A method, device and system for quantitatively and rapidly evaluating stress grade of tunnel

Abstract

The application discloses a kind of tunnel ground stress grade quantitative fast evaluation method, device and system, it is related to geological survey technical field.The method is first to collect the field point related information of survey point core and the secondary stress of surrounding rock obtained by stress recovery test equipment first to the survey point core stress recovery test and the transverse compressive strength obtained by transverse compressive strength test, then according to these data, vertical ground stress, initial ground stress in the horizontal direction of vertical hole axis and correction strength stress ratio are sequentially calculated, finally, according to correction strength stress ratio and the known mapping relationship between ground stress grade and correction strength stress ratio, the ground stress grade of the region where survey point is located is determined, so only a small hole is needed to be drilled for stress relief during tunnel construction, without deep hole, with the advantages of low test cost, can be applied in high ground stress hard rock tunnel and can quickly obtain high ground stress identification result in the field.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geological survey, and particularly relates to a tunnel ground stress grade quantitative rapid evaluation method, device and system based on secondary stress and transverse compressive strength test. BACKGROUND

[0002] In recent years, with the construction of a large number of deep underground projects in China, a series of major disasters caused by high ground stress, such as rock burst and other geological disasters, are increasing. The occurrence of these disasters not only brings great threat to the on-site personnel, but also seriously delays the construction period. Therefore, how to timely and effectively evaluate the ground stress state during the tunnel construction process is particularly important.

[0003] At present, the ground stress grade of a tunnel is mainly determined by the initial ground stress size, high ground stress geological appearance and strength stress ratio during the tunnel construction process.

[0004] Based on the initial ground stress size, the initial ground stress of the rock mass needs to be actually measured, such as using the water pressure cracking method to test the initial ground stress. The drilling depth needs to reach hundreds of meters according to the different tunnel burial depths, the test time is as long as 10-30 days, the cost of a single drilling test is as high as 400-500 thousand yuan, and the test is generally carried out during the survey and design period. Although the hollow inclusion triaxial strain gauge method can be used to measure the initial ground stress during the construction period, the drilling depth needs to reach 20-30 meters, the drilling needs to be assisted by large machinery, and the cost of a single test is about 300 thousand yuan. The above two methods cannot be widely applied to the measurement of the initial ground stress of all tunnels due to the economic cost and test time.

[0005] Based on the high ground stress geological appearance, many high ground stress phenomena cannot be observed at the first time, the disaster occurrence has time lag, and it is a qualitative discrimination. The on-site experience of the discriminant personnel is required to be high, the human factor is large, and the relationship between the severity of the geological appearance and the high ground stress grade is not considered.

[0006] Based on the strength stress ratio, the maximum initial ground stress value in the vertical direction of the tunnel axis also needs to be measured, and the same problems of long test time and high economic cost of tens of thousands of yuan in measuring the initial ground stress exist. At the same time, the uniaxial compressive strength of the rock needs to be measured in the laboratory. When measuring the uniaxial compressive strength of the rock, the rock sampling needs to be carried out on site and sent back to the laboratory for sample preparation, which needs to consume a certain time. In the process of rock sample transportation and sample preparation, a certain disturbance is generated, which leads to a certain gap between the in-situ mechanical parameters of the rock mass and the on-site conditions of the tunnel.

[0007] The three existing technologies for distinguishing high ground stress levels have different problems, such as deep drilling depth, difficult drilling, inability to quickly obtain reference data for providing guidance for on-site construction due to long testing time, and inability to test all high ground stress tunnels due to high economic cost. SUMMARY

[0008] The purpose of the present application is to provide a tunnel ground stress level quantitative rapid evaluation method, device, system, computer equipment, computer readable storage medium and computer program product, to solve the problems of high cost and long time of existing high ground stress level distinguishing schemes.

[0009] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0010] In a first aspect, a tunnel ground stress level quantitative rapid evaluation method is provided, comprising:

[0011] Collecting on-site measurement point related information of a measurement point core and secondary stress of surrounding rock obtained by stress recovery testing equipment on the measurement point core and transverse compressive strength obtained by transverse compressive strength testing, wherein the measurement point core refers to a core obtained by stress relief and removal from a measurement point behind the tunnel face of the tunnel pilot excavation site, the area where the measurement point is located is between the tunnel pilot and the tunnel main tunnel, and the on-site measurement point related information includes rock mass self weight of the measurement point core, rock mass burial depth of the measurement point core, tunnel surrounding rock grade of the tunnel pilot, and distance of the tunnel pilot ahead of the tunnel main tunnel;

[0012] According to the rock mass self weight and rock mass burial depth of the measurement point core, the vertical ground stress S is calculated according to the following formula Z :

[0013] S Z = γ × h

[0014] In the formula, γ represents the rock mass self weight of the measurement point core, and h represents the rock mass burial depth of the measurement point core;

[0015] According to the vertical ground stress S Z and the vertical secondary stress S zz in the secondary stress of surrounding rock, the initial ground stress S X in the vertical tunnel axis horizontal direction is calculated according to the following formula :

[0016] S X = c1 × (m × S Z - n × e × S zz )

[0017] wherein, c1 represents a first calculation parameter determined according to the tunnel surrounding rock grade and negatively correlated with the tunnel surrounding rock grade, m represents a preset second calculation parameter, n represents a preset third calculation parameter, and e represents a fourth calculation coefficient determined according to the distance and negatively correlated with the distance;

[0018] According to the lateral compressive strength, the vertical ground stress S Z and the initial ground stress S X , a modified strength stress ratio CSSR is calculated according to the following formula:

[0019] CSSR = R b ÷ max(S Z , S X )

[0020] wherein, R b represents the lateral compressive strength, and max() represents a maximum value function;

[0021] According to the modified strength stress ratio CSSR and a known mapping relationship between the ground stress grade and the modified strength stress ratio, a ground stress grade of a region where the measuring point is located is determined.

[0022] Based on the above invention content, a new scheme for quickly identifying the ground stress grade of a tunnel based on the secondary stress and the lateral compressive strength test results is provided, that is, first, the field measuring point related information of the measuring point core and the surrounding rock secondary stress obtained by the stress recovery test equipment on the measuring point core and the lateral compressive strength obtained by the lateral compressive strength test are collected, then the vertical ground stress, the initial ground stress in the vertical hole axis horizontal direction and the modified strength stress ratio are calculated in sequence according to these data, and finally, the ground stress grade of the region where the measuring point is located is determined according to the modified strength stress ratio and a known mapping relationship between the ground stress grade and the modified strength stress ratio. In this way, only a small round hole needs to be drilled for stress relief during the tunnel site construction, without the need to drill a deep hole, and all test data can be obtained on site, so that the process is simple and fast, and does not affect normal construction due to short on-site time, has the advantages of low test cost, can be applied to high ground stress hard rock tunnels, and can quickly obtain high ground stress identification results on site, and is convenient for practical application and promotion.

[0023] In one possible design, the surrounding rock secondary stress is measured in the following manner:

[0024] The stress recovery of the measuring point core is carried out on the tunnel site by using a door plug type stress recovery test equipment, and the stress recovery process is automatically controlled through the strain difference before and after stress relief, and finally the recovery load in the vertical direction is obtained;

[0025] The vertical direction secondary stress S is calculated according to the following stress calculation formula zz The secondary stress of the surrounding rock is

[0026] S zz = λ × α × β × F Z ÷ A

[0027] In the formula, λ represents a size influence coefficient determined according to the diameter of the measurement point core and positively correlated with the diameter, α represents a stress equivalent coefficient quantified according to the equivalent elastic modulus of the measurement point core and positively correlated with the quantified equivalent elastic modulus, β represents a confining pressure influence coefficient according to the confining pressure of the measurement point core and positively correlated with the confining pressure, F Z represents the recovery load in the vertical direction when the stress recovery is automatically controlled based on the strain difference to reach a preset strain difference, and A represents the compression area of the measurement point core when compressed in the lateral direction and has A = L × H, L represents the contact width of the saddle-shaped pad of the gate plug type stress recovery test equipment and the measurement point core and has a unit of mm, and H represents the contact height of the saddle-shaped pad and the measurement point core and has a unit of mm.

[0028] In one possible design, the lateral compressive strength is measured in the following manner:

[0029] The measurement point core is placed in the saddle-shaped pad of the gate plug type stress recovery test equipment, and the gate plug type stress recovery test equipment is controlled to compress the measurement point core;

[0030] The load F of the measurement point core when laterally fractured is recorded, and the lateral compressive strength R b of the measurement point core is calculated according to the load F.

[0031] R b = F ÷ A

[0032] In the formula, A represents the compression area of the measurement point core when compressed in the lateral direction and has A = L × H, L represents the contact width of the saddle-shaped pad of the gate plug type stress recovery test equipment and the measurement point core and has a unit of mm, and H represents the contact height of the saddle-shaped pad and the measurement point core and has a unit of mm.

[0033] In a possible design, the first calculation parameter c1 is determined in the following manner: when the tunnel surrounding rock grade is grade II, the first calculation parameter c1 is determined in the numerical range [1.02, 1.14]; when the tunnel surrounding rock grade is grade III, the first calculation parameter c1 is determined in the numerical range [0.97, 1.02]; when the tunnel surrounding rock grade is grade IV, the first calculation parameter c1 is determined in the numerical range [0.89, 0.94]; and when the tunnel surrounding rock grade is grade V, the first calculation parameter c1 is determined in the numerical range [0.83, 0.88];

[0034] And / or, the second calculation parameter m is preset as 2.91.

[0035] And / or, the third calculation parameter n is preset as 1.12.

[0036] And / or, the fourth calculation coefficient e is determined in the following manner: when the distance is less than 20 meters, the fourth calculation coefficient e is determined in the numerical range (0.96, 1.0]; when the distance is greater than or equal to 20 meters and less than 40 meters, the fourth calculation coefficient e is determined in the numerical range (0.94, 0.96]; when the distance is greater than or equal to 40 meters and less than 60 meters, the fourth calculation coefficient e is determined in the numerical range (0.90, 0.94]; when the distance is greater than or equal to 60 meters and less than 80 meters, the fourth calculation coefficient e is determined in the numerical range (0.87, 0.90]; and when the distance is greater than or equal to 80 meters and less than 100 meters, the fourth calculation coefficient e is determined in the numerical range (0.81, 0.87].

[0037] In a possible design, according to the modified intensity stress ratio CSSR and a known mapping relationship between the ground stress grade and the modified intensity stress ratio, a ground stress grade of a region where the measuring point is located is determined, including:

[0038] The known mapping relationship between the ground stress grade and the modified intensity stress ratio is obtained: the modified intensity stress ratio corresponding to a general ground stress grade is greater than 4.5; the modified intensity stress ratio corresponding to a high ground stress grade is greater than 2.5 and less than or equal to 4.5; and the modified intensity stress ratio corresponding to an extremely high ground stress grade is less than or equal to 2.5.

[0039] According to the known mapping relationship, if the corrected intensity stress ratio CSSR is greater than 4.5, it is determined that the ground stress grade of the region where the measuring point is located is a general ground stress grade, if the corrected intensity stress ratio CSSR is greater than 2.5 and less than or equal to 4.5, it is determined that the ground stress grade of the region where the measuring point is located is a high ground stress grade, and if the corrected intensity stress ratio CSSR is less than or equal to 2.5, it is determined that the ground stress grade of the region where the measuring point is located is an extremely high ground stress grade.

[0040] In a second aspect, a device for quantitatively and rapidly evaluating a ground stress grade of a tunnel is provided, which comprises a field information collecting unit, a vertical ground stress calculating unit, an initial ground stress calculating unit, a stress ratio calculating unit and a ground stress grade determining unit.

[0041] The field information collecting unit is configured to collect field measuring point related information of a measuring point core and secondary stress of surrounding rock obtained by stress recovery testing equipment on the measuring point core and transverse compressive strength obtained by transverse compressive strength testing again, wherein the measuring point core refers to a core obtained by stress relief and taken from a measuring point behind a tunnel face of a tunnel pilot, the region where the measuring point is located is between the tunnel pilot and a tunnel main tunnel, and the field measuring point related information includes rock mass self weight of the measuring point core, rock mass burial depth of the measuring point core, tunnel surrounding rock grade of the tunnel pilot and distance of the tunnel pilot ahead of the tunnel main tunnel.

[0042] The vertical ground stress calculating unit is in communication connection with the field information collecting unit and is configured to calculate a vertical ground stress S according to rock mass self weight and rock mass burial depth of the measuring point core according to the following formula. Z

[0043] Z

[0044] In the formula, γ represents the rock mass self weight of the measuring point core, and h represents the rock mass burial depth of the measuring point core.

[0045] The initial ground stress calculating unit is in communication connection with the field information collecting unit and the vertical ground stress calculating unit respectively and is configured to calculate an initial ground stress S in a vertical tunnel axis horizontal direction according to the vertical ground stress S and vertical secondary stress S of the secondary stress of surrounding rock according to the following formula. Z zz X

[0046] X Z zz

[0047] ​​​​​​​​​​In the formula, c1 represents a first calculation parameter determined according to the tunnel surrounding rock grade and negatively correlated with the tunnel surrounding rock grade, m represents a preset second calculation parameter, n represents a preset third calculation parameter, and e represents a fourth calculation coefficient determined according to the distance and negatively correlated with the distance;

[0048] The stress ratio calculation unit is respectively communicatively connected to the field information collection unit and the initial ground stress calculation unit, and is configured to calculate a corrected strength stress ratio CSSR according to the lateral compressive strength, the vertical ground stress S Z , and the initial ground stress S X , according to the following formula:

[0049] CSSR = R b ÷ max(S Z , S X )

[0050] In the formula, R b represents the lateral compressive strength, and max() represents a maximum value function;

[0051] The ground stress grade determination unit is communicatively connected to the stress ratio calculation unit and is configured to determine the ground stress grade of the region where the measuring point is located according to the corrected strength stress ratio CSSR and a known mapping relationship between the ground stress grade and the corrected strength stress ratio.

[0052] In a third aspect, a tunnel ground stress grade quantitative rapid evaluation system is provided, which includes a stress recovery test device and a host computer device that are communicatively connected;

[0053] The stress recovery test device is configured to perform stress recovery testing on a measuring point core to obtain a surrounding rock secondary stress and perform lateral compressive strength testing to obtain a lateral compressive strength, and transmit the surrounding rock secondary stress and the lateral compressive strength to the host computer device. The measuring point core refers to a core obtained by stress relief and removal from a measuring point at a tunnel face behind a tunnel guide excavation site, and the region where the measuring point is located is located between the tunnel guide and a tunnel main tunnel.

[0054] The host computer device is configured to execute the tunnel ground stress grade quantitative rapid evaluation method as described in the first aspect or any possible design of the first aspect.

[0055] In a fourth aspect, the present application provides a computer device, which includes a memory, a processor and a transceiver that are communicatively connected in sequence, wherein the memory is configured to store a computer program, the transceiver is configured to transceive messages, and the processor is configured to read the computer program and execute the tunnel ground stress grade quantitative rapid evaluation method as described in the first aspect or any possible design of the first aspect.

[0056] In a fifth aspect, the present application provides a computer readable storage medium having instructions stored thereon, which when executed on a computer, perform the method for quantitatively and rapidly evaluating the stress grade of a tunnel ground as described in the first aspect or any possible design of the first aspect.

[0057] In a sixth aspect, the present application provides a computer program product comprising a computer program or instructions, which when executed on a computer, implement the method for quantitatively and rapidly evaluating the stress grade of a tunnel ground as described in the first aspect or any possible design of the first aspect.

[0058] The above-mentioned scheme has the following advantages:

[0059] (1) The present application provides a new scheme for rapidly identifying the stress grade of a tunnel ground based on the test results of secondary stress and lateral compressive strength, that is, first collecting the site test point related information of a test point core and the secondary stress of surrounding rock obtained by stress recovery test equipment on the test point core and then performing a lateral compressive strength test to obtain the lateral compressive strength, then sequentially calculating the vertical ground stress, the initial ground stress in the horizontal direction of the vertical hole axis and the modified strength stress ratio according to these data, and finally determining the ground stress grade of the region where the test point is located according to the modified strength stress ratio and the known mapping relationship between the ground stress grade and the modified strength stress ratio. In this way, only a small round hole needs to be drilled for stress relief during tunnel site construction, without the need to drill a deep hole, and all test data can be obtained on site, making the process simple and fast, and not affecting normal construction due to short on-site time. The present application has the advantages of low test cost, application in high ground stress hard rock tunnels and rapid identification of high ground stress on site, and is convenient for practical application and promotion.

[0060] (2) The present application can also provide a modified strength stress ratio for rapidly identifying the stress grade of a tunnel ground, so that the size of the tunnel ground stress can also be quantitatively and rapidly evaluated, providing accurate guidance for site construction. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0062] Figure 1 The flowchart of the method for quantitatively and rapidly evaluating the stress grade of a tunnel ground provided by the embodiments of the present application is shown.

[0063] Figure 2 The position relation example diagram of the measuring point and the tunnel horizontal guide and the tunnel main tunnel provided by the embodiment of the application.

[0064] Figure 3 The structural principle schematic diagram of the secondary stress of the surrounding rock measured by the stress recovery test provided by the embodiment of the application.

[0065] Figure 4 The structural principle schematic diagram of the lateral compressive strength measured by the lateral compressive strength test provided by the embodiment of the application, wherein, Figure 4 (a) in the above figure shows the front structural principle schematic diagram of the lateral compressive strength test, Figure 4 (b) in the above figure shows the side structural principle schematic diagram of the lateral compressive strength test.

[0066] Figure 5 The structural schematic diagram of the tunnel ground stress grade quantitative rapid evaluation device provided by the embodiment of the application.

[0067] Figure 6 The structural schematic diagram of the tunnel ground stress grade quantitative rapid evaluation system provided by the embodiment of the application.

[0068] Figure 7 The structural schematic diagram of the computer device provided by the embodiment of the application.

[0069] In the above figures: 100-tunnel horizontal guide; 200-tunnel main tunnel; 300-site working face; 400-measuring point; 500-the area where the measuring point is located. DETAILED DESCRIPTION

[0070] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the present application will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present application, and for those skilled in the art, other embodiments can also be obtained without creative labor. It should be noted that the description of these embodiment modes is used to help understand the present application, but does not constitute a limitation on the present application.

[0071] It should be understood that although the terms first and second, etc. may be used herein to describe various objects, these objects should not be limited by these terms. These terms are only used to distinguish one object from another object. For example, the first object can be called the second object, and similarly the second object can be called the first object, without departing from the scope of the example embodiments of the present application.

[0072] It should be understood that the term "and / or" that may appear in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, or A and B exist simultaneously. Another example is A, B and / or C, which can mean that any one of A, B, and C or any combination thereof exists. The term " / and" that may appear in this document describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone or A and B exist simultaneously. In addition, the character " / " that may appear in this document generally indicates that the related objects before and after it are in an "or" relationship.

[0073] Example

[0074] like Figures 1-4 As shown, the method for quantitative and rapid assessment of tunnel ground stress level provided in the first aspect of this embodiment can be executed, but is not limited to, by computer equipment with certain computing resources, such as platform servers, personal computers (PCs, referring to a type of multi-purpose computer suitable for personal use in terms of size, price, and performance; desktop computers, laptops, mini-laptops, tablets, and ultrabooks are all considered personal computers), smartphones, personal digital assistants (PDAs), or wearable devices. Figure 1 As shown, the method for quantitative and rapid assessment of tunnel ground stress level may include, but is not limited to, the following steps S1 to S5.

[0075] S1. Collect relevant information about the measuring point rock cores at the site, as well as the secondary stress of the surrounding rock obtained by stress recovery testing of the measuring point rock cores using stress recovery testing equipment, and the lateral compressive strength obtained by lateral compressive strength testing. The measuring point rock cores refer to the rock cores obtained by stress relief and extraction from the measuring point behind the tunnel face at the excavation site of the tunnel pilot tunnel. The area where the measuring point is located is between the tunnel pilot tunnel and the main tunnel. The relevant information about the measuring point includes, but is not limited to, the self-weight of the rock mass of the measuring point rock cores, the burial depth of the rock mass of the measuring point rock cores, the surrounding rock grade of the tunnel pilot tunnel, and the distance of the tunnel pilot tunnel ahead of the main tunnel.

[0076] In step S1, the positional relationship between the measuring point and the tunnel pilot tunnel (i.e., the parallel pilot tunnel to the main tunnel, which serves as an auxiliary tunnel; the relationship between the two is that the main tunnel and the parallel auxiliary tunnel are set up) and the main tunnel is as follows: Figure 2The taking parameters of the measuring point core include, but are not limited to, a diameter of 50 mm and a taking depth of 50 mm. The measuring point core is obtained on site and needs to be tested on site to obtain the secondary stress of the surrounding rock and the lateral compressive strength (in order to adapt to the on-site testing requirements, the stress recovery testing equipment can be, but is not limited to, obtained based on the conventional improvement of the existing gate-type stress recovery testing equipment). The secondary stress of the surrounding rock and the lateral compressive strength can be obtained by inputting by the on-site personnel or transmitted by the stress recovery testing equipment, and the on-site measuring point related information can be obtained by inputting by the on-site personnel. In addition, the on-site measuring point related information can further include, but is not limited to, another distance from the measuring point to the on-site working face.

[0077] In the step S1, specifically, the secondary stress of the surrounding rock can be, but is not limited to, measured in the following manner: first, the stress recovery of the measuring point core is carried out on site by using the gate-type stress recovery testing equipment, and the stress recovery process is automatically controlled through the strain difference before and after stress relief, and finally the recovery load in the vertical direction is obtained; then the vertical secondary stress S zz is calculated according to the following stress calculation formula:

[0078] S zz = λ × α × β × F Z ÷ A

[0079] In the formula, λ represents a size influence coefficient determined according to the diameter of the measuring point core and positively related to the diameter, α represents a stress equivalent coefficient quantified according to the equivalent elastic modulus of the measuring point core and positively related to the quantified level, β represents a confining pressure influence coefficient according to the confining pressure of the measuring point core and positively related to the confining pressure, F Z represents the recovery load in the vertical direction when the stress recovery based on the strain difference automatic control reaches the preset strain difference, and A represents the compression area of the measuring point core when compressed in the lateral direction and A = L × H, L represents the contact width between the saddle-shaped pad of the gate-type stress recovery testing equipment and the measuring point core and has a unit of mm, and H represents the contact height between the saddle-shaped pad and the measuring point core and has a unit of mm. The structural principle of measuring the secondary stress of the surrounding rock by the stress recovery test is a prior art principle, as shown in Figure 3 .

[0080] In the step S1, specifically, the lateral compressive strength can be, but is not limited to, measured in the following manner: first, the measuring point core is placed in the saddle-shaped pad of the gate-type stress recovery testing equipment, and the gate-type stress recovery testing equipment is controlled to pressurize the measuring point core; then the load F of the measuring point core when fractured in the lateral direction is recorded, and the lateral compressive strength R b:

[0081] R b =F÷A

[0082] In the formula, A represents a compression area of the measurement point core when compressed in the lateral direction and has A=L×H, L represents a contact width of a saddle-shaped pad of the plug-type stress recovery testing device and the measurement point core and has a unit of mm, and H represents a contact height of the saddle-shaped pad and the measurement point core and has a unit of mm. The structural principle of measuring the lateral compressive strength through the lateral compressive strength test is a prior principle, as shown in Figure 4 .

[0083] S2. According to the rock mass self-weight and the rock mass burial depth of the measurement point core, the vertical ground stress S Z is calculated according to the following formula.

[0084] S Z =γ×h

[0085] In the formula, γ represents the rock mass self-weight of the measurement point core, and h represents the rock mass burial depth of the measurement point core.

[0086] S3. According to the vertical ground stress S Z and the vertical secondary stress S zz in the secondary stress of the surrounding rock, the initial ground stress S X in the vertical direction of the hole axis is calculated according to the following formula.

[0087] S X =c1×(m×S Z -n×e×S zz )

[0088] In the formula, c1 represents a first calculation parameter determined according to the tunnel surrounding rock grade and negatively related to the tunnel surrounding rock grade, m represents a preset second calculation parameter, n represents a preset third calculation parameter, and e represents a fourth calculation coefficient determined according to the distance and negatively related to the distance.

[0089] In the step S3, the initial ground stress S XThe calculation formula and multiple calculation parameters are obtained based on the fitting of survey data. Specifically, the first calculation parameter c1 is determined as follows: when the tunnel surrounding rock grade is Class II, the first calculation parameter c1 is selected within the numerical range [1.02, 1.14]; when the tunnel surrounding rock grade is Class III, the first calculation parameter c1 is selected within the numerical range [0.97, 1.02]; when the tunnel surrounding rock grade is Class IV, the first calculation parameter c1 is selected within the numerical range [0.89, 0.94]; when the tunnel surrounding rock grade is Class V, the first calculation parameter c1 is selected within the numerical range [0.83, 0.88]; the second calculation parameter m is preset to 2.91; the third calculation parameter n is preset to 1.12; the fourth calculation coefficient e The fourth calculation coefficient e is determined as follows: when the distance is less than 20 meters, the coefficient is selected within the range of (0.96, 1.0); when the distance is greater than or equal to 20 meters and less than 40 meters, the coefficient is selected within the range of (0.94, 0.96); when the distance is greater than or equal to 40 meters and less than 60 meters, the coefficient is selected within the range of (0.90, 0.94); when the distance is greater than or equal to 60 meters and less than 80 meters, the coefficient is selected within the range of (0.87, 0.90); and when the distance is greater than or equal to 80 meters and less than 100 meters, the coefficient is selected within the range of (0.81, 0.87). Furthermore, the initial ground stress S in the tunnel axis direction is considered. Y It also provides some reference for identifying high ground stress in tunnels. Therefore, it can also be based on the secondary stress S along the tunnel axis in the secondary stress of the surrounding rock. yy The initial ground stress S in the tunnel axis direction is calculated according to the following formula. Y For identification applications:

[0090] S Y =c5×a'×(d×S yy ) b

[0091] In the formula, c5 represents the fifth calculation parameter determined based on the tunnel surrounding rock grade and positively correlated with the tunnel surrounding rock grade, a' represents the preset sixth calculation parameter, d represents the seventh calculation coefficient determined based on the other distance from the measuring point to the working face and positively correlated with the other distance, and b represents the preset eighth calculation parameter; the aforementioned initial ground stress S Y The calculation formula and multiple calculation parameters are also obtained based on the fitting of survey data. The specific values ​​of all calculation parameters are shown in Table 1 below:

[0092] Table 1. Values ​​of all calculation parameters

[0093]

[0094] S4. According to the lateral compressive strength, the vertical stress S Z and the initial stress S X , a modified strength stress ratio CSSR is calculated according to the following formula:

[0095] CSSR = R b ÷ max(S Z , S X )

[0096] wherein R b represents the lateral compressive strength, and max() represents a maximum function.

[0097] S5. According to the modified strength stress ratio CSSR and a known mapping relationship between the stress grade and the modified strength stress ratio, a stress grade of the region where the measuring point is located is determined.

[0098] In the step S5, specifically, according to the modified strength stress ratio CSSR and the known mapping relationship between the stress grade and the modified strength stress ratio, the stress grade of the region where the measuring point is located is determined, including but not limited to: first, a known mapping relationship between the stress grade and the modified strength stress ratio is obtained: the modified strength stress ratio corresponding to a general stress grade is greater than 4.5; the modified strength stress ratio corresponding to a high stress grade is greater than 2.5 and less than or equal to 4.5; the modified strength stress ratio corresponding to an extremely high stress grade is less than or equal to 2.5; then, according to the known mapping relationship, if the modified strength stress ratio CSSR is greater than 4.5, it is determined that the stress grade of the region where the measuring point is located is a general stress grade, if the modified strength stress ratio CSSR is greater than 2.5 and less than or equal to 4.5, it is determined that the stress grade of the region where the measuring point is located is a high stress grade, and if the modified strength stress ratio CSSR is less than or equal to 2.5, it is determined that the stress grade of the region where the measuring point is located is an extremely high stress grade.

[0099] Therefore, based on the tunnel ground stress grade quantitative rapid evaluation method described in the foregoing steps S1-S5, a new scheme for quickly identifying the tunnel ground stress grade based on the secondary stress and lateral compressive strength test results is provided, that is, first, the field measurement point related information of the measurement point core and the secondary stress of the surrounding rock obtained by the stress recovery test equipment on the measurement point core and the lateral compressive strength obtained by the lateral compressive strength test are collected, then the vertical ground stress, the initial ground stress in the horizontal direction of the vertical hole axis and the modified strength stress ratio are sequentially calculated according to these data, and finally, the ground stress grade of the region where the measurement point is located is determined according to the modified strength stress ratio and the known mapping relationship between the ground stress grade and the modified strength stress ratio. Thus, only a small circular hole needs to be drilled for stress relief during tunnel construction, without the need to drill a deep hole, and all test data can be obtained on site, making the process simple and fast, and not affecting normal construction due to short on-site time, with the advantages of low test cost, application in high ground stress hard rock tunnels and quick on-site high ground stress identification results, facilitating actual application and promotion.

[0100] As shown in Figure 5 , the second aspect of the present embodiment provides a virtual device for implementing the tunnel ground stress grade quantitative rapid evaluation method of the first aspect, comprising a field information collection unit, a vertical ground stress calculation unit, an initial ground stress calculation unit, a stress ratio calculation unit and a ground stress grade determination unit.

[0101] The field information collection unit is configured to collect the field measurement point related information of the measurement point core and the secondary stress of the surrounding rock obtained by the stress recovery test equipment on the measurement point core and the lateral compressive strength obtained by the lateral compressive strength test, wherein the measurement point core refers to a core obtained by stress relief at the rear wall of the tunnel plane after excavation and from the measurement point, the region where the measurement point is located is between the tunnel plane and the tunnel main tunnel, and the field measurement point related information includes the rock mass self weight of the measurement point core, the rock mass burial depth of the measurement point core, the tunnel surrounding rock grade of the tunnel plane and the distance between the tunnel plane and the tunnel main tunnel.

[0102] The vertical ground stress calculation unit is in communication connection with the field information collection unit and is configured to calculate the vertical ground stress S Z according to the rock mass self weight and the rock mass burial depth of the measurement point core according to the following formula:

[0103] S Z = γ × h

[0104] wherein γ represents the rock mass self weight of the measurement point core and h represents the rock mass burial depth of the measurement point core.

[0105] The initial ground stress calculation unit is communicatively connected to both the field information collection unit and the vertical ground stress calculation unit, and is used to calculate the vertical ground stress S. Z and the vertical secondary stress S in the secondary stress of the surrounding rock zz The initial geostress S in the horizontal direction perpendicular to the tunnel axis is calculated using the following formula. X :

[0106] S X =c1×(m×S) Z -n×e×S zz )

[0107] In the formula, c1 represents a first calculation parameter determined according to the tunnel surrounding rock grade and negatively correlated with the tunnel surrounding rock grade, m represents a preset second calculation parameter, n represents a preset third calculation parameter, and e represents a fourth calculation coefficient determined according to the distance and negatively correlated with the distance.

[0108] The stress ratio calculation unit is communicatively connected to the field information collection unit and the initial ground stress calculation unit, respectively, and is used to calculate the stress ratio based on the lateral compressive strength and the vertical ground stress S. Z and the initial ground stress S X The corrected strength stress ratio (CSSR) is calculated using the following formula:

[0109] CSSR = R b ÷max(S Z ,S X )

[0110] In the formula, R b This represents the transverse compressive strength, and max() represents the function to take the maximum value;

[0111] The geostress level determination unit is communicatively connected to the stress ratio calculation unit and is used to determine the geostress level of the area where the measuring point is located based on the modified strength stress ratio (CSSR) and the known mapping relationship between geostress level and modified strength stress ratio.

[0112] The working process, working details and technical effects of the aforementioned device provided in the second aspect of this embodiment can be found in the method for quantitative and rapid assessment of tunnel ground stress level described in the first aspect, and will not be repeated here.

[0113] like Figure 6 As shown, the third aspect of this embodiment provides a physical system for implementing the quantitative and rapid assessment method for tunnel ground stress level described in the first aspect, including but not limited to stress recovery testing equipment and host computer equipment connected by communication;

[0114] The stress recovery testing device is used for stress recovery testing of a measurement point core to obtain a surrounding rock secondary stress and transverse compressive strength testing to obtain transverse compressive strength, and transmits the surrounding rock secondary stress and the transverse compressive strength to the host computer device, wherein the measurement point core refers to a core obtained by stress relief and taking out from a measurement point at a tunnel face behind a tunnel face of a tunnel excavation site, and the measurement point is located in an area between the tunnel face and a tunnel main tunnel.

[0115] The host computer device is used for executing the tunnel ground stress grade quantitative rapid evaluation method according to the first aspect.

[0116] The working process, working details and technical effects of the foregoing system provided by the third aspect of the embodiment can be referred to the tunnel ground stress grade quantitative rapid evaluation method according to the first aspect, which will not be repeated here.

[0117] As shown in Figure 7 The fourth aspect of the embodiment provides a computer device for executing the tunnel ground stress grade quantitative rapid evaluation method according to the first aspect, which includes a memory, a processor and a transceiver connected in sequence, wherein the memory is used for storing a computer program, the transceiver is used for transmitting and receiving messages, and the processor is used for reading the computer program and executing the tunnel ground stress grade quantitative rapid evaluation method according to the first aspect. Specifically, the memory can include, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a flash memory, a first-in first-out memory (FIFO) and / or a first-in last-out memory (FILO) and the like; and the processor can be, but is not limited to, a microprocessor with a model number of STM32F105 series. In addition, the computer device can further include, but is not limited to, a power module, a display screen and other necessary components.

[0118] The working process, working details and technical effects of the foregoing computer device provided by the fourth aspect of the embodiment can be referred to the tunnel ground stress grade quantitative rapid evaluation method according to the first aspect, which will not be repeated here.

[0119] The fifth aspect of the embodiment provides a computer readable storage medium storing instructions of the tunnel ground stress grade quantitative rapid evaluation method as described in the first aspect, that is, the computer readable storage medium stores instructions, and when the instructions are executed on a computer, the tunnel ground stress grade quantitative rapid evaluation method as described in the first aspect is executed. Wherein, the computer readable storage medium refers to a carrier for storing data, which can include, but is not limited to, floppy disks, optical disks, hard disks, flash memories, USB flash disks and / or memory sticks and other computer readable storage media, and the computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable devices.

[0120] The working process, working details and technical effects of the aforementioned computer readable storage medium provided by the fifth aspect of the embodiment can be referred to the tunnel ground stress grade quantitative rapid evaluation method as described in the first aspect, which will not be described here.

[0121] The sixth aspect of the embodiment provides a computer program product, which includes a computer program or instructions, and the computer program or the instructions realize the tunnel ground stress grade quantitative rapid evaluation method as described in the first aspect when executed on a computer. Wherein, the computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable devices.

[0122] Finally, it should be noted that: the above only describes the preferred embodiments of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for quantitatively and rapidly evaluating stress level in a tunnel, characterized by, The method comprises the following steps: Collecting site point related information of a site point core and secondary stress of surrounding rock and transverse compressive strength of the site point core, wherein the site point core is obtained by stress relief and extraction from a site point behind a tunnel face of a tunnel pilot, the site point is located in an area between the tunnel pilot and a tunnel main tunnel, and the site point related information comprises rock mass self weight of the site point core, rock mass burial depth of the site point core, tunnel surrounding rock grade of the tunnel pilot, and distance between the tunnel pilot and the tunnel main tunnel; According to the rock mass self-weight and the rock mass burial depth of the measuring point core, the vertical ground stress S is calculated according to the following formula Z : S Z = γ x h wherein γ represents the rock mass self weight of the site point core, and h represents the rock mass burial depth of the site point core; According to the vertical stress S Z and the vertical secondary stress S zz in the secondary stress of the surrounding rock, the initial ground stress S X in the horizontal direction of the vertical hole axis is calculated according to the following formula: S X = c1 x (m x S Z - n x e x S zz ) wherein c1 represents a first calculation parameter determined according to the tunnel surrounding rock grade and negatively correlated with the tunnel surrounding rock grade, m represents a preset second calculation parameter, n represents a preset third calculation parameter, and e represents a fourth calculation coefficient determined according to the distance and negatively correlated with the distance; According to the lateral compressive strength, the vertical stress S Z and the initial ground stress S X , the modified strength stress ratio CSSR is calculated as follows: CSSR = R b ÷ max(S Z ,S X ) wherein R b represents the transverse compressive strength, and max() represents a maximum function. According to the corrected strength stress ratio CSSR and a known mapping relationship between in-situ stress grade and corrected strength stress ratio, the in-situ stress grade of the area where the site point is located is determined.

2. The method for quantitatively and rapidly evaluating a stress level in a tunnel according to claim 1, characterized by, The secondary stress of surrounding rock is measured in the following manner: The site point core is subjected to stress recovery on a tunnel site by using a gate valve type stress recovery test device, and the stress recovery process is automatically controlled through the strain difference before and after stress relief, so as to finally obtain the recovery load in the vertical direction; The secondary stress S in the vertical direction is calculated according to the following stress calculation formula zz The secondary stress S in the vertical direction is calculated according to the following stress calculation formula S zz = λ x α x β x F Z ÷ A In the formula, λ represents a size influence coefficient determined according to the diameter of the measurement point core and positively correlated with the diameter, α represents a stress equivalent coefficient according to the quantitative level of the equivalent elastic modulus of the measurement point core and positively correlated with the quantitative level, β represents a confining pressure influence coefficient according to the confining pressure of the measurement point core and positively correlated with the confining pressure, F Z represents the recovery load in the vertical direction when the stress recovery is automatically controlled to reach the preset strain difference value based on the strain difference value, A represents the compression area of the measurement point core when compressed in the transverse direction and has A=L×H, L represents the contact width of the saddle-shaped pad of the gate plug type stress recovery test equipment and the measurement point core and has a unit of mm, and H represents the contact height of the saddle-shaped pad and the measurement point core and has a unit of mm.

3. The method of claim 1, wherein the tunnel stress level is quantitatively and rapidly evaluated by the steps of: The transverse compressive strength is measured in the following manner: ​ The site point core is placed in a saddle-shaped pad of the gate valve type stress recovery test device, and the site point core is subjected to pressure control by the gate valve type stress recovery test device; record the load F of the measuring point core in the lateral fracturing, and calculate the lateral compressive strength R of the measuring point core according to the load F b : R b = F ÷ A wherein A represents the pressure area of the site point core under lateral pressure and A=L×H, L represents the contact width between the saddle-shaped pad of the gate valve type stress recovery test device and the site point core and is in mm, and H represents the contact height between the saddle-shaped pad and the site point core and is in mm.

4. The method for quantitatively and rapidly evaluating a stress level in a tunnel according to claim 1, characterized by, The first calculation parameter c1 is determined in the following manner: when the tunnel surrounding rock grade is grade II, the first calculation parameter c1 is determined in the numerical range [1.02, 1.14]; when the tunnel surrounding rock grade is grade III, the first calculation parameter c1 is determined in the numerical range [0.97, 1.02]; when the tunnel surrounding rock grade is grade IV, the first calculation parameter c1 is determined in the numerical range [0.89, 0.94]; and when the tunnel surrounding rock grade is grade V, the first calculation parameter c1 is determined in the numerical range [0.83, 0.88]; And / or, the second calculation parameter m is preset as 2.91; And / or, the third calculation parameter n is preset as 1.12; And / or, the fourth calculation coefficient e is determined in the following manner: when the distance is less than 20 meters, the fourth calculation coefficient e is determined in the numerical range (0.96, 1.0]; when the distance is greater than or equal to 20 meters and less than 40 meters, the fourth calculation coefficient e is determined in the numerical range (0.94, 0.96]; when the distance is greater than or equal to 40 meters and less than 60 meters, the fourth calculation coefficient e is determined in the numerical range (0.90, 0.94]; when the distance is greater than or equal to 60 meters and less than 80 meters, the fourth calculation coefficient e is determined in the numerical range (0.87, 0.90]; when the distance is greater than or equal to 80 meters and less than 100 meters, the fourth calculation coefficient e is determined in the numerical range (0.81, 0.87].

5. The method for quantitatively and rapidly evaluating a stress level in a tunnel according to claim 1, wherein According to the modified intensity stress ratio CSSR and a known mapping relationship between the ground stress grade and the modified intensity stress ratio, a ground stress grade of a region where the measuring point is located is determined, comprising: The known mapping relationship between the ground stress grade and the modified intensity stress ratio is obtained: the modified intensity stress ratio corresponding to a general ground stress grade is greater than 4.5; the modified intensity stress ratio corresponding to a high ground stress grade is greater than 2.5 and less than or equal to 4.5; and the modified intensity stress ratio corresponding to an extremely high ground stress grade is less than or equal to 2.5; According to the known mapping relationship, if the modified intensity stress ratio CSSR is greater than 4.5, it is determined that the ground stress grade of the region where the measuring point is located is a general ground stress grade; if the modified intensity stress ratio CSSR is greater than 2.5 and less than or equal to 4.5, it is determined that the ground stress grade of the region where the measuring point is located is a high ground stress grade; and if the modified intensity stress ratio CSSR is less than or equal to 2.5, it is determined that the ground stress grade of the region where the measuring point is located is an extremely high ground stress grade.

6. A device for quantitative and rapid assessment of tunnel ground stress level, characterized in that, It comprises a field information collection unit, a vertical ground stress calculation unit, an initial ground stress calculation unit, a stress ratio calculation unit and a ground stress grade determination unit. The field information collection unit is used to collect field measuring point related information of a measuring point core and secondary stress of surrounding rock obtained by stress recovery testing equipment on the measuring point core and transverse compressive strength obtained by further transverse compressive strength testing, wherein the measuring point core refers to a core obtained by stress relief and taken from a measuring point at a tunnel face rear wall of a tunnel pilot, the region where the measuring point is located is between the tunnel pilot and a tunnel main tunnel, and the field measuring point related information includes rock mass self weight of the measuring point core, rock mass burial depth of the measuring point core, tunnel surrounding rock grade of the tunnel pilot and distance of the tunnel pilot ahead of the tunnel main tunnel. The vertical stress calculation unit is connected with the field information collection unit in communication, and is configured to calculate the vertical stress S according to the rock mass weight and the rock mass burial depth of the measuring point core according to the following formula Z : S Z = γ x h In the formula, γ represents the rock mass self weight of the measuring point core, and h represents the rock mass burial depth of the measuring point core. The initial ground stress calculation unit is respectively connected in communication with the field information collection unit and the vertical ground stress calculation unit, and is configured to calculate the initial ground stress S Z and the vertical secondary stress S zz in the secondary stress of the surrounding rock according to the following formula: X : S X = c1 x (m x S Z - n x e x S zz ) In the formula, c1 represents a first calculation parameter determined according to the tunnel surrounding rock grade and negatively related to the tunnel surrounding rock grade, m represents a preset second calculation parameter, n represents a preset third calculation parameter, and e represents a fourth calculation coefficient determined according to the distance and negatively related to the distance. The stress ratio calculation unit is communicatively connected to the field information collection unit and the initial ground stress calculation unit, respectively, and is configured to calculate a modified strength stress ratio CSSR according to the lateral compressive strength, the vertical ground stress S Z and the initial ground stress S X in the following equation. CSSR = R b ÷ max(S Z ,S X ) wherein R b represents the transverse compressive strength, and max() represents a maximum function. The geo-stress grade determination unit is in communication with the stress ratio calculation unit and is configured to determine a geo-stress grade of a region where the measuring point is located according to the modified intensity stress ratio CSSR and a known mapping relationship between geo-stress grades and modified intensity stress ratios.

7. A system for quantitatively and rapidly evaluating stress level of a tunnel, characterized by comprising: a tunnel stress level evaluation device; a tunnel stress level evaluation program; and a tunnel stress level evaluation database. The stress recovery testing device and the host computer device are in communication; The stress recovery testing device is configured to perform stress recovery testing on a measuring point core to obtain a surrounding rock secondary stress and perform lateral compressive strength testing to obtain a lateral compressive strength, and transmit the surrounding rock secondary stress and the lateral compressive strength to the host computer device, wherein the measuring point core is a core obtained by stress relief and extraction from a measuring point at a rear wall of a tunnel face in a tunnel excavation site, and a region where the measuring point is located is between the tunnel face and a main tunnel of the tunnel; The host computer device is configured to perform the tunnel geo-stress grade quantitative rapid evaluation method according to any one of claims 1 to 5.

8. A computer device, comprising: The computer readable storage medium has instructions stored thereon, and when the instructions are executed on a computer, the tunnel geo-stress grade quantitative rapid evaluation method according to any one of claims 1 to 5 is performed.

9. A computer-readable storage medium, characterized in that The computer program or the instructions realize the tunnel geo-stress grade quantitative rapid evaluation method according to any one of claims 1 to 5 when executed on a computer.

10. A computer program product comprising computer programs or instructions, characterized in that, The computer program or the instructions realize the tunnel geo-stress grade quantitative rapid evaluation method according to any one of claims 1 to 5 when executed on a computer.

Images