balance shield machine, that is, set the initial construction position and the final construction position of the tunnel construction layer to be determined by the Y-axis direction of the model, set the surface shrinkage rate of the shield machine construction face to 0%, set the surface shrinkage rate of the shield machine tail to 0.5%, and set the surface progressive shrinkage rate of the shield machine per unit distance to 0.06% / m; Second, perform ground stress balance, then activate the excavated part of the tunnel and the earth pressure balance shield machine, and set a large time step of 1 day to eliminate the influence of this activation action on the surrounding soil; Finally, freeze each ring of soil unit, and activate the tunnel lining, the grouting slurry in the shield tail gap and the soil slurry mixture to perform tunnel construction simulation, and set the simulation time step to 4 hours / ring. The grouting pressure generated during the simulated grouting will act on the outer boundary of the soil slurry mixture.

[0094] Step four: Based on different grouting conditions, multiple back-wall grouting conditions are pre-determined. Then, by setting a time loading term, the running time of the three-dimensional fluid-structure interaction model of the tunnel construction under each back-wall grouting condition is controlled to monitor and obtain the required lining stress. Finally, based on the lining stress and the stress when the lining is just installed, the additional lining stress generated under each back-wall grouting condition can be obtained.

[0095] (1) Based on different grouting conditions, several back-wall grouting scenarios are pre-planned, as follows:

[0096] Firstly, with a grouting rate of 100%, the grouting pressure distribution mode is set to gradient grouting pressure distribution (i.e., 250kPa + 12.96kPa / m). The stress-strain relationship of the grout in the three-dimensional fluid-structure interaction model of the tunnel construction is set to a linear elastic relationship, and the Young's modulus of the grout is set to the Young's modulus on day 28. This allows the three-dimensional fluid-structure interaction model of the tunnel construction to simulate the backfill grouting condition without consolidation and diffusion.

[0097] Secondly, with a grouting rate of 100%, the grouting pressure distribution mode is set to gradient grouting pressure distribution (i.e., 250kPa + 12.96kPa / m), and the stress-strain relationship of the grout in the three-dimensional fluid-structure coupling model of the tunnel construction is set to a concrete model. This allows the three-dimensional fluid-structure coupling model of the tunnel construction to simulate the back wall grouting condition with consolidation but no diffusion.

[0098] Third, with a grouting rate of 200%, the grouting pressure distribution mode is set to gradient grouting pressure distribution (i.e., 250kPa + 12.96kPa / m), and the stress-strain relationship of the soil-grout mixture in the three-dimensional fluid-structure coupling model of tunnel construction is set to a linear elastic relationship. This allows the three-dimensional fluid-structure coupling model of tunnel construction to simulate the backfill grouting condition with consolidation and diffusion.

[0099] (2) The three-dimensional fluid-structure interaction model for tunnel construction is controlled to run under any backfill grouting condition. The soil in the model changes from its original static earth pressure state to an active earth pressure state. The grout will gradually transmit pressure to the lining as time increases. The lining is subjected to predetermined horizontal (i.e., the X-axis direction of the model) and vertical (i.e., the Z-axis direction of the model) soil stress changes. After the three-dimensional fluid-structure interaction model for tunnel construction runs in this way for a period of time (preferably 5 days in this invention), the required lining stress can be monitored. Finally, the difference between the lining stress and the stress when the lining is just installed is used as the additional stress of the lining output. Figure 3 As shown.

[0100] In this embodiment of the invention, the invention constructs a three-dimensional fluid-structure interaction model for tunnel construction that takes into account the diffusion and consolidation of grout behind the lining wall. This model can simulate the changes in additional stress in the lining caused by tunnel construction. The entire operation is simple and easy to perform, and can effectively assist technicians in judging the safety issues of shield tunneling.

[0101] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the composition of a system for determining the additional stress of the lining after grouting behind the shield tunnel wall, provided in an embodiment of the present invention. The system includes:

[0102] The first determining module 210 is used to determine the construction conditions of the shield tunnel to be tested and the geological conditions of the shield tunnel to be tested.

[0103] The second determining module 220 is used to determine the grout conditions required for the shield tunnel to be tested during the back wall grouting process.

[0104] Module 230 is used to build a three-dimensional fluid-structure interaction model of the tunnel construction corresponding to the shield tunnel to be tested by combining the geological conditions, the construction conditions and the slurry conditions and using the finite element analysis method.

[0105] The output module 240 is used to pre-determine multiple grouting conditions behind the wall according to different grouting conditions, and then control the three-dimensional fluid-structure interaction model of tunnel construction to run for a period of time under each grouting condition behind the wall to monitor and obtain the required lining stress. Finally, based on the stress when the lining is just installed and the lining stress, the additional stress of the lining generated under each grouting condition behind the wall can be obtained.

[0106] The content of the above method embodiments is applicable to this system embodiment. The functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are the same as those in the above method embodiments. Therefore, they will not be repeated here.

[0107] Furthermore, embodiments of the present invention also provide a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the method for determining the additional stress of the lining after grouting behind the shield tunnel wall as described in the above embodiments. The computer-readable storage medium includes, but is not limited to, any type of disk (including floppy disk, hard disk, optical disk, CD-ROM, and magneto-optical disk), ROM (Read-Only Memory), RAM (Random Access Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetic cards, or optical cards. In other words, the storage device includes any medium on which a device (e.g., a computer, mobile phone, etc.) stores or transmits information in a readable form, and can be a read-only memory, a disk, or an optical disk, etc.

[0108] also, Figure 5 This is a schematic diagram of the hardware structure of a computer device provided in an embodiment of the present invention. The computer device includes components such as a processor 320, a memory 330, an input unit 340, and a display unit 350. Those skilled in the art will understand that... Figure 5The illustrated device structure is not intended to limit all devices and may include more or fewer components than shown, or combine certain components. The memory 330 can be used to store the computer program 310 and various functional modules. The processor 320 runs the computer program 310 stored in the memory 330, thereby performing various functional applications and data processing of the device. The memory can be internal memory or external memory, or include both internal and external memory. Internal memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, or random access memory. External memory may include hard disks, floppy disks, ZIP disks, USB flash drives, magnetic tapes, etc. The memory 330 disclosed in the embodiments of this invention includes, but is not limited to, these types of memory. The memory 330 disclosed in the embodiments of this invention is only an example and not a limitation.

[0109] Input unit 340 is used to receive signal input and user-input keywords. Input unit 340 may include a touch panel and other input devices. The touch panel can collect user touch operations on or near it (such as operations performed by the user using a finger, stylus, or any suitable object or accessory on or near the touch panel) and drive the corresponding connection device according to a pre-set program; other input devices may include, but are not limited to, one or more of physical keyboards, function keys (such as play control buttons, power buttons, etc.), trackballs, mice, joysticks, etc. Display unit 350 can be used to display user-input information or information provided to the user, as well as various menus of the terminal device. Display unit 350 may be in the form of a liquid crystal display, organic light-emitting diode, etc. Processor 320 is the control center of the terminal device, connecting various parts of the entire device through various interfaces and lines, performing various functions and processing data by running or executing software programs and / or modules stored in memory 320, and calling data stored in memory.

[0110] As one embodiment, the computer device includes a processor 320, a memory 330, and a computer program 310, wherein the computer program 310 is stored in the memory 330 and configured to be executed by the processor 320, and the computer program 310 is configured to perform the method for determining the additional stress of the lining after grouting behind the shield tunnel wall in the above embodiment.

[0111] Although the description of this application has been quite detailed and particularly focused on several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment. Rather, it should be considered as effectively covering the intended scope of this application by referring to the appended claims and taking into account the prior art, which provides for a broad possible interpretation of these claims. Furthermore, the foregoing description of this application with respect to embodiments foreseeable by the inventors is intended to provide a useful description, and non-substantial modifications to this application that have not yet been foreseen may still represent equivalent modifications.

Claims

1. A method for determining the additional stress in the lining after grouting behind the shield tunnel wall, characterized in that, The method includes: Determine the construction conditions of the shield tunnel to be tested and the geological conditions of its location; Determine the slurry conditions to be applied to the shield tunnel under test; Based on the construction conditions, geological conditions, and grout conditions, a three-dimensional fluid-structure interaction model of tunnel construction associated with the shield tunnel to be tested is constructed. Multiple back-wall grouting conditions are set under different grouting conditions. The three-dimensional fluid-structure interaction model of tunnel construction is controlled to run for a period of time under each back-wall grouting condition to monitor the lining stress. The additional lining stress generated under each back-wall grouting condition is then determined by combining the stress when the lining is just installed. The slurry conditions include slurry diffusion parameters, slurry consolidation parameters, and the penetration distance of the slurry when applied to the shield tunnel under test. The grout diffusion parameters include grout density, grout yield stress, grout kinematic viscosity, and the permeability coefficient of the grout in the formation. The grout consolidation parameters include the time corresponding to grout solidification shrinkage to 50%, and the ratio of the Young's modulus of the concrete stable on day 1 to the Young's modulus of the concrete stable on day 28. Combining the grout diffusion parameters and the grout consolidation parameters, the penetration distance of the grout when applied to the shield tunnel under test is determined as follows: In the formula, This is the distance of slurry penetration. For diffusion empirical coefficients, The pore radius of the soil. For diffusion time, For slurry density, , , Both refer to variables. The slurry permeation and diffusion pressure, The density of water, This is the distance from the initial water level to the center of the tunnel. The radius from the outer boundary of the tunnel void to the center of the tunnel. Given a permeation angle within the tunnel, For the slurry yield stress, This refers to the grouting volume. The kinematic viscosity of the slurry. Soil porosity For the lining width, The permeability coefficient is the coefficient by which the slurry diffuses through the formation. This is the acceleration due to gravity.

2. The method for determining the additional stress of the lining after grouting behind the shield tunnel wall according to claim 1, characterized in that, The construction conditions of the shield tunnel to be tested include construction information, earth pressure balance shield machine information, and lining information. The construction information includes the depth of the construction layer and the center of the tunnel; the earth pressure balance shield machine information includes the outer diameter, body length, shield tail void thickness, unit weight, minimum construction thickness and Young's modulus; and the lining information includes the inner and outer diameters, width, unit weight, Young's modulus and Poisson's ratio.

3. The method for determining the additional stress of the lining after grouting behind the shield tunnel wall according to claim 1, characterized in that, The geological conditions of the shield tunnel to be tested include stratum information, basic soil information, and soil stiffness information. The stratigraphic information includes the soil stiffness dependence index and failure ratio of each soil layer on stress level. The basic soil information includes unit weight, effective cohesion, effective internal friction angle, coefficient of earth pressure at rest, and permeability coefficient. The soil stiffness information includes soil shear modulus under reference pressure, shear strain when soil shear modulus drops to 0.7 times, tangent modulus obtained from three-dimensional consolidation test under reference pressure, secant modulus obtained from triaxial consolidated drained shear test under reference pressure, and unloading-reloading modulus obtained from triaxial consolidated drained unloading-reloading test under reference pressure.

4. The method for determining the additional stress of the lining after grouting behind the shield tunnel wall according to claim 1, characterized in that, The construction process of the three-dimensional fluid-structure interaction model for tunnel construction includes: Based on the construction conditions, geological conditions, and slurry conditions, the scope of model analysis is determined; The initial water level and boundary conditions of the three-dimensional fluid-structure interaction model for tunnel construction are set, wherein the boundary conditions include the soil in the model moving freely in the vertical direction, the normal displacement of the four sides of the model being zero, and the displacement of the bottom surface of the model being zero in three directions. Based on the geological conditions of the shield tunnel to be tested, a constitutive model of small-strain hardened soil is constructed. Modulus decay curves were constructed by conducting direct shear tests on soil at the center depth of each soil layer. Based on the actual situation of tunnel construction, the simulation implementation procedures in the three-dimensional fluid-structure interaction model of tunnel construction are proposed, which include setting various working parameters of the earth pressure balance shield machine, activating the earth pressure balance shield machine and the excavated part of the tunnel after the ground stress is balanced, activating the grouting slurry in the tunnel lining and the shield tail gap, and the soil-grout mixture.

5. The method for determining the additional stress of the lining after grouting behind the shield tunnel wall according to claim 1, characterized in that, The setting of multiple back-wall grouting conditions under different grouting conditions includes: When the grouting rate is 100%, the stress-strain relationship of the grout in the three-dimensional fluid-structure interaction model of the tunnel construction is defined by the linear elastic model. At the same time, the Young's modulus of the grout is set to the Young's modulus on the 28th day to form a back-wall grouting condition without diffusion or consolidation. When the grouting rate is 100%, the stress-strain relationship of the grout in the three-dimensional fluid-structure interaction model of the tunnel construction is defined by the concrete model to form a back-wall grouting condition with no diffusion but with consolidation. When the grouting rate is 200%, the stress-strain relationship of the soil-grout mixture in the three-dimensional fluid-structure interaction model of the tunnel construction is defined by the linear elastic model to form a back-wall grouting condition with diffusion and consolidation.

6. The method for determining the additional stress of the lining after grouting behind the shield tunnel wall according to claim 5, characterized in that, The three-dimensional fluid-structure interaction model for tunnel construction is controlled to run for a period of time under any backfill grouting condition to monitor the lining stress. This stress is then combined with the stress at the moment of lining installation to determine the additional lining stress generated under that backfill grouting condition, including: When the three-dimensional fluid-structure interaction model for tunnel construction is running under any backfill grouting condition, the grout gradually transmits pressure to the lining. The soil in the model changes from a static earth pressure state to an active earth pressure state. The soil around the lining is subjected to changes in stress in the vertical direction and a predetermined horizontal direction. After the three-dimensional fluid-structure interaction model for tunnel construction runs in this way for a period of time, the lining stress is monitored. Then, the difference between the lining stress and the stress when the lining is just installed is calculated to obtain the additional stress of the lining.

7. A system for determining the additional stress of the lining after grouting behind the shield tunnel wall, characterized in that, The system includes: The first determination module is used to determine the construction conditions of the shield tunnel to be tested and the geological conditions of its location; The second determining module is used to determine the slurry conditions applied to the shield tunnel under test; A construction module is used to construct a three-dimensional fluid-structure interaction model of tunnel construction associated with the shield tunnel to be tested, by combining the construction conditions, the geological conditions and the slurry conditions. The output module is used to set multiple back wall grouting conditions under different grouting conditions, control the three-dimensional fluid-structure interaction model of tunnel construction to run for a period of time under each back wall grouting condition to monitor the lining stress, and then combine the stress when the lining is just installed to determine the additional lining stress generated under each back wall grouting condition. The slurry conditions include slurry diffusion parameters, slurry consolidation parameters, and the penetration distance of the slurry when applied to the shield tunnel under test. The grout diffusion parameters include grout density, grout yield stress, grout kinematic viscosity, and the permeability coefficient of the grout in the formation. The grout consolidation parameters include the time corresponding to grout solidification shrinkage to 50%, and the ratio of the Young's modulus of the concrete stable on day 1 to the Young's modulus of the concrete stable on day 28. Combining the grout diffusion parameters and the grout consolidation parameters, the penetration distance of the grout when applied to the shield tunnel under test is determined as follows: In the formula, This is the distance of slurry penetration. For diffusion empirical coefficients, The pore radius of the soil. For diffusion time, For slurry density, , , Both refer to variables. The slurry permeation and diffusion pressure, The density of water, This is the distance from the initial water level to the center of the tunnel. The radius from the outer boundary of the tunnel void to the center of the tunnel. Given a permeation angle within the tunnel, For the slurry yield stress, This refers to the grouting volume. The kinematic viscosity of the slurry. Soil porosity For the lining width, The permeability coefficient is the coefficient by which the slurry diffuses through the formation. This is the acceleration due to gravity.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, The processor executes the computer program to implement the method for determining the additional stress of the lining after grouting behind the shield tunnel wall as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for determining the additional stress of the lining after grouting behind the shield tunnel wall as described in any one of claims 1 to 6.

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