Evaluation and control method for response of shield to approach joint tunneling superimposed disturbance

Abstract

The invention discloses a method for evaluating and controlling response of a shield to approaching tunneling superimposed disturbance, and relates to the technical field of shield tunnel construction, the method comprises the following steps: constructing a multi-dimensional information database of stratum conditions of a docking area; the multi-dimensional information database comprises butt-joint section stratum parameters, shield tunneling parameters and butt-joint space-time parameters and is used for extracting preceding shield mechanical behavior characteristics and following shield mechanical behavior characteristics; based on the multi-dimensional information database, analyzing the resistance of the preceding shield structure, and determining the additional load borne by the preceding shield according to the additional load generated by tunneling of the following shield and the initial stress field around the preceding shield; and establishing a response evaluation system of a load-resistance ratio according to the resistance of the preceding shield structure and the additional load borne by the preceding shield to judge a disturbance level, and adopting a micro-disturbance control measure according to a disturbance level judgment result. According to the method, the risks of advanced shield displacement overrun and tunnel instability caused by complex evolution of an additional stress field can be solved.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel construction technology, and more specifically, to a method for evaluating and controlling the response of shield tunneling to superimposed disturbances during close-in tunneling. Background Technology

[0002] With the increasing development of urban underground space, shield tunneling technology is being applied more and more widely in complex geological conditions. Shield tunneling with underground connections is an important engineering technique often used to solve problems related to long-distance tunnel breakthroughs and construction crossings with existing railway lines. Especially in complex strata with varying permeability, the ground disturbance, additional load transfer, and structural response issues generated during the close approach of the subsequent shield tunneling are extremely complex. In such cases, the subsequent shield tunneling may cause the preceding shield to exceed displacement limits, or even lead to tunnel instability, seriously affecting the safety and economy of the project.

[0003] The application of existing shield tunneling docking technology in strata with significant differences in permeability or complex hydrogeological conditions faces numerous challenges. In engineering practice, the additional stress field caused by the subsequent shield tunneling is complex, the distribution of disturbed loads on the preceding shield is unclear, and effective control technologies are lacking. This often leads to risks such as ground instability, shield displacement, and tunnel collapse in actual projects, resulting in high engineering costs and serious safety hazards. Furthermore, traditional shield tunneling docking technologies rely heavily on experience-based judgment and parameter adjustments, lacking systematic evaluation and control methods.

[0004] The existing technology has three main shortcomings: First, the overall research foundation in the field of shield tunneling docking is weak, with few publicly available results and a lack of systematic theoretical and methodological frameworks. Second, existing control technologies mostly rely on empirical parameter adjustments and have not established dynamic load calculation methods based on spatiotemporal effects. They also do not adequately consider the relationship between shield downtime and ground permeability, leading to uncontrollable displacement of the preceding shield due to disturbance. Third, in domestic and international cases, the superposition effect of indirect ground-transmitted loads (ground conduction) and instantaneous collision loads (collision impact) has not been systematically studied, making it impossible to accurately assess and control disturbances during shield tunneling docking. These technical deficiencies make it difficult to achieve accurate disturbance assessment and effective control in shield tunneling docking projects, thus restricting the safety and economy of shield tunneling docking projects.

[0005] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0006] To address the problems in related technologies, this invention proposes a method for evaluating and controlling the response of shield tunneling to superimposed disturbances during close approach tunneling. This method has the advantages of accurately predicting the disturbance load on the preceding shield and achieving micro-disturbance control, thereby solving the problems of inaccurate evaluation and imprecise control of disturbances during close approach tunneling in existing technologies.

[0007] Therefore, the specific technical solution adopted by the present invention is as follows:

[0008] A method for evaluating and controlling the response to superimposed disturbances during near-end tunneling of a shield tunneling machine. This method includes:

[0009] S1. Construct a multi-dimensional information database of geological conditions in the docking area. The multi-dimensional information database includes geological parameters of the docking section, shield tunneling parameters, and docking spatiotemporal parameters, which are used to extract the mechanical behavior characteristics of the preceding shield tunnel and the mechanical behavior characteristics of the subsequent shield tunnel.

[0010] S2. Based on a multidimensional information database, analyze the structural resistance of the first shield tunnel, and determine the additional load on the first shield tunnel based on the additional load generated by the subsequent shield tunneling and the initial stress field around the first shield tunnel; the additional load on the first shield tunnel includes the indirect transmission load from the strata and the instantaneous collision load.

[0011] S3. Based on the resistance of the preceding shield structure and the additional load on the preceding shield, establish a response evaluation system for the load-resistance ratio to determine the disturbance level, and adopt micro-disturbance control measures according to the disturbance level determination results; micro-disturbance control measures include shield structure reinforcement, ground reinforcement of the docking section, and control of subsequent shield tunneling parameters.

[0012] Furthermore, the construction of a multidimensional information database of the geological conditions in the docking area includes: dividing permeability difference zones based on geological exploration and permeability tests, and obtaining geological parameters of the docking section; among which, the permeability difference zones include sand layers and clay interbedded layers; the geological parameters of the docking section include permeability coefficient, porosity, elastic modulus, and cohesion; using the geological parameters of the docking section, combined with shield tunneling parameters and docking spatiotemporal parameters, a multidimensional information database is constructed; the shield tunneling parameters include shield tunneling speed, cutterhead penetration, mud pressure, and grouting volume; the docking spatiotemporal parameters include the distance between the two shields, docking time difference, and shield attitude deviation; based on the multidimensional information database, the influence of the downtime difference on the additional stress field is analyzed, and Darcy's law and Biot's consolidation theory are applied to establish a dynamic coupling model of seepage-stress field to obtain the mechanical behavior characteristics of the preceding shield and the subsequent shield.

[0013] Furthermore, based on a multidimensional information database, the structural resistance of the preceding shield tunnel was analyzed. Based on the additional loads generated by the subsequent shield tunneling and the initial stress field around the preceding shield tunnel, the additional loads experienced by the preceding shield tunnel were determined to include:

[0014] S21. Based on a multi-dimensional information database, the influence of shield tunneling downtime on the additional stress field in different strata is reproduced through numerical simulation in order to extract the previous shield tunneling downtime status.

[0015] S22. Based on the shutdown status of the tunnel boring machine (TBM), the structural resistance of the TBM is evaluated by analyzing its compressive strength, torsional strength, and tensile strength.

[0016] S23. By simulating the additional stress field during the subsequent shield tunneling and combining it with the initial stress field around the preceding shield, the additional load on the preceding shield is calculated.

[0017] Furthermore, based on a multidimensional information database, numerical simulations were used to reproduce the impact of shield tunneling downtime on the additional stress field in different geological strata, in order to extract the preceding shield tunneling downtime states, including:

[0018] S211. Based on the geological condition parameters of the docking section and the shield tunneling parameters in the multidimensional information database, establish a three-dimensional finite element model to simulate the tunnel structure in the sand layer, clay layer and the state of the tunnel under the shutdown of the prior shield; the range of the three-dimensional finite element model is set according to the shield diameter to conform to the Saint-Venant principle.

[0019] S212. Based on the geological condition parameters of the docking section, set up the material constitutive models of the sand layer and clay layer, and set the boundary conditions;

[0020] S213. By simulating groundwater seepage, the pore water pressure calculated from the seepage field is coupled to the stress field as a volume force to update the effective stress, and the seepage-stress equation is obtained through coupling.

[0021] S214. Using the seepage-stress equation, simulate the dissipation of excess pore water pressure and stress relaxation of the pilot shield under different downtime, and extract the additional stress of the nodes around the pilot shield.

[0022] Furthermore, based on the shutdown status of the preliminary tunnel boring machine (TBM), the assessment results of the preliminary TBM's structural resistance were obtained by analyzing its compressive, torsional, and tensile strengths, including:

[0023] S221. The compressive strength of the advance shield is obtained by superimposing the frictional resistance between the soil and the shield shell and the total bearing capacity of the weld of the shield tail anti-retreat steel plate; the frictional resistance between the soil and the shield shell increases with the increase of downtime.

[0024] S222. Calculate the sum of the torsional friction of the soil against the shield, the shear couple of the tail bolts, and the shear couple of the segment bolts to obtain the torsional resistance of the advance shield. The torsional resistance is used to resist the torque transmitted to the tail when the rotating cutterhead of the follow shield collides with the cutterhead of the advance shield.

[0025] S223. By combining the stratum frictional resistance and the tensile bearing capacity of the segment bolts, the tensile capacity of the advance shield is determined. Combined with the compressive and torsional capacity of the advance shield, the structural resistance of the advance shield is evaluated.

[0026] Furthermore, by simulating the additional stress field during the subsequent shield tunneling and combining it with the initial stress field around the preceding shield, the additional loads on the preceding shield are calculated, including:

[0027] S231. By establishing a field coupling model, the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling is simulated, and the evolution law of the subsequent additional stress field is extracted.

[0028] S232. Combining the initial stress field around the tunnel boring machine (TBM) and the subsequent additional stress field, calculate the indirect ground-transmitted load and instantaneous collision load on the surface of the TBM to obtain the additional load on the TBM.

[0029] Among them, by establishing a field coupling model, the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling is simulated, and the evolution law of the subsequent additional stress field is extracted, including:

[0030] S2311. Based on a multidimensional information database, embed dynamic parameters to establish a field coupling model that couples seepage, stress, displacement, and material. Among them, the dynamic parameters include the formation permeability coefficient, mud viscosity, and cutterhead penetration resistance. The cutterhead penetration resistance is equal to the tunneling contact force minus the static contact force.

[0031] S2312. Based on the field coupling model, the seepage path of mud is simulated by the fluid-structure interaction equation, and the stress field propagation range is analyzed by combining the Saint-Venant principle.

[0032] S2313. The finite element method is used to simulate the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling, and the stress gradient difference between the sand layer and the clay layer is quantified.

[0033] Furthermore, the finite element method was used to simulate the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling, quantifying the stress gradient difference between the sand and clay layers. This included: establishing a three-dimensional dynamic finite element model of the subsequent shield tunnel structure and strata; ensuring the model range of the three-dimensional dynamic finite element model conformed to Saint-Venant's principle to guarantee that the boundary did not affect the stress field distribution; simulating the tunnel excavation process using element dynamic activation technology, activating one ring of lining and removing one ring of soil as each ring advanced; gradually applying the cutterhead face support pressure and shield tail grouting pressure as moving surface loads; outputting full-field stress data at preset time intervals and recording the stress state at key time points, drawing three-dimensional stress cloud maps at different times; and quantifying the stress gradient difference between the sand and clay layers through the maximum stress gradient.

[0034] Furthermore, by combining the initial stress field around the pilot tunnel boring machine (PTM) and the subsequent additional stress field, the indirect ground-transmitted load and instantaneous collision load on the surface of the pilot TBM are calculated to obtain the additional loads experienced by the pilot TBM, including:

[0035] S2321. Extract the stress field generated by the subsequent shield tunneling, combine it with the initial stress field around the preceding shield, and use the nodal force difference method to calculate the indirect ground load transmitted to the surface of the preceding shield.

[0036] S2322. Establish a three-dimensional model of the two cutterheads and the surrounding soil, and mesh the contact area of ​​the cutterheads; define the contact type between the cutterheads, use an explicit dynamic solver to perform transient analysis, and output the contact force time history curve to extract the instantaneous collision load; the instantaneous collision load includes the maximum load value, collision torque and action time.

[0037] Furthermore, based on the resistance of the preceding shield structure and the additional loads borne by the preceding shield, a response evaluation system for the load-resistance ratio is established to determine the disturbance level. This includes: comparing the resistance of the preceding shield structure with the additional loads borne by the preceding shield to establish a response evaluation system for the load-resistance ratio; classifying the disturbance level into mild disturbance, moderate disturbance, and severe disturbance based on the comparison results of the load-resistance ratio response evaluation system; triggering automatic monitoring when the disturbance level is mild; optimizing the subsequent shield tunneling parameters when the disturbance level is moderate; and implementing micro-disturbance control measures when the disturbance level is severe.

[0038] The beneficial effects of this invention are as follows:

[0039] (1) This invention constructs a multi-dimensional information database of geological conditions in the docking zone, including geological parameters of the docking section, shield tunneling parameters and docking spatiotemporal parameters. It proposes for the first time a method for analyzing the collaborative mechanical behavior of dual shields. Combined with a dynamic coupling model of seepage-stress field, it realizes accurate simulation and analysis of the additional stress field generated by the shutdown state of the first shield and the tunneling of the second shield under different geological conditions, providing a scientific basis for calculating the additional load on the first shield.

[0040] (2) This invention innovatively proposes a dual-mode phased load calculation method for indirect ground-transmitted load and instantaneous collision load. The spatiotemporal distribution of the additional stress field during the tunneling of the subsequent shield is simulated by the field coupling model. The indirect ground-transmitted load on the surface of the preceding shield is calculated by combining the nodal force difference method. The instantaneous collision load is analyzed by the three-dimensional dynamic model. This breaks through the limitations of traditional static load analysis and realizes the comprehensive quantification of the additional load on the preceding shield under various ground conditions.

[0041] (3) This invention establishes a response evaluation system based on load-resistance ratio. By comparing the resistance of the prior shield structure with the additional load, it scientifically classifies mild, moderate and severe disturbance levels, and triggers corresponding control measures according to different disturbance levels. This forms a three-in-one micro-disturbance control technology system of "strengthening the prior shield structure, reinforcing the strata of the docking section and controlling the parameters of the subsequent shield tunneling". It effectively solves the disturbance problem caused by the near-dock tunneling of shields in various strata, and has significant advantages, especially in geological conditions with complex fluid-solid coupling such as highly permeable strata.

[0042] (4) This invention integrates advanced technologies such as numerical simulation, fluid-structure interaction analysis and dynamic response evaluation. It is applicable to shield docking projects in sections with different permeability (such as sand layers and clay layers). By accurately controlling dynamic parameters such as downtime, permeability coefficient and mud viscosity, it achieves precise docking with micro-disturbance (displacement ≤ ±10mm), which greatly improves the safety and economy of shield docking and provides a systematic technical solution for major projects such as the Three Straits Tunnel. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the core steps of the shield tunneling approach and contact tunneling superimposed disturbance response assessment and control method according to an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the graded response mechanism in the shield tunneling approach and contact tunneling superimposed disturbance response assessment and control method according to an embodiment of the present invention;

[0046] Figure 3 This is a specific implementation diagram of the shield tail anti-backward technology in the shield tunneling approach and contact tunneling superimposed disturbance response assessment and control method according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the control flow for controlling the subsequent shield tunneling parameters in the shield tunneling approach and contact tunneling superimposed disturbance response evaluation and control method according to an embodiment of the present invention;

[0048] Figure 5 This is a flowchart illustrating the method for evaluating and controlling the superimposed disturbance response during the approach tunneling of a shield tunneling machine according to an embodiment of the present invention. Detailed Implementation

[0049] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0050] According to an embodiment of the present invention, a method for evaluating and controlling the response to superimposed disturbances during the approach and contact tunneling of a shield tunneling machine is provided.

[0051] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 and Figure 5 As shown, according to an embodiment of the present invention, a method for evaluating and controlling the response to superimposed disturbances during close-proximity tunneling of a shield tunneling machine is provided. This method includes:

[0052] S1. Construct a multi-dimensional information database of geological conditions in the docking area. The multi-dimensional information database includes geological parameters of the docking section, shield tunneling parameters, and docking spatiotemporal parameters, which are used to extract the mechanical behavior characteristics of the preceding shield tunnel and the mechanical behavior characteristics of the subsequent shield tunnel.

[0053] S2. Based on a multidimensional information database, analyze the structural resistance of the first shield tunnel, and determine the additional load on the first shield tunnel based on the additional load generated by the subsequent shield tunneling and the initial stress field around the first shield tunnel; the additional load on the first shield tunnel includes the indirect transmission load from the strata and the instantaneous collision load.

[0054] S3. Based on the resistance of the preceding shield structure and the additional load on the preceding shield, establish a response evaluation system for the load-resistance ratio to determine the disturbance level, and adopt micro-disturbance control measures according to the disturbance level determination results; micro-disturbance control measures include shield structure reinforcement, ground reinforcement of the docking section, and control of subsequent shield tunneling parameters.

[0055] Specifically, such as Figure 1 As shown, this invention comprises six major steps. Specifically, these include: Step 1, determining the geological conditions of the docking zone; Step 2, extracting the shutdown status of the preliminary shield tunnel; Step 3, assessing the structural resistance of the preliminary shield tunnel; Step 4, analyzing the additional loads during docking excavation; Step 5, evaluating the response; and Step 6, three-in-one micro-disturbance control.

[0056] Specifically, in step 1, this invention extracts mechanical behavior features. This invention proposes a method for studying the mechanical behavior of preceding and subsequent shield tunnels, including the geological conditions of the docking section, the tunneling status and parameters of the preceding and subsequent shield tunnels, and the time difference between the docking of the preceding and subsequent shield tunnels, in order to determine the mechanical behavior features of the preceding and subsequent shield tunnels.

[0057] Specifically, in step 2, this invention extracts the evolution law of the additional stress field. This invention establishes a research model and analysis method for the evolution law of the additional stress field based on fluid-structure interaction analysis to understand the evolution law of the additional stress field during shield docking. In step 2, the preceding shield is not considered; only the evolution law of the additional stress field generated by the subsequent shield during tunneling is considered. The additional stress is different at different times and locations.

[0058] Specifically, in steps 3 and 4, this invention performs a structural resistance assessment of the lead tunnel boring machine (TBM) and extracts additional loads. This invention establishes a spatiotemporal distribution pattern and calculation method for the additional loads on the lead TBM, obtaining the indirect additional loads transmitted from the ground layer to the lead TBM from far to near, as well as the instantaneous dynamic disturbance load at the moment of docking and collision between the lead and follow-up TBMs. During this analysis, the lead TBM begins to bear the additional stress from step 2. This invention obtains the additional stress at each point by comparing the stress at each location of the lead TBM at a certain moment with the original ground stress. Finally, the two cutterheads collide, generating collision loads of compression or torsion.

[0059] Specifically, in step 5, the present invention performs a response assessment. By establishing a response assessment model for the preceding and following tunnel boring machines (TBMs), the response levels of the preceding and following TBMs are evaluated.

[0060] Specifically, in step 6, the present invention performs micro-disturbance control. The micro-disturbance quantitative control technology developed in this invention includes pre-shield structural reinforcement (segment tying, tail shield anti-backlash design, main drive anti-backlash design, etc.), stage stratum reinforcement (tunnel radial grouting, shield radial grouting, external ultra-strong curtain grouting, etc.), and subsequent shield tunneling parameter control (support pressure, tunneling speed, attitude control, mud index, cutterhead rotation speed, etc.) to achieve precise micro-disturbance alignment.

[0061] In one embodiment, constructing a multidimensional information database of the geological conditions in the docking zone includes: dividing permeability difference sections based on geological exploration and permeability tests, and obtaining geological parameters of the docking section; wherein, the permeability difference sections include sand layers and clay interbedded layers; the geological parameters of the docking section include permeability coefficient, porosity, elastic modulus, and cohesion; using the geological parameters of the docking section, combined with shield tunneling parameters and docking spatiotemporal parameters, a multidimensional information database is constructed; the shield tunneling parameters include shield tunneling speed, cutterhead penetration, mud pressure, and grouting volume; the docking spatiotemporal parameters include the distance between the two shields, docking time difference, and shield attitude deviation; based on the multidimensional information database, the influence of the downtime difference on the additional stress field is analyzed, and Darcy's law and Biot's consolidation theory are applied to establish a dynamic coupling model of seepage-stress field to obtain the mechanical behavior characteristics of the preceding shield and the subsequent shield.

[0062] It should be noted that the research objects of this invention include two typical strata: homogeneous sand layers and heterogeneous clay-sand interbedded layers (clay interbedded layers). In step 1, the clay interbedded layers refer to the macroscopic strata classification. In step 2, when performing microscopic material analysis, this invention uses "clay layers" to establish a numerical model, abstracting and defining the clay material portion of the "clay interbedded layers" as a material unit for mechanical calculations.

[0063] Specifically, the determination of the geological conditions in the docking zone in step 1 of this invention includes:

[0064] 1) Geological exploration and permeability tests were conducted to obtain the stratigraphic parameters (permeability coefficient, porosity, elastic modulus, cohesion, etc.) of the docking section, and to divide the sand layer, clay interlayer, and other sections with different permeability characteristics.

[0065] 2) Construct a three-dimensional information database (multidimensional information database) containing 30 parameters to achieve multidimensional correlation between geological conditions, construction parameters, and docking time differences. Parameters include: formation permeability coefficient (k), porosity (n), elastic modulus (E), cohesion (c), and internal friction angle (k). ), soil density (ρ), consolidation coefficient (cv), initial pore water pressure (u0), excess pore water pressure dissipation rate, formation type (sand / clay / interbedded), seepage path length (L), pore water pressure gradient ( u), shield diameter (D), shield tunneling speed (V), cutterhead penetration (P), cutterhead rotation speed (N), mud pressure (P) 泥浆 ), mud viscosity (μ), mud specific gravity (γ), shield tail grouting pressure (P) 注浆 ), Grouting volume (Q) 注浆 ), support pressure (Q) 支护 ), tunnel boring machine downtime (t) 停机 ), static contact force (F) 静 ), tunneling contact force (F) 掘 The parameters are: distance between the two shields (r), docking time difference (Δt), horizontal deviation of shield attitude (Δx), vertical deviation of shield attitude (Δy), and angle deviation of shield attitude (Δθ).

[0066] Specifically, the mechanical behavior characteristics of the preceding and subsequent tunnel boring machines extracted in this invention include:

[0067] 1) Zoning of formation permeability characteristics: Based on geological exploration and permeability tests, divide the formation into permeability-differentiated sections such as sand layers and clay interbedded layers, and clarify the key parameters such as permeability coefficient (k), porosity (n), elastic modulus (E), and cohesion (c) of different formations.

[0068] 2) Construction of a multidimensional information database:

[0069] Formation parameters of the docking section: permeability coefficient, initial pore water pressure (u0), consolidation coefficient (cv), soil density (ρ);

[0070] Shield tunneling parameters: shield tunneling speed (V), cutterhead penetration (P), mud pressure (P_mud), grouting volume (Q) 注浆 );

[0071] Spatiotemporal parameters for docking: distance between the two shields (r), docking time difference (Δt), shield attitude deviation (Δx / Δy / Δθ).

[0072] 3) The effect of downtime difference on the additional stress field: Through numerical simulation, the dissipation of excess pore water pressure and stress relaxation under different downtime are simulated.

[0073] 4) Apply Darcy's law and Biot's consolidation theory to establish a dynamic coupling of seepage and stress field.

[0074] Specifically, among the 30 parameters selected in this invention, the establishment of the stratum parameters for the docking section is for the purpose of understanding the environmental conditions around the shield and the initial stress field; the establishment of the shield tunneling parameters is for the purpose of analyzing the mechanical behavior of the two shields during docking.

[0075] In one embodiment, based on a multidimensional information database, the structural resistance of the preceding shield tunnel is analyzed, and based on the additional loads generated by the subsequent shield tunneling and the initial stress field around the preceding shield tunnel, the additional loads borne by the preceding shield tunnel are determined to include:

[0076] S21. Based on a multi-dimensional information database, the influence of shield tunneling downtime on the additional stress field in different strata is reproduced through numerical simulation in order to extract the previous shield tunneling downtime status.

[0077] S22. Based on the shutdown status of the tunnel boring machine (TBM), the structural resistance of the TBM is evaluated by analyzing its compressive strength, torsional strength, and tensile strength.

[0078] S23. By simulating the additional stress field during the subsequent shield tunneling and combining it with the initial stress field around the preceding shield, the additional load on the preceding shield is calculated.

[0079] In one embodiment, based on a multidimensional information database, numerical simulation is used to reproduce the impact of shield tunneling downtime on the additional stress field in different geological strata, in order to extract the preceding shield tunneling downtime states, including:

[0080] S211. Based on the geological condition parameters of the docking section and the shield tunneling parameters in the multidimensional information database, establish a three-dimensional finite element model to simulate the tunnel structure in the sand layer, clay layer and the state of the tunnel under the shutdown of the prior shield; the range of the three-dimensional finite element model is set according to the shield diameter to conform to the Saint-Venant principle.

[0081] S212. Based on the geological condition parameters of the docking section, set up the material constitutive models of the sand layer and clay layer, and set the boundary conditions;

[0082] S213. By simulating groundwater seepage, the pore water pressure calculated from the seepage field is coupled to the stress field as a volume force to update the effective stress, and the seepage-stress equation is obtained through coupling.

[0083] S214. Using the seepage-stress equation, simulate the dissipation of excess pore water pressure and stress relaxation of the pilot shield under different downtime, and extract the additional stress of the nodes around the pilot shield.

[0084] In one embodiment, setting boundary conditions includes: fixing the vertical displacement of the bottom of the model and applying normal constraints; setting free drainage boundaries, impermeable boundaries, or constant head based on the actual hydrological conditions around the model; generating an initial stress field around the tunnel boring machine by gravity loading and distributing the pore water pressure according to hydrostatic pressure.

[0085] Specifically, in step 2, this invention extracts the preliminary shield tunneling machine shutdown state and uses numerical simulation to reproduce the impact of shield tunneling machine shutdown time on the additional stress field in different geological strata. This includes:

[0086] 1) Model building and parameter setting, specifically including:

[0087] Model building:

[0088] ① Establish a three-dimensional finite element model to simulate the tunnel structure (sand layer, clay layer) and the stationary pilot shield (pilot shield in shutdown state).

[0089] ② The model range should cover at least three times the diameter of the shield tunnel in both the transverse and longitudinal regions to conform to the Saint-Venant principle and ensure that the boundary does not affect the stress field distribution.

[0090] ③The initial shield tunneling is set to a static state, and only the interaction between ground seepage and stress field is considered.

[0091] Set up the material constitutive model:

[0092] ① The sand layer is modeled using the Mohr-Coulomb model, with input parameters including permeability coefficient (k), elastic modulus (E), and internal friction angle (k). ), cohesion (c). The clay layer adopts the modified Cambridge model, considering the consolidation coefficient (c). v ) and the characteristics of pressure dissipation of ultrastatic pore water.

[0093] ② The shield structure adopts elastic shell elements, with the steel having an elastic modulus of (E=210GPa) and a Poisson's ratio of (ν=0.3). The friction coefficient (μ=0.2~0.4) is set at the contact surface between the shield and the soil.

[0094] Set boundary conditions:

[0095] ① The bottom of the three-dimensional finite element model is fixed with vertical displacement (U) z =0), apply normal constraints (U) around the perimeter. x =0 or U y =0).

[0096] ②Based on the actual hydrological conditions around the three-dimensional finite element model, set free drainage boundaries, impermeable boundaries, or constant head (zero flow).

[0097] ③ An initial stress field is generated by gravity loading, and the pore water pressure is distributed according to the hydrostatic pressure.

[0098] 2) Fluid-structure interaction analysis settings, specifically including:

[0099] ① Applying Darcy's law to simulate groundwater seepage, the seepage velocity is calculated using the following equation. The expression for simulating groundwater seepage is:

[0100] ;

[0101] In the formula, q is the seepage velocity (m / s); k is the permeability coefficient of the medium (m). 2 μ is the dynamic viscosity of the fluid (Pa·s); p is the pressure gradient (Pa / m); ρ l Fluid density (kg / m³) 3 g is the acceleration due to gravity (m / s²). 2 ).

[0102] ② The pore water pressure calculated from the seepage field is coupled to the stress field as a volume force to update the effective stress, with the following expression:

[0103] σ'=σ-u;

[0104] In the formula, σ' is the effective stress (Pa), which determines the soil deformation and strength; σ is the total stress (Pa), which is generated by the external load and the soil's own weight; and u is the pore water pressure (Pa), which includes hydrostatic pressure and excess pore water pressure.

[0105] ③ Using Biot's consolidation theory, coupled with the seepage-stress equation, the expression is:

[0106] ·(σ')+ρ t g=0;

[0107] In the formula, ·(σ') represents the additional stress; ρ t Soil density (kg / m³) 3 g is the acceleration due to gravity (m / s²).2 ).

[0108] 3) Working conditions and loading design, specifically including:

[0109] ① The simulation conditions include two different working conditions: sand layer and clay layer.

[0110] ② Calculate the initial geostress and pore water pressure.

[0111] ③ Keep the shield structure fixed and simulate the dissipation of excess pore water pressure and stress relaxation under different downtime conditions.

[0112] ④ Output stress field data once per hour.

[0113] 4) Result extraction and analysis, specifically including:

[0114] ① Extract the additional stress around the nodes of the tunnel boring machine and output a spatiotemporal distribution cloud map;

[0115] ② Compare the stress concentration areas in the sand and clay layers;

[0116] ③ Plot the curve of excess pore water pressure over time to evaluate the consolidation rate.

[0117] Specifically, time difference levels are defined as: short time difference (sand layer ≤ 3 days, clay ≤ 30 days), medium time difference (sand layer 3-7 days, clay 1-6 months), and long time difference (sand layer > 7 days, clay > 6 months).

[0118] In one embodiment, based on the shutdown status of the preliminary tunnel boring machine (TBM), the assessment results of the structural resistance of the preliminary TBM are obtained by analyzing its compressive strength, torsional strength, and tensile strength. These results include:

[0119] S221. The compressive strength of the advance shield is obtained by superimposing the frictional resistance between the soil and the shield shell and the total bearing capacity of the weld of the shield tail anti-retreat steel plate; the frictional resistance between the soil and the shield shell increases with the increase of downtime.

[0120] S222. Calculate the sum of the torsional friction of the soil against the shield, the shear couple of the tail bolts, and the shear couple of the segment bolts to obtain the torsional resistance of the advance shield. The torsional resistance is used to resist the torque transmitted to the tail when the rotating cutterhead of the follow shield collides with the cutterhead of the advance shield.

[0121] S223. By combining the stratum frictional resistance and the tensile bearing capacity of the segment bolts, the tensile capacity of the advance shield is determined. Combined with the compressive and torsional capacity of the advance shield, the structural resistance of the advance shield is evaluated.

[0122] Specifically, in step 3 of this invention, the preliminary shield tunneling structure resistance assessment is performed, including:

[0123] During the tunnel boring machine (TBM) docking process, the disturbance-bearing capacity (structural resistance) of the preceding TBM needs to be comprehensively evaluated from three aspects: compressive strength, torsional strength, and longitudinal tensile strength. The longitudinal force exerted by the soil at the TBM's front end on the TBM is transmitted to the TBM's tail end after the soil's frictional resistance. The longitudinal force at the tail end is borne by the welds of the anti-reverse steel plate. Therefore, the compressive strength is mainly ensured by the combined effect of the soil frictional resistance and the anti-reverse device at the tail end. The total compressive strength is obtained by superimposing the frictional resistance between the soil and the TBM shell with the total bearing capacity of the welds of the anti-reverse steel plate at the tail end. Compared to the frictional resistance between the soil and the TBM shell during a short-term shutdown, the frictional resistance between the soil and the TBM shell during a long-term shutdown and subsequent re-push is greater.

[0124] F = F1 + F2;

[0125] In the formula, F is the compressive strength of the tunnel boring machine (TBM); F1 is the frictional resistance between the soil and the TBM shell; and F2 is the total bearing capacity of the welded joints of the tail anti-retreat steel plate.

[0126] During the tunnel boring machine (TBM) docking process, the cutterhead of the following TBM will collide with the cutterhead of the preceding TBM, transferring some of the torque to the tail shield via the preceding TBM cutterhead-main drive-shield. The torsional resistance is achieved through the soil encapsulation effect combined with the tail shield anti-backlash bolts and segment bolts.

[0127] T = T1 + T2 + T3;

[0128] In the formula, T is the torsional resistance of the lead shield, T1 is the torsional friction resistance of the soil against the shield, T2 is the shear couple of the tail bolt, and T3 is the shear couple of the segment bolt.

[0129] The tensile strength of the tunnel boring machine is composed of the superposition of the ground friction and the tensile bearing capacity of the segment bolts.

[0130] L = L1 + L2;

[0131] In the formula, L is the tensile strength of the tunnel boring machine; L1 is the ground frictional resistance; and L2 is the tensile bearing capacity of the segment bolts.

[0132] In one embodiment, by simulating the additional stress field during the subsequent tunnel boring machine's (TBM) excavation and combining it with the initial stress field around the preceding TBM, the additional load on the preceding TBM is calculated, including:

[0133] S231. By establishing a field coupling model, the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling is simulated, and the evolution law of the subsequent additional stress field is extracted.

[0134] S232. Combining the initial stress field around the tunnel boring machine (TBM) and the subsequent additional stress field, calculate the indirect ground-transmitted load and instantaneous collision load on the surface of the TBM to obtain the additional load on the TBM.

[0135] Among them, by establishing a field coupling model, the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling is simulated, and the evolution law of the subsequent additional stress field is extracted, including:

[0136] S2311. Based on a multidimensional information database, embed dynamic parameters to establish a field coupling model that couples seepage, stress, displacement, and material. Among them, the dynamic parameters include the formation permeability coefficient, mud viscosity, and cutterhead penetration resistance. The cutterhead penetration resistance is equal to the tunneling contact force minus the static contact force.

[0137] S2312. Based on the field coupling model, the seepage path of mud is simulated by the fluid-structure interaction equation, and the stress field propagation range is analyzed by combining the Saint-Venant principle.

[0138] S2313. The finite element method is used to simulate the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling, and the stress gradient difference between the sand layer and the clay layer is quantified.

[0139] In one embodiment, the finite element method is used to simulate the spatiotemporal distribution of the additional stress field during subsequent shield tunneling, quantifying the stress gradient difference between the sand and clay layers, including:

[0140] A three-dimensional dynamic finite element model of the subsequent shield tunnel structure and strata was established; the model range of the three-dimensional dynamic finite element model conforms to Saint-Venant's principle to ensure that the boundary does not affect the stress field distribution.

[0141] The unit dynamic activation technology is used to simulate the tunnel excavation process. Each time a ring is advanced, a ring of lining is activated and a ring of soil is removed. The cutterhead face support pressure and the shield tail grouting pressure are applied step by step as moving surface loads.

[0142] Output full-field stress data according to preset time intervals, record the stress state at key time points, and draw three-dimensional stress cloud maps at different times;

[0143] The stress gradient difference between the sand layer and the clay layer is quantified by using the maximum stress gradient.

[0144] In one embodiment, by combining the initial stress field around the advance shield and the subsequent additional stress field, the indirect ground-transmitted load and instantaneous collision load on the surface of the advance shield are calculated to obtain the additional loads experienced by the advance shield, including:

[0145] S2321. Extract the stress field generated by the subsequent shield tunneling, combine it with the initial stress field around the preceding shield, and use the nodal force difference method to calculate the indirect ground load transmitted to the surface of the preceding shield.

[0146] S2322. Establish a three-dimensional model of the two cutterheads and the surrounding soil, and mesh the contact area of ​​the cutterheads; define the contact type between the cutterheads, use an explicit dynamic solver to perform transient analysis, and output the contact force time history curve to extract the instantaneous collision load; the instantaneous collision load includes the maximum load value, collision torque and action time.

[0147] Specifically, the present invention performs additional load analysis for docking tunneling in step 4, including:

[0148] Step 4.1: Extraction of the evolution law of subsequent additional stress field:

[0149] Specifically, a field coupling model (a four-field coupling model of "seepage-stress-displacement-material") is established, embedding dynamic parameters such as formation permeability coefficient, mud viscosity, and cutterhead penetration resistance (cutterhead penetration resistance = tunneling contact force - static contact force; these two parameters of the subsequent tunnel boring machine have been supplemented in the database in step 1).

[0150] Specifically, the "seepage-stress-displacement-material" four-field coupling model includes: Seepage field: based on Darcy's law (simulating the seepage path of mud through fluid-structure interaction equations) to simulate the seepage path of mud and groundwater and the distribution of pore water pressure; Stress field: based on Biot's consolidation theory (using Biot's consolidation theory in step 2 to couple the seepage-stress equations) to simulate the change of effective stress, and coupling the pore water pressure calculated from the seepage field as a volume force to the stress field; Displacement field: solving the displacement response of the strata and structure caused by the change of stress field through the finite element method; Material field: dynamically simulating the tunneling process through element birth and death technology (activating one ring of lining unit and removing one ring of soil unit for each ring advanced), and applying the cutterhead face support pressure and shield tail grouting pressure as surface loads moving with the tunneling to reflect the dynamic changes of the tunneling material.

[0151] Specifically, the seepage field, stress field, and displacement field correspond to the physical fields in classical geotechnical engineering numerical simulation. In this invention, the somewhat vague term "material field" is specifically interpreted as the dynamic change process of "tunneling material (soil and lining)" simulated through "unit birth and death technology" and "moving load".

[0152] Specifically, the seepage path of the slurry is simulated using the fluid-structure interaction equation (Darcy's law) (combined with the database from step 1, Darcy's law is used to simulate the actual slurry seepage path in engineering projects to better reflect the evolution of the real additional stress field). The range of stress field propagation is analyzed using Saint-Venant's principle (the impact is negligible when it is greater than 3 times the shield diameter). It should be noted that Saint-Venant's principle is defined as follows: if the resultant force and resultant moment of the load acting on a small area (or volume) of an elastic body are both equal to zero, then the stress is almost zero in areas far from the load area. Based on engineering experience, this invention only considers the stress within a range of 3 times the shield diameter; the impact is negligible when it is greater than 3 times the shield diameter.

[0153] ;

[0154] In the formula, q is the Darcy velocity (unit: m / s); k is the medium permeability (unit: m). 2 μ is the fluid dynamic viscosity (unit: Pa·s); p is the pressure gradient (unit: Pa / m); ρ l Fluid density (unit: kg / m³) 3 g is the gravitational acceleration vector (unit: m / s²). 2 ).

[0155] Specifically, the finite element method was used to simulate the spatiotemporal distribution of the additional stress field during subsequent shield tunneling, quantifying the stress gradient differences between the sand and clay layers. Among these:

[0156] 1) Construction of a three-dimensional dynamic finite element model, specifically including:

[0157] ① Establish a 3D model of the subsequent shield tunnel structure and strata (sand layer, clay layer). The model range must satisfy Saint-Venant's principle to ensure that the boundary does not affect the stress field distribution (when modeling, the soil boundary should be set larger than 3 times the shield diameter required by Saint-Venant's principle, because the simulated stress field results will not appear in the range of 3 times the shield diameter. Therefore, we require the boundary to be set to 3 times the shield diameter required by Saint-Venant's principle).

[0158] ②The constitutive and parameter settings for the shield structure, sand layer, and clay layer are the same as those in step 1.

[0159] 2) Simulate the tunnel excavation process, specifically including:

[0160] ① The unit dynamic activation technology (the "birth and death unit" technology of numerical simulation software) is adopted. For each ring advanced, a ring of lining is "born" and a ring of soil is "dead". The advancement speed is taken according to the conventional value.

[0161] ②At the same time, the cutterhead face support pressure and the shield tail grouting pressure are applied as moving surface loads gradually.

[0162] 3) Spatiotemporal distribution data monitoring and extraction, specifically including:

[0163] ① Output full-field stress data every 0.1 hours of tunneling, focusing on recording key time points (cutterhead entry, stable tunneling, and machine shutdown), and draw three-dimensional stress cloud maps at different times.

[0164] 4) Quantification of stress gradient between sand and clay layers, specifically including:

[0165] A larger maximum stress gradient indicates more significant stress concentration, directly determining the formation instability risk level (sand layer > clay layer); the maximum principal stress change dominates the shear failure of the sand layer (e.g., soil splitting in front of the cutterhead); the minimum principal stress change dominates the compressive deformation of the clay layer (e.g., soil compression settlement around the shield); the radial distance derivative is a key variable determining the stress attenuation rate. `max` ensures that the quantification results cover the most unfavorable working conditions. The expression for quantifying the stress gradient difference between the sand and clay layers using the maximum stress gradient is:

[0166] ;

[0167] In the formula, G max The maximum stress gradient (MPa / m) represents the extreme value of principal stress variation per unit distance in the formation, reflecting the intensity of disturbance. The maximum principal stress change (MPa) represents the maximum principal stress increment (tensile / compressive stress) caused by subsequent shield tunneling. The minimum principal stress change (MPa) characterizes the minimum principal stress increment (constraint stress) caused by subsequent shield tunneling; Δ r The radial distance differential (m) represents the change in radial distance from the center of the shield cutterhead after the calculation point.

[0168] Step 4.2, Extraction of additional loads on the tunnel boring machine:

[0169] (1) For the calculation of indirect loads transmitted through the strata, the stress field generated by the subsequent shield tunneling in step 2 is first extracted. Combined with the initial stress field around the preceding shield (obtained by numerical simulation of the influence of shield downtime on the additional stress field in different strata during the extraction of the preceding shield's shutdown state in step 2), the spatiotemporal distribution of indirect loads (indirect loads transmitted through the strata) on the surface of the preceding shield is calculated using the nodal force difference method. The expression is as follows:

[0170] ;

[0171] In the formula, q 间接 For the indirect additional load on the surface of the tunnel boring machine (indirectly transmitted load from the strata); ∑q 后行(x,y,z) represents the stress field generated by the subsequent shield tunneling in step 2 (located at x,y,z); ∑q 先行初始 This represents the initial stress field around the tunnel boring machine.

[0172] (2) For instantaneous collision loads, a three-dimensional model of the two cutterheads and the surrounding soil is established using finite element software. The contact area of ​​the cutterheads is finely meshed to ensure stress concentration is captured. The cutterheads are modeled as elastoplastic materials, and the soil is modeled as Mohr-Coulomb or Drucker-Prager constitutive models. Damping parameters are set to simulate energy dissipation. The contact between the cutterheads is defined as “surface-to-surface contact” or “automatic contact”. A penalty function method or Lagrange multiplier method suitable for impact analysis is selected. The soil boundary is simulated with spring-damped elements or infinite elements to simulate the far-field effect, constrain the tail degree of freedom of the tunnel boring machine, and simulate the fixed conditions during actual advancement. A transient analysis is performed using an explicit dynamic solver. A reasonable time step is set, the contact force time history curve is output, and the maximum load value, collision torque, and action time are extracted.

[0173] In one embodiment, a response evaluation system for the load-resistance ratio is established based on the resistance of the preceding shield structure and the additional loads borne by the preceding shield to determine the disturbance level, including:

[0174] The resistance of the preceding shield structure is compared with the additional loads borne by the preceding shield to establish a response evaluation system for the load-resistance ratio.

[0175] Based on the comparison results of the load-resistance ratio response evaluation system, the disturbance level is divided into mild disturbance, moderate disturbance and severe disturbance.

[0176] When the disturbance level is mild, automatic monitoring is triggered; when the disturbance level is moderate, the subsequent shield tunneling parameters are optimized; when the disturbance level is severe, micro-disturbance control measures are taken.

[0177] Specifically, the response evaluation in step 5 of this invention includes:

[0178] Compare the indirect ground-transmitted load and instantaneous collision load obtained in step 3 with the bearing capacity of the tunnel boring machine (the structural resistance of the tunnel boring machine). If the resistance capacity is strong, no treatment is required. If the resistance capacity is insufficient, micro-disturbance control measures need to be taken.

[0179] (1) Establish a response evaluation system for the load-resistance ratio (λ), the expression of which is:

[0180] ;

[0181] In the formula, λ 压 , λ 扭 , λ 拉These represent the disturbance levels for pressure, torque, and tension, respectively; T 碰撞 The peak value of the collision torque; ∇q 间接 To transmit the load gradient (reflecting longitudinal tensile force); q 间接 F represents the indirect additional load on the surface of the tunnel boring machine (indirect load transmitted from the strata); T represents the compressive strength of the tunnel boring machine; L represents the torsional strength of the tunnel boring machine; and L represents the tensile strength of the tunnel boring machine.

[0182] (2) Disturbance level classification rules, based on λ value to determine the disturbance level, as shown in Table 1.

[0183] Table 1 Disturbance Level Classification Rules

[0184] (3) Dynamic feedback control triggering, such as Figure 2 As shown, it specifically includes:

[0185] ① Light / moderate disturbance: Triggers automatic monitoring and automatically activates the tunneling parameter optimization module in step 6 (adjusting support pressure, tunneling speed, etc.).

[0186] ② Severe disturbance: Triggering the three-in-one micro-disturbance control technology (structural reinforcement + stratum consolidation + tunneling parameter adjustment)

[0187] In one embodiment, the micro-disturbance control measures include shield structure reinforcement, ground reinforcement of the docking section, and control of subsequent shield tunneling parameters, wherein:

[0188] The shield tunnel structure reinforcement includes segment tying technology, tail-end anti-backlash technology, and main drive anti-backlash technology. Specifically, it includes: determining the reinforcement range of the longitudinal segments of the shield tunnel and determining the length, width, and thickness of the longitudinal reinforcement steel plates; welding and fixing the longitudinal reinforcement steel plates to the anchor steel plates; and using a full-ring reinforcement method to longitudinally reinforce the shield tunnel; installing anchor plates and rubber protective layers on the assembled segments; after retracting the jacks, assembling the welded steel plates as a whole at the corresponding positions of the segments; installing anchor bolts and tightening the sealing gaskets; and welding and fixing the steel plates to the shield shell after completing the installation of the full-ring steel plates; determining the planar dimensions and weld range of the anti-backlash steel plates; and optimizing the anti-backlash steel plate parameters based on the strength calculation results of the anti-backlash steel plate base material and welds.

[0189] The ground reinforcement of the docking section includes radial grouting of the tunnel, radial grouting of the shield body, and ultra-strong curtain grouting outside the tunnel. Specifically, it includes: using the synchronous grouting system of the rear shield tail for pressure-controlled grouting, pausing grouting and letting it stand when the grouting pressure continues to rise to the set threshold, and restarting it after the pressure dissipates; injecting reinforcement grout into the slurry chamber in stages based on the pre-set flushing pipeline of the slurry chamber of the advance shield, and sequentially carrying out the initial filling of the lower part, the pressure maintenance filling of the middle part, and the sealing filling of the upper part; and performing radial grouting of the shield body and advanced compensation grouting outside the shield in the order from bottom to top through the pre-set radial grouting holes and advanced grouting holes on the shield shell.

[0190] The control of subsequent shield tunneling parameters involves dynamically adjusting the tunneling speed, penetration depth, cutterhead rotation speed, and face support pressure to ensure that the sum of the subsequent penetration resistance and the subsequent face support pressure does not exceed the static earth pressure of the preceding shield, thereby minimizing the additional stress generated by the subsequent shield.

[0191] Specifically, the present invention achieves three-in-one micro-disturbance control in step 6. The micro-disturbance control measures in this invention include: preliminary shield structure reinforcement (segment tying, targeted design for shield tail backlash prevention, targeted design for main drive backlash prevention, etc.), ground reinforcement of the docking section (continuous pressure maintenance grouting at the shield tail, phased pressure control and filling reinforcement of the slurry chamber of the preliminary shield, radial and advance compensation grouting of the shield body, etc.), and subsequent shield tunneling parameter control (support pressure, tunneling speed, attitude control, slurry indicators, cutterhead rotation speed, etc.) to achieve precise micro-disturbance docking, including:

[0192] (1) Shield tunneling structure reinforcement technology, specifically including:

[0193] 1) Segment Reinforcement Technology: ① Determine the longitudinal segment reinforcement range of the shield tunnel, and then determine the length L (m) of the longitudinal reinforcement steel plate; ② Determine the dimensions of the longitudinal reinforcement steel plate, specifically the width a (mm) and thickness b (mm); ③ Weld and fix the longitudinal reinforcement steel plate to the anchor steel plate; ④ The arrangement of the longitudinal reinforcement steel plate and anchor steel plate of the shield tunnel structure must match the longitudinal bolts between the rings to ensure good overall connection and good shared stress between the longitudinal reinforcement steel plate and the bolts, thereby maximizing the strength of both; ⑤ The longitudinal reinforcement of the shield tunnel adopts a whole-ring reinforcement method to ensure uniform stiffness distribution across the entire annular section, thus ensuring uniform stress distribution on the annular section of the tunnel structure. This ensures stronger resistance of the preceding shield segment structure.

[0194] 2) Shield Tail Anti-Retreat Technology: ① Install anchor plates and neoprene rubber protective layers on the assembled tunnel segments. ② After the water-stopping device components are manufactured in the factory and transported to the site, a set of jacks is retracted, and the welded steel plate 1, steel plate 2, and steel round pressure strip are assembled as a whole at the corresponding positions on the tunnel segments, such as... Figure 3The image shown is a cross-sectional view of the shield tail water-stopping device applying the shield tail anti-retreat technology of this invention. ③ Drill holes in the segments to install anchor bolts, and tighten the bolts while pressing the sealing gaskets. During the installation of the anchor bolts, ensure that each anchor bolt is subjected to synchronous and uniform force. ④ Install steel plate 3 ( Figure 3 Two types of steel plates (3) are used, and they are installed alternately. The first type of steel plate (3) is installed simultaneously with the removal of the jacks, while the second type of steel plate (3) is installed before the freezing construction. ⑤ Repeat steps 2-4 to complete the installation of the entire ring of steel plates (1, 2, and 3). After settlement stabilizes, steel plate (2) is securely welded to the shield shell. Simultaneously, the anchor plate is welded to steel plate (2) using connecting steel plates. After welding, grouting is performed to fill the gaps at the shield tail and between steel plate (1) and the segment concrete. After filling, water pressure is used to check the sealing of the water-stopping device.

[0195] 3) Main drive anti-reverse technology: This invention determined the planar dimensions of the anti-reverse steel plate by examining and analyzing the spatial position of the main drive; clarified the reasonable range of the weld by considering the sealing of the main drive; clarified the design basis for the main drive anti-reverse reinforcement by determining the backward force of the main drive telescopic cylinder; and optimized the parameters of the anti-reverse steel plate by verifying the strength of the base material and weld of the anti-reverse steel plate, thus ensuring that the risk of main drive backward movement during shield docking is eliminated.

[0196] (2) Ground reinforcement technology for the docking section, specifically including:

[0197] 1) Continuous Pressure Maintenance Grouting at the Shield Tail: Utilizing the synchronous grouting system at the tail of the advancing shield, continuous and intermittent pressure-controlled grouting is performed using a stable, low-shrinkage grout as the tunnel approaches the docking area. By monitoring the grouting pressure and flow rate in real time, the grouting strategy is dynamically adjusted. When the grouting pressure continuously rises to a set threshold, grouting is paused and allowed to stand until the pressure dissipates before restarting. This ensures that the grout fully fills the gap at the shield tail and continuously penetrates into the surrounding soil, forming a uniform and dense reinforcement ring.

[0198] 2) Phased Pressure Control Filling and Reinforcement of the Pre-existing Shield Tunnel's Slurry Chamber: After the pre-existing shield tunnel stops, using the pre-installed upper, middle, and lower flushing pipes in its slurry chamber, reinforcing grout is injected into the slurry chamber in stages to replace and solidify the original slurry inside, forming rigid support to prevent deformation of the shield head due to its own weight. Simultaneously, it seals the soil ahead, eliminating the risk of water and sand inrush, and actively reinforces the soil ahead and around the tunnel. Specific steps include: a) Initial Filling of the Lower Part: First, low-strength mortar is injected into the slurry chamber through the lower flushing pipes to initially fill the lower part of the slurry chamber. The filling height must be higher than the lower edge of the front hatch to ensure effective sealing of the lower part of the hatch. b) Mid-section pressure maintenance filling: After the initial filling grout reaches a certain strength, low-strength mortar continues to be injected through the mid-section flushing pipe; simultaneously, overflow grout is discharged through the upper pipe. During this process, the pressure in the slurry chamber is monitored and controlled in real time to maintain it stably at a preset target value slightly higher than the static soil and water pressure of the stratum, in order to prevent instability of the working face; when mortar flows out of the overflow pipe, the overflow valve is closed, and grouting continues until the grouting pressure reaches the preset upper limit and then stops. c) Upper final sealing filling: After the mid-section filling grout reaches a certain strength, cement grout is injected through the upper flushing pipe until the slurry chamber is completely filled and the predetermined sealing and reinforcement strength is achieved.

[0199] 3) Radial and Advanced Compensation Grouting of the Shield Body: Utilizing pre-set radial and advanced grouting holes on the shield shell, precise compensation grouting is performed in layers to fill voids around the shield caused by construction disturbances, sealing the shield, filling voids, and stabilizing the surrounding strata. Specific steps include: a) Radial Grouting of the Shield Body: First, the valves of the radial grouting holes at the front of the shield body are opened and cleared, and the grouting pipeline is connected. A single-liquid grout system is used, and grouting is performed from bottom to top. The grouting pressure is monitored in real time during the grouting process. When the pressure reaches the preset termination pressure value, grouting in that hole is stopped to ensure that the grout diffuses fully without fracturing the strata. b) Advanced Compensation Grouting Outside the Shield Body: Subsequently, the valves of the advanced grouting holes are opened and cleared. High-pressure media is used to pre-clear the grouting pipeline. After confirming that the pipeline is unobstructed, the grouting system is connected for pressure grouting. The grouting sequence and pressure control principles are the same as in step a, aiming to further reinforce and seal the soil outside the radial grouting range. c) Grouting effect verification and closed-loop control: After all grouting operations are completed and the grout reaches a certain strength, sample drilling inspections are carried out on the grouting holes; by checking for water leakage in the boreholes, the sealing and integrity of the grouting body are quantitatively evaluated; if leakage is found, the supplementary grouting process for the corresponding area is immediately initiated, and the effect is verified again, forming a closed-loop quality control process of "grouting-inspection-reinforcement" until the area is completely sealed.

[0200] (3) Control of subsequent shield tunneling parameters: Tunneling speed and penetration depth are the core dynamic parameters affecting the stability of the excavation face. Too slow a tunneling speed prolongs the soil exposure time, increasing the risk of seepage; too fast a speed will cause the soil stress release rate to exceed the response capacity of the mud support, easily leading to local collapse. Furthermore, it easily generates excessive additional loads in the strata, thus disturbing the preceding shield and the surrounding rock. Penetration depth reflects the depth the cutterhead penetrates into the soil per revolution. Its relationship with tunneling speed and cutterhead rotation speed is V=P×N (V is tunneling speed, P is penetration depth, and N is cutterhead rotation speed). Excessive penetration depth will exacerbate cutterhead vibration and soil disturbance. Therefore, it is possible to adjust the tunneling parameters according to the following... Figure 4 The control process in the tunnel minimizes additional stress by dynamically adjusting the support pressure at the tunnel face.

[0201] Specifically, such as Figure 4 As shown, the following parameters are input from the database in step 1: the tunneling speed of the subsequent shield, static contact force, tunneling contact force, face support pressure, and static earth pressure of the preceding shield. The difference between the subsequent tunneling contact force and the static contact force yields the subsequent penetration resistance. The subsequent penetration resistance is summed with the subsequent face support pressure. If the sum is greater than the static earth pressure of the preceding shield, it indicates that the additional stress on the subsequent shield is too high, and the face support pressure of the subsequent shield should be reduced. If the sum is less than or equal to the static earth pressure of the preceding shield, it indicates that the additional stress generated by the subsequent shield is 0, and tunneling can proceed according to the current tunneling parameters.

[0202] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling of a shield tunneling machine, characterized in that, include: S1. Construct a multi-dimensional information database of the stratigraphic conditions in the docking area; The multidimensional information database includes geological parameters of the docking section, tunnel boring parameters, and spatiotemporal parameters of the docking section, which are used to extract the mechanical behavior characteristics of the preceding tunnel boring machine and the mechanical behavior characteristics of the subsequent tunnel boring machine. S2. Based on a multidimensional information database, analyze the structural resistance of the first shield tunnel, and determine the additional load on the first shield tunnel based on the additional load generated by the subsequent shield tunneling and the initial stress field around the first shield tunnel; the additional load on the first shield tunnel includes the indirect transmission load from the strata and the instantaneous collision load. S3. Based on the resistance of the preceding shield structure and the additional load on the preceding shield, establish a response evaluation system for the load-resistance ratio to determine the disturbance level, and adopt micro-disturbance control measures according to the disturbance level determination results; the micro-disturbance control measures include shield structure reinforcement, ground reinforcement of the docking section, and control of subsequent shield tunneling parameters.

2. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 1, characterized in that, The multidimensional information database for constructing the stratigraphic conditions of the docking zone includes: Based on geological exploration and permeability tests, permeability difference zones were delineated, and stratigraphic parameters of the connecting zones were obtained; wherein, the permeability difference zones include alternating layers of sand and clay; the stratigraphic parameters of the connecting zones include permeability coefficient, porosity, elastic modulus, and cohesion; Using the geological parameters of the docking section, combined with shield tunneling parameters and docking spatiotemporal parameters, a multidimensional information database is constructed; the shield tunneling parameters include shield tunneling speed, cutterhead penetration, mud pressure and grouting volume; the docking spatiotemporal parameters include the distance between the two shields, docking time difference, and shield attitude deviation. Based on the multidimensional information database, the influence of downtime difference on the additional stress field is analyzed, and Darcy's law and Biot's consolidation theory are applied to establish a dynamic coupling model of seepage-stress field to obtain the mechanical behavior characteristics of the preceding and subsequent shield tunnels.

3. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 1, characterized in that, The method, based on a multidimensional information database, analyzes the structural resistance of the preceding shield tunnel and, based on the additional loads generated by the subsequent shield tunneling and the initial stress field around the preceding shield tunnel, determines that the additional loads on the preceding shield tunnel include: S21. Based on a multi-dimensional information database, the influence of shield tunneling downtime on the additional stress field in different strata is reproduced through numerical simulation in order to extract the previous shield tunneling downtime status. S22. Based on the shutdown status of the tunnel boring machine (TBM), the structural resistance of the TBM is evaluated by analyzing its compressive strength, torsional strength, and tensile strength. S23. By simulating the additional stress field during the subsequent shield tunneling and combining it with the initial stress field around the preceding shield, the additional load on the preceding shield is calculated.

4. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 3, characterized in that, The method, based on a multidimensional information database, uses numerical simulation to reproduce the impact of shield tunneling downtime on the additional stress field in different geological strata, in order to extract the preliminary shield tunneling downtime status, including: S211. Based on the geological condition parameters of the docking section and the shield tunneling parameters in the multidimensional information database, a three-dimensional finite element model is established to simulate the tunnel structure in the sand layer, clay layer and the state of the shield tunneling machine being stopped; the range of the three-dimensional finite element model is set according to the shield diameter to conform to the Saint-Venant principle. S212. Based on the geological condition parameters of the docking section, set up the material constitutive models of the sand layer and clay layer, and set the boundary conditions; S213. By simulating groundwater seepage, the pore water pressure calculated from the seepage field is coupled to the stress field as a volume force to update the effective stress, and the seepage-stress equation is obtained through coupling. S214. Using the seepage-stress equation, simulate the dissipation of excess pore water pressure and stress relaxation of the pilot shield under different downtime, and extract the additional stress of the nodes around the pilot shield.

5. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 4, characterized in that, The boundary conditions include: Fix the vertical displacement of the bottom of the model and apply normal constraints; Based on the actual hydrological conditions around the model, set free drainage boundaries, impermeable boundaries, or constant head; An initial stress field is generated around the tunnel boring machine by gravity loading, and the pore water pressure is distributed according to the hydrostatic pressure.

6. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 4, characterized in that, The expression for the simulated groundwater seepage is: ； In the formula, q is the seepage velocity; k is the permeability coefficient of the medium; and μ is the dynamic viscosity of the fluid. p is the pressure gradient; ρ l Where is the fluid density; g is the acceleration due to gravity; The expression for coupling the pore water pressure calculated from the seepage field as a volume force to the stress field to update the effective stress is as follows: σ'=σ-u; In the formula, σ' is the effective stress, which is used to determine the deformation and strength of the soil; σ is the total stress, which is generated by the external load and the self-weight of the soil; u is the pore water pressure, including hydrostatic pressure and excess pore water pressure. The coupling yields the following expression for the seepage-stress equation: ·(s')+r t g=0; In the formula, ·(σ') represents the additional stress; ρ t ρ is the soil density; g is the acceleration due to gravity.

7. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 3, characterized in that, The assessment results of the structural resistance of the preliminary shield tunnel, obtained by analyzing its compressive, torsional, and tensile strengths based on its shutdown status, include: S221. The compressive strength of the advance shield is obtained by superimposing the frictional resistance between the soil and the shield shell and the total bearing capacity of the weld of the shield tail anti-retreat steel plate; the frictional resistance between the soil and the shield shell increases with the increase of downtime. S222. Calculate the sum of the torsional friction resistance of the soil against the shield, the shear couple of the tail bolts and the segment bolts to obtain the torsional resistance of the advance shield; the torsional resistance is used to resist the torque transmitted to the tail when the rotating cutterhead of the follow shield collides with the cutterhead of the advance shield. S223. By combining the stratum frictional resistance and the tensile bearing capacity of the segment bolts, the tensile capacity of the advance shield is determined. Combined with the compressive and torsional capacity of the advance shield, the structural resistance of the advance shield is evaluated.

8. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 3, characterized in that, The calculation of the additional load on the preceding shield tunnel by simulating the additional stress field during the subsequent shield tunneling, combined with the initial stress field around the preceding shield tunnel, includes: S231. By establishing a field coupling model, the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling is simulated, and the evolution law of the subsequent additional stress field is extracted. S232. Combining the initial stress field around the first shield and the subsequent additional stress field, calculate the indirect ground-transmitted load and instantaneous collision load on the surface of the first shield to obtain the additional load on the first shield.

9. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 8, characterized in that, The method involves establishing a field coupling model to simulate the spatiotemporal distribution of the additional stress field during subsequent shield tunneling, and extracting the evolution law of the subsequent additional stress field, including: S2311. Based on a multidimensional information database, dynamic parameters are embedded to establish a field coupling model that couples seepage, stress, displacement, and material; wherein, the dynamic parameters include the formation permeability coefficient, mud viscosity, and cutterhead penetration resistance, and the cutterhead penetration resistance is equal to the tunneling contact force minus the static contact force; S2312. Based on the field coupling model, the seepage path of mud is simulated by the fluid-structure interaction equation, and the stress field propagation range is analyzed by combining the Saint-Venant principle. S2313. The finite element method is used to simulate the spatiotemporal distribution of the additional stress field during the subsequent shield tunneling, and the stress gradient difference between the sand layer and the clay layer is quantified.

10. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 9, characterized in that, The finite element method is used to simulate the spatiotemporal distribution of the additional stress field during subsequent shield tunneling, quantifying the stress gradient difference between the sand and clay layers, including: A three-dimensional dynamic finite element model of the subsequent shield tunnel structure and strata is established; the model range of the three-dimensional dynamic finite element model conforms to Saint-Venant's principle to ensure that the boundary does not affect the stress field distribution; The unit dynamic activation technology is used to simulate the tunnel excavation process. Each time a ring is advanced, a ring of lining is activated and a ring of soil is removed. The cutterhead face support pressure and the shield tail grouting pressure are applied step by step as moving surface loads. Output full-field stress data according to preset time intervals, record the stress state at key time points, and draw three-dimensional stress cloud maps at different times; The stress gradient difference between the sand layer and the clay layer is quantified by using the maximum stress gradient.

11. The method for evaluating and controlling the response to superimposed disturbances during near-intersection tunneling as described in claim 10, characterized in that, The expression for quantifying the difference in stress gradient between the sand layer and the clay layer by using the maximum stress gradient is as follows: ； In the formula, G max The maximum stress gradient is used to characterize the extreme values ​​of principal stress variation per unit distance in the formation; The maximum principal stress change is used to characterize the maximum principal stress increment caused by subsequent shield tunneling. The minimum principal stress change is used to characterize the minimum principal stress increment caused by subsequent shield tunneling. Δ r The radial distance differential is used to characterize the change in radial distance between the center of the shield cutterhead after the calculation point distance.

12. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 8, characterized in that, The method combines the initial stress field around the advance shield and the subsequent additional stress field to calculate the indirect ground-transmitted load and instantaneous collision load on the surface of the advance shield, thereby obtaining the additional loads experienced by the advance shield, including: S2321. Extract the stress field generated by the subsequent shield tunneling, combine it with the initial stress field around the preceding shield, and use the nodal force difference method to calculate the indirect ground load transmitted to the surface of the preceding shield. S2322. Establish a three-dimensional model of the two cutterheads and the surrounding soil, and mesh the contact area of ​​the cutterheads; define the contact type between the cutterheads, use an explicit dynamic solver to perform transient analysis, and output the contact force time history curve to extract the instantaneous collision load; the instantaneous collision load includes the maximum load value, collision torque and action time.

13. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 12, characterized in that, The expression for calculating the indirectly transmitted load on the surface of the tunnel boring machine (TBM) using the nodal force difference method is as follows: ； In the formula, q 间接 For the indirect transfer of loads to the strata on the surface of the tunnel boring machine; ∑q 后行 (x,y,z) represents the stress field generated by the shield tunneling after the position (x,y,z); ∑q 先行初始 This represents the initial stress field around the tunnel boring machine.

14. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling of a shield tunneling machine according to claim 1, characterized in that, The establishment of a load-resistance ratio response evaluation system based on the resistance of the preceding shield structure and the additional loads on the preceding shield to determine the disturbance level includes: The resistance of the prior shield structure is compared with the additional load on the prior shield to establish a response evaluation system for the load-resistance ratio. Based on the comparison results of the load-resistance ratio assessment system, the disturbance level is divided into mild disturbance, moderate disturbance and severe disturbance. When the disturbance level is mild, automatic monitoring is triggered; when the disturbance level is moderate, the subsequent shield tunneling parameters are optimized; when the disturbance level is severe, micro-disturbance control measures are taken. The expression for the load-resistance ratio response evaluation system is as follows: ； In the formula, λ 压 , λ 扭 , λ 拉 These are respectively pressure disturbance level, torque disturbance level, and tensile disturbance level; T 碰撞 This represents the peak value of the collision torque. q 间接 For the transmission of load gradient; q 间接 F represents the indirect additional load on the surface of the tunnel boring machine (TBM); T represents the compressive strength of the TBM; T represents the torsional strength of the TBM; and L represents the tensile strength of the TBM.

15. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 1, characterized in that, The shield tunneling structure reinforcement includes: Determine the reinforcement range of the longitudinal segments of the shield tunnel and the length, width and thickness of the longitudinal reinforcement steel plate. Weld the longitudinal reinforcement steel plate to the anchoring steel plate and reinforce the shield tunnel longitudinally using the whole ring reinforcement method. On the assembled segments, anchor plates and rubber protective layers are installed by planting rebars. After the jacks are withdrawn, the welded steel plates are assembled as a whole in the corresponding positions of the segments. Anchor bolts are installed and sealing gaskets are tightened. After the entire ring of steel plates is installed, the steel plates are welded and fixed to the shield shell. The planar dimensions and weld range of the anti-reverse steel plate were determined, and the parameters of the anti-reverse steel plate were optimized based on the strength calculation results of the base material and weld of the anti-reverse steel plate.

16. The method for evaluating and controlling the response to superimposed disturbances during near-intercept tunneling as described in claim 15, characterized in that, The ground reinforcement of the docking section includes: Pressure-controlled grouting is carried out using the synchronous grouting system at the tail of the rear-moving shield. When the grouting pressure continues to rise to the set threshold, grouting is paused and left to stand until the pressure dissipates, at which point it is restarted. Based on the pre-set flushing pipeline of the slurry chamber of the tunnel boring machine, the reinforcing slurry is injected into the slurry chamber in stages, and the initial filling of the lower part, the pressure maintenance filling of the middle part, and the sealing filling of the upper part are carried out in sequence. Radial grouting and advanced grouting of the shield body are carried out in a bottom-to-top sequence through the pre-set radial grouting holes and advanced grouting holes on the shield shell.

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