Tunnel water inflow calculation method and system based on geophysical prospecting parameters and near-field dynamics

Abstract

The application provides a tunnel water inflow calculation method and system based on geophysical parameters and near-field dynamics, relates to the fields of tunnel engineering and geotechnical engineering, takes a rock mass region to be calculated for water inflow as a target region, and the calculation steps are as follows: obtaining geophysical data of the target region in front of a tunnel face; according to the geophysical data, discretizing the target region into a plurality of material points, and constructing a numerical calculation model of the target region in front of the tunnel face; based on the initialized numerical calculation model, simulating excavation disturbance by using a near-field dynamics solid field and fluid field coupling equation until the excavation process is completed; in the simulation of the excavation disturbance, the water inflow of a flow section in the target region is calculated in real time by using an equivalent node flow method; and the application realizes high-precision analysis of tunnel water inflow prediction and fracture evolution process by fusing geophysical multi-source data and near-field dynamics theory.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tunnel engineering and geotechnical engineering, and particularly relates to a tunnel water inflow calculation method and system based on geophysical parameters and near-field dynamics. BACKGROUND

[0002] With the rapid growth of infrastructure construction, a large number of tunnel projects need to pass through complex hydrogeological environments such as karst areas and fault zones. In these areas, groundwater activities are frequent, and sudden water inflow disasters are prone to occur during tunnel construction, which seriously affects construction safety and project progress.

[0003] In the field of tunnel engineering, the development of geophysical technology has made geotechnical engineering parameter measurement widely used, but a single geophysical method often cannot simultaneously measure the accurate rock mass mechanical properties and hydrological permeability characteristics, resulting in insufficient key parameters for water inflow prediction and limited prediction accuracy. The traditional numerical simulation method is based on the theory of continuum mechanics, which has limitations in simulating the initiation, expansion and evolution of complex seepage channels in rock mass fractures, and is difficult to effectively handle discontinuity problems, affecting its reliability and accuracy in tunnel water inflow prediction.

[0004] Therefore, the existing tunnel water inflow calculation method has the problems of inaccurate rock mass parameter acquisition, difficult simulation of crack dynamic expansion, and significant boundary effect. SUMMARY

[0005] To solve the above problems, the present application provides a tunnel water inflow calculation method and system based on geophysical parameters and near-field dynamics, which realizes high-precision analysis of tunnel water inflow prediction and crack evolution process by fusing geophysical multi-source data and near-field dynamics theory.

[0006] According to some embodiments, the present application adopts the following technical solutions:

[0007] The tunnel water inflow calculation method based on geophysical parameters and near-field dynamics takes the rock mass region to be calculated as the target region, and the calculation steps are as follows:

[0008] Obtain geophysical data of the target region in front of the tunnel face;

[0009] Discretize the target region into a plurality of material points according to the geophysical data, and construct a numerical calculation model of the target region in front of the tunnel face;

[0010] Based on the initialized numerical calculation model, use the near-field dynamics solid field and fluid field coupling equation to simulate the excavation disturbance until the excavation process is completed;

[0011] In the excavation disturbance simulation, the equivalent node flow method is used to calculate the water inflow of the flow section in the target region in real time.

[0012] According to some embodiments, the present application adopts the technical solutions as follows:

[0013] The tunnel water inflow calculation system based on geophysical parameters and near-field dynamics regards a rock mass region to be calculated for water inflow as a target region, and comprises:

[0014] The acquisition module is configured to acquire geophysical data of the target region in front of the tunnel face.

[0015] The construction module is configured to discretize the target region into a plurality of material points according to the geophysical data, and construct a numerical calculation model of the target region in front of the tunnel face.

[0016] The simulation module is configured to perform excavation disturbance simulation based on the initialized numerical calculation model by using a near-field dynamics solid field and fluid field coupling equation until the excavation process ends.

[0017] In the excavation disturbance simulation, the water inflow of the flow section in the target region is calculated in real time by using an equivalent node flow method.

[0018] According to some embodiments, the present application adopts the technical solutions as follows:

[0019] A computer program product comprises a computer program, which, when executed by a processor, implements the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics.

[0020] According to some embodiments, the present application adopts the technical solutions as follows:

[0021] A non-transitory computer readable storage medium is used to store computer instructions, which, when executed by a processor, implement the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics.

[0022] According to some embodiments, the present application adopts the technical solutions as follows:

[0023] An electronic device comprises a processor, a memory and a computer program, wherein the processor is connected with the memory, and the computer program is stored in the memory; when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device performs the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] (1) Through multi-parameter geophysical prospecting means, the key parameters of the rock mass in front of the working face are obtained by inversion, which breaks through the limitation of insufficient information of single geophysical prospecting means, and significantly improves the accuracy of rock mass mechanics and hydrogeological parameters, and provides a reliable data basis for water inflow prediction.

[0026] (2) The non-local near-field dynamic theory is adopted, which overcomes the problem that the traditional continuous medium model cannot simulate the initiation, expansion and discontinuous deformation of rock mass cracks, and can truly reflect the dynamic evolution process of the crack channel under excavation disturbance, so as to more accurately depict the seepage path and water inflow mechanism.

[0027] (3) Through the bidirectional coupling calculation of solid field and fluid field, combined with the excavation disturbance algorithm of step-by-step stress release and the equivalent node flow method, the dynamic and high-precision prediction of water inflow in the tunnel construction process is realized, and the early warning ability of water inrush disaster under complex geological conditions is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which form a part of this description, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments of the application, and their

[0029] Figure 1 The water inflow calculation framework based on geophysical multi-parameter near-field dynamics in Example 1.

[0030] Figure 2 The near-field dynamics particle principle diagram of Example 1.

[0031] Figure 3 The stress release diagram in the excavation disturbance process of Example 1. DETAILED DESCRIPTION

[0032] The application will be further described below in conjunction with the drawings and examples.

[0033] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0034] It should be noted that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the exemplary embodiments according to the application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "comprise" are used in the specification, it means that the presence of the features, steps, operations, devices, components and / or their combinations is indicated.

[0035] Near-field dynamics is a new numerical simulation method based on the principle of non-local action. It replaces the traditional differential equation with integral equation, avoids the mathematical singularity caused by stress concentration at the crack tip, and can effectively describe the spontaneous initiation, evolution and failure process of material cracks. In addition, near-field dynamics has a unified form of fluid field and solid mechanics field, which is convenient for coupling calculation. Moreover, near-field dynamics does not need special treatment when dealing with large deformation problems, and can naturally simulate the discontinuous change of rock mass during crack propagation. Therefore, it is particularly suitable for simulating the progressive failure process of rock mass and the dynamic evolution mechanism of seepage channel caused by tunnel excavation unloading. Therefore, the near-field dynamics model combined with multi-parameter geophysical prospecting technology can more comprehensively and accurately reveal the evolution law of tunnel water inrush disaster, realize high-precision and high-efficiency prediction of water inrush, and has important theoretical significance and application value for ensuring the safety of tunnel construction.

[0036] The application provides a tunnel water inrush amount calculation method and system based on geophysical prospecting parameters and near-field dynamics, aiming to solve the problems of inaccurate rock mass parameter acquisition, difficult simulation of crack dynamic expansion and significant boundary effect in the traditional method by fusing geophysical prospecting multi-source data and near-field dynamics theory, so as to realize high-precision analysis of tunnel water inrush amount prediction and crack evolution process.

[0037] Embodiment 1

[0038] In an embodiment of the application, a tunnel water inrush amount calculation method based on geophysical prospecting parameters and near-field dynamics is provided. The rock mass region to be calculated for water inrush is taken as a target region, and the calculation steps are as follows:

[0039] Obtaining geophysical prospecting data of the target region in front of the tunnel face;

[0040] Discretizing the target region into a plurality of material points according to the geophysical prospecting data, and constructing a numerical calculation model of the target region in front of the tunnel face;

[0041] Based on the initialized numerical calculation model, using the coupling equation of the solid field and the fluid field of near-field dynamics, simulating the excavation disturbance until the excavation process is completed;

[0042] In the excavation disturbance simulation, the water inrush amount of the flow section in the target region is calculated in real time by using the equivalent node flow method.

[0043] As an embodiment, the tunnel water inrush amount calculation method based on geophysical prospecting parameters and near-field dynamics of the application realizes high-precision analysis of tunnel water inrush amount prediction and crack evolution process by fusing geophysical prospecting multi-source data and near-field dynamics theory, as shown in Figure 1 The specific implementation process is as follows:

[0044] S1 Geophysical prospecting multi-parameter acquisition and discrete modeling;

[0045] The TSP (Tunnel Seismic Prediction) method, seismic wave method, and hydrological field method are used to obtain geophysical data (P-wave velocity, S-wave velocity, rock density, and water pressure data of discrete measuring points) in front of the tunnel face, calculate physical parameters (density, elastic modulus, Poisson's ratio, initial permeability coefficient, and initial water pressure attribute), and establish a discrete numerical calculation model.

[0046] The specific operation steps of the TSP method and the seismic wave method are as follows:

[0047] Seismic waves are excited on the tunnel face, and reflection and refraction signals of the seismic waves are received by the arranged geophones, the propagation velocity and waveform characteristics of the seismic waves are analyzed, the arrival time and propagation path of the reflected waves are analyzed, and the P-wave velocity and the S-wave velocity are calculated. The Poisson's ratio and the dynamic elastic modulus in front of the tunnel face can be obtained.

[0048] (1)

[0049] wherein, is the Poisson's ratio, and ρ is the rock density, which is obtained through field testing. In addition, the static elastic modulus can be obtained from the dynamic elastic modulus using empirical formulas or experimental data fitting.

[0050] The specific operation steps of the hydrological field method are as follows:

[0051] Multiple measuring points are arranged in front of the tunnel face, water level meters or pressure sensors are installed through drilling to measure water pressure values, based on the measured water pressure values, interpolation methods are used to interpolate the discrete water pressure values to the entire target area to form a continuous water pressure field , and then according to Darcy's law and the seepage control equation, a seepage field model in front of the tunnel face is established, and the seepage control equation is:

[0052] (2)

[0053] wherein, is the permeability coefficient in front of the tunnel face, and the least squares method or other optimization algorithms (such as genetic algorithm, particle swarm optimization, etc.) are used to minimize the objective function to realize the permeability coefficient inversion.

[0054] Since the permeability coefficient at the water-bearing cave or fracture will be very large, the obtained permeability coefficient is classified, and the critical value is determined by experience or laboratory test , when , the position is marked as a water-bearing cave or fracture area.

[0055] At this point, the physical parameters in front of the tunnel face were obtained and the area was divided using geophysical methods. The area was divided into water-bearing karst caves, fissures, and intact rock masses. Only the water-bearing karst caves or fissures were specially marked, while the rest were ordinary rock masses and were not specifically marked.

[0056] Discrete modeling specifically includes:

[0057] The rock mass region in front of the tunnel face where the water inflow is to be studied is discretized into a set of material points in space, each material point... This includes the mechanical characteristics and parameters of the rock mass, i.e., its physical parameters, including the elastic modulus. Poisson's ratio ,density p Permeability coefficient Physical parameters such as initial water pressure For two-dimensional analysis to construct the physical information set of the research domain :

[0058] (3)

[0059] S2 near-field dynamics coupling equations of solid and fluid fields;

[0060] Figure 2 This is a schematic diagram of near-field dynamics of matter points, such as... Figure 2 As shown, Representing a point of matter The circular neighborhood, for Other interacting matter points in the neighborhood, The neighborhood radius, for The velocity at time t for , The relative position vector, The relative displacement of the material points after the shape change, based on Figure 2 The near-field dynamics of the material point principle, the governing equations of the near-field dynamics of the solid field in step S1, and the nonlocal force density are expressed as follows:

[0061] (4)

[0062] (5)

[0063] in, for exist t acceleration at any moment For solid density, for the body force at the point, the force density of the classical near-field dynamics, the volume of the interaction point , , respectively, , the deformed position, the relative displacement of the material point after shape change, the micro potential energy at the point, the micro modulus of the model, the elongation of the bond.

[0064] the elongation is expressed as:

[0065] (6)

[0066] For two-dimensional analysis, the micro modulus is determined according to the elastic modulus and Poisson's ratio :

[0067] (8)

[0068] wherein, is the neighborhood radius, is the thickness, and all the near-field dynamics parameter calculation parameters can be obtained from the physical information set in S1 .

[0069] Further, in the near-field dynamics theory of the fluid field in S2, the fractured rock mass is divided into a matrix area and a fracture area , the bond between the material points and (i.e. the interaction bond connecting two material points) is regarded as a fluid channel, and based on Darcy's law, the fluid flow vector of the material point t at the time is:

[0070] (9)

[0071] wherein, K r is the macroscopic permeability of the matrix area , p is the fluid pressure.

[0072] According to the mass conservation, the control equation of the near-field dynamics fluid flow is: ​

[0073] (10)

[0074] where, Q b represents Biot modulus, p f is fluid viscosity, p f represents fluid density, is a source-sink term, is the matrix calculated permeability, which can be obtained by the near-field dynamic permeability coefficient equivalence relationship.

[0075] Assuming that the fluid flow in the fracture zone follows Darcy's law, then:

[0076] (11)

[0077] where, c f is fluid compressibility, is the fracture calculated permeability, which can be obtained by the fracture zone macroscopic permeability K f .

[0078] For two-dimensional analysis, the fracture permeability coefficient K f with the fracture opening w updated by the cubic law:

[0079] (12)

[0080] where, p f is fluid viscosity.

[0081] Further, the initial permeability can be obtained according to the physical information set in S1 , for the area marked as a solution cavity, set as an empty material point, and keep the water pressure full state.

[0082] According to the Biot theory, the force density after coupling the solid mechanics field can be expressed as:

[0083] (13)

[0084] where, α represents the Biot coefficient, p represents the fluid pore pressure coefficient, is a function that determines the bond breakage state:

[0085] (14)

[0086] wherein, s 0 is the critical value of bond breakage, 0 and 1 represent the bond breakage and integrity respectively.

[0087] Based on the connection bond breakage state, the damage parameter at the material point x is defined as:

[0088] (15)

[0089] When , it means that all the bonds at x have been broken, and the point is completely destroyed.

[0090] The crack distribution of the target area is determined by the damage parameter, and then the crack opening w is directly measured according to the crack distribution , and finally the crack permeability coefficient is updated according to formula (12).

[0091] S3 model of rock mass excavation disturbance algorithm in front of the working face;

[0092] In the rock mass excavation disturbance algorithm in front of the working face, the rock mass remains in a stable equilibrium state under the stress condition in the unexcavated stage, and then the excavation step is carried out at the working face, so that the surrounding rock enters the construction disturbance stage.

[0093] In particular, the stress release ratio is set to simulate the stress release process in the tunnel excavation process, and in this process, the interaction force (i.e. non-local interaction force of near-field dynamics) between the material points in the excavation area and the material points outside the excavation area is not directly deleted, as shown in p , but the excavation process is divided into multiple stages, and the force is released gradually, i.e. the unbalanced force is released in stages.

[0094] Further, when the iterative material points are all in the non-excavated area, the near-field dynamic non-local interaction force remains unchanged, and when at least one of the iterative material points is in the excavation area, the interaction force is released p 1% of the force (i.e. (1- p 1)% of the unexcavated state) first, and after a certain number of iterations, it is released p 2% (i.e. (1- p 2)% of the unexcavated state) in the next stage, until finally 100% (i.e. 0% of the unexcavated state) is released, and the force is set to zero, realizing the complete excavation step simulation. p 1 and p 2 are constants from 0 to 100, which can be adjusted according to the specific release rate, wherein p 1 mn 2, three-stage or four-stage release can also be set according to actual needs, then hm 1 Figure 1 2 Figure 13 Figure 1 4.

[0095] Further, after the excavation is completed, the material points in the excavation area are not deleted, only the interaction relationship between the material points in the regions is changed, and the physical information array of the whole material point remains unchanged, without matrix reorganization and re-searching of the adjacent material points. When the calculation needs to simplify the model, the structure and the surrounding strata are modeled, and the remaining strata are simplified as boundary conditions acting on the four sides of the model to reduce the calculation cost.

[0096] S4 numerical solution and water inflow calculation;

[0097] In the numerical solution and water inflow calculation, an adaptive time step control method meeting the Von-Neumann stability condition is adopted. In order to adapt to the stable calculation of quasi-static loading and damage expansion process, an adaptive dynamic relaxation algorithm composed of virtual inertia and damping terms is introduced:

[0098] (16)

[0099] In the formula, D is a virtual diagonal density matrix, and the vector X is the initial position and initial displacement of the discrete point, respectively, U is a damping coefficient, m is an interaction force vector.

[0100] In addition, the solid field and fluid field control equations (10) and (13) need to be solved by numerical iteration method to obtain non-local force, displacement, water pressure, etc. All discrete material points are iterated and calculated in each time step, and after multiple time step iteration calculation, a stable solution is finally obtained. The fluid field velocity is relatively slow and the time span is large, while the deformation and damage process of the solid field is relatively small compared with the seepage process. Therefore, when coupling calculation, two different time steps are set, and the fluid field time step is smaller than the solid field.

[0101] Further, the method used for water inflow calculation is the equivalent node flow method, which expresses the seepage flow on any flow section as the algebraic sum of the products of the conductance coefficient and the water pressure of the material point The calculation accuracy of the seepage flow obtained is the same order as the calculation accuracy of the water pressure solution:

[0102] (17)

[0103] wherein, represents the total water inflow through the first m flow section, Figure 1 ​The number of material points representing the flow cross section, ​ The number of neighborhood material points interacting with the flow cross section, the conduction coefficient Determined by the permeability coefficient and unit shape parameters, The water pressure of the material points is real-time changing.

[0104] Example 2

[0105] In an embodiment of the present application, a tunnel water inflow calculation method based on geophysical parameter and near-field dynamics is provided. Taking a deep buried karst limestone tunnel as an example, the method comprises:

[0106] I. Scheme description

[0107] 1. Engineering scene and original data collection

[0108] Relying on a deep buried karst limestone tunnel, the burial depth is 180 m, the tunnel excavation section is horseshoe-shaped, the excavation span is 12 m, and the height is 10 m. The area of 20 m (longitudinally) x 30 m (laterally) in front of the working face is set as the target area for predicting water inflow.

[0109] On site, TSP303 type tunnel seismic advanced prediction system is used for seismic wave method data collection: a vertical shot hole of φ38 mm and 0.3 m deep is drilled at the center of the working face, 10 g of emulsion explosive source charge is loaded into the hole, the detonation voltage is 400 V, and the measured main frequency is 400 Hz; 24 three-component acceleration type geophones are arranged 2 m away from the working face, the geophone model is 28 Hz SM-24, the trace interval is 1 m, and the geophones are arranged in an "L" shape array, the outer circle geophones are coupled with the tunnel wall by gypsum to ensure that the coupling rate is more than 95%. The sampling rate of the collection station is set to 20 kHz, the recording length is 512 ms, the trigger mode uses explosion machine loop trigger, 2 times of effective shot sets are recorded on site, the signal-to-noise ratio is higher than 25 dB after band-pass filtering (80-800 Hz), clear direct P and S waves and reflection events from the depth range of 5-25 m in front are obtained, providing high-fidelity original data for subsequent wave velocity inversion and rock mass parameter extraction.

[0110] 2. Wave velocity inversion and dynamic elastic parameter calculation

[0111] Firstly, the STA / LTA (short-time window / long-time window) algorithm is used to automatically pick up the direct P wave and S wave first arrivals of each trace, and the to-time error is less than 1 ms by manual interaction. Combined with the minimum travel time inversion, a 1D horizontal layered velocity model is established. After 20 iterations of inversion, the average longitudinal wave velocity V p = 4800 m / s, the transverse wave velocity V s = 2600 m / s is obtained. According to the core test on site, the rock mass density , the dynamic elastic modulus is calculated as 43.8 GPa and the Poisson's ratio is 0.25 by substituting the elastic wave theory formula. In order to associate with the static elastic modulus required for near-field dynamics calculation, triaxial compression tests are performed on 6 groups of limestone samples in the laboratory, and the correlation coefficient is obtained. The static elastic modulus is 29.2 GPa, which is substituted into the subsequent discrete model together with the Poisson's ratio, and the error is less than 5% through cross-validation.

[0112] 3. Permeability coefficient inversion and cave identification.

[0113] Three horizontal φ75mm advanced boreholes are constructed at 5m, 10m and 15m in front of the working face, and a micro piezoresistive water pressure gauge is installed in the borehole to measure the stable water pressure of 0.45MPa, 0.62MPa and 0.78MPa. With Darcy's law as a constraint, genetic algorithm (population 40, crossover probability 0.8, mutation probability 0.1, iteration 100 times) is used to perform inversion in the interval of , and the optimal solution is . When , the unit is marked as a cave / fracture area, and the permeability coefficient field file k_field.txt is generated accordingly.

[0114] 4. Discrete modeling script and output format.

[0115] The target area is discretized into 0.5m×0.5m grids, and the node (i.e. material point) coordinates are generated from 0 to 20m in the vertical direction and 0 to 30m in the horizontal direction. For each node, the following values are assigned in turn: density , static elastic modulus 29.2 GPa, Poisson's ratio 0.25, permeability coefficient k read from the field file k_field.txt, initial water pressure, and cave marking according to . The final output is a CSV format file, i.e. the physical information set , each line containing the node number, horizontal coordinate, vertical coordinate, density, elastic modulus, Poisson's ratio, permeability coefficient, initial water pressure, and cave marking, which is directly called by the subsequent near-field dynamics solution.

[0116] Example 3

[0117] In an embodiment of the present application, a tunnel water inflow calculation method based on geophysical parameters and near-field dynamics is provided, comprising:

[0118] 1. Model establishment.

[0119] According to S1 step, the tunnel face two-dimensional plane strain calculation domain is established: transverse 30 m (along the tunnel axis direction), longitudinal 35 m (perpendicular to the tunnel axis direction). The model is discretized by regular grid, grid spacing 0.25 m, a total of 16800 material points. The neighborhood radius of each material point is 3.015 times the grid spacing, which meets the accuracy requirements of near-field dynamics, and all material point parameters are configured.

[0120] 2. Excavation area definition.

[0121] The "excavation area" is defined within the scope of 1.5 m of one cycle footage: taking the current mileage of the tunnel face as the starting point, dividing a 1.5 m wide area in the transverse direction, and dividing the actual excavation area within the scope of 11 m of longitudinal tunnel height.

[0122] All material points located in this rectangular range are marked as "excavation area points", and the rest of the material points are "non-excavation area points"; after the marking process is completed, a Boolean array flag(i) is formed, flag(i)=1 indicates excavation points, flag(i)=0 indicates non-excavation points, and this array remains unchanged in all subsequent sub-steps and is not modified with stress release.

[0123] 3. Stress step-by-step release scheme.

[0124] This embodiment adopts a four-stage stress release, and the release ratio is taken empirically: , , , .

[0125] When the material points are all in the "non-excavation area", the near-field dynamics non-local interaction force remains unchanged, and when at least one of the iteration material points is in the "excavation area", the non-local force density is stepwise reduced due to the emptying of the excavation interface, and the reduction coefficient β is taken as: stage I: β =0.85, stage II: β =0.60, stage III: β =0.25, stage IV: β =0, and the force density is set to zero at stage IV to realize complete excavation step simulation.

[0126] Each stage is further divided into 3 calculation iteration sub-steps, and 1.5 m excavation is completed in 12 sub-steps to ensure smooth transition.

[0127] 4. Excavation array iteration scheme.

[0128] The "excavation region point" is completed without deleting the material points in the actual corresponding region, only changing the force density effect between the materials in the regions, and the physical information array of the overall material point remains unchanged, without matrix reorganization and re-searching of the adjacent material points.

[0129] Embodiment 4

[0130] In an embodiment of the present application, a tunnel water inflow calculation method based on geophysical parameters and near-field dynamics is provided, comprising:

[0131] 1. In step S1, the TSP advanced detection and borehole water pressure test are used on site to obtain the longitudinal wave velocity, transverse wave velocity, rock density and water pressure data of the discrete measuring points within 30m in front of the working face.

[0132] According to these data, the Poisson's ratio, elastic modulus and permeability coefficient of each place are calculated, and the water-bearing fractured zone is marked as a "high permeability zone". Then, the rock mass in this section is discretized into a material point set with a side length of 0.2m, and each point carries five attributes including density, elastic modulus, Poisson's ratio, initial permeability coefficient and initial water pressure, thereby completing the discrete modeling.

[0133] After modeling, the model is initialized, mainly including: initializing all calculation parameters according to the geophysical data and model construction, including: the number of material points, the neighborhood radius, the neighborhood of each material point, the boundary condition, the material point coordinates, etc.; at the same time, the non-local force between the material points and the elongation of the bond are set and initialized, which lays a foundation for the subsequent coupling calculation of fluid field and solid field; in addition, the calculation permeability coefficient and the conduction coefficient of the rock mass are calculated and initialized.

[0134] 2. Enter step S2, the program automatically establishes a neighborhood list for each material point, and establishes the coupling equations of the solid field and the fluid field according to the near-field dynamics theory.

[0135] In the solid field, the damage of the rock mass is judged by the elongation and fracture of the bond; in the fluid field, the bond that has not been fractured is regarded as a seepage channel that can pass water.

[0136] In the initial state, all bonds are not fractured, the macroscopic permeability of the fractured zone is converted into a fracture opening function by the cubic law, and the permeability of the matrix zone is inversed on site.

[0137] The fluid-structure coupling is realized through the Biot coefficient: when the bond of a certain point gradually fractures, its equivalent permeability increases, the water pressure gradient further drives the seepage, in turn reduces the effective stress of the rock mass, promotes the fracture of more bonds, and forms a two-way coupling.

[0138] 3. Step S3 simulates the disturbance of the working face excavation.

[0139] The excavation of 2m in one time is divided into four stress release stages: the first stage releases 10% of the stress, the second stage releases 30%, the third stage releases 60%, and the fourth stage completely releases. Each step only reduces the interaction force between the material points in the excavation area and their neighborhood points, without deleting any material points, so as to avoid the trouble of reorganizing the matrix required by the traditional finite element method, and to naturally simulate the surrounding rock loosening and crack opening caused by the gradual exposure of the excavation face.

[0140] 4. When the stress release is completed, the water inflow calculation in step S4 is entered.

[0141] At this time, the program sets a vertical flow section on the tunnel face, and the section contains a plurality of material points. For each point, the current water pressure is first read, and then the conduction capacity of the point is calculated according to the unit shape and real-time permeability. Subsequently, the conduction capacity of each point is multiplied by the corresponding water pressure, and the algebraic sum of the products of all points in the section is obtained, that is, the instantaneous water inflow through the section at this time is obtained.

[0142] Since near-field dynamics allows real-time updating of permeability with crack opening, as the excavation step advances, the permeability of the crack zone gradually increases, the water pressure difference remains unchanged or even slightly decreases, and the water inflow continuously rises, reflecting the process of "crack opening - increased seepage - more crack opening".

[0143] Example 5

[0144] In an embodiment of the present application, a tunnel water inflow calculation method based on geophysical parameters and near-field dynamics is provided, comprising:

[0145] A1 Geophysical multi-parameter acquisition

[0146] A2 solution construction;

[0147] A3 calculation parameter initialization;

[0148] A4 excavation disturbance simulation;

[0149] A5 result analysis.

[0150] Further, the main content of A1 geophysical multi-parameter acquisition is: collecting multi-source physical parameters in front of the tunnel face by using geophysical technology. By exciting seismic waves on the tunnel face and arranging geophones to receive seismic wave reflection and refraction signals, the longitudinal wave velocity and transverse wave velocity are calculated by analyzing the arrival time and propagation path of the reflected wave, and the Poisson's ratio and dynamic elastic modulus of the rock mass are further obtained. Combined with hydrological field measurement, the water pressure distribution and permeability coefficient parameters are obtained, and the regions containing water caves and the like are marked to construct the physical information set of the research domain.

[0151] Further, the A2 solving area construction mainly includes: on the basis of the geophysical data, a numerical calculation model of the tunnel face front is constructed. The model includes a tunnel excavation area, surrounding rock, a cave and other special areas, and these areas are discretely processed to determine the physical properties of each material point, such as elastic modulus, Poisson's ratio, density, permeability coefficient, initial water pressure and the like. At the same time, appropriate boundary conditions are set to ensure that the model boundary matches the actual engineering and prepares for subsequent fluid-solid coupling analysis.

[0152] Further, the A3 calculation parameter initialization mainly includes: according to the geophysical data and model construction, all calculation parameters are initialized. Including: the number of material points, the neighborhood radius, the neighborhood of each material point, the boundary condition, the material point coordinates and the like. At the same time, the non-local force between the material points and the elongation rate between the keys are set and initialized, which lays a foundation for the subsequent coupling calculation of the fluid field and the solid field. In addition, the calculation permeability coefficient and the conduction coefficient of the rock mass are calculated and initialized.

[0153] Further, the A4 excavation disturbance simulation mainly includes: setting the initial ground stress and water pressure condition to hold a stable equilibrium state, the excavation process is divided into multiple stages, and the acting force is released gradually in proportion. In the solid field iteration time step, the non-local force, acceleration, displacement, stress and the like are calculated, if the elongation rate is greater than the set critical damage elongation rate, the non-local force between the keys disappears, and the damage parameter and the calculation permeability coefficient are updated. The fluid field updates the water pressure distribution of the rock mass according to the changed permeability coefficient, and the equivalent node flow method is used to calculate the water inflow at the tunnel face, until the excavation process is completed.

[0154] Further, the A5 result analysis mainly includes: outputting the tunnel face excavation disturbance simulation result, visualizing and analyzing the water inflow process and water pressure distribution at the tunnel face.

[0155] Embodiment 6

[0156] In an embodiment of the present application, a tunnel water inflow calculation system based on geophysical parameters and near-field dynamics is provided, which takes a rock mass region to be calculated as a target region, including:

[0157] The acquisition module is configured to acquire geophysical data of the target region in front of the tunnel face;

[0158] The construction module is configured to discretize the target region into a plurality of material points according to the geophysical data, and construct a numerical calculation model of the target region in front of the tunnel face;

[0159] The simulation module is configured to simulate the excavation disturbance based on the initialized numerical calculation model by using the near-field dynamics solid field and fluid field coupling equation until the excavation process is completed.

[0160] The computing module is configured to calculate the water inflow of the flow cross section in the target area after the simulation ends by using the equivalent node flow method.

[0161] Embodiment 7

[0162] In an embodiment of the present application, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics.

[0163] Embodiment 8

[0164] In an embodiment of the present application, a non-transitory computer-readable storage medium is provided, which is used to store computer instructions, and the computer instructions, when executed by a processor, implement the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics.

[0165] Embodiment 9

[0166] In an embodiment of the present application, an electronic device is provided, comprising a processor, a memory, and a computer program; wherein the processor is connected with the memory, and the computer program is stored in the memory; when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device implements the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics.

[0167] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system), and computer program product according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices generate a device that implements the functions specified in the flowcharts and / or block diagrams. ​ The functions specified in one flow or multiple flows and / or blocks ​ The devices that implement the functions specified in one block or multiple blocks.

[0168] These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operation steps are performed on the computer or other programmable data processing devices to generate a computer-implemented process, so that the instructions executed on the computer or other programmable data processing devices provide a device that implements the functions specified in the flowcharts and / or block diagrams. ​ The functions specified in one flow or multiple flows and / or blocks ​ The steps that implement the functions specified in one block or multiple blocks.

[0169] The above describes the specific embodiments of the present application in conjunction with the drawings, but is not a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications or variations made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the scope of protection of the present application.

Claims

1. A tunnel water inflow calculation method based on geophysical parameters and near-field dynamics, characterized in that, The rock mass region to be calculated for water inflow is taken as a target region, and the calculation steps are: Obtaining geophysical data of the target region in front of the tunnel face; According to the geophysical data, the target region is discretized into a plurality of material points to construct a numerical calculation model of the target region in front of the tunnel face; Based on the initialized numerical calculation model, the near-field dynamic solid field and fluid field coupling equation is used to simulate the excavation disturbance until the excavation process is completed; In the excavation disturbance simulation, the equivalent node flow method is used to calculate the water inflow of the flow section in the target region in real time; The construction of the numerical calculation model of the target region in front of the tunnel face is to discretize the target region into a set of material points in space, each material point carrying density, elastic modulus, Poisson's ratio, initial permeability coefficient and initial water pressure attribute to form a target region physical information set; The near-field dynamic solid field and fluid field coupling equation is based on the near-field dynamic theory that when the key gradually breaks, the equivalent permeability increases, the water pressure gradient further drives the seepage, in turn reduces the effective stress of the rock mass, promotes the breaking of more keys, forms a two-way coupling, and thus establishes the coupling equation of the solid field and the fluid field; The excavation disturbance simulation is to divide the excavation process into multiple stress release stages, step by step to reduce the non-local force density, and realize the step-by-step release of stress.

2. The tunnel water inflow calculation method based on geophysical parameters and near field dynamics according to claim 1, characterized in that, The geophysical data is collected by geophysical technology to obtain the longitudinal wave velocity, transverse wave velocity, rock mass density and water pressure data of the discrete measuring points within a predetermined range in front of the tunnel face. 3.The tunnel water inflow calculation method based on geophysical parameters and near field dynamics according to claim 1, wherein, The initialization includes the number of material points, neighborhood radius, neighborhood of each material point, boundary conditions, material point coordinates; non-local force between material points, elongation between keys; calculated permeability coefficient and conductivity coefficient of the rock mass.

4. The tunnel water inflow calculation method based on geophysical parameters and near field dynamics according to claim 1, characterized in that, The equivalent node flow method is used to calculate the water inflow of the flow section in the target region in real time, which includes: The flow section contains a plurality of material points, for each point, the current water pressure is read first, then the conductivity of the material point is calculated according to the unit shape and real-time permeability; subsequently, the conductivity of each point is multiplied by the corresponding water pressure, and the algebraic sum of the products of all points in the section is obtained to get the instantaneous water inflow through the section at the current time.

5. A tunnel water inflow calculation system based on geophysical parameters and near field dynamics, characterized in that, The tunnel water inflow calculation method based on geophysical parameters and near-field dynamics according to any one of claims 1-4 takes the rock mass region to be calculated for water inflow as a target region, and the calculation steps are: The obtaining module is configured to obtain geophysical data of the target region in front of the tunnel face; The construction module is configured to discretize the target region into a plurality of material points according to the geophysical data to construct a numerical calculation model of the target region in front of the tunnel face; The simulation module is configured to use the near-field dynamic solid field and fluid field coupling equation based on the initialized numerical calculation model to simulate the excavation disturbance until the excavation process is completed; In the excavation disturbance simulation, the equivalent node flow method is used to calculate the water inflow of the flow section in the target region in real time.

6. A non-transitory computer-readable storage medium, comprising: The non-transitory computer readable storage medium is configured to store computer instructions, and the computer instructions are executed by a processor to implement the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics according to any one of claims 1-4.

7. An electronic device, comprising: The electronic device comprises: A processor, a memory and a computer program; the processor is connected with the memory, and the computer program is stored in the memory; when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the tunnel water inflow calculation method based on geophysical parameters and near-field dynamics according to any one of claims 1-4.

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