Method for determining the water diffusion coefficient of rock and related equipment for simulating the water absorption process

Abstract

The application provides a rock moisture diffusion coefficient determination and water absorption process simulation method and related equipment, which is used for characterizing the water absorption state of each particle at a mesoscopic level through a mesoscopic saturation coefficient on the basis of a particle discrete element technology, realizing numerical fine modeling, and thus can accurately and efficiently restore the rock water absorption process, thereby having significantly improved practical value.

Description

Technical Field

[0001] This application relates to the field of rock seepage process analysis, specifically to methods and related equipment for determining the rock moisture diffusion coefficient and simulating the water absorption process. Background Technology

[0002] As a porous material, rock possesses the physical and mechanical property of water absorption. When water seeps into the pores from its surface, it diffuses naturally, comes into contact with the rock's interior, and undergoes complex physical, mechanical, and chemical interactions, causing damage to the rock structure. In geotechnical engineering practice, rocks are frequently eroded by water sources such as rainwater, rivers, groundwater, and water vapor. The presence of water weakens the rock's strength and stiffness, leading to many engineering geological hazards, such as tunnel water inrush, roadway collapse, and surface subsidence in mining areas. The extent of water's influence within rock strata plays a decisive role in predicting engineering geological hazards. Therefore, the quantitative characterization of the distribution, diffusion range, and uniformity of water in rock strata has significant engineering implications.

[0003] Obtaining the diffusion characteristics of water in rock strata in the field presents certain technical challenges, so indoor experiments and numerical simulations are often used for research.

[0004] Common indoor testing methods calculate the macroscopic water content by measuring the weight of dry and water-containing rock samples, but this method cannot describe the diffusion state of water inside the rock, thus making it impossible to accurately measure the water content inside the rock. In addition, due to the non-uniformity of the collected samples, the test results are prone to dispersion. Since the water absorption pattern cannot be predicted in advance, the amount of water absorbed by the rock cannot be controlled, and the diffusion state of water in the rock at a specific water content cannot be determined.

[0005] Numerical simulation methods often use finite element software coupled with a humidity field to simulate the diffusion state of water in rocks. However, it is difficult to consider the internal fissures of rocks as discontinuous media materials and their anisotropy at the microscopic level. In this case, particle discrete element method can consider the structural randomness at the microscopic level and more realistically reflect the diffusion law of water inside rocks.

[0006] However, in the research process of existing related technologies, the inventors found that most of the current methods for characterizing water diffusion in rocks based on particle discrete element are achieved through the action of coupled fluid forces, but there are three main problems: (1) It cannot quantify the diffusion characteristics of water in rocks, characterize the water absorption process of rocks, and cannot measure the real-time water content and water diffusion coefficient of rocks; (2) The simulation range is limited, and the state it represents is the seepage process of saturated rocks, which fails to reflect the water absorption process of rocks from dry to saturated; (3) Due to its reliance on fluid mesh, its calculation speed is slow and it is not suitable for simulation of large-scale engineering projects, so its practical value is obviously limited. Summary of the Invention

[0007] This application provides a method and related equipment for determining the water diffusion coefficient of rocks and simulating the water absorption process. Based on the discrete element method for particles, the water absorption state of each particle is characterized at the microscopic level by using the microscopic saturation coefficient, thus realizing refined numerical modeling. Therefore, it can accurately and efficiently reproduce the water absorption process of rocks, thereby significantly improving its practical value.

[0008] In a first aspect, this application provides a method for determining the water diffusion coefficient of rocks and simulating the water absorption process, the method comprising:

[0009] After identifying the target rock sample, the water absorption coefficient of the target rock sample at different water absorption times was obtained through rock water absorption tests.

[0010] Construct the initial particle skeleton of the discrete element standard rock sample model and ensure that the internal stress of the discrete element standard rock sample model is fully balanced;

[0011] A discrete element program based on mass conservation and water diffusion equation was developed, and the relationship between macroscopic and mesoscopic parameters in the discrete element standard rock sample model was established to simulate the natural diffusion law of water inside the rock. The relationship between macroscopic and mesoscopic parameters includes the relationship between water diffusion coefficient and saturation coefficient.

[0012] Establish water absorption boundary conditions and initial conditions in the discrete element standard rock sample model, change the macroscopic water diffusion coefficient, simulate the water absorption process and obtain the macroscopic saturation coefficient-time curve under different macroscopic water diffusion coefficients until the curve matches the sample saturation coefficient.

[0013] Based on the discrete element standard rock sample model with calibrated parameters, discrete element simulations of rocks under various working conditions and different water absorption states were carried out.

[0014] In conjunction with the first aspect of this application, in a first possible implementation of the first aspect of this application, the method further includes:

[0015] The rock was processed into standard samples of Φ50mm×100mm. The standard samples were placed in an oven at 105℃~110℃ and dried for 12 hours. After being taken out, they were placed in a desiccator to cool to room temperature and weighed.

[0016] In the rock water absorption test, water was first injected to 1 / 4 of the height of the standard sample. Then, water was injected to 1 / 2 and 3 / 4 of the height of the standard sample every 2 hours. After 6 hours, the water was added to 20 mm above the top surface of the standard sample. The standard sample was then submerged in water and allowed to absorb water freely.

[0017] In conjunction with the first aspect of this application, in a second possible implementation of the first aspect of this application, the sample saturation coefficient of the target rock sample at different water absorption times is obtained through a rock water absorption test, including:

[0018] In the rock water absorption test, after the target rock sample has absorbed water freely and its mass has not changed, the sample saturation coefficient at different water absorption times is calculated using the following formula:

[0019]

[0020]

[0021]

[0022] Where W is the rock water absorption rate, m1 is the mass of the water-soaked rock at different water absorption times, and m is the mass of the dried rock sample. s denoted as saturated water absorption rate of the rock, m2 as saturated mass of the water-soaked rock sample, and w as the rock saturation coefficient.

[0023] In conjunction with the first aspect of this application, in the third possible implementation of the first aspect of this application, the mesoscopic water diffusion formula incorporated into the discrete element program is as follows:

[0024]

[0025] Where t is time, w i * Let be the microscopic saturation coefficient of particle i, N be the number of all particles adjacent to particle i, and d be the saturation coefficient of particle i. ij Let Δw be the microscopic moisture diffusion coefficient between particle i and particle j. ij * L represents the difference in microscopic saturation coefficient between particle i and particle j. ij Let be the center distance between particle i and particle j.

[0026] In conjunction with the first aspect of this application, in the fourth possible implementation of the first aspect of this application, the conversion relationship between the macroscopic moisture diffusion coefficient and the mesoscopic moisture diffusion coefficient programmed into the discrete element method is as follows:

[0027]

[0028]

[0029] Where, d ic Let V be the mesoscopic moisture diffusion coefficient of particle i at contact c, D be the macroscopic moisture diffusion coefficient tensor of particle i within its equivalent watershed volume, and V be the microscopic moisture diffusion coefficient of particle i at contact c. i Let l be the equivalent continuous flow domain volume of particle i. ic Let d be the distance from the center of particle i to the contact boundary. ijLet d be the microscopic moisture diffusion coefficient of particle i and particle j. jc Let be the microscopic moisture diffusion coefficient of particle i at contact c.

[0030] In conjunction with the first aspect of this application, in the fifth possible implementation of the first aspect of this application, for the simulation of the water absorption process, the macroscopic saturation coefficient of the model required to obtain the macroscopic saturation coefficient-time curve is obtained by the following formula:

[0031]

[0032] Where w is the macroscopic and microscopic saturation coefficient, N is the number of all particles adjacent to particle i, and w i * V is the microscopic saturation coefficient of particle i. i Let w be the equivalent continuous flow domain volume of particle i. is * Let w be the microscopic saturation coefficient of particle i under saturated conditions. is * Take 1.0.

[0033] In conjunction with the first aspect of this application, in the sixth possible implementation of the first aspect of this application, the content of discrete element simulation specifically includes:

[0034] Numerical simulation study of water absorption process of standard cylindrical and other rock samples of different shapes;

[0035] Determination of the water diffusion coefficient of standard cylinders and other rocks of different shapes;

[0036] The deterioration patterns of geotechnical macro- and micro-parameters under different saturation coefficients were combined.

[0037] Secondly, this application provides an apparatus for determining the water diffusion coefficient of rocks and simulating the water absorption process, the apparatus comprising:

[0038] The acquisition unit is used to obtain the sample saturation coefficient of the target rock sample at different water absorption times through a rock water absorption test after the target rock sample has been determined.

[0039] The building blocks are used to construct the initial particle skeleton of the discrete element standard rock sample model and to ensure that the internal stress of the discrete element standard rock sample model is fully balanced.

[0040] The compilation unit is used to compile discrete element programs based on mass conservation and water diffusion equations, and to establish the relationship between macroscopic and microscopic parameters in the discrete element standard rock sample model to simulate the natural diffusion law of water inside the rock. The relationship between macroscopic and microscopic parameters includes the relationship between water diffusion coefficient and saturation coefficient.

[0041] The simulation unit is used to establish water absorption boundary conditions and initial conditions in the discrete element standard rock sample model, change the macroscopic water diffusion coefficient, simulate the water absorption process, and obtain the macroscopic saturation coefficient-time curve under different macroscopic water diffusion coefficients until the curve matches the sample saturation coefficient.

[0042] The development unit is used to conduct discrete element simulations of rocks under various working conditions and different water absorption states based on a discrete element standard rock sample model with completed calibration parameters.

[0043] In conjunction with the second aspect of this application, in a first possible implementation of the second aspect of this application, the acquiring unit is further configured to:

[0044] The rock was processed into standard samples of Φ50mm×100mm. The standard samples were placed in an oven at 105℃~110℃ and dried for 12 hours. After being taken out, they were placed in a desiccator to cool to room temperature and weighed.

[0045] In the rock water absorption test, water was first injected to 1 / 4 of the height of the standard sample. Then, water was injected to 1 / 2 and 3 / 4 of the height of the standard sample every 2 hours. After 6 hours, the water was added to 20 mm above the top surface of the standard sample. The standard sample was then submerged in water and allowed to absorb water freely.

[0046] In conjunction with the second aspect of this application, in a second possible implementation of the second aspect of this application, the obtaining unit is specifically used for:

[0047] In the rock water absorption test, after the target rock sample has absorbed water freely and its mass has not changed, the sample saturation coefficient at different water absorption times is calculated using the following formula:

[0048]

[0049]

[0050]

[0051] Where W is the rock water absorption rate, m1 is the mass of the water-soaked rock at different water absorption times, and m is the mass of the dried rock sample. s denoted as saturated water absorption rate of the rock, m2 as saturated mass of the water-soaked rock sample, and w as the rock saturation coefficient.

[0052] In conjunction with the second aspect of this application, in a third possible implementation of the second aspect of this application, the mesoscopic water diffusion formula incorporated into the discrete element program is as follows:

[0053]

[0054] Where t is time, w i *Let be the microscopic saturation coefficient of particle i, N be the number of all particles adjacent to particle i, and d be the saturation coefficient of particle i. ij Let Δw be the microscopic moisture diffusion coefficient between particle i and particle j. ij * L represents the difference in microscopic saturation coefficient between particle i and particle j. ij Let be the center distance between particle i and particle j.

[0055] In conjunction with the second aspect of this application, in the fourth possible implementation of the second aspect of this application, the conversion relationship between the macroscopic moisture diffusion coefficient and the mesoscopic moisture diffusion coefficient programmed into the discrete element method is as follows:

[0056]

[0057]

[0058] Where, d ic Let V be the mesoscopic moisture diffusion coefficient of particle i at contact c, D be the macroscopic moisture diffusion coefficient tensor of particle i within its equivalent watershed volume, and V be the microscopic moisture diffusion coefficient of particle i at contact c. i Let l be the equivalent continuous flow domain volume of particle i. ic Let d be the distance from the center of particle i to the contact boundary. ij Let d be the microscopic moisture diffusion coefficient of particle i and particle j. jc Let be the microscopic moisture diffusion coefficient of particle i at contact c.

[0059] In conjunction with the second aspect of this application, in the fifth possible implementation of the second aspect of this application, for the simulation of the water absorption process, the macroscopic saturation coefficient of the model required to obtain the macroscopic saturation coefficient-time curve is obtained by the following formula:

[0060]

[0061] Where w is the macroscopic and microscopic saturation coefficient, N is the number of all particles adjacent to particle i, and w i * V is the microscopic saturation coefficient of particle i. i Let w be the equivalent continuous flow domain volume of particle i. is * Let w be the microscopic saturation coefficient of particle i under saturated conditions. is * Take 1.0.

[0062] In conjunction with the second aspect of this application, in the sixth possible implementation of the second aspect of this application, the content of discrete element simulation specifically includes:

[0063] Numerical simulation study of water absorption process of standard cylindrical and other rock samples of different shapes;

[0064] Determination of the water diffusion coefficient of standard cylinders and other rocks of different shapes;

[0065] The deterioration patterns of geotechnical macro- and micro-parameters under different saturation coefficients were combined.

[0066] Thirdly, this application provides a processing device, including a processor and a memory, wherein a computer program is stored in the memory, and when the processor invokes the computer program in the memory, it executes the method provided by the first aspect of this application or any possible implementation of the first aspect of this application.

[0067] Fourthly, this application provides a computer-readable storage medium storing a plurality of instructions adapted for loading by a processor to perform the method provided in the first aspect of this application or any possible implementation thereof.

[0068] From the above, it can be concluded that this application has the following beneficial effects:

[0069] When observing water diffusion in rocks using discrete element method (DEM) technology, this application, on the one hand, after determining the target rock sample, obtains the sample saturation coefficient at different water absorption times through rock water absorption tests; on the other hand, it constructs the initial particle skeleton of the DEM standard rock sample model and ensures sufficient stress balance within the model. Then, it develops a DEM program based on mass conservation and the water diffusion equation, and establishes the relationship between macroscopic and mesoscopic parameters in the DEM standard rock sample model to simulate the natural diffusion law of water within the rock. At this point, water absorption boundary conditions are established in the DEM standard rock sample model. By changing the macroscopic moisture diffusion coefficient and initial conditions, the water absorption process is simulated, and the macroscopic saturation coefficient-time curves under different macroscopic moisture diffusion coefficients are obtained until the curve matches the sample saturation coefficient. Subsequently, based on the discrete element standard rock sample model with calibrated parameters, discrete element simulations of rocks under various working conditions and different water absorption states can be carried out. In this process, the water absorption state of each particle is characterized at the microscopic level by the microscopic saturation coefficient, realizing numerical refinement modeling. Therefore, the rock water absorption process can be accurately and efficiently reproduced, thus having significantly improved practical value. Attached Figure Description

[0070] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0071] Figure 1This is a schematic flowchart of a method for determining the rock moisture diffusion coefficient and simulating the water absorption process in this application.

[0072] Figure 2 This is a schematic diagram of a scenario in which the internal stress of the numerical model in this application is fully balanced.

[0073] Figure 3 This is a schematic cross-sectional view of the water absorption boundary condition in the numerical model of this application.

[0074] Figure 4 This is a schematic diagram of a longitudinal section of the water absorption boundary condition in the numerical model of this application;

[0075] Figure 5 This is a comparative diagram showing the experimental and simulation results of the macroscopic saturation coefficient-water absorption time variation law of the numerical model of this application;

[0076] Figure 6 This is a schematic cross-sectional view of the diffusion pattern of water inside the numerical model under different macroscopic saturation coefficients in this application;

[0077] Figure 7 This is a schematic diagram of the longitudinal section of the water diffusion pattern inside the numerical model of this application under different macroscopic saturation coefficients;

[0078] Figure 8 This is a schematic diagram of a device for measuring the rock moisture diffusion coefficient and simulating the water absorption process, as described in this application.

[0079] Figure 9 This is a schematic diagram of one type of processing equipment used in this application. Detailed Implementation

[0080] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0081] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules is not necessarily limited to those explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or devices. The naming or numbering of steps appearing in this application does not imply that the steps in the method flow must be performed in the chronological / logical order indicated by the naming or numbering. The execution order of named or numbered process steps can be changed according to the desired technical purpose, as long as the same or similar technical effect is achieved.

[0082] The module division described in this application is a logical division. In practical applications, there may be other division methods. For example, multiple modules may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection between modules shown or discussed may be through some interfaces, and the indirect coupling or communication connection between modules may be electrical or other similar forms, none of which are limited in this application. Furthermore, the modules or sub-modules described as separate components may or may not be physically separated, may or may not be physical modules, or may be distributed in multiple circuit modules. Some or all of the modules may be selected to achieve the purpose of the solution in this application according to actual needs.

[0083] Before introducing the method for determining the rock moisture diffusion coefficient and simulating the water absorption process provided in this application, the background content involved in this application will be introduced first.

[0084] The method, apparatus, and computer-readable storage medium for determining the rock moisture diffusion coefficient and simulating the water absorption process provided in this application can be applied to processing equipment. Based on the particle discrete element method, it can characterize the water absorption state of each particle at the microscopic level through the microscopic saturation coefficient, thereby realizing numerical refinement modeling. Therefore, it can accurately and efficiently reproduce the rock water absorption process, thus having significantly improved practical value.

[0085] The method for determining the rock moisture diffusion coefficient and simulating the water absorption process mentioned in this application can be implemented by a device for determining the rock moisture diffusion coefficient and simulating the water absorption process, or by different types of processing devices such as servers, physical hosts, or user equipment (UE) that integrate such a device. The device for determining the rock moisture diffusion coefficient and simulating the water absorption process can be implemented in hardware or software. The UE can specifically be a terminal device such as a smartphone, tablet, laptop, desktop computer, or personal digital assistant (PDA). The processing devices can be configured in a cluster.

[0086] The following section introduces the method for determining the rock moisture diffusion coefficient and simulating the water absorption process provided in this application.

[0087] First, refer to Figure 1 , Figure 1 This invention illustrates a flowchart of the method for determining the rock moisture diffusion coefficient and simulating the water absorption process. The method provided in this application specifically includes the following steps S101 to S105:

[0088] Step S101: After determining the target rock sample, obtain the sample saturation coefficient of the target rock sample at different water absorption times through a rock water absorption test;

[0089] It is understandable that after determining the target rock sample as the object of observation for this water absorption process, the water absorption process can be observed through the numerical simulation method configured in this application. For this numerical simulation method, this application also uses actual parameters to play a guiding role, thereby promoting a higher precision numerical simulation effect.

[0090] In response, a rock water absorption test can be conducted on the target rock sample to measure the easily observable saturation coefficient, which is recorded as the sample saturation coefficient for subsequent data use.

[0091] Among them, rock sample refers to rock specimen or rock sample.

[0092] Furthermore, it is easy to understand that, for this application, the target rock sample can be either a ready-made or existing rock sample, or a rock sample prepared in this application.

[0093] As a practical implementation method, this application also provides a set of rock sample preparation procedures. Correspondingly, the method of this application may also include the following:

[0094] Specifically, within the requirements of the "Standard for Test Methods of Engineering Rock Mass GB T50266-99", the rock is processed into a standard sample of Φ50mm×100mm, the standard sample is placed in an oven at 105℃~110℃ for 12 hours, and after being taken out, it is placed in a desiccator to cool to room temperature (20℃±2℃) and weighed.

[0095] Before the test, the rock samples can be divided into groups, with one group kept dry (as a control group) and the rest subjected to water absorption tests.

[0096] When conducting water absorption tests on the target rock sample, the following can be included:

[0097] First, fill the standard sample with water to 1 / 4 of its height. Then, fill the standard sample with water to 1 / 2 and 3 / 4 of its height every 2 hours. After 6 hours, add water to 20 mm above the top surface of the standard sample. The standard sample is then allowed to absorb water freely after being submerged.

[0098] After the specimen has absorbed water for a period of time, the soaked rock sample can be taken out, the surface moisture of the target rock sample can be wiped off with a damp gauze, and its mass can be weighed immediately. Then, the target rock sample is put back into the water absorption container to continue to absorb water freely. This process is repeated until the mass of the target rock sample does not change from the mass of the previous water absorption time (the same, or the mass difference is not significant and is within the same range). It can be considered that the water absorption state of the rock sample has reached saturation.

[0099] Furthermore, this application also provides a specific implementation method for quantifying and measuring the saturation coefficient. Specifically, in the process of obtaining the sample saturation coefficient of the target rock sample at different water absorption times through rock water absorption tests, the following can be included:

[0100] In the rock water absorption test, after the mass of the target rock sample has not changed after free water absorption, the sample saturation coefficient at different water absorption times is calculated using the following formulas (1), (2), and (3):

[0101]

[0102]

[0103]

[0104] Where W is the rock water absorption rate, m1 is the mass of the water-soaked rock at different water absorption times, and m is the mass of the dried rock sample. s denoted as saturated water absorption rate of the rock, m2 as saturated mass of the water-soaked rock sample, and w as the rock saturation coefficient.

[0105] This provides a concrete implementation plan for calculating the saturation coefficient.

[0106] Step S102: Construct the initial particle skeleton of the discrete element standard rock sample model and ensure that the internal stress of the discrete element standard rock sample model is fully balanced.

[0107] In addition to measuring the saturation coefficient of the sample, a numerical model of the particle discrete element can be constructed. This application refers to the numerical model as the discrete element standard rock sample model.

[0108] For this discrete element standard rock sample model, in the initial model construction stage, its initial particle skeleton can be constructed first, and then it can be adjusted to an equilibrium state.

[0109] Specifically, as another practical implementation method, this application can be based on PFC. 3D Software and other application environments are used to construct a discrete element method (DEM) standard rock sample model. Spherical particles representing the mineral composition of the rock are randomly generated within the numerical computation domain. Overlapping particles repel each other under the influence of unbalanced forces until the unbalanced forces decrease to a certain threshold, at which point the numerical model as a whole reaches force equilibrium. Figure 2 The diagram shows a scenario where the internal stress of the numerical model in this application is fully balanced.

[0110] Step S103: Compile a discrete element program based on mass conservation and water diffusion equation, and establish the relationship between macroscopic and microscopic parameters in the discrete element standard rock sample model to simulate the natural diffusion law of water inside the rock. The relationship between macroscopic and microscopic parameters includes the relationship between water diffusion coefficient and saturation coefficient.

[0111] After configuring the initial particle skeleton and ensuring sufficient internal stress balance, and completing the initial configuration of the numerical model, the configuration of the numerical model can then be completed.

[0112] At this point, the discrete element model can be used to incorporate the relevant relationships involved in water diffusion in the rock sample into the numerical model. These relevant relationships can be configured in the form of equations and formulas.

[0113] Specifically, the relevant relationships concerning water diffusion in rock samples refer to the relationship between macroscopic and microscopic parameters in the numerical model, such as the relationship between the water diffusion coefficient and the saturation coefficient, in order to simulate the natural diffusion law and process of water inside the rock.

[0114] As a practical implementation method, this application incorporates a microscopic water diffusion formula from a discrete element method, which can be specifically:

[0115]

[0116] Where t is time, w i *Let be the microscopic saturation coefficient of particle i, N be the number of all particles adjacent to particle i, and d be the saturation coefficient of particle i. ij Let Δw be the microscopic moisture diffusion coefficient between particle i and particle j. ij * L represents the difference in microscopic saturation coefficient between particle i and particle j. ij Let be the center distance between particle i and particle j.

[0117] Correspondingly, its application principle can be referred to as follows:

[0118] This application assumes that water transfer occurs between particle units (pores and particles constitute particle units), and considers that the difference in the microscopic saturation coefficient of the particles is the reason for water conduction between them. The following equation (4) is listed as the mass conservation equation for the microscopic saturation coefficient of the particles:

[0119]

[0120] Among them, w i * Let be the microscopic saturation coefficient of particle i, characterizing the moisture content of the particle, with a value ranging from 0 to 1, where 0 represents the dry state and 1 represents the fully saturated state, t represents time, and f represents the water content of the particle. i Let i be the flow rate of water particles.

[0121] The average flow rate of each particle within its equivalent continuous flow domain can be calculated by the following equation (5). Furthermore, using the Gaussian formula, equation (5) becomes equation (6):

[0122]

[0123]

[0124] Among them, V i Let n be the equivalent continuous flow volume of the particle. i Let be the normal vector on the contact area S of the equivalent continuous flow domain of the particle.

[0125] In the discrete element method, it is assumed that water is conducted between particles through contact, so equation (6) can be discretized into equation (7):

[0126]

[0127] In the formula, N is the number of all particles adjacent to particle i, and f ij Let ΔS be the water flow rate between particle i and particle j. i Let n be the equivalent flow area between particle i and particle j. ij Let Q be the normal vector over the equivalent flow domain contact area between particle i and particle j. ij Let be the flow rate of water between particle i and particle j.

[0128] Neglecting gravity, the interparticle water flux f ij With water flow rate Q ij It can be calculated according to Darcy's law, as shown in equations (8) and (9) below.

[0129]

[0130]

[0131] Where, Δw ij * L represents the difference in microscopic saturation coefficient between particle i and particle j. ij Let d be the center distance between particle i and particle j. ij Let be the microscopic moisture diffusion coefficient between particle i and particle j.

[0132] Substituting equations (7) and (9) into equation (4) yields equation (10), which is the microscopic water diffusion equation for the particle discrete element method. Transforming it into a difference form allows it to be incorporated into the particle discrete element program, as shown in equation (11).

[0133]

[0134]

[0135] It is understandable that this section provides a specific implementation plan for the treatment of water diffusion in detail, and also reveals the specific derivation process. It has obvious practical value for practical applications and is easy to implement.

[0136] Furthermore, in step S103, there may be a transformation relationship between the macroscopic moisture diffusion coefficient and the microscopic moisture diffusion coefficient.

[0137] As another practical implementation method, the conversion relationship between the macroscopic moisture diffusion coefficient and the mesoscopic moisture diffusion coefficient, which is programmed into the discrete element method here, can be specifically described as follows:

[0138]

[0139]

[0140] Where, d ic Let V be the mesoscopic moisture diffusion coefficient of particle i at contact c, D be the macroscopic moisture diffusion coefficient tensor of particle i within its equivalent watershed volume, and V be the microscopic moisture diffusion coefficient of particle i at contact c. i Let l be the equivalent continuous flow domain volume of particle i. ic Let d be the distance from the center of particle i to the contact boundary. ij Let d be the microscopic moisture diffusion coefficient of particle i and particle j. jcLet be the microscopic moisture diffusion coefficient of particle i at contact c.

[0141] Correspondingly, its application principle can be referred to as follows:

[0142] The microscopic water diffusion coefficient is calculated as follows: The average water flux of each particle within its equivalent flow volume can be calculated by the following equation (12). In the discrete element method, assuming that water between particles is conducted through contact, the following equation (12) can be discretized into the form of the following equation (13):

[0143]

[0144]

[0145] Where, ΔS ic —The area of ​​particle i at contact c; l ic — The distance from the center of the particle unit to the contact boundary.

[0146] Using Darcy's law, the water flux f at contact c of particle i can be calculated. ic As shown in equation (14).

[0147]

[0148] Where, d ic — The microscopic moisture diffusion coefficient of particle i at contact c, n ic —The normal vector between particle i and contact c, Δw ij * The difference in the microscopic saturation coefficient of particle i at contact c can be obtained by the following formula (15).

[0149]

[0150] Furthermore, substituting equations (14) and (15) into equation (13), we obtain equation (16):

[0151]

[0152] According to the tensor theorem, the mesoscopic moisture diffusion coefficient d of particle i at contact c is... ic The principal component (d) of the microscopic moisture diffusion coefficient can be used to determine the water diffusion coefficient. 1 ic ,d 2 ic ,d 3 ic Its unit vector e in the direction of mesoscopic diffusion ic The corresponding principal variable (e) 1 ic ,e 2 ic ,e3 ic This is represented as shown in equation (17):

[0153]

[0154] The macroscopic water diffusion coefficient is calculated as follows: According to Darcy's law, the water flux f of particle i in the equivalent watershed is... i It can be calculated using the following formula (18):

[0155]

[0156] In the formula, D is the macroscopic water diffusion coefficient tensor of particle i in its equivalent watershed volume, which can be expressed by its principal component as follows (19):

[0157] D = D 1 +D 2 +D 3 (19)

[0158] Combining equations (16), (17), and (18), we obtain equation (20):

[0159]

[0160] Assume that the material properties of the equivalent flow domain volume within particle i are homogeneous and isotropic, i.e. D = D 1 =D 2 =D 3 =D xx =D yy =D zz Equation (20) above becomes equation (21) below:

[0161]

[0162] In three-dimensional space, the above equation (21) is further transformed into the following equation (22):

[0163]

[0164] For the microscopic moisture diffusion coefficient d of particles i and j ij The equivalent calculation can be performed using the harmonic mean in the following formula (23):

[0165]

[0166] Equations (22) and (23) above represent the conversion relationship between the macroscopic water diffusion coefficient and the microscopic water diffusion coefficient. By inputting the macroscopic water diffusion coefficient D, it can be automatically converted into the microscopic water diffusion coefficient within the program, thereby changing the diffusion properties of water in the numerical model.

[0167] It is understandable that this section deals with the conversion relationship between macroscopic and microscopic moisture diffusion coefficients. It provides a specific implementation plan through formulas and also reveals the specific derivation process, which has significant practical value for practical applications and facilitates implementation.

[0168] Step S104: Establish water absorption boundary conditions and initial conditions in the discrete element standard rock sample model, change the macroscopic water diffusion coefficient, simulate the water absorption process, and obtain the macroscopic saturation coefficient-time curve under different macroscopic water diffusion coefficients until the curve matches the sample saturation coefficient.

[0169] After incorporating correlations into the numerical model (discrete element standard rock sample model) to simulate the diffusion law of water in the rock sample, the model parameters can then be further optimized based on the water diffusion simulation, i.e., the water absorption process simulation.

[0170] At this point, the water absorption boundary and initial conditions in the model can be established first.

[0171] The establishment of water absorption boundary conditions may include:

[0172] The outermost grain microscopic saturation coefficient of the rock sample in the numerical model is set to a constant 1.0 to simulate the continuous replenishment of water around the rock during natural water absorption. Figure 3 , Figure 4 The schematic diagrams of the transverse and longitudinal sections of the water absorption boundary conditions of the numerical model of this application are shown respectively.

[0173] The initial conditions can include:

[0174] The initial microscopic saturation coefficient of the outermost layer of the rock sample in the numerical model was set to 1.0, and the initial microscopic saturation coefficient of the other particles was set to 0.0.

[0175] After establishing the water absorption boundary and initial conditions in the model, the program can be run to simulate the water absorption process and the diffusion of water in the rock. The model parameters can then be adjusted based on the obtained macroscopic saturation coefficient-time curves under different macroscopic water diffusion coefficients.

[0176] As another practical implementation method, the macro saturation coefficient of the model required for the macro saturation coefficient-time curve obtained by simulating the water absorption process is calculated as shown in the following formula (24). In the discrete element method, it can also be discretized into the form of the following formula (25).

[0177] Obtained through the following formula:

[0178]

[0179]

[0180] Where w is the macroscopic and microscopic saturation coefficient, w * To observe the saturation coefficient in detail, w s * w is the microscopic saturation coefficient under saturated conditions. s * Let w be 1.0, N be the number of all particles adjacent to particle i, and w be the number of particles adjacent to particle i. i * V is the microscopic saturation coefficient of particle i. i Let w be the equivalent continuous flow domain volume of particle i. is * Let w be the microscopic saturation coefficient of particle i under saturated conditions. is * Take 1.0.

[0181] It is understandable that this section provides a specific implementation plan for the macroscopic saturation coefficient of the model required for the macroscopic saturation coefficient-time curve, and also reveals its specific derivation process. It has obvious practical value for practical applications and is easy to implement.

[0182] It is understandable that during the model debugging process based on simulation, the debugging effect can be judged by the sample saturation coefficient obtained at the beginning. When the macro saturation coefficient-time curve under different macro water diffusion coefficients matches the sample saturation coefficient, it can be considered that the debugging has been completed, the model parameters have been calibrated, and a discrete element standard rock sample model that can be put into practical application is obtained.

[0183] Step S105: Based on the discrete element standard rock sample model with completed calibration parameters, conduct discrete element simulations of rocks under various working conditions and different water absorption states.

[0184] Once the discrete element standard rock sample model with calibrated parameters is obtained, it can be put into practical application of discrete element simulation, thereby providing specific data basis for the analysis of water absorption process and water diffusion in rocks.

[0185] From the above content, it can be seen that this application has the following characteristics:

[0186] 1. The water diffusion coefficient, which reflects the change of natural water content of real rock samples with water absorption time, was determined by numerical method, realizing the quantitative characterization of natural water diffusion in rocks;

[0187] 2. By inverting the water content-time curve of the numerical model, the distribution of water inside the rock at a specific water content can be obtained, which makes up for the lack of control over the water absorption process of the rock in the laboratory test;

[0188] 3. By characterizing the water absorption state of each particle at the microscopic level through the microscopic saturation coefficient, a refined numerical modeling is achieved, which can more fundamentally reflect the water absorption characteristics of rocks.

[0189] 4. By combining the strength deterioration law of rocks under different water contents, the simulation of the deterioration and instability process of engineering rock mass under water-rich conditions can be applied, which can serve as a favorable basis for the stability evaluation of geotechnical engineering under specific hydrogeological conditions and has good engineering application prospects.

[0190] As another practical implementation method, the process of performing discrete element simulation using a standard rock sample model may specifically include the following:

[0191] 1. Numerical simulation study of water absorption process of standard cylindrical and other rock samples of different shapes;

[0192] 2. Determination of the water diffusion coefficient of standard cylinders and other rocks of different shapes;

[0193] 3. Deterioration patterns of geotechnical macro- and micro-parameters under different saturation coefficients.

[0194] To further understand the above content, this application can also be illustrated with the following set of examples.

[0195] The saturation coefficients of standard cylindrical shale rock samples obtained from rock water absorption tests at different water absorption times are shown in Table 1 below.

[0196] Table 1 - Saturation coefficient of rock samples at different water absorption times

[0197]

[0198] Based on the discrete element method (DEM) standard rock sample model, a program was written to perform calculations. In this example, samples with a radius of 0.68-1.13 mm and a density of 2500 kg / m³ were generated. 3 The particles are filled within the 50mm×100mm cylindrical computational boundary. When the unbalanced force is eliminated, the numerical model as a whole reaches force equilibrium, and the particles in the numerical model are in full contact.

[0199] Establish water absorption boundary conditions and initial conditions. By changing the macroscopic water diffusion coefficient, obtain the "saturation coefficient-time" curves under different macroscopic water diffusion coefficients until the numerical simulation curve matches the saturation coefficient of the previous samples to a high degree. Figure 5 The diagram illustrates a comparison between experimental and simulation results of the macroscopic saturation coefficient versus water absorption time variation law of the numerical model in this application, outputting the macroscopic moisture diffusion coefficient of the model. In this case, the macroscopic moisture diffusion coefficient obtained is 8.14 × 10⁻⁹ m. 2 / s, Figure 6and Figure 7 The cross-sectional and longitudinal cross-sectional diagrams of the water diffusion pattern inside the numerical model of this application under different macroscopic saturation coefficients are given respectively (represented by the distribution state of the microscopic saturation coefficient).

[0200] In summary, as can be seen from the above, when observing water diffusion in rocks using the discrete element method (DEM), this application, on the one hand, after determining the target rock sample, obtains the sample saturation coefficient at different water absorption times through rock water absorption tests; on the other hand, it constructs the initial particle framework of the DEM standard rock sample model, ensures sufficient stress balance within the model, and then develops a DEM program based on mass conservation and the water diffusion equation, establishing the relationship between macroscopic and mesoscopic parameters in the DEM standard rock sample model to simulate the natural diffusion law of water within the rock. At this point, in the DEM standard rock sample model... By establishing water absorption boundary conditions and initial conditions, changing the macroscopic moisture diffusion coefficient, simulating the water absorption process, and obtaining macroscopic saturation coefficient-time curves under different macroscopic moisture diffusion coefficients until the curve matches the sample saturation coefficient, subsequent discrete element simulations of rocks under various working conditions and different water absorption states can be carried out based on the calibrated discrete element standard rock sample model. In this process, the water absorption state of each particle is characterized at the microscopic level by the microscopic saturation coefficient, realizing refined numerical modeling. Therefore, the rock water absorption process can be accurately and efficiently reproduced, thus significantly improving its practical value.

[0201] The above is an introduction to the method for determining the rock moisture diffusion coefficient and simulating the water absorption process provided in this application. In order to facilitate better implementation of the method for determining the rock moisture diffusion coefficient and simulating the water absorption process provided in this application, this application also provides an apparatus for determining the rock moisture diffusion coefficient and simulating the water absorption process from the perspective of functional modules.

[0202] See Figure 8 , Figure 8 This is a schematic diagram of a device for measuring the rock moisture diffusion coefficient and simulating the water absorption process, as described in this application. Specifically, the device 800 for measuring the rock moisture diffusion coefficient and simulating the water absorption process may include the following structure:

[0203] The acquisition unit 801 is used to obtain the sample saturation coefficient of the target rock sample at different water absorption times through a rock water absorption test after the target rock sample is determined.

[0204] The building element 802 is used to construct the initial particle skeleton of the discrete element standard rock sample model and to fully balance the internal stress of the discrete element standard rock sample model.

[0205] Unit 803 is used to develop a discrete element program based on mass conservation and water diffusion equation, and to establish the relationship between macroscopic and microscopic parameters in the discrete element standard rock sample model to simulate the natural diffusion law of water inside the rock. The relationship between macroscopic and microscopic parameters includes the relationship between water diffusion coefficient and saturation coefficient.

[0206] Simulation unit 804 is used to establish water absorption boundary conditions and initial conditions in the discrete element standard rock sample model, change the macroscopic water diffusion coefficient, simulate the water absorption process, and obtain the macroscopic saturation coefficient-time curve under different macroscopic water diffusion coefficients until the curve matches the sample saturation coefficient.

[0207] Unit 805 is used to conduct discrete element simulations of rocks under various working conditions and different water absorption states based on a discrete element standard rock sample model with completed calibration parameters.

[0208] In one exemplary implementation, the acquisition unit 801 is further configured to:

[0209] The rock was processed into standard samples of Φ50mm×100mm. The standard samples were placed in an oven at 105℃~110℃ and dried for 12 hours. After being taken out, they were placed in a desiccator to cool to room temperature and weighed.

[0210] In the rock water absorption test, water was first injected to 1 / 4 of the height of the standard sample. Then, water was injected to 1 / 2 and 3 / 4 of the height of the standard sample every 2 hours. After 6 hours, the water was added to 20 mm above the top surface of the standard sample. The standard sample was then submerged in water and allowed to absorb water freely.

[0211] In yet another exemplary implementation, the acquisition unit 802 is specifically used for:

[0212] In the rock water absorption test, after the target rock sample has absorbed water freely and its mass has not changed, the sample saturation coefficient at different water absorption times is calculated using the following formula:

[0213]

[0214]

[0215]

[0216] Where W is the rock water absorption rate, m1 is the mass of the water-soaked rock at different water absorption times, and m is the mass of the dried rock sample. s denoted as saturated water absorption rate of the rock, m2 as saturated mass of the water-soaked rock sample, and w as the rock saturation coefficient.

[0217] In yet another exemplary implementation, the mesoscopic water diffusion formula programmed into the discrete element program is:

[0218]

[0219] Where t is time, w i * Let be the microscopic saturation coefficient of particle i, N be the number of all particles adjacent to particle i, and d be the saturation coefficient of particle i. ij Let Δw be the microscopic moisture diffusion coefficient between particle i and particle j. ij * L represents the difference in microscopic saturation coefficient between particle i and particle j. ij Let be the center distance between particle i and particle j.

[0220] In another exemplary implementation, the conversion relationship between the macroscopic moisture diffusion coefficient and the mesoscopic moisture diffusion coefficient programmed into the discrete element method is as follows:

[0221]

[0222]

[0223] Where, d ic Let V be the mesoscopic moisture diffusion coefficient of particle i at contact c, D be the macroscopic moisture diffusion coefficient tensor of particle i within its equivalent watershed volume, and V be the microscopic moisture diffusion coefficient of particle i at contact c. i Let l be the equivalent continuous flow domain volume of particle i. ic Let d be the distance from the center of particle i to the contact boundary. ij Let d be the microscopic moisture diffusion coefficient of particle i and particle j. jc Let be the microscopic moisture diffusion coefficient of particle i at contact c.

[0224] In another exemplary implementation, for simulating the water absorption process, the macroscopic saturation coefficient of the model required to obtain the macroscopic saturation coefficient-time curve is obtained by the following formula:

[0225]

[0226] Where w is the macroscopic and microscopic saturation coefficient, N is the number of all particles adjacent to particle i, and w i * V is the microscopic saturation coefficient of particle i. i Let w be the equivalent continuous flow domain volume of particle i. is * Let w be the microscopic saturation coefficient of particle i under saturated conditions. is * Take 1.0.

[0227] In yet another exemplary implementation, the discrete element simulation specifically includes:

[0228] Numerical simulation study of water absorption process of standard cylindrical and other rock samples of different shapes;

[0229] Determination of the water diffusion coefficient of standard cylinders and other rocks of different shapes;

[0230] The deterioration patterns of geotechnical macro- and micro-parameters under different saturation coefficients were combined.

[0231] This application also provides a processing device from a hardware architecture perspective, see [link / reference]. Figure 9 , Figure 9 This diagram illustrates a structural schematic of the processing device of this application. Specifically, the processing device may include a processor 901, a memory 902, and an input / output device 903. The processor 901 executes the computer program stored in the memory 902 to implement, for example... Figure 1 The steps of the method for determining the rock moisture diffusion coefficient and simulating the water absorption process in the corresponding embodiment; or, when the processor 901 executes the computer program stored in the memory 902, it implements the following: Figure 8 Corresponding to the functions of each unit in the embodiment, the memory 902 is used to store the functions executed by the processor 901 as described above. Figure 1 The computer program required for the method of determining the rock moisture diffusion coefficient and simulating the water absorption process in the corresponding embodiment.

[0232] For example, a computer program may be divided into one or more modules / units, one or more of which are stored in memory 902 and executed by processor 901 to complete this application. One or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in a computer device.

[0233] The processing device may include, but is not limited to, processor 901, memory 902, and input / output device 903. Those skilled in the art will understand that the illustrations are merely examples of the processing device and do not constitute a limitation on the processing device. It may include more or fewer components than illustrated, or combine certain components, or different components. For example, the processing device may also include network access devices, buses, etc., and processor 901, memory 902, input / output device 903, etc., are connected via a bus.

[0234] The processor 901 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the processing device, connecting various parts of the device through various interfaces and lines.

[0235] The memory 902 can be used to store computer programs and / or modules. The processor 901 implements various functions of the computer device by running or executing the computer programs and / or modules stored in the memory 902 and by calling data stored in the memory 902. The memory 902 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, application programs required for at least one function, etc.; the data storage area may store data created according to the use of the processing device, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0236] When processor 901 executes a computer program stored in memory 902, it can specifically perform the following functions:

[0237] After identifying the target rock sample, the water absorption coefficient of the target rock sample at different water absorption times was obtained through rock water absorption tests.

[0238] Construct the initial particle skeleton of the discrete element standard rock sample model and ensure that the internal stress of the discrete element standard rock sample model is fully balanced;

[0239] A discrete element program based on mass conservation and water diffusion equation was developed, and the relationship between macroscopic and mesoscopic parameters in the discrete element standard rock sample model was established to simulate the natural diffusion law of water inside the rock. The relationship between macroscopic and mesoscopic parameters includes the relationship between water diffusion coefficient and saturation coefficient.

[0240] Establish water absorption boundary conditions and initial conditions in the discrete element standard rock sample model, change the macroscopic water diffusion coefficient, simulate the water absorption process and obtain the macroscopic saturation coefficient-time curve under different macroscopic water diffusion coefficients until the curve matches the sample saturation coefficient.

[0241] Based on the discrete element standard rock sample model with calibrated parameters, discrete element simulations of rocks under various working conditions and different water absorption states were carried out.

[0242] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the apparatus, processing equipment, and corresponding units for determining the rock moisture diffusion coefficient and simulating the water absorption process described above can be found in the following reference: Figure 1 The specific methods for determining the rock moisture diffusion coefficient and simulating the water absorption process in the corresponding embodiments will not be repeated here.

[0243] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0244] Therefore, this application provides a computer-readable storage medium storing a plurality of instructions that can be loaded by a processor to execute the present application. Figure 1 The steps of the method for determining the rock moisture diffusion coefficient and simulating the water absorption process in the corresponding embodiment can be found in the following example. Figure 1 The methods for determining the rock moisture diffusion coefficient and simulating the water absorption process in the corresponding embodiments will not be repeated here.

[0245] The computer-readable storage medium may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0246] Because of the instructions stored in the computer-readable storage medium, the present application can be executed as described above. Figure 1 The steps of the method for determining the rock moisture diffusion coefficient and simulating the water absorption process in the corresponding embodiments can therefore achieve the results of this application. Figure 1 The beneficial effects that can be achieved by the method of measuring the rock moisture diffusion coefficient and simulating the water absorption process in the corresponding embodiment are detailed in the preceding description and will not be repeated here.

[0247] The method, apparatus, processing equipment, and computer-readable storage medium for determining the rock moisture diffusion coefficient and simulating the water absorption process provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method of rock moisture diffusion coefficient determination and water absorption process simulation, characterized by, The method includes: After identifying the target rock sample, the water saturation coefficient of the target rock sample at different water absorption times was obtained through a rock water absorption test. Construct the initial particle skeleton of the discrete element standard rock sample model and ensure that the internal stress of the discrete element standard rock sample model is fully balanced; A discrete element program based on mass conservation and water diffusion equations was developed, and the relationship between macroscopic and mesoscopic parameters in the discrete element standard rock sample model was established to simulate the natural diffusion law of water inside the rock. The relationship between macroscopic and mesoscopic parameters includes the relationship between water diffusion coefficient and saturation coefficient. In the discrete element standard rock sample model, water absorption boundary conditions and initial conditions are established, the macroscopic water diffusion coefficient is changed, the water absorption process is simulated, and the macroscopic saturation coefficient-time curves under different macroscopic water diffusion coefficients are obtained until the curve matches the saturation coefficient of the sample. Based on the discrete element standard rock sample model with the completed calibration parameters, discrete element simulations of rocks under various working conditions and different water absorption states are carried out. The process of obtaining the water saturation coefficient of the target rock sample at different water absorption times through rock water absorption tests includes: In the rock water absorption test, after the target rock sample has freely absorbed water and its mass has not changed, the saturation coefficient of the target rock sample at different water absorption times is calculated using the following formula: ， ， ， Wherein, W is the water absorption rate of rock, m1 is the mass of the immersed rock at different water absorption time, m is the mass of the dry rock sample, W s is the saturated water absorption rate of rock, m2 is the saturated mass of the immersed rock sample, and w is the rock saturation coefficient. The mesoscopic water diffusion formula incorporated into the discrete element program is as follows: ， where t is time, w i * is the microsopic water saturation coefficient of the particle i, N is the number of all particles adjacent to the particle i, d ij is the microsopic water diffusion coefficient of the particle i and particle j, Δ w ij * is the difference of the microsopic water saturation coefficient of the particle i and the particle j, L ij is the center distance of the particle i and the particle j; The conversion relationship between the macroscopic moisture diffusion coefficient and the microscopic moisture diffusion coefficient programmed into the discrete element method is as follows: ， ， wherein, d ic Dc is the mesoscopic moisture diffusion coefficient of the particle i at the contact c, D is the macroscopic moisture diffusion coefficient tensor of the particle i within its equivalent flow domain volume, V i Vc is the equivalent continuous flow domain volume of the particle i, l ic d is the distance from the center of the particle i to the contact boundary, d ij Dij is the mesoscopic moisture diffusion coefficient of the particle i and the particle j, d jc Dc is the mesoscopic moisture diffusion coefficient of the particle i at the contact c.

2. The method of claim 1, wherein, The method further includes: The rock was processed into standard samples of Φ50mm×100mm. The standard samples were placed in an oven at 105°C~110°C for 12 hours, removed and cooled to room temperature in a desiccator, and their mass was weighed. In the rock water absorption test, water was first injected to 1 / 4 of the height of the standard sample. Then, water was injected to 1 / 2 and 3 / 4 of the height of the standard sample every 2 hours. After 6 hours, the water was added to 20 mm above the top surface of the standard sample. The standard sample was then submerged in water and allowed to absorb water freely.

3. The method of claim 1, wherein, For the simulation of the water absorption process, the macroscopic saturation coefficient of the model required to obtain the macroscopic saturation coefficient-time curve is obtained by the following formula: ， wherein, w is the macroscopic water saturation coefficient, w is * is the mesoscopic water saturation coefficient of the particle i in the saturated state, w is * is taken as 1.

0.

4. The method of claim 1, wherein, Discrete element simulation specifically includes: Numerical simulation study of water absorption process of standard cylindrical and other rock samples of different shapes; Determination of the water diffusion coefficient of standard cylinders and other rocks of different shapes; The deterioration patterns of geotechnical macro- and micro-parameters under different saturation coefficients were combined.

5. An apparatus for determining the water diffusion coefficient of rocks and simulating the water absorption process, characterized in that, The device includes: The acquisition unit is used to obtain the sample saturation coefficient of the target rock sample at different water absorption times through a rock water absorption test after the target rock sample is determined. The building unit is used to construct the initial particle skeleton of the discrete element standard rock sample model and to fully balance the internal stress of the discrete element standard rock sample model. The compilation unit is used to compile a discrete element program based on mass conservation and water diffusion equation, and to establish the relationship between macroscopic and microscopic parameter indices in the discrete element standard rock sample model to simulate the natural diffusion law of water inside the rock. The relationship between the macroscopic and microscopic parameter indices includes the relationship between the water diffusion coefficient and the saturation coefficient. The simulation unit is used to establish water absorption boundary conditions and initial conditions in the discrete element standard rock sample model, change the macroscopic water diffusion coefficient, simulate the water absorption process, and obtain the macroscopic saturation coefficient-time curve under different macroscopic water diffusion coefficients until the curve matches the sample saturation coefficient. The development unit is used to conduct discrete element simulations of rocks under various working conditions and different water absorption states based on the discrete element standard rock sample model with completed calibration parameters. The apparatus is used to perform the method according to any one of claims 1 to 4.

6. A processing device, characterized by It includes a processor and a memory, wherein the memory stores a computer program, and the processor executes the method as described in any one of claims 1 to 4 when it invokes the computer program in the memory.

7. A computer readable storage medium characterized in that, The computer-readable storage medium stores a plurality of instructions adapted for loading by a processor to perform the method of any one of claims 1 to 4.

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