Method and system for determining thickness of water-resisting rock mass considering uncertainty of rock mass parameters

Abstract

The method and system for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters disclosed by the present invention include: obtaining the rock mass integrity coefficient and multiple groups of rock mass parameters at the position of the water-bearing body; determining the rock mass homogeneity according to the rock mass integrity coefficient; determining the probability distribution of the rock mass parameters through the rock mass homogeneity, multiple groups of rock mass parameters and the Weibull probability density distribution function, taking the rock mass parameters corresponding to the maximum probability as the center, determining the rock mass parameter interval when the sum of probabilities is a set value, and selecting the rock mass parameters from this parameter interval to form a calculation parameter data set; analyzing the calculation parameter data set through different water-resisting rock mass calculation models, obtaining the thickness of the water-resisting rock mass corresponding to each model, and determining the final thickness of the water-resisting rock mass according to the thickness of the water-resisting rock mass corresponding to each model. The accuracy of the thickness of the water-resisting rock mass is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of determining the thickness of a water-resisting rock mass, and in particular to a method and system for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] When a tunnel crosses a karst area, affected by complex geological conditions and other factors, it often encounters large-scale geological disasters such as water inrush and mud gushing. Tunnel water inrush, with its high incidence rate, suddenness, and great harm, severely restricts the development of underground engineering construction in karst areas. Compared with geological disasters such as tunnel collapses and rock bursts, water inrush disasters are the most serious among various types of tunnel disasters, and their harms are mainly manifested in the following aspects: First, it endangers construction safety; second, it causes ground settlement or collapse; third, it reduces and depletes water resources above the ground; fourth, it leads to water pollution.

[0004] In the field of preventing and controlling water inrush in karst tunnels, the safety thickness of the water-resisting layer is a very crucial concept. How to reasonably determine the distance between the tunnel structure and the water-bearing geological body is a very core concept and construction index, and proper application can play an important role in preventing water inrush. When there is a karst water-bearing structure near the tunnel, the stability of the surrounding rock (i.e., the water-resisting layer) between it and the tunnel is the key to preventing water inrush. If the thickness of the water-resisting layer is too small, it is difficult to resist the combined action of excavation and karst water, and serious losses are often suffered due to sudden water inrush and mud gushing. However, if the thickness of the water-resisting layer is too large, it lacks economy and brings inconvenience and waste to the subsequent treatment work of the water-bearing structure. The water-resisting layer generally shows in preventing water inrush that when advanced prediction means (such as geophysical exploration or advanced drilling, etc.) detect the existence of a water-bearing structure ahead, a certain thickness of the water-resisting layer needs to be reserved for the next treatment work. At this time, the reasonable thickness of the water-resisting layer helps to ensure both economy and safety.

[0005] When the existing methods determine the thickness of the water-resisting layer, they all take the tunnel surrounding rock parameters as a fixed value, and fail to fully consider the discontinuity of the rock mass medium and the discreteness of the rock mass parameters. Since the rock mass in nature has the typical characteristic of inhomogeneity, the accuracy of the thickness of the water-resisting layer determined by the existing methods for determining the thickness of the water-resisting layer is relatively low, and the guiding effect on actual projects is average. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a method and system for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters. When determining the thickness of the water-resisting rock mass, the discreteness and uncertainty of rock mass parameters are considered. Multiple groups of rock mass parameters are collected from the location of the water-bearing body, and the probability distribution of the rock mass parameters is calculated. Rock mass parameters are selected from multiple groups of rock mass parameters according to the probability distribution to form a calculation parameter data set, and then the thickness of the water-resisting rock mass is accurately calculated. The thickness of the water-resisting rock mass is more in line with the actual project, and thus can effectively guide the on-site construction.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In the first aspect, a method for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters is proposed, including:

[0009] Obtain the rock mass integrity coefficient and multiple groups of rock mass parameters at the location of the water-bearing body;

[0010] Determine the rock mass homogeneity according to the rock mass integrity coefficient;

[0011] Determine the probability distribution of the rock mass parameters through the rock mass homogeneity, multiple groups of rock mass parameters and the Weibull probability density distribution function. Taking the rock mass parameters corresponding to the maximum probability as the center, determine the rock mass parameter interval when the sum of probabilities is a set value, and select rock mass parameters from this parameter interval to form a calculation parameter data set;

[0012] Analyze the calculation parameter data set through different calculation models of the water-resisting rock mass to obtain the thickness of the water-resisting rock mass corresponding to each model. Determine the final thickness of the water-resisting rock mass according to the thickness of the water-resisting rock mass corresponding to each model.

[0013] In the second aspect, a method for determining the construction risk level of a water-resisting rock considering the uncertainty of rock mass parameters is proposed, including:

[0014] Determine the final thickness of the water-resisting rock mass through the method for determining the thickness of the water-resisting rock mass disclosed in the first aspect;

[0015] Among them, the thickness of the water-resisting rock mass calculated by the calculation model of the water-resisting rock mass based on the strength theory is used as the first reference value;

[0016] Take the minimum value of the thickness of the water-resisting rock mass calculated by the calculation model of the water-resisting rock mass based on the shear theory and the calculation model of the water-resisting rock mass based on the catastrophe theory as the second reference value;

[0017] When the distance between the tunnel face and the water-bearing cavity is less than the first reference value and greater than the second reference value, determine that the construction safety risk level is a major risk level;

[0018] When the distance between the tunnel face and the water-bearing cavity is less than the second reference value, determine that the construction safety risk level is an extremely high risk level.

[0019] In a third aspect, a system for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters is proposed, including:

[0020] A data acquisition module for acquiring the rock mass integrity coefficient and multiple groups of rock mass parameters at the position of the water-bearing body;

[0021] A rock mass homogeneity acquisition module for determining the rock mass homogeneity according to the rock mass integrity coefficient;

[0022] A calculation parameter data set acquisition module for determining the probability distribution of rock mass parameters through the rock mass homogeneity, multiple groups of rock mass parameters, and the Weibull probability density distribution function, taking the rock mass parameters corresponding to the maximum probability as the center, determining the rock mass parameter interval when the sum of probabilities is a set value, and selecting rock mass parameters from this parameter interval to form a calculation parameter data set;

[0023] A water-resisting rock mass thickness determination module for analyzing the calculation parameter data set through different water-resisting rock mass calculation models, obtaining the water-resisting rock mass thickness corresponding to each model, and determining the final water-resisting rock mass thickness according to the water-resisting rock mass thickness corresponding to each model.

[0024] In a fourth aspect, an electronic device is proposed, including a memory, a processor, and computer instructions stored on the memory and running on the processor. When the computer instructions are run by the processor, the steps of the method for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters are completed.

[0025] In a fifth aspect, a computer-readable storage medium is proposed for storing computer instructions. When the computer instructions are executed by the processor, the steps of the method for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters are completed.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] When calculating the thickness of the water-resisting rock mass, the present invention takes into account the discreteness and uncertainty of the rock mass parameters, collects multiple groups of rock mass parameters at the position of the water-bearing body, calculates the probability distribution of the rock mass parameters, selects the rock mass parameters from the multiple groups of rock mass parameters according to the probability distribution to form a calculation parameter data set, and then accurately calculates the thickness of the water-resisting rock mass. The thickness of the water-resisting rock mass is more in line with the actual project, and thus can effectively guide the on-site construction. The present invention takes into account the calculation errors of different calculation models of the water-resisting rock mass, analyzes the calculation parameter data set through different calculation models of the water-resisting rock mass, determines the thickness of the water-resisting rock mass corresponding to each model, and then selects the maximum value from the thicknesses of the water-resisting rock mass corresponding to different models as the final thickness of the water-resisting rock mass, effectively ensuring the accuracy of the determination of the thickness of the water-resisting rock mass and being more adaptable to the actual project. When determining the thickness of the water-resisting rock mass corresponding to each model, the present invention calculates the probability distribution of the thickness of the water-resisting rock mass, and selects the thickness of the water-resisting rock mass corresponding to the cumulative probability exceeding a certain value as the thickness of the water-resisting rock mass corresponding to each model, making the thickness of the water-resisting rock mass corresponding to each model obtained more accurate. When determining the final thickness of the water-resisting rock mass through the more accurate thickness of the water-resisting rock mass corresponding to each model, the accuracy of the determination of the thickness of the water-resisting rock mass is further improved. The present invention analyzes the data of the calculation parameter data set through three calculation models of the water-resisting rock mass respectively, and uses the obtained thickness of the water-resisting rock mass as the construction reference value, which can effectively guide the construction of the water-resisting rock mass. The advantages of the additional aspects of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application.

[0029] Figure 1 It is a flowchart of the disclosed method for the embodiment; Figure 2 It is a diagram showing the development of solution cavities in Yesanguan Tunnel;

[0030] Figure 3 It is a probability distribution diagram of the thickness of the water-resisting rock mass calculated by different calculation models of the water-resisting rock mass. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] Embodiment 1

[0035] When a tunnel crosses a karst area, it is often affected by complex geological conditions and other factors and will encounter large-scale geological disasters such as water inrush and mud gushing. Tunnel water inrush, with its high incidence, suddenness, and great harm, seriously restricts the development of underground engineering construction in karst areas. Compared with geological disasters such as tunnel collapses and rock bursts, water inrush disasters are the most serious among various types of tunnel disasters, and their harms are mainly manifested in the following aspects: First, it endangers construction safety; second, it causes ground settlement or collapse; third, it reduces and depletes water resources above the ground; fourth, it leads to water pollution.

[0036] The basic characteristics of karst water are abundant water volume but uneven distribution, and the dynamic changes in the storage area are very large. At the same time, the water-bearing structures in karst areas have various forms, ranging from small solution gaps and fissures to large solution cavities and solution pipes, with diverse horizontal and vertical forms, and they are often closely interconnected. Coupled with the participation of different surrounding geological structures, the water-bearing structures in karst areas and the recharge, runoff, and discharge relationships of karst water are extremely complex. Based on the above characteristics, it is very difficult to predict and control tunnel water inrush disasters in karst areas.

[0037] In the field of prevention and control of tunnel water inrush in karst areas, the safe thickness of the water-inrush prevention layer is a very key concept. How to reasonably determine the distance between the tunnel structure and the water-bearing geological body is a very core concept and construction index, and proper application can play an important role in water-inrush prevention. When there is a karst water-bearing structure near the tunnel, the stability of the surrounding rock (i.e., the water-inrush prevention layer) between it and the tunnel is the key to preventing water inrush. If the thickness of the water-inrush prevention layer is too small, it is difficult to resist the combined action of excavation and karst water, and serious losses are often suffered due to sudden water inrush and mud gushing. However, if the thickness of the water-inrush prevention layer is too large, it lacks economy and brings inconvenience and waste to the subsequent treatment work of the water-bearing structure. The water-inrush prevention layer generally shows in water-inrush prevention that when advanced prediction means (such as geophysical exploration or advanced drilling) detect the existence of a water-bearing structure ahead, a certain thickness of the water-inrush prevention layer needs to be reserved for the next treatment work. At this time, the reasonable thickness of the water-inrush prevention layer helps to ensure both economy and safety.

[0038] At present, there is no unified and standardized calculation method for the water-inrush prevention and water-resisting rock mass in tunnels. The research on the minimum safety thickness of the water-inrush prevention rock stratum mainly starts from two aspects: one is to study the influence of the morphology, distribution trend, groundwater conditions and geological environment of the karst cave itself on the tunnel surrounding rock; the other is to study the physical and mechanical properties, rock mass integrity, joint fissure conditions and external engineering loads of the rock stratum through which the tunnel passes, etc., which are related to the safety thickness of the water-inrush prevention layer. The current calculation methods mainly determine the minimum safety thickness through theoretical analysis (qualitative analysis method, semi-quantitative analysis method, quantitative analysis method), numerical simulation method (studying different surrounding rock grades and different spatial positions of water-bearing structures), and physical simulation method, and a large number of beneficial results have been obtained. In addition, through the study of the minimum safety thickness of the fissured rock mass between the tunnel face and the high-pressure water-bearing body in karst tunnels, the "two-zone" theory is proposed, and a calculation formula that reasonably reflects the minimum safety thickness of the cracked rock mass under blasting excavation disturbance and water pressure action is derived, and it is verified by engineering examples. Li Lang et al. established a mechanical model for the minimum safety thickness of the water-inrush prevention rock disk, and adopted the similar model test method to carry out a series of model tests on the water-inrush prevention rock disk for the water inrush and gushing disasters in front of the tunnel face. By focusing on studying the failure mode and failure mechanism of the rock stratum under the coupling action of earthquake and karst water pressure, theoretical models for the minimum safety thickness of the rock stratum between the free face and the filled karst cave are established by using the quasi-static method, elastic mechanics method and Bishop method. Zhang Qun simulated the water-inrush process of the tunnel by using a finite element program that can consider fluid-solid coupling, and established a calculation model for the minimum safety thickness of the water-inrush prevention rock stratum by using multiple linear fitting and theoretical analysis. Chu Handong studied the variation law of the thickness of the water-resisting rock mass with different surrounding rock grades based on numerical simulation, and fitted the calculation formula for the thickness of the water-resisting rock mass.

[0039] In short, in the above research, the parameters of the tunnel surrounding rock are mostly input as a fixed value to consider the failure characteristics of the rock mass structure. However, the rock mass in nature has the typical characteristic of heterogeneity. The existing research fails to fully consider the discontinuity of the rock mass medium and the discreteness of the rock mass parameters, and the guiding effect of the theoretical calculation results on practical engineering is generally average.

[0040] In view of the engineering problem of the safety thickness of the water-resisting rock mass for the tunnel water-inrush disaster, this embodiment proposes a method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters on the basis of considering the discreteness and uncertainty of rock mass parameters. First, three classic calculation models for the thickness of the water-resisting rock mass are summarized, the concept of rock mass homogeneity is introduced, the calculation method of rock mass homogeneity is determined, a method for determining the probability parameters of the rock mass based on rock mass homogeneity is proposed, and a probability analysis method for the safety thickness of water-inrush prevention is established based on the classic calculation model for the thickness of the water-resisting rock mass. Finally, the accuracy of the established method is verified through typical engineering cases.

[0041] A detailed description is given to the method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters disclosed in this embodiment.

[0042] Method for determining thickness of water-resisting rock mass considering uncertainty of rock mass parameters, comprising:

[0043] S1: Obtain the rock mass integrity coefficient and multiple groups of rock mass parameters at the position of the water-bearing body.

[0044] Specifically:

[0045] Determine the position of the water-bearing body through advanced geological prediction.

[0046] Determine the rock mass integrity coefficient and multiple groups of rock mass parameters through engineering geological investigation and laboratory tests.

[0047] Each group of rock mass parameters includes the surrounding rock grade, elastic modulus, Poisson's ratio, tensile strength, cohesion, friction angle, and saturated uniaxial compressive strength of the surrounding rock.

[0048] The multiple groups of rock mass parameters are the rock mass parameters at different position points at the position of the water-bearing body.

[0049] The rock mass integrity coefficient can be determined by wave velocity on site. Given that there is little relevant research on the homogeneity of rock mass at present, if this parameter of the rock mass integrity coefficient is not involved in the actual project, the rock mass integrity coefficient is determined according to the surrounding rock grade on site. The rock integrity coefficient is determined by taking the average of the upper and lower limits of the classification standard. Table 1 shows the rock mass classification standard commonly used in engineering based on the rock mass integrity coefficient.

[0050] Table 1 Rock mass classification standard commonly used in engineering based on rock mass integrity coefficient

[0051]

[0052] In addition, data such as tunnel structure parameters and water-bearing structure parameters at the position of the water-bearing body also need to be obtained for subsequent calculation of the thickness of the water-resisting rock mass.

[0053] The tunnel structure parameters include the cross-section width, cross-section height, and tunnel depth of the tunnel.

[0054] The water-bearing structure parameters include the cavity water pressure of the water-bearing structure.

[0055] S2: Determine the rock mass homogeneity according to the rock mass integrity coefficient.

[0056] Specifically:

[0057] Introduce the concept of homogeneity into the rock mass. The rock mass homogeneity mIt can represent the integrity of the rock mass, that is, the higher the rock mass homogeneity, the lower the development degree of structural planes in the rock mass, and the better the integrity of the rock mass; on the contrary, the lower the rock mass homogeneity, the higher the development degree of structural planes in the rock mass, and the worse the integrity of the rock mass. Thus, the concept of rock mass integrity can be borrowed to express the rock mass homogeneity. Combining with the engineering rock mass classification standard, when the rock mass quality is at grade II or above, the rock mass integrity Kv > 0.55. As shown in Table 1, taking the boundary of grade II surrounding rock as the standard, the relationship between rock mass integrity Kv and rock mass homogeneity m can be defined as:

[0058] (1)

[0059] Substitute the obtained rock mass integrity coefficient into formula (1), and the rock mass homogeneity can be calculated.

[0060] S3: Through the rock mass homogeneity, multiple groups of rock mass parameters and the Weibull probability density distribution function, determine the probability distribution of rock mass parameters. Taking the rock mass parameters corresponding to the maximum probability as the center, determine the interval of rock mass parameters when the sum of probabilities is the set value, and select rock mass parameters from this parameter interval to form a calculation parameter data set. Among them, input the rock mass homogeneity and multiple groups of rock mass parameters into the Weibull probability density distribution function to calculate the probability distribution of rock mass parameters. The Weibull probability density distribution function is constructed using the three-parameter Weibull distribution function.

[0061] Specifically: As a natural heterogeneous material, rock has its mesoscopic structural characteristics and local mechanical properties. Macroscopically, the deformation and failure process of the rock mass is actually a process of gradual accumulation of micro-damage. The results of a large number of rock mechanics tests show that the strength distribution of rock-like materials has a large discreteness. Therefore, the method of probability statistics can be used to study the heterogeneity of the rock mass. The classical statistical methods applied to the field of rock mechanics include the lognormal distribution theory and the Weibull distribution theory. Among them, after W. Weibull carried out fundamental research based on the weakest link principle in 1939, the research results of later scholars found that this theory can well describe the strength characteristics of materials. At present, the Weibull distribution theory has been widely applied. Assuming that under the action of structural planes, the rock mass parameters of its elementary rock mass conform to the Weibull probability density distribution, it can be expressed as:

[0062] (2)

[0063] Among them, X is the rock mass parameter of the basic unit of the rock mass, including elastic modulus, compressive strength, tensile strength, etc., X 0 and mis the Weibull distribution parameter. m is the rock mass homogeneity, determined by S2, X 0 is the actual rock mass parameter measured on site and is the rock mass parameter obtained from S1.

[0064] Substitute the rock mass parameters obtained from S1 and the rock mass homogeneity obtained from S2 into formula (2) to calculate the probability distribution of each group of rock mass parameters.

[0065] Taking the rock mass parameter corresponding to the maximum probability as the center, determine the rock mass parameter interval when the probability sum is the set value, and select the rock mass parameters from this parameter interval to form the calculation parameter data set.

[0066] Since, in the Weibull distribution function of the physical and mechanical parameters of the rock mass, if the sum of the probabilities of its distribution function exceeds 80% within a certain upper and lower bound, it can represent the inhomogeneity of the mechanical properties of the rock mass in nature. Therefore, in this embodiment, the set value is set to 80%.

[0067] The process of solving and determining the distribution function of the Weibull distribution function within 80% is as follows: Based on formula (2), extract specific m and X The maximum probability of the rock mass parameter under 0, and then based on this maximum probability, start cycling with a step size of 0.001, and calculate downward the lower limit rock mass parameter X 1 and the upper limit rock mass parameter X 2 corresponding to a certain probability respectively, and then perform definite integration on the probability in the X 1, X 2] interval, then the total probability corresponding to the X 1, X 2] interval can be obtained. When the total probability is greater than the set value, jump out of the loop. At this time, X 1, X 2 are the upper and lower boundaries of the corresponding parameter interval.

[0068] Perform fixed equal division on the obtained parameter interval X 1, X 2] to obtain multiple partition intervals, and the demarcation points of each interval are the selected rock mass parameters, forming the calculation parameter data set.

[0069] S4: Analyze the calculation parameter data set through different water - resisting rock mass calculation models to obtain the water - resisting rock mass thickness corresponding to each model, and determine the final water - resisting rock mass thickness according to the water - resisting rock mass thickness corresponding to each model.

[0070] Since the concept of the thickness of the self-sealing rock mass was proposed, it has received extensive attention due to its importance in the safe construction of tunnels. In response to the adverse geology of a water-rich solution cavity existing in front of the heading face, after conducting a mechanical analysis of the water inrush process, three typical mechanical models of the water-sealing rock mass were established based on strength theory, shear theory, and catastrophe theory.

[0071] The calculation models of the water-sealing rock mass adopted in this embodiment are the calculation model of the water-sealing rock mass based on strength theory, the calculation model of the water-sealing rock mass based on shear theory, and the calculation model of the water-sealing rock mass based on catastrophe theory.

[0072] The calculation model of the water-sealing rock mass based on strength theory is:

[0073] (3)

[0074] Where: is the Poisson's ratio of the water-sealing rock mass, is the water pressure in the solution cavity of the water-bearing structure, is the tensile stress of the water-sealing rock mass.

[0075] The calculation model of the water-sealing rock mass based on shear theory is:

[0076] (4)

[0077] Where D is the end face height of the tunnel, is the friction angle of the surrounding rock.

[0078] The calculation model of the water-sealing rock mass based on catastrophe theory is:

[0079] (5)

[0080] Where E is the elastic modulus of the water-sealing rock mass.

[0081] Substitute the calculation parameter data set selected by S3 into different calculation models of the water-sealing rock mass to obtain the thickness of the water-sealing rock mass corresponding to each model.

[0082] According to the thickness of the water-sealing rock mass corresponding to each model, determine the final thickness of the water-sealing rock mass. The specific process is as follows:

[0083] Determine the probability distribution of the thickness of the water-sealing rock mass corresponding to each model, and based on this probability distribution, determine the thickness of the water-sealing rock mass determined by each model;

[0084] Select the maximum value from the thicknesses of the water-sealing rock mass determined by each model as the final thickness of the water-sealing rock mass.

[0085] The process of determining the probability distribution of the thickness of the water-sealing rock mass corresponding to each model is:

[0086] Determine the maximum and minimum values of the thickness of the water-resisting rock mass corresponding to each model. Taking the minimum value as the lower limit and the maximum value as the upper limit, determine the thickness interval of the water-resisting rock mass corresponding to each model. Divide each thickness interval of the water-resisting rock mass into multiple equally spaced small intervals, determine the probability of the thickness of the water-resisting rock mass appearing in each small interval, and obtain the probability distribution of the thickness of the water-resisting rock mass corresponding to each model.

[0087] For the thickness of the water-resisting rock mass corresponding to each model, select the thickness of the water-resisting rock mass corresponding to the cumulative probability exceeding a certain value from the probability distribution of the thickness of the water-resisting rock mass corresponding to this model as the thickness of the water-resisting rock mass determined for this model.

[0088] Compare and verify the method for determining the thickness of the water-resisting rock mass disclosed in this embodiment with the data of actual projects.

[0089] The selected actual project is the Yesanguan Tunnel Project. The Yesanguan Tunnel crosses about 8.77 km of limestone strata, accounting for 63% of the tunnel. There are developed underground rivers, karst cavities and fault zones in the tunnel site area. Among them, the No. 3 underground river has a good hydraulic connection with the "+602" karst cavity, making the tunnel at the "+602" karst cavity section have a huge risk of water inrush and mud gushing, as Figure 2 shown. When tunneling to the karst cavity at DK124 + 602, a large-scale water inrush occurred near the tunnel face, accompanied by a large amount of mud, sand and boulders gushing out. The water inrush volume reached 151,000 m 3 in only half an hour, and the volume of mud and rock gushing out reached 53,500 m 3 . After that, the karst water volume fluctuated, and dropped to about 260,000 m 3 / d the next day. Considering the characteristics of the large scale, high water pressure and complex and large amount of fillers of the "+602" karst cavity. Finally, in order to make full use of the convenient conditions in the dry season, it was determined to take a drainage tunnel to directly reveal the karst cave for drainage and energy dissipation. The relevant parameters of the drainage tunnel are shown in Table 2.

[0090] Table 2 Statistical parameters of Yesanguan Tunnel

[0091]

[0092] The calculation results show that when not considering the rock mass homogeneity, the thickness of the water-resisting rock mass determined based on the strength theory is 2.37 m. When considering the rock mass homogeneity, the range of the thickness of the water-resisting rock mass determined based on the strength theory is [1.87, 4.47]. Divide the above range into 10 intervals, and the specific values are (1.87, 2.13, 2.39, 2.65, 2.91, 3.17, 3.43, 3.69, 3.95, 4.21, 4.47). Calculate the probability of the water-resisting rock mass appearing in the 10 intervals as (16.3%, 28.9%, 21.4%, 14.6%, 8.4%, 4.6%, 3.1%, 1.5%, 0.5%, 0.7 %), as Figure 3 shown in (a) of

[0093] When the rock mass homogeneity is not considered, the thickness of the water-resisting rock mass determined based on the shear theory is 0.58 m. When the rock mass homogeneity is considered, the minimum range of the thickness of the water-resisting rock mass determined based on the shear theory is [0.37, 1.26]. The above range is divided into 10 intervals, and the specific values are (0.50, 0.53, 0.55, 0.58, 0.60, 0.63, 0.66, 0.68, 0.71, 0.73, 0.76). The probabilities of the water-resisting rock mass appearing in the 10 intervals are calculated as (2.1%, 9.1%, 17.0%, 20.6%, 18.7%, 14.4%, 9.6%, 5.4%, 2.3%, 0.7%), as shown in Figure 3 Figure (b) below.

[0094] When the rock mass homogeneity is not considered, the thickness of the water-resisting rock mass determined based on the catastrophe theory is 0.87 m. When the rock mass homogeneity is considered, the thickness range of the water-resisting rock mass determined based on the catastrophe theory is [0.83, 0.96]. The above range is divided into 10 intervals, and the specific values are (0.83, 0.84, 0.85, 0.87, 0.88, 0.89, 0.91, 0.92, 0.93, 0.95, 0.96). The probabilities of the water-resisting rock mass appearing in the 10 intervals are calculated as (8.3%, 11.2%, 13.5%, 13.7%, 12.7%, 11.0%, 10.4%, 7.6%, 6.4%, 5.2%), as shown in Figure 3 Figure (c) below.

[0095] The method for determining the thickness of the water-resisting rock mass disclosed in this embodiment can consider the probabilities of the rock mass parameters, and calculate the thickness and range of the water-resisting rock mass under various parameter composite conditions. In actual engineering, the thickness of the water-resisting rock mass adopted at the face of Yeshan Pass Tunnel is 2.4 - 3.0 m. Table 3 shows that the thickness of the water-resisting rock mass calculated based on the strength theory is closer to the actual situation, and there is a certain safety factor, making the project safer. The results based on the catastrophe theory and the shear theory are about half of the reserved value, and further discussion is needed in practical use.

[0096] Table 3 Calculation results of the thickness of the water-resisting rock mass based on probability analysis

[0097]

[0098] Therefore, it is recommended that in the actual use process, especially for the structures calculated by the shear model and the catastrophe model, the thickness of the water-resisting rock mass should be set based on the maximum calculated value.

[0099] Combined with the method for determining the thickness of the water-resisting rock mass proposed in this embodiment, when encountering bad geological bodies on site, the recommended on-site practical application process Figure 1As shown in the figure. First, based on the results of advanced geological prediction and engineering geological exploration, the spatial position relationship between the tunnel and the water-bearing body is determined. The tunnel structure parameters, rock mass parameters, and water-bearing structure parameters are obtained through laboratory tests and in-situ tests. Then, two aspects of research are continued. The first aspect: combining the above parameters to conduct a risk assessment of the water and mud inrush disasters occurring at the site. The second aspect: combining the above parameters and the method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters proposed in this embodiment, calculating the thickness of the water-resisting rock mass as the minimum safety thickness to guide the construction.

[0100] In the method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters disclosed in this embodiment, when calculating the thickness of the water-resisting rock mass, the discreteness and uncertainty of rock mass parameters are considered. Multiple groups of rock mass parameters are collected from the position of the water-bearing body, and the probability distribution of the rock mass parameters is calculated. Rock mass parameters are selected from multiple groups of rock mass parameters according to the probability distribution to form a calculation parameter data set, and then the thickness of the water-resisting rock mass is accurately calculated. This thickness of the water-resisting rock mass is more in line with the actual project and can effectively guide the on-site construction. In addition, the present invention also considers the calculation errors of different calculation models for the water-resisting rock mass. By analyzing the calculation parameter data set through different calculation models for the water-resisting rock mass, the thickness of the water-resisting rock mass corresponding to each model is determined. Then, the maximum value among the thicknesses of the water-resisting rock mass corresponding to different models is selected as the final thickness of the water-resisting rock mass, effectively ensuring the accuracy of the determination of the thickness of the water-resisting rock mass and better adapting to the actual project. And when determining the thickness of the water-resisting rock mass corresponding to each model, the probability distribution of the thickness of the water-resisting rock mass is calculated, and the thickness of the water-resisting rock mass corresponding to the cumulative probability exceeding a certain value is selected as the thickness of the water-resisting rock mass corresponding to each model, making the thickness of the water-resisting rock mass corresponding to each model obtained more accurate. When determining the final thickness of the water-resisting rock mass through the more accurate thickness of the water-resisting rock mass corresponding to each model, the accuracy of the determination of the thickness of the water-resisting rock mass is further improved.

[0101] Embodiment 2

[0102] In this embodiment, a method for determining the construction risk level of the water-resisting rock mass considering the uncertainty of rock mass parameters is disclosed, including:

[0103] Determine the final thickness of the water-resisting rock mass through the method for determining the thickness of the water-resisting rock mass disclosed in Embodiment 1;

[0104] Among them, the thickness of the water-resisting rock mass calculated by the calculation model of the water-resisting rock mass based on the strength theory is used as the first reference value;

[0105] The minimum value among the thicknesses of the water-resisting rock mass calculated by the calculation model of the water-resisting rock mass based on the shear theory and the calculation model of the water-resisting rock mass based on the catastrophe theory is used as the second reference value;

[0106] When the distance between the tunnel face and the water-bearing solution cavity is less than the first reference value and greater than the second reference value, the construction safety risk level is determined to be a major risk level;

[0107] When the distance between the tunnel face and the water-bearing solution cavity is less than the second reference value, the construction safety risk level is determined to be an extreme risk level.

[0108] Specifically, in the actual engineering application, without considering the influence of blasting, the calculation result of the strength theory model can be used as a relatively safe value to guide the construction. In addition, the calculation results of the catastrophe theory and the shear theory are used as a lower limit value in the actual application. When the distance between the tunnel face and the water-bearing solution cavity is less than the first reference value and greater than the second reference value, the construction safety risk level at the construction site should be raised to the major risk level. When it is less than the second reference value, the construction safety risk level at the construction site should be raised to the extreme risk level, and the construction should be stopped immediately and the personnel should be evacuated.

[0109] Embodiment 3

[0110] In this embodiment, a system for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters is disclosed, including:

[0111] A data acquisition module for acquiring the rock mass integrity coefficient and multiple groups of rock mass parameters at the position of the water-bearing body;

[0112] A rock mass homogeneity acquisition module for determining the rock mass homogeneity according to the rock mass integrity coefficient;

[0113] A calculation parameter data set acquisition module for determining the probability distribution of rock mass parameters through the rock mass homogeneity, multiple groups of rock mass parameters and the Weibull probability density distribution function, taking the rock mass parameters corresponding to the maximum probability as the center, determining the rock mass parameter interval when the sum of probabilities is a set value, and selecting rock mass parameters from this parameter interval to form a calculation parameter data set;

[0114] A water-resisting rock mass thickness determination module for analyzing the calculation parameter data set through different water-resisting rock mass calculation models, obtaining the water-resisting rock mass thickness corresponding to each model, and determining the final water-resisting rock mass thickness according to the water-resisting rock mass thickness corresponding to each model.

[0115] Embodiment 4

[0116] In this embodiment, an electronic device is disclosed, including a memory, a processor, and computer instructions stored on the memory and running on the processor. When the computer instructions are run by the processor, the steps of the method for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters disclosed in Embodiment 1 are completed.

[0117] Embodiment 5

[0118] In this embodiment, a computer-readable storage medium is disclosed for storing computer instructions, which, when executed by a processor, complete the steps of the method for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters disclosed in Embodiment 1.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for determining the thickness of a water-resisting rock mass considering the uncertainty of rock mass parameters, characterized in that, Including: Obtaining the rock mass integrity coefficient and multiple groups of rock mass parameters at the position of the water-bearing body; Determining the rock mass homogeneity according to the rock mass integrity coefficient; Through the rock mass homogeneity, multiple groups of rock mass parameters and the Weibull probability density distribution function, determining the probability distribution of the rock mass parameters, taking the rock mass parameters corresponding to the maximum probability as the center, determining the rock mass parameter interval when the sum of probabilities is a set value, and selecting the rock mass parameters from this parameter interval to form a calculation parameter data set; Analyzing the calculation parameter data set through different water-resisting rock mass calculation models, obtaining the water-resisting rock mass thickness corresponding to each model, and determining the final water-resisting rock mass thickness according to the water-resisting rock mass thickness T corresponding to each model; The water-resisting rock mass calculation models are the water-resisting rock mass calculation model based on strength theory, the water-resisting rock mass calculation model based on shear theory and the water-resisting rock mass calculation model based on catastrophe theory; The water-resisting rock mass calculation model based on strength theory is: （3） Wherein: is the Poisson's ratio of the water-resisting rock mass, is the water pressure in the solution cavity of the water-bearing structure, is the tensile stress of the water-resisting rock mass; The water-resisting rock mass calculation model based on shear theory is: （4） Where: D is the end face height of the tunnel, is the friction angle of the surrounding rock; The water-resisting rock mass calculation model based on catastrophe theory is: （5） Wherein, E is the elastic modulus of the water-resisting rock mass.

2. The method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters as claimed in claim 1, wherein The specific process of determining the final water-resisting rock mass thickness according to the water-resisting rock mass thickness corresponding to each model is: Determining the probability distribution of the water-resisting rock mass thickness corresponding to each model, and determining the water-resisting rock mass thickness determined by each model according to this probability distribution; Selecting the maximum value from the water-resisting rock mass thicknesses determined by each model as the final water-resisting rock mass thickness.

3. The method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters according to claim 2, characterized in that, The process of determining the probability distribution of the water-resisting rock mass thickness corresponding to each model is: Determining the maximum value and the minimum value of the water-resisting rock mass thickness; Taking the minimum value as the lower limit and the maximum value as the upper limit to determine the minimum thickness interval of the water-resisting rock mass; Dividing the minimum thickness interval into multiple equally spaced small intervals; Determining the probability that the water-resisting rock mass thickness appears in each small interval, and obtaining the probability distribution of the water-resisting rock mass thickness.

4. The method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters according to claim 2, wherein For the water-resisting rock mass thickness corresponding to each model, selecting the water-resisting rock mass thickness corresponding to the cumulative probability exceeding a certain value from the probability distribution of the water-resisting rock mass thickness corresponding to this model as the water-resisting rock mass thickness determined by this model.

5. The method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters according to claim 1, characterized in that, The Weibull probability density distribution function is constructed by using the three-parameter Weibull distribution function.

6. Method for determining construction risk level of water-resisting rock mass considering uncertainty of rock mass parameters, characterized in that, Including: Determining the final water-resisting rock mass thickness by the method described in any one of claims 1-5; Wherein, taking the water-resisting rock mass thickness calculated by the water-resisting rock mass calculation model based on strength theory as the first reference value; Taking the minimum value of the water-resisting rock mass thicknesses calculated by the water-resisting rock mass calculation model based on shear theory and the water-resisting rock mass calculation model based on catastrophe theory as the second reference value; When the distance between the tunnel face and the water-bearing cavity is less than the first reference value and greater than the second reference value, determining that the construction safety risk level is a major risk level; When the distance between the tunnel face and the water-bearing cavity is less than the second reference value, determining that the construction safety risk level is an extremely high risk level.

7. A system for determining the thickness of an impermeable rock mass considering the uncertainty of rock mass parameters, characterized in that, Including: A data acquisition module for acquiring the rock mass integrity coefficient and multiple groups of rock mass parameters at the position of the water-bearing body; A rock mass homogeneity acquisition module for determining the rock mass homogeneity according to the rock mass integrity coefficient; The calculation parameter data set acquisition module is used to determine the probability distribution of rock mass parameters through the rock mass homogeneity, multiple groups of rock mass parameters and the Weibull probability density distribution function, determine the rock mass parameter interval when the sum of probabilities is a set value with the rock mass parameters corresponding to the maximum probability as the center, and select rock mass parameters from this parameter interval to form a calculation parameter data set; The water-resisting rock mass thickness determination module is used to analyze the calculation parameter data set through different water-resisting rock mass calculation models, obtain the water-resisting rock mass thickness corresponding to each model, and determine the final water-resisting rock mass thickness according to the water-resisting rock mass thickness corresponding to each model; The water-resisting rock mass calculation models are the water-resisting rock mass calculation model based on strength theory, the water-resisting rock mass calculation model based on shear theory and the water-resisting rock mass calculation model based on catastrophe theory; The water-resisting rock mass calculation model based on strength theory is: （3） Wherein: is the Poisson's ratio of the water-resisting rock mass, is the water pressure in the solution cavity of the water-bearing structure, is the tensile stress of the water-resisting rock mass; The water-resisting rock mass calculation model based on shear theory is: （4） Where: D is the end face height of the tunnel, is the friction angle of the surrounding rock; The water-resisting rock mass calculation model based on catastrophe theory is: （5） Wherein, E is the elastic modulus of the water-resisting rock mass.

8. An electronic device, characterized in that, It includes a memory, a processor and computer instructions stored on the memory and running on the processor. When the computer instructions are run by the processor, the steps of the method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters according to any one of claims 1-5 are completed.

9. A computer-readable storage medium, characterized in that, It is used to store computer instructions. When the computer instructions are executed by the processor, the steps of the method for determining the thickness of the water-resisting rock mass considering the uncertainty of rock mass parameters according to any one of claims 1-5 are completed.

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