A method for predicting synchronous grouting quantity of a shield tunnel

Abstract

The application discloses a synchronous grouting quantity prediction method for a shield tunnel, and comprises the following steps: according to an elastic-plastic theory, a filling volume of a soil body rebound to a shield tail gap is established; under the action of a synchronous grouting pressure, a compression deformation of the soil body along a tunnel radial direction is calculated based on an equivalent columnar structure model; slurry on a seepage path is divided into a Bingham fluid (a non-Newtonian fluid), a mixture and a Newton fluid, a theoretical solution of a radial seepage diffusion distance of a tunnel section is established, and the synchronous grouting quantity of the part is calculated according to a soil body void ratio and a seepage distance; and according to a superposition model, a synchronous grouting quantity prediction and calculation formula under the action of comprehensive factors is established. According to the application, a theoretical prediction method suitable for a synchronous grouting diffusion distance and a synchronous grouting quantity of a sandy stratum is established through a superposition method of deformation, space filling, seepage diffusion range.

Description

Technical Field

[0001] This invention relates to the technical field of shield tunnel engineering, and in particular to a method for predicting the synchronous grouting volume in shield tunnels. Background Technology

[0002] Synchronous grouting in shield tunnels is an indispensable technological step in shield tunneling. Due to the high porosity and significant differences in pore distribution in soft soil strata (especially sandy strata), the permeability of the strata exhibits significant anisotropy, leading to marked anisotropy and heterogeneity in the penetration and diffusion of the grout during synchronous grouting in shield tunneling. Furthermore, the presence of pores and their varying geometric dimensions make it difficult to establish uniform technical performance indicators for the grout in engineering projects, resulting in considerable uncertainty and even arbitrariness in the selection of grouting parameters. In addition, groundwater can exert a complex combination of effects on the grout, including dynamic water pressure and dilution.

[0003] For a long time, researchers have studied the adaptability of various grouts to permeable strata through indoor simulation experiments, investigated the deformation and pressure dissipation characteristics of grout bodies behind shield tunnel walls through model tests, and studied the ground loss and surface settlement caused by shield tunnels through centrifugal model tests. In terms of theoretical research, based on grout materials such as Newtonian fluids, Bingham fluids, and power-type fluids, and considering the time-dependent viscosity of the grout, corresponding grout permeation and diffusion models and theoretical calculation methods for grout permeation and diffusion have been established. In terms of numerical simulation, seepage numerical models have been established in conjunction with engineering and geological characteristics, and commercial numerical software platforms have been used to simulate construction methods and calculate and analyze construction parameters. The research results have provided support for the selection and optimization of grouting schemes and parameters in shield tunnel construction. However, due to the complexity of engineering geological conditions, soil pore state, and the anisotropy and heterogeneity of groundwater, the above research methods are difficult to accurately simulate engineering geological conditions and process parameters. Most research results differ significantly from actual engineering conditions and remain at the stage of quantitative analysis and qualitative application. There is an urgent need to establish theoretical prediction methods for synchronous grouting diffusion distance and grouting volume applicable to sandy strata. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for predicting the synchronous grouting volume in shield tunnels. This method establishes a theoretical prediction method for the synchronous grouting diffusion distance and grouting volume applicable to sandy strata by superimposing deformation and spatial filling permeation diffusion ranges. To achieve the above-mentioned objectives and other advantages of the present invention, a method for predicting the synchronous grouting volume in shield tunnels is provided, comprising:

[0005] S1. Based on the elastic-plastic theory, establish the filling volume of the shield tail void due to soil rebound;

[0006] S2. The compressive deformation of the soil along the tunnel radial direction under synchronous grouting pressure is calculated using an equivalent columnar structure model.

[0007] S3. The grout in the seepage path is divided into Bingham fluid (non-Newtonian fluid), mixture and Newton fluid. The theoretical solution of the radial seepage diffusion distance of the tunnel section is established and the grouting volume of this part is calculated according to the soil porosity and seepage distance.

[0008] S4. Establish a calculation formula for predicting the synchronous grouting volume of the shield tunnel under the combined effects of factors based on the superposition model.

[0009] Preferred options also include:

[0010] (1 Considering the displacement effect of grout on water under grouting pressure, a model of grout flow and its gradual change state in the flow tube is established.)

[0011] (2) Based on the slurry gradual state diagram, the slurry state in the flow tube is divided into three characteristic states: Bingham non-Newtonian fluid, mixture and Newtonian fluid, and a practical calculation method for viscosity coefficient under the response state is established.

[0012] (3 Considering soil deformation, grouting disturbance and grout permeability characteristics, a superimposed model for predicting grouting volume and its theoretical solution are established.

[0013] Preferably, ignoring the flow losses of soil particles and groundwater, the space in which the synchronous grouting slurry exists is such that after the shield tunnel segments are installed and the shield tail is dislodged, a 50-100mm annular gap is formed between the tunnel wall and the soil, and the soil unloads and generates radial elastic recovery displacement; at the same time, the grouting system starts to synchronously grout into the annular gap to fill the gap and partially restore the soil unloading displacement and the volume change of the slurry infiltrating and diffusing into the soil under the action of injection pressure and gravity during the grouting process.

[0014] Preferably, a soil elastic recovery displacement calculation model is constructed, which includes the use of a virtual columnar structure to represent the soil stress release and recovery displacement in any θ direction. The radial soil unloading recovery displacement in the tunnel corresponding to any θ is as follows:

[0015]

[0016] in,

[0017] β=γξ μ H+γξ μ Rcosθ+4C;

[0018]

[0019]

[0020] Preferably, the method includes a soil elastic displacement model under synchronous grouting, wherein the soil surrounding the tunnel is assumed to be an elastic body (including nonlinear elasticity), and its radial equivalent deformation stiffness is k(θ). The radial displacement of the soil under the action of grout is as follows:

[0021]

[0022] Where p0 is the grouting pressure, MPa; γ g The bulk density of the slurry is kN / m³. 3 .

[0023] Preferably, this includes establishing a grouting permeation model, which includes establishing a one-dimensional virtual seepage model and establishing a model of grout flow and its gradual change state within the flow pipe. The formula for the theoretical permeation distance in the virtual fluid pipe is:

[0024]

[0025] In the formula: ξ e The void ratio of the soil;

[0026] γ w The specific weight of water, kN / m³ 3 ;

[0027] H ow The water level is relative to the tunnel axis, in meters (m).

[0028] Preferably, the method further includes establishing a composite superposition model of deformation and volume diffusion, wherein the composite superposition model considers the grout to be an incompressible fluid, and the grout penetration completely fills the soil pores in the diffusion area, wherein the grout penetration per unit length of the tunnel is:

[0029]

[0030] Compared with existing technologies, the advantages of this invention are as follows: By establishing a radial one-dimensional virtual equivalent seepage model passing through the centroid of the tunnel cross-section, and dividing the grout along the seepage path into Bingham fluid, a mixture, and Newton fluid, a diffusion and seepage calculation method for Bingham non-Newtonian fluids is established. Furthermore, by using the superposition method of deformation and spatial filling seepage diffusion range, a theoretical prediction method for synchronous grouting diffusion distance and grouting volume suitable for sandy strata is established. Attached Figure Description

[0031] Figure 1 A diagram of the tunnel engineering area and its characterization unit cell for the method of predicting synchronous grouting volume in shield tunnels according to the present invention;

[0032] Figure 2The diagram shows the deformation and volume diffusion superposition model of the shield tunnel synchronous grouting volume prediction method according to the present invention.

[0033] Figure 3 This is a diagram of the soil elastic recovery displacement calculation model for the shield tunnel synchronous grouting volume prediction method according to the present invention;

[0034] Figure 4 The diagram shows the elastic displacement model of soil under synchronous grouting action according to the synchronous grouting volume prediction method for shield tunnels of the present invention.

[0035] Figure 5 A one-dimensional virtual seepage model diagram of the shield tunnel synchronous grouting volume prediction method according to the present invention;

[0036] Figure 6 This is a conceptual diagram illustrating the state of grout and water within the flow tube in the shield tunnel synchronous grouting volume prediction method according to the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Reference Figure 1-6 A method for predicting the synchronous grouting volume of a shield tunnel includes: S1, establishing the filling volume of the shield tail void due to soil rebound based on elastoplastic theory;

[0039] S2. The compressive deformation of the soil along the tunnel radial direction under synchronous grouting pressure is calculated using an equivalent columnar structure model.

[0040] S3. The grout in the seepage path is divided into Bingham fluid (non-Newtonian fluid), mixture and Newton fluid. The theoretical solution of the radial seepage diffusion distance of the tunnel section is established and the grouting volume of this part is calculated according to the soil porosity and seepage distance.

[0041] S4. Establish a calculation formula for predicting the synchronous grouting volume of the shield tunnel under the combined effects of factors based on the superposition model.

[0042] Furthermore, it also includes:

[0043] (1 Considering the displacement effect of grout on water under grouting pressure, a model of grout flow and its gradual change state in the flow tube is established.)

[0044] (2) Based on the slurry gradual state diagram, the slurry state in the flow tube is divided into three characteristic states: Bingham non-Newtonian fluid, mixture and Newtonian fluid, and a practical calculation method for viscosity coefficient under the response state is established.

[0045] (3 Considering soil deformation, grouting disturbance and grout permeability characteristics, a superimposed model for predicting grouting volume and its theoretical solution are established.

[0046] Reference Figure 1 The space where the synchronous grouting slurry exists is such that after the shield segment is installed and the shield tail is removed, a 50-100mm annular gap is formed between the tunnel wall and the soil. The soil unloads and generates radial elastic recovery displacement. At the same time, the grouting system starts to synchronously grout into the annular gap to fill the gap and partially restore the soil unloading displacement. The volume change of the grout during the grouting process is superimposed on the volume change of the slurry penetrating and diffusing into the soil under the action of injection pressure and gravity.

[0047] Reference Figure 2 A calculation model for the elastic recovery displacement of soil is constructed, which includes the stress release and recovery displacement of soil in any θ direction, which can be equivalently expressed by a virtual columnar structure. The radial unloading recovery displacement of the tunnel soil corresponding to any θ is as follows:

[0048]

[0049] in,

[0050] β=γξ μ H+γξ μ Rcosθ+4C;

[0051]

[0052]

[0053] Furthermore, this includes a soil elastic displacement model under synchronous grouting, in which the soil surrounding the tunnel is assumed to be an elastic body (including nonlinear elasticity), with a radial equivalent deformation stiffness of k(θ). The radial displacement of the soil under the action of grout is as follows:

[0054]

[0055] Where p0 is the grouting pressure, MPa; γ g The bulk density of the slurry is kN / m³. 3 .

[0056] Reference Figure 4 This includes establishing a grouting permeability model, which comprises establishing a one-dimensional virtual seepage model and establishing a model of grout flow and its gradual change state within a flow pipe. The theoretical formula for the permeation distance in the virtual fluid pipe is:

[0057]

[0058] In the formula: ξ e The void ratio of the soil;

[0059] γ w The specific weight of water, kN / m³ 3 ;

[0060] H ow The water level is relative to the tunnel axis, in meters (m).

[0061] Reference Figure 5-6 It also includes establishing a composite superposition model of deformation and volume diffusion, in which the grout is considered to be an incompressible fluid, and the grout penetration completely fills the soil pores in the diffusion area, wherein the grout penetration per unit length of the tunnel is:

[0062]

[0063] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention, and applications, modifications and variations thereof will be apparent to those skilled in the art.

[0064] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for predicting the synchronous grouting volume in a shield tunnel, characterized in that, Includes the following steps: S1. Based on the elastic-plastic theory, establish the filling volume of the shield tail void due to soil rebound; S2. Calculate the compressive deformation of the soil along the tunnel radial direction under synchronous grouting pressure using an equivalent columnar structure model; construct a soil elastic recovery displacement calculation model, including arbitrary... The stress release and recovery displacement of soil in any direction can be equivalently expressed by a virtual columnar structure, yielding arbitrary... The corresponding radial soil unloading recovery displacement in the tunnel is as follows: ； in, ; ； ; ; S3. The grout along the seepage path is divided into Bingham non-Newtonian fluid, a mixture, and Newtonian fluid. A theoretical solution for the radial seepage diffusion distance of the tunnel cross-section is established, and the grouting volume for this part is calculated based on the soil porosity and seepage distance. This includes a soil elastic displacement model under synchronous grouting, in which the soil surrounding the tunnel is assumed to be an elastic body with a radial equivalent deformation stiffness of... k ( The radial displacement of the soil under the action of grout is as follows: （2）， in, p 0 represents the grouting pressure, in MPa; The bulk density of the slurry is kN / m³. 3 ; S4. Establish a calculation formula for predicting the synchronous grouting volume of the shield tunnel under the combined effects of factors based on the superposition model; including establishing a grouting permeability model, which includes establishing a one-dimensional virtual seepage model and establishing a model of grout flow and its gradual change state in the flow pipe. The formula for the theoretical permeation distance of the virtual fluid pipe is: (3)； In the formula: The void ratio of the soil; The specific weight of water, kN / m³ 3 ; H ow The water level height relative to the tunnel axis, in meters (m). This also includes establishing a composite superposition model of deformation and volume diffusion, in which the grout is considered to be an incompressible fluid, and the grout penetration completely fills the soil pores in the diffusion area, wherein the grout penetration per unit length of the tunnel is: (4)。 2. The method for predicting the synchronous grouting volume of a shield tunnel as described in claim 1, characterized in that, Also includes: (1 Considering the displacement effect of grout on water under grouting pressure, a model of grout flow and its gradual change state in the flow tube is established.) (2) Based on the slurry gradual state diagram, the slurry state in the flow tube is divided into three characteristic states: Bingham non-Newtonian fluid, mixture and Newtonian fluid, and a practical calculation method for viscosity coefficient under the response state is established. (3 Considering soil deformation, grouting disturbance and grout permeability characteristics, a superimposed model for predicting grouting volume and its theoretical solution are established.) 3. The method for predicting the synchronous grouting volume of a shield tunnel as described in claim 1, characterized in that, The space where the synchronous grouting slurry exists is the annular gap of 50-100mm formed between the tunnel wall and the soil after the shield segments are installed and the shield tail is dislodged. The soil unloads and generates radial elastic recovery displacement. At the same time, the grouting system starts to synchronously grout into the annular gap to fill the gap and partially restore the soil unloading displacement. The volume change of the grout in the soil during the grouting process is superimposed by the volume change of the grout infiltrating and diffusing into the soil under the action of injection pressure and gravity.

Images