Method and system for analyzing three-dimensional stability coefficient of tunnel face

Abstract

The invention discloses a tunnel face three-dimensional stability coefficient analysis method and system. The system comprises a model construction module and a stability analysis module. The model building module is used for building a tunnel face prism-wedge body model of a tunnel according to mechanical parameters of tunnel surrounding rock, tunnel burial depth height and the length of an unsupported section in the construction process, and determining various model parameters of the tunnel face prism-wedge body model by analyzing the tunnel face prism-wedge body model. And the stability analysis module constructs a limit support force calculation model of the tunnel face based on a Mogi-Coulomb strength criterion, and analyzes a three-dimensional stability coefficient of the tunnel face through the constructed limit support force calculation model according to various model parameters of the prism-wedge body model of the tunnel face. The Mogi-Coulomb strength criterion fully considers the interaction among the middle principal stress, the surrounding rock and the supporting structure, the stability of the tunnel face is evaluated through the constructed limit supporting force calculation model, and the accuracy of stability evaluation of the tunnel face can be greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of applying stable tension or pressure to test the strength characteristics of solid materials by mechanical stress, and particularly relates to a method and system for analyzing the three-dimensional stability coefficient of a tunnel face. Background Art

[0002] With the continuous growth of traffic demand, the application of single-hole four-lane tunnels is becoming more and more widespread. At present, the research on mechanized construction technology for two-lane and three-lane highway tunnels has become a hot field, and some of the technologies have become relatively mature. Compared with two-lane and three-lane tunnels, the construction of single-hole four-lane tunnels faces more challenges and technical problems. The excavation section of such tunnels is larger, the construction process is more complex, the technical difficulty is higher, the construction quality control is more difficult, and the safety risk is significantly increased. There are still many core problems and technical bottlenecks in the mechanized construction of single-hole four-lane tunnels, including the optimization of construction techniques, the supporting use of mechanical equipment, the design and implementation of the support system, the construction quality control, and the safety guarantee. These problems lead to an increase in the difficulty of designing and implementing the support system, and problems such as surrounding rock instability and collapse are likely to occur during the construction process of the existing technologies, directly affecting construction safety. The stability of the tunnel face is one of the key factors for tunnel construction safety. However, the existing stability evaluation methods are mostly based on two-dimensional analysis and do not fully consider the interaction between the surrounding rock and the support structure in three-dimensional space, resulting in insufficient accuracy of the evaluation results. Therefore, there is an urgent need for an evaluation method based on three-dimensional numerical simulation to more accurately evaluate the stability of the tunnel face, thereby improving the safety and efficiency of construction. Summary of the Invention

[0003] Aiming at the deficiencies of the existing technology, the present invention proposes a method and system for analyzing the three-dimensional stability coefficient of a tunnel face, which can significantly improve the accuracy of the tunnel face stability evaluation. The specific technical solutions are as follows:

[0004] In the first aspect, a method for analyzing the three-dimensional stability coefficient of a tunnel face is provided. In the first feasible implementation manner of the first aspect, it includes:

[0005] Establish a prism-wedge model of the tunnel face according to the tunnel construction data, and analyze the prism-wedge model of the tunnel face to determine various model parameters of the prism-wedge model of the tunnel face;

[0006] Construct a limit support force calculation model based on the Mogi-Coulomb strength criterion, and analyze the three-dimensional stability coefficient of the tunnel face by using the limit support force calculation model according to the various model parameters.

[0007] Combined with the first feasible implementation manner of the first aspect, in the second feasible implementation manner of the first aspect, analyzing the three-dimensional stability coefficient of the tunnel face includes:

[0008] Based on the ultimate support force calculation model, the three-dimensional stability coefficient of the tunnel face is analyzed by the limit equilibrium method according to the model parameters.

[0009] Combined with the second implementation manner of the first aspect, in the third implementation manner of the first aspect, analyzing the three-dimensional stability coefficient of the tunnel face by the limit equilibrium method includes:

[0010] Calculating the stability coefficient according to two set initial stability coefficients;

[0011] Calculating the reduced model parameters by the strength reduction method based on the stability coefficient;

[0012] Calculating the ultimate support force by the ultimate support force calculation model according to the reduced model parameters, and comparing the ultimate support force with the safety threshold;

[0013] In response to the ultimate support force exceeding the safety threshold, recalculating the ultimate support force based on the stability coefficient;

[0014] Looping in this way until the ultimate support force is lower than the safety threshold to obtain the three-dimensional stability coefficient of the tunnel face.

[0015] Combined with the third implementation manner of the first aspect, in the fourth implementation manner of the first aspect, calculating the stability coefficient according to the set initial stability coefficient includes:

[0016] Calculating the stability coefficient by the bisection method according to the two initial stability coefficients.

[0017] In a second aspect, a system for analyzing the three-dimensional stability coefficient of a tunnel face is provided. In the first implementation manner of the second aspect, it includes:

[0018] A model construction module configured to establish a prism-wedge model of the tunnel face based on tunnel construction data, and analyze the prism-wedge model of the tunnel face to determine the model parameters of the prism-wedge model of the tunnel face;

[0019] A stability analysis module configured to construct an ultimate support force calculation model based on the Mogi-Coulomb strength criterion, and analyze the three-dimensional stability coefficient of the tunnel face by the ultimate support force calculation model according to the model parameters.

[0020] Combined with the first implementation manner of the second aspect, in the second implementation manner of the second aspect, the stability analysis module includes:

[0021] A data analysis unit configured to analyze the three-dimensional stability coefficient of the tunnel face by the limit equilibrium method based on the ultimate support force calculation model according to the model parameters.

[0022] Combined with the second implementation manner of the second aspect, in the third implementation manner of the second aspect, the analysis module includes:

[0023] A stability coefficient unit configured to calculate a stability coefficient according to two set initial stability coefficients;

[0024] A model parameter unit configured to calculate reduced model parameters by using the strength reduction method based on the stability coefficient;

[0025] A limit analysis unit configured to calculate a limit support force by using a limit support force calculation model according to the reduced model parameters, and compare the limit support force with a safety threshold;

[0026] In response to the limit support force exceeding the safety threshold, recalculate the limit support force based on the stability coefficient;

[0027] Repeat this cycle until the limit support force is lower than the safety threshold to obtain the three-dimensional stability coefficient of the tunnel face.

[0028] Combined with the third implementation manner of the second aspect, in the fourth implementation manner of the second aspect, the stability coefficient unit calculates the stability coefficient by using the bisection method.

[0029] Beneficial effects: By using the tunnel face three-dimensional stability coefficient analysis method and system of the present invention, a prism-wedge body model of the tunnel face can be established through tunnel construction data. Then, based on the Mogi-Coulomb strength criterion, a limit support force calculation model of the tunnel face is constructed. By analyzing the constructed prism-wedge body model of the tunnel face through the limit support force calculation model, the three-dimensional stability coefficient of the tunnel face is obtained. Since the Mogi-Coulomb strength criterion comprehensively considers the intermediate principal stress in three-dimensional space and the interaction between the surrounding rock and the support structure, the accuracy of the tunnel face stability evaluation can be greatly improved, achieving the purpose of accurately evaluating the tunnel face stability and providing a scientific basis for the optimization of the construction plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation manners of the present invention, the drawings required for use in the specific implementation manners will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn to actual scale.

[0031] Figure 1 It is a flowchart of the tunnel face three-dimensional stability coefficient analysis method provided by an embodiment of the present invention;

[0032] Figure 2 It is a flowchart of analyzing the stability coefficient by using the limit equilibrium method provided by an embodiment of the present invention;

[0033] Figure 3 The system block diagram of the three-dimensional stability coefficient analysis system for the tunnel face provided by an embodiment of the present invention;

[0034] Figure 4 The structural schematic diagram of the prism-wedge body model of the tunnel face provided by an embodiment of the present invention. Specific embodiments

[0035] The embodiments of the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0036] As Figure 1 shown in the flowchart of the three-dimensional stability coefficient analysis method for the tunnel face, the analysis method includes:

[0037] Step 1: Establish a prism-wedge body model of the tunnel face according to the tunnel construction data, and analyze the prism-wedge body model of the tunnel face to determine various model parameters of the prism-wedge body model of the tunnel face;

[0038] Step 2: Construct a limit support force calculation model based on the Mogi-Coulomb strength criterion, and analyze the three-dimensional stability coefficient of the tunnel face by using the limit support force calculation model according to the various model parameters.

[0039] Specifically, first, considering the mechanical parameters of the tunnel surrounding rock, the buried depth of the tunnel, and the length of the unsupported section during the construction process, a prism-wedge body model of the tunnel face is established. The constructed prism-wedge body model of the tunnel face is as Figure 4 shown. By analyzing the prism-wedge body model of the tunnel face, various model parameters of the prism-wedge body model of the tunnel face can be determined, such as the helix radius at points H and E in the prism-wedge body model of the tunnel face, the included angle of the helix radii at points H and E, etc.

[0040] Then, a limit support force calculation model of the tunnel face can be constructed based on the Mogi-Coulomb strength criterion. According to the various model parameters of the prism-wedge body model of the tunnel face, the three-dimensional stability coefficient of the tunnel face is analyzed by using the constructed limit support force calculation model. Since the Mogi-Coulomb strength criterion fully considers the intermediate principal stress and the interaction between the surrounding rock and the support structure, the accuracy of the stability evaluation of the tunnel face can be greatly improved by evaluating the stability of the tunnel face through the constructed limit support force calculation model.

[0041] In this embodiment, a limit support force calculation model of the tunnel face is constructed based on the Mogi-Coulomb strength criterion, as follows:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] M Z +M Q =M T +M C +M L ;

[0050] wherein, M Z , M Q , M T , M C are respectively the self-gravity moment of the prism, the vertical load moment of the prism, the sum of the front normal force moment and the tangential moment of the wedge, and the tangential force moments on both sides of the wedge. M L is the support force moment of the tunnel face, LSP1 is the support force of the tunnel face, LSP is the ultimate support force of the tunnel face, R E is the radius of the helix at point E, K is the tunnel face span, is the friction angle, D is the tunnel face height, δ H is Figure 4 the included angle between R and R H in

[0051] R i , l i , h i , β i , δ i are respectively the rotation radius, bottom length, height, angle between the bottom of the strip and the horizontal direction, and rotation angle of the i-th soil strip obtained after dividing the prism by the slice method. γ is the unit weight of the surrounding rock.

[0052] L Z is the length of the unsupported section, L VE is the horizontal distance between point E and point V in the prism-wedge model of the tunnel face, L OE is the horizontal distance between point 0 and point E in the prism-wedge model of the tunnel face, q is the vertical load, and its specific calculation formula is as follows:

[0053]

[0054] Among them, q0 is the surface load, M0 is the tunnel burial depth, c is the cohesion, and K′ is the ratio of the cross-sectional area to the perimeter of the prism. The specific calculation formulas are as follows:

[0055]

[0056] ξ is the lateral earth pressure coefficient at the slip surface. The specific calculation formula is as follows:

[0057]

[0058] Among them, σ3 is the minimum principal stress, both B and C are coefficients, and η is the maximum principal stress angle.

[0059]

[0060]

[0061]

[0062]

[0063] Among them, σ1 and σ2 are the maximum principal stress and the intermediate principal stress respectively. Based on the Mogi-Coulomb strength criterion, σ1 = Bσ3 + C. Both k and d are material parameters. The specific calculation formulas are as follows:

[0064]

[0065] ξ′ is the horizontal earth pressure coefficient of the wedge. The specific calculation formula is as follows:

[0066]

[0067] In this embodiment, optionally, in step 2, analyzing the three-dimensional stability coefficient of the tunnel face includes:

[0068] Based on the ultimate support force calculation model, analyze the three-dimensional stability coefficient of the tunnel face by using the limit equilibrium method according to each model parameter.

[0069] Specifically, based on the established calculation model of the ultimate support force of the tunnel face, the limit equilibrium method can be used to analyze the prism-wedge model of the tunnel face. By using the limit equilibrium method and the calculation model of the limit support force, the instability of the surrounding rock above the tunnel face under three-dimensional conditions, different surrounding rock mechanical parameters and the influence of the tunnel burial depth can be effectively simulated, and the accuracy of the stability evaluation of the tunnel face can be improved.

[0070] In this embodiment, optionally, using the limit equilibrium method to analyze the three-dimensional stability coefficient of the tunnel face includes:

[0071] Step 2-1: Calculate the stability coefficient according to two set initial stability coefficients.

[0072] Step 2-2: Use the strength reduction method based on the stability coefficient to calculate the reduced model parameters.

[0073] Step 2-3: Calculate the ultimate support force using the ultimate support force calculation model according to the reduced model parameters, and compare the ultimate support force with the safety threshold.

[0074] In response to the ultimate support force exceeding the safety threshold, recalculate the ultimate support force based on the stability coefficient.

[0075] Repeat this process until the ultimate support force is lower than the safety threshold to obtain the three-dimensional stability coefficient of the tunnel face.

[0076] Specifically, as Figure 2 shown, first, two initial stability coefficients S0 and S1 can be set, and the median calculated according to the set initial stability coefficients S0 and S1 is used as the stability coefficient S. Then, based on the stability coefficient S, the strength reduction method can be used to calculate the reduced model parameters. In this embodiment, the model parameters can be cohesion and friction angle, and the specific calculation formulas are as follows:

[0077]

[0078] After that, the reduced cohesion c s and friction angle can be substituted into the ultimate support force calculation model to calculate the ultimate support force LSP of the tunnel face. If the ultimate support force LSP < 0, then set S = S0; otherwise, set S = S1. Then, compare the calculated ultimate support force with the safety threshold. In this embodiment, the safety threshold can be set to 0.01 kPa. If the ultimate support force LSP ≤ 0.01 kPa, then use the stability coefficient S as the three-dimensional stability coefficient of the tunnel face. Otherwise, if the ultimate support force LSP > 0.01 kPa, recalculate the stability coefficient according to the set initial stability coefficients, and calculate the reduced model parameters according to the recalculated stability coefficient to calculate a new ultimate support force for re-judgment. Repeat this process until the calculated ultimate support force satisfies LSP ≤ 0.01 kPa, and use the stability coefficient S as the three-dimensional stability coefficient of the tunnel face.

[0079] In this embodiment, optionally, in step 2-1, calculating the stability coefficient according to the set initial stability coefficient includes: calculating the stability coefficient by using the dichotomy method based on the two initial stability coefficients. The specific calculation formula is: S = (S0 + S1) / 2. It should be understood that by gradually approaching the critical instability state of the tunnel face through the strength reduction method, the dichotomy method can quickly narrow the calculation interval of the stability coefficient S, so as to efficiently find the critical value. Compared with other methods, the dichotomy method can ensure a fast convergence speed, accurate results, and avoid a large number of trial-and-error calculations, and is an effective tool for dealing with nonlinear problems.

[0080] As Figure 3 shown in the system block diagram of the three-dimensional stability coefficient analysis system for the tunnel face, the analysis system includes:

[0081] A model construction module configured to establish a prism-wedge body model of the tunnel face according to the tunnel construction data and analyze the prism-wedge body model of the tunnel face to determine various model parameters of the prism-wedge body model of the tunnel face;

[0082] A stability analysis module configured to construct a limit support force calculation model based on the Mogi-Coulomb strength criterion and analyze the three-dimensional stability coefficient of the tunnel face by using the limit support force calculation model according to the various model parameters.

[0083] Specifically, the analysis system includes a model construction module and a stability analysis module. Among them, the model construction module can establish a prism-wedge body model of the tunnel face according to the mechanical parameters of the tunnel surrounding rock, the tunnel buried depth, and the length of the unlined section during construction, and determine various model parameters of the prism-wedge body model of the tunnel face by analyzing the prism-wedge body model of the tunnel face. The stability analysis module can construct a limit support force calculation model of the tunnel face based on the Mogi-Coulomb strength criterion and analyze the three-dimensional stability coefficient of the tunnel face through the constructed limit support force calculation model according to the various model parameters of the prism-wedge body model of the tunnel face. Since the Mogi-Coulomb strength criterion fully considers the intermediate principal stress and the interaction between the surrounding rock and the support structure, evaluating the stability of the tunnel face through the constructed limit support force calculation model can greatly improve the accuracy of the stability evaluation of the tunnel face.

[0084] In this embodiment, optionally, the stability analysis module includes:

[0085] A data analysis unit configured to analyze the three-dimensional stability coefficient of the tunnel face by using the limit equilibrium method based on the limit support force calculation model according to the various model parameters.

[0086] Specifically, the stability analysis module includes a model construction unit and a data analysis unit. Among them, the model construction unit can construct a calculation model for calculating the ultimate support force of the tunnel face based on the Mogi-Coulomb strength criterion. The constructed calculation model for the ultimate support force of the tunnel face is as described above and will not be elaborated here. The data analysis unit can perform a stability analysis on the prism-wedge model of the tunnel face constructed by the model construction module using the limit equilibrium method based on the ultimate support force calculation model constructed by the model construction unit, so as to effectively simulate the instability of the surrounding rock above the tunnel face under three-dimensional conditions, different surrounding rock mechanical parameters, and the influence of tunnel burial depth, and improve the accuracy of the stability evaluation of the tunnel face.

[0087] In this embodiment, optionally, the data analysis unit includes:

[0088] A stability coefficient unit configured to calculate a stability coefficient according to two set initial stability coefficients;

[0089] A model parameter unit configured to calculate the reduced model parameters using the strength reduction method based on the stability coefficient;

[0090] An ultimate analysis unit configured to calculate the ultimate support force using the ultimate support force calculation model according to the reduced model parameters and compare the ultimate support force with a safety threshold;

[0091] In response to the ultimate support force exceeding the safety threshold, recalculate the ultimate support force based on the stability coefficient;

[0092] Repeat this cycle until the ultimate support force is lower than the safety threshold to obtain the three-dimensional stability coefficient of the tunnel face.

[0093] Specifically, the data analysis unit includes a stability coefficient unit, a model parameter unit, and an ultimate analysis unit. Among them, the stability coefficient unit can calculate the stability coefficient according to two set initial stability coefficients. The model parameter unit can calculate the reduced model parameters using the strength reduction algorithm according to the stability coefficient S calculated by the stability coefficient unit.

[0094] The ultimate analysis unit can substitute the cohesion and friction angle calculated by the model parameter unit into the ultimate support force calculation model to calculate the ultimate support force of the tunnel face. And compare the ultimate support force with the corresponding threshold. If the ultimate support force LSP < 0, then set S = S0, otherwise, set S = S1. The ultimate analysis unit can also compare the calculated ultimate support force with the safety threshold. If the ultimate support force LSP ≤ 0.01 kPa, then use the stability coefficient S as the three-dimensional stability coefficient of the tunnel face.

[0095] Conversely, if the ultimate support force LSP > 0.01 kPa, the stability coefficient unit recalculates the stability coefficient according to the initial stability coefficient set by the limit analysis unit. The model parameter unit then calculates the reduced model parameters based on the recalculated stability coefficient. The limit analysis unit recalculates the new ultimate support force for judgment, and this cycle continues until the calculated ultimate support force satisfies LSP ≤ 0.01 kPa. The stability coefficient S obtained at this time is used as the three-dimensional stability coefficient of the tunnel face.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A method for analyzing the three-dimensional stability coefficient of a tunnel face, characterized in that: include: Establish a prism-wedge model of the tunnel face according to the tunnel construction data, analyze the prism-wedge model of the tunnel face, and determine various model parameters of the prism-wedge model of the tunnel face; An ultimate support force calculation model is constructed based on the Mogi-Coulomb strength criterion, and the ultimate support force calculation model is used to analyze the three-dimensional stability coefficient of the tunnel face according to various model parameters.

2. The method for analyzing the three-dimensional stability coefficient of a tunnel face according to claim 1 is characterized in that: Analyze the three-dimensional stability coefficient of the tunnel face, including: Based on the ultimate support force calculation model, the three-dimensional stability coefficient of the tunnel face is analyzed using the limit equilibrium method according to various model parameters.

3. The method for analyzing the three-dimensional stability coefficient of a tunnel face according to claim 2 is characterized in that: The three-dimensional stability coefficient of the tunnel face is analyzed by the limit equilibrium method, including: The stability coefficient is calculated based on the two initial stability coefficients set; Based on the stability coefficient, the strength reduction method is used to calculate the reduced model parameters; The ultimate support force is calculated using the ultimate support force calculation model according to the reduced model parameters, and the ultimate support force is compared with the safety threshold; In response to the ultimate support force exceeding a safety threshold, recalculating the ultimate support force based on the stability factor; This cycle is repeated until the ultimate support force is lower than the safety threshold, and the three-dimensional stability coefficient of the tunnel face is obtained.

4. The method for analyzing the three-dimensional stability coefficient of a tunnel face according to claim 3 is characterized in that: The stability factor is calculated based on the set initial stability factor, including: The stability coefficient is calculated based on the two initial stability coefficients using a dichotomy method.

5. A three-dimensional stability coefficient analysis system for a tunnel face, characterized in that: include: A model building module is configured to establish a tunnel face prism-wedge model according to tunnel construction data, analyze the tunnel face prism-wedge model, and determine various model parameters of the tunnel face prism-wedge model; The stability analysis module is configured to construct an ultimate support force calculation model based on the Mogi-Coulomb strength criterion, and use the ultimate support force calculation model to analyze the three-dimensional stability coefficient of the tunnel face according to various model parameters.

6. The three-dimensional stability coefficient analysis system for tunnel face according to claim 5 is characterized in that: The stability analysis module comprises: The data analysis unit is configured to analyze the three-dimensional stability coefficient of the tunnel face by using the limit equilibrium method according to various model parameters based on the ultimate support force calculation model.

7. The three-dimensional stability coefficient analysis system for tunnel face according to claim 6 is characterized in that: The data analysis unit comprises: A stability coefficient unit, configured to calculate a stability coefficient based on two set initial stability coefficients; A model parameter unit, configured to calculate the reduced model parameters by using the strength reduction method based on the stability coefficient; A limit analysis unit is configured to calculate the limit support force using the limit support force calculation model according to the reduced model parameters, and compare the limit support force with a safety threshold; In response to the ultimate support force exceeding a safety threshold, recalculating the ultimate support force based on the stability factor; This cycle is repeated until the ultimate support force is lower than the safety threshold, and the three-dimensional stability coefficient of the tunnel face is obtained.

8. The three-dimensional stability coefficient analysis system for tunnel face according to claim 7 is characterized in that: The stability coefficient unit calculates the stability coefficient using a dichotomy method.

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