Calculation method of limit support pressure for shield close docking engineering considering seepage

Abstract

The application provides a kind of limit support pressure calculation method of shield close docking engineering considering seepage, comprising the following steps: collecting stratum and tunnel parameters at shield docking position;Determine the height of instability region and the inclination of sliding surface according to fitting formula, the instability shape of excavation face in engineering practice or the result of numerical simulation;Based on limit equilibrium method, establish mathematical model of instability region;Force analysis is carried out on the mathematical model, and the balance equation in horizontal direction and vertical direction is established;Obtain the distribution of water head field near the excavation face according to the relevant parameters in numerical simulation or construction scheme, and calculate the seepage force;Calculate the remaining unknown parameters in the balance equation and substitute the seepage force to obtain the limit support pressure.The calculation method of the application considers the influence of seepage, and the limit support pressure of the excavation face under close docking engineering obtained is more accurate, which provides a reference for the stability problem of the excavation face of shield close docking engineering.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a method for calculating the ultimate support pressure in shield tunneling close-range docking projects that takes into account seepage. Background Technology

[0002] With the booming development of China's economy, large-scale cross-river and cross-sea tunnel projects have begun to be constructed on a large scale. Completed tunnels, such as the Shiziyang Tunnel of the Guangzhou-Shenzhen-Hong Kong High-Speed ​​Railway, were constructed using shield tunneling technology. Planned strait tunnels, such as those in Qiongzhou Bay and Bohai Bay, are also planned to utilize shield tunneling technology. In these large-scale tunnel projects, to overcome the difficulties of single shield tunneling, the method of using two shield tunnels to excavate in opposite directions and dock underground has become a new trend. The stability of the tunnel excavation face during docking is crucial. Insufficient support pressure at the excavation face can lead to instability and collapse, causing serious consequences such as casualties and damage to the shield tunneling machine. Although the stability of the excavation face of a single tunnel has been extensively studied, there is a lack of consideration for the stability of the excavation face in shield docking projects. Traditional mathematical models of excavation face support pressure are usually based on single tunnel projects, and their application to shield docking projects differs significantly. There is still no clear method for accurately calculating the ultimate support pressure required for the excavation face under shield docking conditions. Currently, there is an urgent need for a method for calculating the ultimate support pressure of shield docking projects that considers seepage, providing theoretical support for shield docking projects. Summary of the Invention

[0003] To address the above technical problems, this invention discloses a method for calculating the ultimate support pressure of shield tunneling near-distance docking projects that takes into account seepage. By considering the influencing factors of seepage, the ultimate support pressure of shield tunneling near-distance docking projects can be obtained, thereby determining the actual support pressure required at the excavation face. This method is applicable to slurry shield tunnels and can be used for docking projects of large-diameter shield tunnels under the sea.

[0004] The technical solution adopted by this invention is as follows:

[0005] A method for calculating the ultimate support pressure in near-distance shield tunneling projects considering seepage includes the following steps:

[0006] Step S1: Based on the construction plan and survey report, collect the geological and tunnel parameters at the shield docking location, and obtain the tunnel overburden thickness C, tunnel diameter D, docking distance L, and unit weight of water γ. w Soil weight γ, internal friction angle Cohesion c, soil lateral pressure coefficient K0, height h0 from the bottom of the tunnel to the surface water level;

[0007] Step S2: Based on the actual unstable shape of the excavation face or the results of numerical simulation, obtain the height K of the unstable region and the inclination angle θ of the sliding surface; wherein, the height K of the unstable region can also be obtained by fitting a formula.

[0008] Step S3: Based on the limit equilibrium method, establish a mathematical model of the wedge-shaped body in the unstable region according to the height K of the unstable region and the inclination angle θ of the sliding surface. Based on the longitudinal section diagram of the ultimate support pressure calculation model for the shield tunneling connection project, obtain the shear force T1 and normal force N1 on the side of the wedge-shaped body that connects with the opposing tunnel, the shear force T2 and normal force N2 at the bottom of the wedge-shaped body, the shear force T3 and normal force N3 on the side of the sliding surface, the shear force T4 and normal force N4 on the two sides of the wedge-shaped body, the weight W of the wedge-shaped body, the horizontal seepage force F, and the support pressure P. c The vertical earth pressure σ acting above the wedge v Based on the transverse cross-section of the ultimate support pressure calculation model for shield tunneling docking projects, the equivalent cross-sectional width B of the model is obtained.

[0009] Step S4: Perform force analysis on the mathematical model and establish equilibrium equations in both the horizontal and vertical directions;

[0010] The vertical equilibrium equation is:

[0011] BLσ v +W=T1+N2 cos θ+(T2+2T3+2T4)sin θ (1),

[0012] The equilibrium equation in the horizontal direction is:

[0013]

[0014] Step S5: Obtain the water head h from the piezometer at the shield excavation face based on the numerical simulation results or construction plan. F Based on the water head distribution, the approximate distribution function h(x,y,z) of the groundwater head field is obtained as follows:

[0015]

[0016] In the formula, α is the parameter of the approximate expression of the head field;

[0017] Integrating the distribution function with respect to the y-direction yields the average hydraulic head h inside the sliding body along the y-direction. * :

[0018]

[0019] Substituting equation (3) into equation (4) yields the horizontal seepage force F:

[0020]

[0021] In the formula, S1 is the sliding surface of the wedge, and S2 is the tunnel excavation face;

[0022] Step S6: Calculate the remaining unknown parameters in the equilibrium equations;

[0023] Based on the analysis diagram of the shear force T3 on the side of the wedge, we obtain...

[0024]

[0025] In the formula, K' is the instability height on the right side of the wedge, z is the distance from the top of the triangle to the i-th soil strip, and L z dz is the height of the trapezoidal strip; dz is the integral infinitesimal element; the instability height K' on the right side of the wedge is calculated using equation (18):

[0026] K′=KL tan θ (18),

[0027] Trapezoidal bar height L z The result is obtained by using equation (19):

[0028]

[0029] Where z is the distance from the top of the wedge to the integral element;

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] Substituting equations (6)-(12) into the vertical equilibrium equation (1), we get:

[0037]

[0038] Substituting the seepage force and other parameters into the horizontal equilibrium equation (2), we can obtain the support pressure P. c :

[0039]

[0040] As a further improvement of the present invention, in step S2, K is calculated using equation (15):

[0041] K = 29.84 (L / D) 2 +17.79(L / D)+0.075 (15).

[0042] As a further improvement of the present invention, in step S3, the equivalent cross-sectional width B of the model is calculated using equation (16):

[0043] B = πK / 4 (16).

[0044] As a further improvement of the present invention, in step S5, the approximate expression parameter α of the head field is calculated using equation (17):

[0045]

[0046] This invention also discloses a calculation system for the ultimate support pressure in shield tunneling near-distance docking projects that takes into account seepage, comprising:

[0047] The engineering parameter acquisition module obtains the tunnel overburden thickness C, tunnel diameter D, docking distance L, and unit weight of water γ based on the construction plan and survey report. w Soil weight γ, internal friction angle Cohesion c, soil lateral pressure coefficient K0, height h0 from the bottom of the tunnel to the surface water level;

[0048] The model parameter acquisition module obtains the height K of the unstable region and the inclination angle θ of the sliding surface based on the actual unstable shape of the excavation face or the numerical simulation results.

[0049] The mathematical model building module is used to establish a mathematical model of the wedge-shaped body in the unstable region based on the limit equilibrium method, according to the height K of the unstable region and the inclination angle θ of the sliding surface. Based on the longitudinal section diagram of the ultimate support pressure calculation model for the shield tunneling connection project, it obtains the shear force T1 and normal force N1 on the side of the wedge-shaped body where it connects with the opposing tunnel, the shear force T2 and normal force N2 at the bottom of the wedge, the shear force T3 and normal force N3 on the side of the sliding surface, the shear force T4 and normal force N4 on the two sides of the wedge, the weight W of the wedge, the horizontal seepage force F, and the support pressure P. c The vertical earth pressure σ acting above the wedge v The equivalent cross-sectional width B of the model is obtained from the transverse section diagram of the ultimate support pressure calculation model for shield tunneling docking projects.

[0050] The analysis module is used to perform force analysis on the mathematical model and establish equilibrium equations in both the horizontal and vertical directions.

[0051] The vertical equilibrium equation is:

[0052] BLσ v +W=T1+N2 cos θ+(T2+2T3+2T4)sin θ (1),

[0053] The equilibrium equation in the horizontal direction is:

[0054]

[0055] The horizontal seepage force calculation module is used to obtain the hydraulic head h of the piezometer at the shield tunneling face based on numerical simulation results or construction plans. F Based on the water head distribution, the approximate distribution function h(x,y,z) of the groundwater head field is obtained as follows:

[0056]

[0057] In the formula, α is the parameter of the approximate expression of the head field;

[0058] Integrating the distribution function with respect to the y-direction yields the average hydraulic head h inside the sliding body along the y-direction. * :

[0059]

[0060] Substituting equation (3) into equation (4) yields the horizontal seepage force F:

[0061]

[0062] In the formula, S1 is the sliding surface of the wedge, and S2 is the tunnel excavation face;

[0063] The support pressure calculation module, based on the T3 analysis diagram of the shear force on the side of the wedge, obtains the following:

[0064]

[0065] In the formula, K' is the instability height on the right side of the wedge, z is the distance from the top of the triangle to the i-th soil strip, and L z Let dz be the height of the trapezoidal strip, and dz be the integral infinitesimal element; the instability height K' on the right side of the wedge is calculated using equation (18):

[0066] K′=K-Ltanθ (18),

[0067] Trapezoidal bar height L z The result is obtained by using equation (19):

[0068]

[0069] Where z is the distance from the top of the wedge to the integral element;

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] Substituting equations (6)-(12) into the vertical equilibrium equation (1), we get:

[0077]

[0078] Substituting the seepage force and other parameters into the horizontal equilibrium equation (2), we can obtain the support pressure P. c :

[0079]

[0080] As a further improvement of the present invention, in the model parameter acquisition module, K is calculated using equation (15):

[0081] K = 29.84 (L / D) 2 +17.79(L / D)+0.075(15).

[0082] As a further improvement of the present invention, in the mathematical model establishment module, the equivalent cross-sectional width B of the model is calculated using equation (16):

[0083] B = πK / 4 (16).

[0084] As a further improvement of the present invention, in the support pressure calculation module, the parameter α of the approximate expression of the head field is calculated using equation (17):

[0085]

[0086] This invention discloses a computing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the above-described method for calculating the ultimate support pressure of shield tunneling close-range docking projects considering seepage.

[0087] This invention discloses a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above-described method for calculating the ultimate support pressure of shield tunneling close-range docking projects considering seepage.

[0088] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0089] The technical solution of this invention takes into account the influence of seepage force and establishes a mathematical model for the instability of the excavation face of a shield tunnel with close connection based on the limit equilibrium method. It can be used to calculate the ultimate support pressure of the excavation face with high accuracy, which is conducive to maintaining the support pressure of the shield excavation face within a safe range and reducing the probability of casualties and economic losses. It fills the theoretical gap in calculating the ultimate support pressure of the excavation face of shield tunnel with close connection. Attached Figure Description

[0090] Figure 1 This is a flowchart illustrating the calculation method for the ultimate support pressure of a shield tunneling close-range docking project considering seepage, as described in Embodiment 1 of the present invention.

[0091] Figure 2 This is a longitudinal cross-sectional view of the ultimate support pressure calculation model for shield tunneling docking project according to Embodiment 1 of the present invention.

[0092] Figure 3 This is a cross-sectional view of the ultimate support pressure calculation model for shield tunneling docking project according to Embodiment 1 of the present invention.

[0093] Figure 4 This is a calculation diagram of the shear force T3 on the side of the wedge in Embodiment 1 of the present invention.

[0094] Figure 5 This is a comparison chart of the results calculated in Embodiment 1 of the present invention and the results simulated by finite element software. Detailed Implementation

[0095] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0096] like Figure 1 As shown, a method for calculating the ultimate support pressure in shield tunneling docking projects considering seepage includes the following steps:

[0097] Step S1: Based on the construction plan and survey report, determine the tunnel overburden thickness C, tunnel diameter D, connection distance L, and unit weight of water γ. w Soil weight γ, internal friction angle Cohesion c, soil lateral pressure coefficient K0, and height h0 from the bottom of the tunnel to the surface water level.

[0098] Step S2: Obtain the height K of the unstable region and the inclination angle θ of the sliding surface based on the actual unstable shape of the excavation face or the results of numerical simulation. K can also be obtained from the fitting formula.

[0099] Step S3: Based on the limit equilibrium method, establish a mathematical model of the instability region. For example... Figure 2 The longitudinal section of the shield tunneling docking project ultimate support pressure calculation model shown indicates that the forces acting on the wedge include: shear force T1 and normal force N1 on the side where the wedge connects with the opposing tunnel; shear force T2 and normal force N2 at the bottom of the wedge; shear force T3 and normal force N3 on the sliding surface side; shear force T4 and normal force N4 on the two sides of the wedge; wedge weight W; horizontal seepage force F; and support pressure P. c The vertical earth pressure σ acting above the wedge v ;according to Figure 3 The transverse cross-section of the ultimate support pressure calculation model for shield tunneling docking project can be used to obtain the equivalent cross-sectional width B of the model.

[0100] Step S4: Perform force analysis on the mathematical model and establish equilibrium equations in both the horizontal and vertical directions.

[0101] The vertical equilibrium equation is:

[0102] BLσ v +W=T1+N2cosθ+(T2+2T3+2T4)sinθ (1),

[0103] The equilibrium equation in the horizontal direction is:

[0104]

[0105] Step S5: Obtain the water head h from the piezometer at the shield excavation face based on the numerical simulation results or construction plan. F Based on the water head distribution, the approximate distribution function h(x,y,z) of the groundwater head field is obtained as follows:

[0106]

[0107] In the formula, α is the parameter of the approximate expression of the head field;

[0108] Integrating the distribution function with respect to the y-direction yields the average hydraulic head h inside the sliding body along the y-direction. * :

[0109]

[0110] Substituting equation (3) into equation (4) yields the horizontal seepage force F:

[0111]

[0112] In the formula, S1 is the sliding surface of the wedge, and S2 is the tunnel excavation face;

[0113] Step S6: Calculate the remaining unknown parameters in the equilibrium equations. According to... Figure 4The calculation diagram of the shear force T3 on the side of the wedge shown can be used to obtain:

[0114]

[0115] In the formula, K' is the instability height on the right side of the wedge, z is the distance from the top of the triangle to the i-th soil strip, and L... z Let dz be the height of the trapezoidal strip, and dz be the integral infinitesimal element; the instability height K' on the right side of the wedge is calculated using the following formula:

[0116] K′=K-Ltanθ (18),

[0117] Trapezoidal bar height L z The following formula is used to calculate:

[0118]

[0119] Where z is the distance from the top of the wedge to the integral element;

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126] Substituting the above equation into the vertical equilibrium equation, we get N2:

[0127]

[0128] Substituting the seepage force and other parameters into the horizontal equilibrium equation yields the support pressure P. c for:

[0129]

[0130] In step S2, K can be obtained by the following formula:

[0131] K = 29.84 (L / D) 2 +17.79(L / D)+0.075 (15).

[0132] In step S3, the equivalent cross-sectional width B of the model is:

[0133] B = πK / 4 (16).

[0134] In step S5, the parameter α of the approximate expression for the head field is obtained by the following formula:

[0135]

[0136] In addition to the above calculation method, this specific embodiment also provides a calculation system for the ultimate support pressure of shield tunneling near-distance docking projects that takes into account seepage. This system includes:

[0137] The engineering parameter acquisition module obtains the tunnel overburden thickness C, tunnel diameter D, docking distance L, and unit weight of water γ based on the construction plan and survey report. w Soil weight γ, internal friction angle Cohesion c, soil lateral pressure coefficient K0, height h0 from the bottom of the tunnel to the surface water level;

[0138] The model parameter acquisition module uses finite element software for numerical simulation. Based on the simulation results of the instability of the close-connection excavation face of the shield tunnel, the height K of the instability zone and the inclination angle θ of the sliding surface are obtained.

[0139] The mathematical model building module is used to establish a mathematical model of the wedge-shaped body in the unstable region based on the limit equilibrium method, according to the height K of the unstable region and the inclination angle θ of the sliding surface. Based on the longitudinal section diagram of the ultimate support pressure calculation model for the shield tunneling connection project, it obtains the shear force T1 and normal force N1 on the side of the wedge-shaped body where it connects with the opposing tunnel, the shear force T2 and normal force N2 at the bottom of the wedge, the shear force T3 and normal force N3 on the side of the sliding surface, the shear force T4 and normal force N4 on the two sides of the wedge, the weight W of the wedge, the horizontal seepage force F, and the support pressure P. c The vertical earth pressure σ acting above the wedge v The equivalent cross-sectional width B of the model is obtained from the transverse section diagram of the ultimate support pressure calculation model for shield tunneling docking projects.

[0140] The analysis module is used to perform force analysis on the mathematical model and establish equilibrium equations in both the horizontal and vertical directions; the equilibrium equation in the vertical direction is:

[0141] BLσ v +W=T1+N2cosθ+(T2+2T3+2T4)sinθ (1),

[0142] The equilibrium equation in the horizontal direction is:

[0143]

[0144] The horizontal seepage force calculation module is used to obtain the hydraulic head h of the piezometer at the shield tunneling face based on numerical simulation results or construction plans. F Based on the water head distribution, the approximate distribution function h(x,y,z) of the groundwater head field is obtained as follows:

[0145]

[0146] In the formula, α is the parameter of the approximate expression of the head field;

[0147] Integrating the distribution function with respect to the y-direction yields the average hydraulic head h inside the sliding body along the y-direction. * :

[0148]

[0149] Substituting equation (3) into equation (4) yields the horizontal seepage force F:

[0150]

[0151] In the formula, S1 is the sliding surface of the wedge, and S2 is the tunnel excavation face;

[0152] The support pressure calculation module, based on the T3 analysis diagram of the shear force on the side of the wedge, obtains the following:

[0153]

[0154] In the formula, K' is the instability height on the right side of the wedge, z is the distance from the top of the triangle to the i-th soil strip, and L z Let dz be the height of the trapezoidal strip, and dz be the integral infinitesimal element; the instability height K' on the right side of the wedge is calculated using equation (18):

[0155] K′=KL tan θ (18),

[0156] Trapezoidal bar height L z The result is obtained by using equation (19):

[0157]

[0158] Where z is the distance from the top of the wedge to the integral element;

[0159]

[0160]

[0161]

[0162]

[0163]

[0164]

[0165] Substituting equations (6)-(12) into the vertical equilibrium equation (1), we get:

[0166]

[0167] Substituting the seepage force and other parameters into the horizontal equilibrium equation (2), we can obtain the support pressure P. c :

[0168]

[0169] In the model parameter acquisition module, K is calculated using equation (15):

[0170] K = 29.84 (L / D) 2 +17.79(L / D)+0.075 (15).

[0171] In the mathematical model building module, the equivalent cross-sectional width B of the model is calculated using equation (16):

[0172] B = πK / 4 (16).

[0173] In the support pressure calculation module, the parameter α of the approximate expression for the head field is calculated using equation (17):

[0174]

[0175] The following description is based on specific embodiments.

[0176] Example 1

[0177] like Figure 1 As shown, a method for calculating the ultimate support pressure in shield tunneling near-distance docking projects considering seepage includes the following steps:

[0178] Step 1: Based on the construction plan and survey report, determine the tunnel overburden thickness C = 7m, tunnel diameter D = 14m, connection distance L = 5.6m, and the unit weight of water γ. w =10kN / m 3 Soil weight γ = 18 kN / m 3 internal friction angle Cohesion c = 2 kPa, soil lateral pressure coefficient K0 = 0.7, height h0 from tunnel bottom to surface water level = 31 m. Equivalent cross-sectional width B of the model:

[0179] B = πK / 4 = 9.78.

[0180] Step 2: Numerical simulation is performed using finite element software. Based on the results of the simulation of the instability of the close-distance docking excavation face of the shield tunnel, the sliding surface inclination angle θ = 48° is obtained. The height of the instability area K = 12.45m can be obtained by fitting formula {15}.

[0181] K = 29.84 (L / D) 2+17.79(L / D)+0.075 (15)

[0182] Step 3: Based on the numerical simulation results or construction plan, obtain the water head h from the piezometer at the shield excavation face. F =14m, approximate expression for head field distribution parameter α:

[0183]

[0184] The approximate distribution function h(x, y, z) of the groundwater head field is obtained based on the head distribution.

[0185]

[0186] Integrating the distribution function with respect to the y-direction yields the average hydraulic head h inside the sliding body along the y-direction. * :

[0187]

[0188] Substituting the formula for the approximate distribution function h(x, y, z) into h * The horizontal seepage force F can be obtained from the formula:

[0189]

[0190] In the formula, S1 is the sliding surface of the wedge and S2 is the tunnel excavation face.

[0191] Step 4: Calculate the remaining unknown parameters in the equilibrium equation.

[0192]

[0193]

[0194]

[0195]

[0196]

[0197]

[0198]

[0199] Substituting the above formula into the vertical equilibrium equation, we get N2:

[0200]

[0201] Substituting the seepage force and other parameters into the horizontal equilibrium equation yields the support pressure P. c for:

[0202]

[0203] Compare the results calculated using this method with those obtained through finite element software simulation, such as... Figure 5 As shown, this method has good accuracy in close-range docking situations.

[0204] The method in this embodiment establishes a mathematical model considering seepage by analyzing the unstable shape of the excavation face under close-range shield docking. This model can calculate the ultimate support pressure of the excavation face in large-diameter shield docking projects on the seabed, providing a theoretical reference for shield docking projects.

[0205] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for calculating the ultimate support pressure in shield tunneling near-distance docking projects considering seepage, characterized in that, Includes the following steps: Step S1: Based on the construction plan and survey report, obtain the tunnel overburden thickness C, tunnel diameter D, docking distance L, and unit weight of water γ. w Soil weight γ, internal friction angle Cohesion c, soil lateral pressure coefficient K0, height h0 from the bottom of the tunnel to the surface water level; Step S2: Numerical simulation is performed using finite element software. Based on the results of the simulated instability of the close-connection excavation face of the shield tunnel, the height K of the unstable region and the inclination angle θ of the sliding surface are obtained. Step S3: Based on the limit equilibrium method, establish a mathematical model of the wedge-shaped body in the unstable region according to the height K of the unstable region and the inclination angle θ of the sliding surface. Based on the longitudinal section diagram of the ultimate support pressure calculation model for the shield tunneling connection project, obtain the shear force T1 and normal force N1 on the side of the wedge-shaped body connecting with the opposing tunnel, the shear force T2 and normal force N2 at the bottom of the wedge-shaped body, the shear force T3 and normal force N3 on the side of the sliding surface, the shear force T4 and normal force N4 on the two sides of the wedge-shaped body, the weight W of the wedge-shaped body, the horizontal seepage force F, and the support pressure P. c The vertical earth pressure σ acting above the wedge v The equivalent cross-sectional width B of the model is obtained from the transverse section diagram of the ultimate support pressure calculation model for shield tunneling docking projects. Step S4: Perform force analysis on the mathematical model and establish equilibrium equations in both the horizontal and vertical directions; The vertical equilibrium equation is: BLσ v +W=T1+N2cosθ+(T2+2T3+2T4)sinθ (1), The equilibrium equation in the horizontal direction is: Step S5: Obtain the water head h from the piezometer at the shield excavation face based on the numerical simulation results or construction plan. F Based on the water head distribution, the approximate distribution function h(x,y,z) of the groundwater head field is obtained as follows: In the formula, α is the parameter of the approximate expression of the head field; Integrating the distribution function with respect to the y-direction yields the average hydraulic head h inside the sliding body along the y-direction. * : Substituting equation (3) into equation (4) yields the horizontal seepage force F: In the formula, S1 is the sliding surface of the wedge, and S2 is the tunnel excavation face; Step S6: Calculate the remaining unknown parameters in the equilibrium equations; Based on the analysis diagram of the shear force T3 on the side of the wedge, we obtain: In the formula, K' is the instability height on the right side of the wedge, z is the distance from the top of the triangle to the i-th soil strip, and L z Let dz be the height of the trapezoidal strip, and dz be the integral infinitesimal element; the instability height K' on the right side of the wedge is calculated using equation (18): K′=K-Ltanθ (18), Trapezoidal bar height L z The result is obtained by using equation (19): Where z is the distance from the top of the wedge to the integral element; Substituting equations (6)-(12) into the vertical equilibrium equation (1), we get: Substituting the seepage force and other parameters into the horizontal equilibrium equation (2), we can obtain the support pressure P. c :

2. The method for calculating the ultimate support pressure of shield tunneling near-distance docking projects considering seepage, as described in claim 1, is characterized in that: In step S2, K is calculated using equation (15): K=29.84(L / D) 2 +17.79(L / D)+0.075 (15)。 3. The method for calculating the ultimate support pressure of shield tunneling near-distance docking projects considering seepage, as described in claim 1, is characterized in that: In step S3, the equivalent cross-sectional width B of the model is calculated using equation (16): B = πK / 4 (16).

4. The method for calculating the ultimate support pressure of shield tunneling near-distance docking projects considering seepage, as described in claim 1, is characterized in that: In step S5, the approximate expression for the head field, parameter α, is calculated using equation (17):

5. A calculation system for ultimate support pressure in shield tunneling near-distance docking projects considering seepage, characterized in that, include: The engineering parameter acquisition module obtains the tunnel overburden thickness C, tunnel diameter D, docking distance L, and unit weight of water γ based on the construction plan and survey report. w Soil weight γ, internal friction angle Cohesion c, soil lateral pressure coefficient K0, height h0 from the bottom of the tunnel to the surface water level; The model parameter acquisition module uses finite element software for numerical simulation. Based on the simulation results of the instability of the close-connection excavation face of the shield tunnel, the height K of the instability zone and the inclination angle θ of the sliding surface are obtained. The mathematical model building module is used to establish a mathematical model of the wedge-shaped body in the unstable region based on the limit equilibrium method, according to the height K of the unstable region and the inclination angle θ of the sliding surface. Based on the longitudinal section diagram of the ultimate support pressure calculation model for the shield tunneling connection project, it obtains the shear force T1 and normal force N1 on the side of the wedge-shaped body where it connects with the opposing tunnel, the shear force T2 and normal force N2 at the bottom of the wedge, the shear force T3 and normal force N3 on the side of the sliding surface, the shear force T4 and normal force N4 on the two sides of the wedge, the weight W of the wedge, the horizontal seepage force F, and the support pressure P. c The vertical earth pressure σ acting above the wedge v ; The equivalent cross-sectional width B of the model is obtained from the transverse section diagram of the ultimate support pressure calculation model for shield tunneling docking project. The analysis module is used to perform force analysis on the mathematical model and establish equilibrium equations in both the horizontal and vertical directions. The vertical equilibrium equation is: BLσ v +W=T1+N2cosθ+(T2+2T3+2T4)sinθ (1), The equilibrium equation in the horizontal direction is: The horizontal seepage force calculation module is used to obtain the hydraulic head h of the piezometer at the shield tunneling face based on numerical simulation results or construction plans. F Based on the water head distribution, the approximate distribution function h(x,y,z) of the groundwater head field is obtained as follows: In the formula, α is the parameter of the approximate expression of the head field; Integrating the distribution function with respect to the y-direction yields the average hydraulic head h inside the sliding body along the y-direction. * : Substituting equation (3) into equation (4) yields the horizontal seepage force F: In the formula, S1 is the sliding surface of the wedge, and S2 is the tunnel excavation face; The support pressure calculation module, based on the T3 analysis diagram of the shear force on the side of the wedge, obtains the following: In the formula, K' is the instability height on the right side of the wedge, z is the distance from the top of the triangle to the i-th soil strip, and L z Let dz be the height of the trapezoidal strip, and dz be the integral infinitesimal element; the instability height K' on the right side of the wedge is calculated using equation (18): K′=K-Ltanθ (18), Trapezoidal bar height L z The result is obtained by using equation (19): Where z is the distance from the top of the wedge to the integral element; Substituting equations (6)-(12) into the vertical equilibrium equation (1), we get: Substituting the seepage force and other parameters into the horizontal equilibrium equation (2), we can obtain the support pressure P. c :

6. The ultimate support pressure calculation system for shield tunneling close-range docking projects considering seepage, as described in claim 5, is characterized in that: In the model parameter acquisition module, K is calculated using equation (15): K=29.84(L / D) 2 +17.79(L / D)+0.075 (15)。 7. The ultimate support pressure calculation system for shield tunneling close-range docking projects considering seepage, as described in claim 5, is characterized in that: In the mathematical model building module, the equivalent cross-sectional width B of the model is calculated using equation (16): B = πK / 4 (16).

8. The ultimate support pressure calculation system for shield tunneling close-range docking projects considering seepage, as described in claim 5, is characterized in that: In the support pressure calculation module, the parameter α of the approximate expression for the head field is calculated using equation (17):

9. A computing device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, it implements the steps of the method for calculating the ultimate support pressure of shield tunneling close-range docking projects considering seepage, as described in any one of claims 1-4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, it performs the steps of the method for calculating the ultimate support pressure of shield tunneling close-range docking projects considering seepage, as described in any one of claims 1-4.

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