Surrounding rock quality evaluation method

Abstract

The present invention provides a surrounding rock quality evaluation method, including: obtaining basic rock quality indicators based on surrounding rock in-situ testing; obtaining rock quality indicators based on basic rock quality indicators, groundwater influence coefficient, rock layer variation coefficient and layer number influence coefficient; obtaining rock quality classification evaluation results based on rock quality indicators; constructing a two-dimensional rock quality distribution model along the roadway and a three-dimensional rock quality distribution model on the working face based on surrounding rock in-situ testing and rock quality classification evaluation results. The surrounding rock quality evaluation method is a method based on surrounding rock in-situ testing, which can quickly test multiple parameters of rock mass and accurately evaluate surrounding rock quality. It can obtain multiple in-situ test data by drilling, and directly use them for subsequent surrounding rock quality evaluation, providing basic data and design basis for surrounding rock control such as support, reinforcement and fracturing.

Description

Technical Field

[0001] The invention relates to the technical field of mining, and in particular to a surrounding rock quality evaluation method. Background Art

[0002] The lithology, physics, mechanics and other characteristics of coal and rock are the core parameters related to rock strata migration and surrounding rock deformation and destruction during coal mining, and are the basic basis for preventing and controlling disaster threats such as roof collapse, large deformation of surrounding rock, and rock burst. Most parameters are obtained through laboratory tests, which are not only inefficient and costly, but also because the test data obtained out of the original environment has a greatly reduced guiding significance for engineering practice. Rock mass quality evaluation is the basic work related to rock mass classification and its stability control method, and the accuracy of the basic parameters required for such evaluation methods is crucial.

[0003] In-situ testing methods are increasingly being used due to their high efficiency, low cost, and greater value of in-situ parameters. However, the parameters required in traditional rock quality evaluation methods basically rely on test results in the laboratory, and there is a lack of rock quality evaluation methods based on in-situ testing. Moreover, traditional rock quality evaluation is also based on single-point data, and its adaptability is limited to the situation where coal mine sedimentary rocks vary greatly. Therefore, it is not conducive to real-time and accurate guidance of regional mining planning, rock disaster prediction and early warning, and advanced prevention and control. Summary of the invention

[0004] The present invention provides a surrounding rock quality evaluation method to solve one of the defects in the prior art. It can accurately and comprehensively evaluate the regional quality of tunnel surrounding rocks through multi-parameter in-situ test data, provide data support and judgment basis for tunnel surrounding rock stability analysis and evaluation, monitoring and surrounding rock classification, and provide support for disaster control such as roof disasters, surrounding rock instability and impact ground pressure, so as to be more conducive to real-time and accurate guidance of regional mining planning, rock disaster prediction and early warning, and advanced prevention and control.

[0005] The present invention provides a surrounding rock quality evaluation method, comprising:

[0006] Obtain basic rock mass quality indicators based on in-situ testing of surrounding rock;

[0007] Based on the basic quality index of rock mass, groundwater influence coefficient, rock layer variation coefficient and layer number influence coefficient, the in-situ quality index of rock mass is obtained;

[0008] Based on the in-situ quality indicators of the rock mass, obtain the rock mass quality classification evaluation results;

[0009] Based on the results of in-situ testing of surrounding rock and classification and evaluation of rock mass quality, a two-dimensional rock mass distribution model along the tunnel strike and a three-dimensional rock mass distribution model at the working face were constructed.

[0010] According to the surrounding rock quality evaluation method of the present invention, the basic quality index of the rock mass is obtained based on the in-situ test of the surrounding rock, which includes:

[0011] Obtain rock formation weighted strength and rock integrity index based on in-situ testing of surrounding rock;

[0012] Based on the weighted strength of rock formations and rock integrity index, basic rock mass quality indicators are obtained.

[0013] According to the surrounding rock quality evaluation method of the present invention, the basic quality index of the rock mass is obtained based on the in-situ test of the surrounding rock, which includes:

[0014] Based on the in-situ test of the surrounding rock, the average in-situ test strength of each rock layer, as well as the crack opening and crack trace length of each crack are obtained;

[0015] Obtaining the weighted strength of the rock formation based on the average in-situ test strength of each rock formation and the thickness of each rock formation;

[0016] Based on the fracture aperture and fracture trace length of each fracture, the sum of the fracture cross-sectional areas of the rock formation is obtained;

[0017] Based on the ratio of the sum of the cross-sectional areas of the rock formation fractures to the total area exposed by the rock formation drilling, the fracture area ratio is obtained;

[0018] Based on the proportion of fracture area, the rock integrity index is obtained;

[0019] Based on the weighted strength of rock formations and rock integrity index, basic rock mass quality indicators are obtained.

[0020] According to the surrounding rock quality evaluation method of the present invention, the groundwater influence coefficient is obtained based on the basic quality index of the rock mass, the surrounding rock fissure water pressure and the tunnel water output.

[0021] According to the surrounding rock quality evaluation method of the present invention, based on the average in-situ test strength of each rock layer, the mean of the in-situ test strengths of all rock layers and the standard deviation of the in-situ test strengths of all rock layers, the standard score of the strength of each rock layer is obtained;

[0022] Based on the standard score of each rock formation strength, the rock formation variation influence coefficient is obtained.

[0023] According to the surrounding rock quality evaluation method of the present invention, based on the mapping relationship between the measured surrounding rock range and the number of rock layers, the layer number influence coefficient is obtained.

[0024] According to the surrounding rock quality evaluation method of the present invention, the surrounding rock in-situ test includes:

[0025] Drill holes at any position of the surrounding rock in the tunnel;

[0026] Based on the borehole peep method, the surrounding rock structure image is obtained, and the fracture opening and fracture trace length of each fracture in each rock layer are obtained based on the surrounding rock structure image;

[0027] Obtaining the natural gamma ray intensity of each rock layer in the borehole, and determining the lithology range of each rock layer based on the natural gamma ray intensity of each rock layer;

[0028] Based on the borehole penetration method, the in-situ test strength of each rock layer is obtained;

[0029] Based on the lithology range of each rock layer, the surrounding rock structure image and the in-situ test strength, the layered lithology and thickness of each rock layer are obtained.

[0030] According to the surrounding rock quality evaluation method of the present invention, the construction of a two-dimensional rock mass quality distribution model along the roadway strike and a three-dimensional rock mass quality distribution model at the working face based on the surrounding rock in-situ test and rock mass quality evaluation results includes:

[0031] In-situ testing of surrounding rock was performed based on multiple drilling positions in the same tunnel to obtain a single tunnel geological model and a two-dimensional rock mass distribution model along the tunnel strike.

[0032] Based on the geological model of a single tunnel of multiple tunnels, a three-dimensional geological model of the working face is obtained;

[0033] Based on the three-dimensional geological model of the working face and the rock mass quality classification and evaluation results, a three-dimensional rock mass quality distribution model of the working face is constructed.

[0034] According to the surrounding rock quality evaluation method of the present invention, the in-situ test of surrounding rock based on multiple drilling positions in the same tunnel to obtain a single tunnel geological model includes:

[0035] Based on the in-situ testing of surrounding rock at multiple drilling positions along the axial direction of the same roadway, a single roadway geological model is obtained;

[0036] Based on the geological model of a single tunnel, the interpolation method and thermal cloud map characterization method are used to obtain the rock mass distribution cloud map along the axial direction of the tunnel.

[0037] According to the surrounding rock quality evaluation method of the present invention, an interpolation method and a thermal cloud image characterization method are used to construct a two-dimensional rock mass quality distribution model along the tunnel strike and a three-dimensional rock mass quality distribution model at the working face.

[0038] The surrounding rock quality evaluation method provided by the present invention is to drill holes on the surrounding rock to be tested, and then perform various field tests on the surrounding rock to be tested in situ based on the holes and obtain corresponding data parameters, which is the surrounding rock in-situ test. The present invention is to perform in-situ testing of the surrounding rock before the actual project starts, and obtain the basic rock quality index BQ through the test results; then according to the basic rock quality index BQ, the groundwater influence coefficient K 1 , rock layer variation coefficient K2 And the layer number influence coefficient K 3 , obtain the in-situ quality index of the rock mass [BQ]; thus, based on the in-situ quality index of the rock mass [BQ], obtain the rock mass quality classification evaluation results. By determining the rock mass quality classification evaluation results, the rock mass quality can be clearly classified, and the deformation and failure prediction of the surrounding rock and the selection of the control form can be carried out according to the classification results. Moreover, on the basis of completing the rock mass quality classification evaluation, based on the surrounding rock in-situ test and rock mass quality classification evaluation results, a two-dimensional rock mass quality distribution model along the roadway strike and a three-dimensional rock mass quality distribution model of the working face are constructed, thereby providing a basis for the prediction of the rock stratum migration and collapse laws and the mine pressure manifestation laws during the mining process of the working face, and providing a basis for rock stratum control and disaster advance management. It can be seen that the surrounding rock quality evaluation method can obtain one or more in-situ test data of the surrounding rock mass by drilling, and directly use the in-situ test data in the rock mass quality evaluation of the surrounding rock, providing basic data and design basis for surrounding rock control such as support, reinforcement, and fracturing.

[0039] The in-situ testing technology of surrounding rock is an important testing technology. It can not only efficiently test a large range of surrounding rock, but also the in-situ test data can better reflect the actual engineering environment than the laboratory test results, and has greater guiding significance for engineering practice. The present invention adopts large-scale in-situ testing to obtain the basic parameters of surrounding rock such as strength, lithology, structure and thickness of surrounding rock, and fully considers environmental factors such as groundwater, stratification and rock layer variation and rock mass factors itself, and proposes a surrounding rock quality evaluation method based on in-situ testing of rock mass, so as to accurately evaluate the rock mass quality of the tested surrounding rock. The surrounding rock quality evaluation method constructs a two-dimensional rock mass distribution model along the direction of the tunnel and a three-dimensional rock mass distribution model of the working face through large-scale distributed test drilling data, which provides data for surrounding rock classification and subsequent surrounding rock stability analysis and rock layer migration law analysis, and provides support for disaster control such as roof disaster, surrounding rock instability and rock burst.

[0040] The evaluation of the rock mass quality of the surrounding rock is the basic work related to the rock mass classification and its stability control method. The accuracy of the basic parameters required for the evaluation method is crucial. Compared with the traditional judgment method of the rock mass quality evaluation of the tunnel surrounding rock in the prior art, which is to send the collected tunnel surrounding rock samples to the laboratory for testing to obtain test data, the test process is inefficient and costly, and the guiding significance of the test data for engineering practice is greatly reduced due to the separation from the in-situ environment. The present invention uses multi-parameter in-situ data to evaluate the rock mass quality of the tunnel surrounding rock, which can greatly improve the generation efficiency and accuracy of the quality evaluation results, and can provide a basis for the prediction of the rock layer migration and collapse law, the law of mine pressure manifestation, etc. during the mining process of the working face, and provide a basis for rock layer control and advanced disaster management, so that the subsequent surrounding rock stability analysis and judgment is more accurate and efficient, and provides guidance for the support of the subsequent tunnel or similar conditions. It can also take relevant control measures in time in the early stage of tunnel service according to the judgment results to avoid the instability of the tunnel, and conduct a comprehensive and large-scale early stability pre-evaluation of the tunnel surrounding rock, which is very important for the advanced control of the expected deformation and damage of the tunnel. Moreover, the stability judgment result can realize the reasonable and differentiated support of the tunnel, take early control measures in a timely and scientific manner, reduce the risk of tunnel disasters, and realize efficient and economical tunnel excavation and maintenance.

[0041] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted, and the advantages brought about by the technical features of these technical solutions described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 is a flow chart of a surrounding rock quality evaluation method provided by an embodiment of the present invention;

[0044] Figure 2 It is a color map of a comprehensive drilling information map based on surrounding rock in-situ testing in the surrounding rock quality evaluation method provided by an embodiment of the present invention;

[0045] Figure 3 It is a grayscale image of a comprehensive drilling information image based on surrounding rock in-situ testing in the surrounding rock quality evaluation method provided by an embodiment of the present invention;

[0046] Figure 4It is a color map of a single tunnel geological model map in the surrounding rock quality evaluation method provided by an embodiment of the present invention;

[0047] Figure 5 is a grayscale image of a single tunnel geological model image in the surrounding rock quality evaluation method provided by an embodiment of the present invention;

[0048] Figure 6 It is a color map of the rock mass quality drilling assessment of a certain tunnel and the predicted rock mass quality distribution along the tunnel direction provided by a specific embodiment of the present invention;

[0049] Figure 7 It is a grayscale map of drilling assessment of rock mass quality in a certain tunnel and prediction of rock mass distribution along the direction of the tunnel provided by a specific embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] like Figure 1 As shown, the surrounding rock quality evaluation method provided by the embodiment of the present invention includes:

[0052] Based on the in-situ test of surrounding rock, the basic rock quality index BQ is obtained;

[0053] Based on the basic rock mass quality index BQ, groundwater influence coefficient K 1 , rock layer variation coefficient K 2 And the layer number influence coefficient K 3 , obtain the rock mass in-situ quality index [BQ];

[0054] Based on the rock mass in-situ quality index [BQ], obtain the rock mass quality classification evaluation results;

[0055] Based on the results of in-situ testing of surrounding rock and classification and evaluation of rock mass quality, a two-dimensional rock mass distribution model along the tunnel strike and a three-dimensional rock mass distribution model at the working face were constructed.

[0056] The surrounding rock quality evaluation method described in the present invention can clearly classify the rock quality by determining the rock quality classification evaluation results, and predict the deformation and destruction of the surrounding rock and select the control form according to the classification results. In addition, on the basis of completing the rock quality classification evaluation, based on the surrounding rock in-situ test and rock quality classification evaluation results, a two-dimensional rock quality distribution model along the roadway direction and a three-dimensional rock quality distribution model of the working face are constructed, thereby providing a basis for the prediction of the rock stratum migration and collapse laws and the mine pressure manifestation laws during the working face mining process, and providing a basis for rock stratum control and advanced disaster management. It can be seen that the surrounding rock quality evaluation method can obtain one or more in-situ test data of the surrounding rock mass by drilling, and directly use the in-situ test data in the rock quality evaluation of the surrounding rock, providing basic data and design basis for surrounding rock control such as support, reinforcement, and fracturing, so as to more accurately control the surrounding rock.

[0057] The in-situ testing technology of surrounding rock is an important testing technology. It can not only efficiently test a large range of surrounding rocks, but also the in-situ test data can better reflect the actual engineering environment than the laboratory test results, and has greater guiding significance for engineering practice. The present invention adopts large-scale in-situ testing to obtain the basic parameters of surrounding rocks such as strength, lithology, structure and thickness of surrounding rocks, and fully considers environmental factors such as groundwater, stratification and rock layer variation and rock mass factors itself, and proposes a surrounding rock quality evaluation method based on in-situ testing of rock mass, so as to more efficiently and accurately evaluate the rock mass quality of the tested surrounding rock. The surrounding rock quality evaluation method constructs a two-dimensional rock mass distribution model along the direction of the tunnel and a three-dimensional rock mass distribution model of the working face through large-scale distributed test drilling data, which provides a more accurate data basis for surrounding rock classification and subsequent surrounding rock stability analysis and rock layer migration law analysis, and provides strong support for the control of disasters such as roof disasters, surrounding rock instability and rock burst.

[0058] The evaluation of the rock mass quality of the surrounding rock is the basic work related to the rock mass classification and its stability control method. The accuracy of the basic parameters required for the evaluation method is crucial. Compared with the traditional judgment method of the rock mass quality evaluation of the tunnel surrounding rock in the prior art, which is to send the collected tunnel surrounding rock samples to the laboratory for testing to obtain test data, the test process is inefficient and costly, and the guiding significance of the test data for engineering practice is greatly reduced due to the separation from the in-situ environment. The present invention uses multi-parameter in-situ data to evaluate the rock mass quality of the tunnel surrounding rock, which can greatly improve the generation efficiency and accuracy of the quality evaluation results, and can provide a basis for the prediction of the rock layer migration and collapse law, the law of mine pressure manifestation, etc. during the mining process of the working face, and provide a basis for rock layer control and advanced disaster management, so that the subsequent surrounding rock stability analysis and judgment is more accurate and efficient, and provides guidance for the support of the subsequent tunnel or similar conditions. It can also take relevant control measures in time at the early stage of tunnel service according to the judgment results to avoid the instability of the tunnel, and conduct a comprehensive and large-scale early stability pre-evaluation of the tunnel surrounding rock, which is very important for the advanced control of the expected deformation and damage of the tunnel. Moreover, the subsequent stability judgment results can realize the reasonable and differentiated support of the tunnel, take early control measures in a timely and scientific manner, reduce the risk of tunnel disasters, and realize efficient and economical tunnel excavation and maintenance.

[0059] In this embodiment, the above-mentioned surrounding rock in-situ test includes:

[0060] Drill holes at any position of the surrounding rock in the tunnel;

[0061] Based on the borehole peep method, the surrounding rock structure image is obtained, and the crack opening w and crack trace length l of each crack in each rock layer are obtained based on the surrounding rock structure image;

[0062] Obtaining the natural gamma ray intensity of each rock layer in the borehole, and determining the lithology range of each rock layer based on the natural gamma ray intensity of each rock layer;

[0063] Based on the borehole penetration method, the in-situ test strength of each rock layer is obtained;

[0064] Based on the lithology range of each rock layer, surrounding rock structure image and in-situ test strength R 0 , obtain the stratified lithology and thickness H of each rock layer.

[0065] According to an embodiment provided by the present invention, considering the actual engineering operation and the on-site environment, the in-situ test of the surrounding rock implemented on the surrounding rock specifically includes:

[0066] A test location is selected in any tunnel in the coal mine and a borehole of a certain depth is drilled into the surrounding rock;

[0067] The drilling peek method is used to observe the surrounding rock structure and obtain high-definition images of the surrounding rock structure through observation;

[0068] The natural gamma ray tester is used to test the natural gamma ray intensity of different rock layers, and based on the natural gamma ray intensity, the range of lithology of each rock layer in the surrounding rock is preliminarily determined according to the empirical method;

[0069] The borehole penetration method is used to obtain the in-situ strength of each rock layer, so as to subsequently obtain the average in-situ test strength R of each rock layer. 0 ;

[0070] By integrating the borehole structure image, natural gamma ray intensity and the in-situ intensity of each rock layer, more accurate stratified lithology and the thickness H of each rock layer are obtained within the range of lithology values ​​of each rock layer, and a single borehole comprehensive geomechanical model is constructed;

[0071] The single borehole comprehensive geomechanical model described in this embodiment includes the following: Figure 2 and Figure 3 The comprehensive borehole information diagram based on in-situ measurements shown in the figure contains geological and mechanical parameter information such as the stratified lithology of the surrounding rock layers, the thickness H of each rock layer, the natural gamma intensity, the structural image, and the in-situ strength of each rock layer, as well as geometric information such as three-dimensional coordinates.

[0072] In this embodiment, the basic rock mass quality index BQ can be obtained by in-situ testing of the surrounding rock. The basic rock mass quality index BQ and the groundwater influence coefficient K 1 , rock layer variation coefficient K 2 And the layer number influence coefficient K 3 Calculate the rock mass in-situ quality index [BQ]. The rock mass in-situ quality index is [BQ], then [BQ] = BQ-100 (K 1 +K 2 +K 3 ).

[0073] According to an embodiment provided by the present invention, based on the in-situ test of the surrounding rock, obtaining the basic rock quality index BQ includes:

[0074] Based on the in-situ test of surrounding rock, the weighted strength R of rock formation and the rock integrity index Kv are obtained;

[0075] Based on the weighted strength R of the rock formation and the rock integrity index Kv, the basic rock quality index BQ is obtained.

[0076] According to a specific embodiment provided by the present invention, based on the in-situ test of the surrounding rock, obtaining the basic rock quality index BQ further includes:

[0077] Based on the in-situ test of the surrounding rock, the average in-situ test strength R of each rock layer is obtained. 0 , and the crack opening w and crack trace length l of each crack;

[0078] Based on the average in-situ test strength R of each rock layer 0 and the thickness H of each rock layer, and obtain the weighted strength R of the rock layer;

[0079] Based on the crack opening w and crack trace length l of each crack, the sum of the cross-sectional areas S of the rock formation cracks is obtained;

[0080] Based on the sum of the cross-sectional areas of the rock fractures S and the total area of ​​rock formation drilling exposure S 0 The ratio of the crack area k is obtained. l ;

[0081] Based on the crack area ratio k l , and obtain the rock integrity index K v ;

[0082] Based on the rock formation weighted strength R and rock integrity index K v , obtain the basic rock quality index BQ.

[0083] In this embodiment, the borehole penetration method is used for in-situ strength testing, and the surrounding rock structure is observed in combination with the borehole penetration method. Through the observation, a high-definition surrounding rock structure image is obtained to determine the thickness H of each rock layer and the average in-situ test strength R of each rock layer. 0 , then the rock formation weighted strength Wherein, m is the number of rock layers in the surrounding rock being measured revealed by drilling.

[0084] The surrounding rock structure image is processed by drilling peek to obtain the number of cracks in each rock layer n and the crack opening w and crack trace length l of each crack. The product of the crack opening w and the crack trace length l is the cross-sectional area of ​​the crack, so the sum of the cross-sectional areas of the cracks in the rock layer is Fracture area ratio k l k l =S / S 0 , S 0 The total area exposed by drilling for the formation.

[0085] Definition of rock integrity index K v The ratio of crack area to k l The corresponding relationship with the rock integrity is shown in Table 1. l Correspondingly selected rock integrity index K v .

[0086] Table 1

[0087] <![CDATA[k l ]]> 0～0.1％ 0.1％～0.4％ 0.4％～0.7％ 0.7％～1.0％ ≥1.0％ <![CDATA[K v ]]> 1～0.95 0.95～0.65 0.65～0.35 0.35～0.05 0.05 Completeness whole More complete More broken broken Extremely Broken

[0088] The calculation method of Kv for the first 4 columns is:

[0089] The reference standard is GB / T50218-2014 "Engineering Rock Mass Classification Standard" (issued on August 27, 2014, and implemented on May 1, 2015), then the basic rock mass quality index BQ = 100 + 3R + 250K v .

[0090] According to an embodiment provided by the present invention, the groundwater influence coefficient K is obtained based on the basic rock mass quality index BQ, the surrounding rock fissure water pressure p and the tunnel water output Q. 1 .

[0091] In this embodiment, the tunnel surrounding rock fissure water pressure p (MPa) and tunnel water output Q (L / min·10m) are obtained by testing the tunnel surrounding rock. Referring to Table 2 below, the groundwater influence coefficient K is determined in combination with the basic rock mass quality index BQ. 1 .

[0092] Table 2

[0093]

[0094] According to an embodiment provided by the present invention, based on the average in-situ test strength R of each rock formation 0 , the mean μ of the in-situ test strength of all rock formations and the standard deviation σ of the in-situ test strength of all rock formations, and obtain the standard score z of the strength of each rock formation;

[0095] Based on the standard score z of each rock layer strength, the rock layer variation influence coefficient K is obtained. 2 .

[0096] In this embodiment, the average in-situ test strength R of each rock layer is used. 0 The quotient of the difference between the mean μ of the in-situ test strength of all rock formations and the standard deviation σ of the in-situ test strength of all rock formations is the standard score z of the strength of each rock formation, that is, the standard score z of the strength of each rock formation = (R 0 -μ) / σ. Among the standard scores of each rock layer strength, the minimum standard score of each rock layer strength is selected. The rock layer variation influence coefficient K can be determined through the following Table 3: 2 When the minimum rock strength is greater than 40MPa, it is not applicable and the value is 0.

[0097] Table 3

[0098]

[0099] According to an embodiment provided by the present invention, based on the mapping relationship between the measured surrounding rock range and the number of rock layers, the layer number influence coefficient K is obtained. 3 .

[0100] In this embodiment, the number of rock layers is the number of rock layers within 10m of the measured surrounding rock. The number of rock layers is obtained based on the in-situ test of the surrounding rock. The layer number influence coefficient K is determined according to the following Table 4. 3 In other embodiments, when the measured surrounding rock exceeds the range of 10m, the number of layers in the first row of the table below increases by 1 for every 5m increase in depth, and the number of layers in the second row increases by 1. 3 The value remains unchanged.

[0101] Table 4

[0102] Number of rock layers within 10m 1 2 3 4 5 ≥6 <![CDATA[K 3 ]]> 0 0.2 0.4 0.6 0.8 1

[0103] In this embodiment, after obtaining the basic rock mass quality index BQ and the groundwater influence coefficient K 1 , rock layer variation coefficient K 2 And the layer number influence coefficient K 3 After that, the rock mass in-situ quality index [BQ] is calculated [BQ] = BQ-100 (K 1 +K 2 +K 3 ).

[0104] According to the calculation results, the rock mass quality is classified with reference to Table 5 below, and the deformation and failure prediction of the surrounding rock and the selection of the control form are carried out according to the classification results.

[0105] Table 5

[0106]

[0107] According to an embodiment provided by the present invention, the construction of a two-dimensional rock mass distribution model along the tunnel strike and a three-dimensional rock mass distribution model on the working face based on the surrounding rock in-situ test and rock mass quality evaluation results includes:

[0108] In-situ testing of surrounding rock was performed based on multiple drilling positions in the same tunnel to obtain a single tunnel geological model and a two-dimensional rock mass distribution model along the tunnel strike.

[0109] Based on the geological model of a single tunnel of multiple tunnels, a three-dimensional geological model of the working face is obtained;

[0110] Based on the three-dimensional geological model of the working face and the rock mass quality classification and evaluation results, a three-dimensional rock mass quality distribution model of the working face is constructed.

[0111] According to an embodiment provided by the present invention, performing in-situ testing of surrounding rocks at multiple drilling positions in the same tunnel to obtain a geological model of a single tunnel includes:

[0112] Based on the in-situ testing of surrounding rock at multiple drilling positions along the axial direction of the same roadway, a single roadway geological model is obtained;

[0113] Based on the geological model of a single tunnel, the interpolation method and thermal cloud map characterization method are used to obtain the rock mass distribution cloud map along the axial direction of the tunnel.

[0114] According to an embodiment provided by the present invention, an interpolation method and a thermal cloud image characterization method are used to construct a two-dimensional rock mass distribution model along the direction of the tunnel and a three-dimensional rock mass distribution model of the working face.

[0115] In this embodiment, the above-mentioned surrounding rock in-situ test is used for any test borehole in the same tunnel to obtain a single borehole comprehensive geomechanical model, and the single borehole comprehensive geomechanical models obtained from multiple test boreholes in the same tunnel are combined to establish a single tunnel geological model obtained from multiple test boreholes along the tunnel axis, and then obtain the distribution characteristics of the roof rock layer along the tunnel axis. In addition, combined with the above-mentioned rock mass quality evaluation results, the interpolation method and thermal cloud map characterization method are used to obtain the rock mass quality distribution cloud map along the tunnel axis, providing a basis for tunnel stability assessment, prediction, monitoring, etc.

[0116] In this embodiment, the drilling data obtained by in-situ testing of multiple surrounding rocks in two or more lanes of the working face are combined with the following Figure 4 and Figure 5 The geological models of the single tunnels of the multiple tunnels shown in the figure are combined to establish a three-dimensional geological model of the working face. In addition, based on the rock mass quality evaluation results, the interpolation method and the thermal cloud image representation method are used to construct a two-dimensional rock mass quality distribution model along the tunnel direction and a three-dimensional rock mass quality distribution model of the working face, which provides a basis for the prediction of the rock stratum migration and collapse laws and the law of mine pressure manifestation during the mining process of the working face, and provides a basis for rock stratum control and advanced disaster management.

[0117] The surrounding rock quality evaluation method described in this embodiment can establish a transparent geological model based on the in-situ measured data of the borehole, and can perform accurate numerical calculations based on the model to simulate the rock movement and surrounding rock deformation caused by tunnel excavation, working face mining, etc., and can predict the law of mine pressure manifestation based on the measured data of similar conditions to guide engineering design and production practice; moreover, the geological model and rock mass distribution model constructed by the surrounding rock quality evaluation method can accurately show the geological and geometric characteristics of the surrounding rock, and can provide accurate basic parameters for intelligent mining.

[0118] Based on the above embodiments, a specific embodiment is given as follows.

[0119] like Figure 6 and Figure 7 As shown in the figure, a coal mine is mining a new working face in a new mining area. The rock mass characteristics are unknown. In order to provide a basic reference for the subsequent working face and mining area, a series of in-situ drilling tests are carried out in the tunneling tunnel to evaluate the quality of the surrounding rock and its changes. A typical drilling test and quality assessment process is as follows.

[0120] 1. Drilling in-situ parameter test

[0121] Drill holes with a diameter of 56 mm and a depth of 20 m.

[0122] The borehole was peeped and the rock mass image was obtained and digitized, revealing 20 fractures in the borehole, as well as the opening degree and trace length of each fracture, as shown in Table 6.

[0123] Table 6 Crack parameters

[0124]

[0125]

[0126] The hydraulic fracturing method was used to measure the ground stress in the intact rock section deep in the borehole, and the maximum principal stress was found to be 19.6MPa.

[0127] The in-situ strength test of rock mass was carried out by using the borehole penetration method. Combined with the peep image, the number of rock layers revealed was 6. The thickness and in-situ strength of each rock layer were obtained, as shown in Table 7.

[0128] Table 7 Drilling exposure rock formation parameters

[0129] Layer number Rock layer thickness (m) Average strength (MPa) 1 2.5 18.1 2 4 23.2 3 3.2 13.7 4 5.6 28.6 5 2.8 32 6 1.9 24.3

[0130] 2. Calculation of basic rock mass quality and in-situ quality indicators

[0131] According to the calculation of the fracture data, the cross-sectional area of ​​the fracture exposed by the drilling is 0.024m 2 , crack area ratio k l It is 0.68%, and the rock integrity index Kv is 0.37.

[0132] After weighting, the weighted strength R of the borehole rock mass is 23.9 MPa. After the strength of each layer is converted to standard points, the minimum standard value is -1.57, so K 2 The value is 0.6; the number of rock layers exposed in the shallow part of the borehole of 10m is 4, so K 3 The value is 0.6.

[0133] The basic rock mass quality index BQ is

[0134] BQ = 100 + 3R + 250Kv = 264.2

[0135] The water discharge from the roof of the tunnel in the test area was monitored and counted. The tunnel was dripping, and the flow rate Q was 8L / min·10m, so K 1 The value is 0.2.

[0136] Then the rock mass in-situ quality index [BQ] is

[0137] [BQ] = BQ - 100 (K 1 +K 2 +K 3 )=264.2-100×(0.2+0.6+0.6)=124.2

[0138] According to the classification standards, the surrounding rock of this borehole and the surrounding area it represents is classified as poor, and surrounding rock control and stability monitoring should be strengthened.

[0139] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0140] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating surrounding rock quality, characterized in that: include: Obtain basic rock mass quality indicators based on in-situ testing of surrounding rock; Based on the basic quality index of rock mass, groundwater influence coefficient, rock layer variation coefficient and layer number influence coefficient, the in-situ quality index of rock mass is obtained; Based on the in-situ quality indicators of the rock mass, obtain the rock mass quality classification evaluation results; Based on the results of in-situ testing of surrounding rock and classification and evaluation of rock mass quality, a two-dimensional rock mass distribution model along the tunnel strike and a three-dimensional rock mass distribution model at the working face were constructed; Among them, it also includes: Based on the weighted strength of rock formations and rock integrity index, basic rock mass quality indicators are obtained; Based on the basic quality indicators of rock mass, the water pressure in surrounding rock fissures and the water output of the roadway, the groundwater influence coefficient is obtained; Based on the average in-situ test strength of each rock formation, the mean of the in-situ test strengths of all rock formations and the standard deviation of the in-situ test strengths of all rock formations, the standard score of the strength of each rock formation is obtained; Based on the standard score of each rock layer strength, the rock layer variation influence coefficient is obtained; Based on the mapping relationship between the measured surrounding rock range and the number of rock layers, the layer number influence coefficient is obtained.

2. The surrounding rock quality evaluation method according to claim 1, characterized in that: The basic rock mass quality indicators obtained based on the in-situ test of the surrounding rock include: Based on in-situ testing of surrounding rock, the weighted strength of rock formations and rock integrity index are obtained.

3. The surrounding rock quality evaluation method according to claim 2, characterized in that: The basic rock mass quality indicators obtained based on the in-situ test of the surrounding rock include: Based on the in-situ test of the surrounding rock, the average in-situ test strength of each rock layer, as well as the crack opening and crack trace length of each crack are obtained; Obtaining the weighted strength of the rock formation based on the average in-situ test strength of each rock formation and the thickness of each rock formation; Based on the fracture aperture and fracture trace length of each fracture, the sum of the fracture cross-sectional areas of the rock formation is obtained; Based on the ratio of the sum of the cross-sectional areas of the rock formation fractures to the total area exposed by the rock formation drilling, the fracture area ratio is obtained; Based on the proportion of fracture area, the rock integrity index is obtained; Based on the weighted strength of rock formations and rock integrity index, basic rock mass quality indicators are obtained.

4. The surrounding rock quality evaluation method according to claim 1, characterized in that: The surrounding rock in-situ test includes: Drill holes at any position of the surrounding rock in the tunnel; Based on the borehole peep method, the surrounding rock structure image is obtained, and the fracture opening and fracture trace length of each fracture in each rock layer are obtained based on the surrounding rock structure image; Obtaining the natural gamma ray intensity of each rock layer in the borehole, and determining the lithology range of each rock layer based on the natural gamma ray intensity of each rock layer; Based on the borehole penetration method, the in-situ test strength of each rock layer is obtained; Based on the lithology range of each rock layer, the surrounding rock structure image and the in-situ test strength, the layered lithology and thickness of each rock layer are obtained.

5. The surrounding rock quality evaluation method according to any one of claims 1 to 4, characterized in that: The construction of a two-dimensional rock mass distribution model along the roadway strike and a three-dimensional rock mass distribution model at the working face based on the surrounding rock in-situ test and rock mass quality evaluation results includes: In-situ testing of surrounding rock was performed based on multiple drilling positions in the same tunnel to obtain a single tunnel geological model and a two-dimensional rock mass distribution model along the tunnel strike. Based on the geological model of a single tunnel of multiple tunnels, a three-dimensional geological model of the working face is obtained; Based on the three-dimensional geological model of the working face and the rock mass quality classification and evaluation results, a three-dimensional rock mass quality distribution model of the working face is constructed.

6. The surrounding rock quality evaluation method according to claim 5, characterized in that: The in-situ testing of surrounding rocks based on multiple drilling positions in the same tunnel to obtain a single tunnel geological model includes: Based on the in-situ testing of surrounding rock at multiple drilling positions along the axial direction of the same roadway, a single roadway geological model is obtained; Based on the geological model of a single tunnel, the interpolation method and thermal cloud map characterization method are used to obtain the rock mass distribution cloud map along the axial direction of the tunnel.

7. The surrounding rock quality evaluation method according to claim 5, characterized in that: The interpolation method and thermal cloud image representation method are used to construct a two-dimensional rock mass distribution model along the tunnel strike and a three-dimensional rock mass distribution model at the working face.

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