Method and device for classifying surrounding rock of large underground cavern in complex layered rock mass

Abstract

The application discloses a large-scale underground cavern surrounding rock grading correction method and device for complex layered rock mass, which comprises the following steps: step S1: for the tunnel section where the tunnel body is located in the same type of tilted stratum, basic surrounding rock grading is carried out to obtain the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum; step S2: judging the complex layered rock mass structure combination type and layer thickness proportion, the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum is respectively graded and corrected to obtain the corrected surrounding rock grade. According to the grading correction of the initial surrounding rock grade according to the complex layered rock mass structure combination type and the layer thickness proportion, the subjective influence is reduced, and through the surrounding rock grade quantization, the tunnel surrounding rock classification effect is remarkable.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of surrounding rock classification, in particular to a surrounding rock classification correction method for large underground caverns in complex layered rock masses and a device thereof. BACKGROUND

[0002] At present, a large number of tunnels with complex geological conditions have emerged, which have the common characteristics that the lithological combination relationship of surrounding rock is complex, and the tunnel body passes through strata with different degrees of tilting, but the existing tunnel design specification does not consider the influence of the structure combination type and layer thickness ratio of complex layered rock masses, and only considers the influence of tunnel burial depth for safety consideration, so that the accurate tunnel surrounding rock classification result cannot be obtained.

[0003] The existing surrounding rock classification method has the following problems:

[0004] (1) Although the existing tunnel surrounding rock classification considers the influence of factors such as rock mass strength and integrity coefficient, the current tunnel surrounding rock classification management method does not consider the structure combination type and layer thickness ratio of complex layered rock masses, and the method for composite layered surrounding rock classification is missing.

[0005] (2) At present, the method combining quantification and qualitative is used for surrounding rock classification, generally, the geological engineer proposes the classification grade of surrounding rock, and the tunnel engineer proposes the engineering measures respectively according to different surrounding rock grades, and considers the influence of factors such as tunnel burial depth, underground water, ground temperature and heat in different degrees, but only relying on engineers is greatly affected by human factors, and the geological engineer often over-considered or did not consider comprehensively, resulting in inaccurate surrounding rock grade division and causing safety hazards or waste of engineering resources.

[0006] (3) The existing specification does not clearly regulate the tilting, unloading and weathering degree of underground cavern surrounding rock, resulting in subjective arbitrariness in the classification of underground cavern surrounding rock, and due to the large amount of engineering, the engineering design measures cannot effectively deal with this part of the risk, which may be insufficient or wasteful; but for the surrounding rock classification of large underground cavern groups with obvious tilting deformation, the influence of different degrees of tilting needs to be considered comprehensively.

[0007] For example, the stratum lithology of a large underground cavern tunnel is the lower Permian Jidong Long Formation (P1j) and the upper Triassic Hongpo Formation (T3hn), in which the main bedrock lithology is: metamorphic basalt, metamorphic sandstone, slate, mudstone and marlstone combination. The rock mass structure type combination relationship is mainly soft-hard-soft, hard-soft-hard, and the layer thickness is uneven.

[0008] According to the public method of “Code for Geological Exploration of Water Conservancy and Hydropower Engineering”, the basic surrounding rock classification of the stratum lithology of the underground cavern tunnel is mainly grade II and III surrounding rock, and part is grade IV and V surrounding rock.

[0009] However, the above surrounding rock classification method does not consider the influence of the layered rock mass structure combination type and layer thickness proportion on the decomposition result, resulting in low accuracy of the decomposition result.

[0010] Since the simpler the layered rock mass combination relationship is, the stronger the surrounding rock arch forming ability is, and the more complex the layered rock mass combination relationship is, the weaker the surrounding rock arch forming ability is, for safety consideration, a simple layered rock mass combination relationship is inclined to be used in surrounding rock classification, but such classification method can meet the safety requirement, but will cause waste of surrounding rock resources.

[0011] In order to improve the accuracy of surrounding rock classification, avoid human factor interference, and avoid waste of surrounding rock resources, a more accurate surrounding rock classification correction method is needed. SUMMARY

[0012] The application provides a complex layered rock mass large underground cavern surrounding rock classification correction method, which fully considers the complex layered rock mass structure combination type and layer thickness proportion in surrounding rock classification, and improves the accuracy of the classification result.

[0013] The application provides a complex layered rock mass large underground cavern surrounding rock classification correction method, which includes the following steps:

[0014] Step S1: for the tunnel section where the tunnel body is located in the same type of tilted stratum, basic surrounding rock classification is carried out to obtain the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum;

[0015] Step S2: judging the complex layered rock mass structure combination type and layer thickness proportion of the tunnel section, the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum is respectively classified and corrected to obtain the corrected surrounding rock grade;

[0016] The initial surrounding rock grade includes:

[0017] The initial surrounding rock grade of the tunnel body located in Q1 / Q2 stratum is II, III, IV and V;

[0018] The initial surrounding rock grade of the tunnel body located in Q3 stratum is III, IV and V;

[0019] The initial surrounding rock grade of the tunnel body located in Q4 stratum is IV and V;

[0020] Wherein, Q1 represents non-tilted rock mass, Q2 represents weakly tilted rock mass, Q3 represents strongly tilted rock mass, and Q4 represents extremely strongly tilted rock mass.

[0021] Preferably, the initial surrounding rock grade of the tunnel body located in Q1 / Q2 stratum is corrected according to the following steps:

[0022] Step S211: determining whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, if the determination result is yes, no modification is made, and if the determination result is no, the next step is performed;

[0023] Step S212: determining whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, if the determination result is yes, the initial surrounding rock grade II, III, IV and V is modified to III, IV, V and V, and if the determination result is no, the next step is performed;

[0024] Step S213: determining whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is less than 30%, if the determination result is yes, no modification is made, and if the determination result is no, the next step is performed;

[0025] Step S214: determining whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is 30% to 50%, if the determination result is yes, the initial surrounding rock grade II, III, IV and V is modified to III, IV, V and V, and if the determination result is no, the next step is performed;

[0026] Step S215: determining whether the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is greater than 50%, if the determination result is yes, the initial surrounding rock grade II, III, IV and V is modified to IV, IV, V and V.

[0027] Preferably, the initial surrounding rock grade of the tunnel body located in the Q3 stratum is modified according to the following steps:

[0028] Step S221: determining whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, if the determination result is yes, no modification is made, and if the determination result is no, the next step is performed;

[0029] Step S222: determining whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, if the determination result is yes, the initial surrounding rock grade III, IV and V is modified to IV, IV and V, and if the determination result is no, the next step is performed;

[0030] Step S223: determining whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is less than 50%, if the determination result is yes, no modification is made, and if the determination result is no, the next step is performed;

[0031] Step S224: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 50%, if the result is yes, the initial surrounding rock grade III, IV, V is corrected to IV, V, V.

[0032] Preferably, the initial surrounding rock grade of the tunnel body located in Q4 stratum is corrected in the following steps:

[0033] Step S231: judging whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is less than 30%, if the result is no, the next step is performed;

[0034] Step S232: judging whether the complex layered rock mass structure combination type is hard-soft-hard and the soft rock layer thickness ratio is greater than 30%, if the result is yes, the initial surrounding rock grade IV, V is corrected to V, V, if the result is no, the next step is performed;

[0035] Step S233: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is less than 30%, if the result is yes, no correction is performed, if the result is no, the next step is performed;

[0036] Step S234: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 30%, if the result is yes, the initial surrounding rock grade IV, V is corrected to V, V.

[0037] Another aspect of the present application also provides a complex layered rock mass large underground cavern surrounding rock grading correction device for the method as described above, comprising:

[0038] An initial grading module is used for basic surrounding rock grading for the tunnel section located in the same type of dump stratum, to obtain the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum;

[0039] A correction module is used for judging the complex layered rock mass structure combination type and the layer thickness ratio of the tunnel section, and grading correction is performed on the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum respectively, to obtain the corrected surrounding rock grade; the initial surrounding rock grade comprises:

[0040] The initial surrounding rock grade of the tunnel body located in Q1 / Q2 stratum is II, III, IV, V;

[0041] The initial surrounding rock grade of the tunnel body located in Q3 stratum is III, IV, V;

[0042] The initial surrounding rock grade of the tunnel body located in Q4 stratum is IV, V;

[0043] Wherein, Q1 represents an un-poured rock mass, Q2 represents a weak-poured rock mass, Q3 represents a strong-poured rock mass, and Q4 represents an extremely strong-poured rock mass.

[0044] Preferably, the correction module comprises:

[0045] The first Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0046] The second Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to III, IV, V and V, and if the judgment result is no, the next step is performed.

[0047] The third Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is less than 30%, if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0048] The fourth Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is 30% to 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to III, IV, V and V, and if the judgment result is no, the next step is performed.

[0049] The fifth Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to IV, IV, V and V.

[0050] Preferably, the correction module comprises:

[0051] The first Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0052] The second Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade III, IV and V is corrected to IV, IV and V, and if the judgment result is no, the next step is performed.

[0053] The third Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness accounts for less than 50%, and if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0054] The fourth Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness accounts for more than 50%, and if the judgment result is yes, the initial surrounding rock grade III, IV and V is corrected to IV, V and V.

[0055] Preferably, the correction module comprises:

[0056] The first Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness accounts for less than 30%, and no correction is performed, and if the judgment result is no, the next step is performed.

[0057] The second Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness accounts for more than 30%, and if the judgment result is yes, the initial surrounding rock grade IV and V is corrected to V and V, and if the judgment result is no, the next step is performed.

[0058] The third Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness accounts for less than 30%, and if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0059] The fourth Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness accounts for more than 30%, and if the judgment result is yes, the initial surrounding rock grade IV and V is corrected to V and V.

[0060] The application can produce beneficial effects, including:

[0061] 1) The complex layered rock mass large underground cavern surrounding rock classification correction method provided by the application corrects the initial surrounding rock grade according to the complex layered rock mass structure combination type and the layer thickness ratio, reduces the subjective influence, and through the surrounding rock grade quantization, the tunnel surrounding rock classification correction effect is remarkable.

[0062] 2) The complex stratified rock mass large underground cavern surrounding rock classification correction method provided by the application is used for basic surrounding rock classification of a tunnel body section located in the same type of tilted stratum, and a surrounding rock classification correction method based on a complex stratified rock mass structure combination type and a layer thickness proportion is introduced to correct the basic surrounding rock grade, so as to quantize and standardize the tunnel surrounding rock classification. After the surrounding rock grade is corrected by using the method, the III-grade surrounding rock is increased by 28.76%, and the IV-grade and V-grade surrounding rocks are reduced correspondingly. Through the quantization of the surrounding rock grade, the surrounding rock classification correction effect is remarkable, and the accuracy of the surrounding rock grade division can be effectively improved BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 The complex stratified rock mass large underground cavern surrounding rock classification correction method provided by the application is shown in the figure;

[0064] Figure 2 The complex stratified rock mass large underground cavern surrounding rock classification correction device provided by the application is shown in the figure;

[0065] Figure 3 The complex stratified rock mass large underground cavern Q1 / Q2 stratum surrounding rock classification correction device provided by the application is shown in the figure;

[0066] Figure 4 The complex stratified rock mass large underground cavern Q3 stratum surrounding rock classification correction device provided by the application is shown in the figure;

[0067] Figure 5 The complex stratified rock mass large underground cavern Q4 stratum surrounding rock classification correction device provided by the application is shown in the figure; DETAILED DESCRIPTION

[0068] In order to make the objects, technical solutions, and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described below in connection with the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, rather than all the embodiments of the application. The components of the embodiments of the application described and shown in the drawings can be arranged and designed in various different configurations.

[0069] Therefore, the following detailed description of the embodiments of the application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0070] The technical means not described in detail in the application and not used to solve the technical problems of the application are set according to common knowledge in the art, and various common knowledge setting modes can be implemented.

[0071] Referring to Figure 1 The application provides a large underground cavern surrounding rock classification correction method of complex stratified rock mass, comprising the following steps:

[0072] Step S1: for a tunnel section where the tunnel body is located in the same type of tilted stratum, performing basic surrounding rock classification to obtain initial surrounding rock grades of the tunnel body located in Q1-Q4 stratum;

[0073] Step S2: judging the complex stratified rock mass structure combination type and layer thickness proportion of the tunnel section, and respectively correcting the initial surrounding rock grades of the tunnel body located in Q1-Q4 stratum to obtain the corrected surrounding rock grades;

[0074] The initial surrounding rock grades include:

[0075] The initial surrounding rock grades of the tunnel body located in Q1 / Q2 stratum are II, III, IV and V;

[0076] The initial surrounding rock grades of the tunnel body located in Q3 stratum are III, IV and V;

[0077] The initial surrounding rock grades of the tunnel body located in Q4 stratum are IV and V;

[0078] Wherein, Q1 represents an un-tilted rock mass, Q2 represents a weakly tilted rock mass, Q3 represents a strongly tilted rock mass, and Q4 represents an extremely strongly tilted rock mass.

[0079] The method takes the complex stratified rock mass structure combination type and layer thickness proportion as the main concern, and after correcting the existing specification classification results, the proportion of high-grade surrounding rock in the classification results can be effectively reduced, and the classification results are more reasonable.

[0080] Preferably, the initial surrounding rock grades of the tunnel body located in Q1 / Q2 stratum are corrected according to the following steps:

[0081] Step S211: judging whether the complex stratified rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness proportion is less than 50%, if the result is yes, no correction is performed, and if the result is no, the next step is performed;

[0082] Step S212: judging whether the complex stratified rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness proportion is greater than 50%, if the result is yes, the initial surrounding rock grades II, III, IV and V are corrected to III, IV, V and V, and if the result is no, the next step is performed;

[0083] Step S213: judging whether the complex stratified rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness proportion is less than 30%, if the result is yes, no correction is performed, and if the result is no, the next step is performed;

[0084] Step S214: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is 30% to 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is modified to III, IV, V and V, and if the judgment result is no, the next step is judged;

[0085] Step S215: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is modified to IV, IV, V and V.

[0086] Preferably, the initial surrounding rock grade of the tunnel body located in Q3 stratum is modified by the following steps:

[0087] Step S221: judging whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no modification is made, and if the judgment result is no, the next step is judged;

[0088] Step S222: judging whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade III, IV and V is modified to IV, IV and V, and if the judgment result is no, the next step is judged;

[0089] Step S223: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no modification is made, and if the judgment result is no, the next step is judged;

[0090] Step S224: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade III, IV and V is modified to IV, V and V.

[0091] Preferably, the initial surrounding rock grade of the tunnel body located in Q4 stratum is modified by the following steps:

[0092] Step S231: judging whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is less than 30%, no modification is made, and if the judgment result is no, the next step is judged;

[0093] Step S232: judging whether the complex layered rock mass structure combination type is hard-soft-hard and the soft rock layer thickness ratio is greater than 30%, if the judgment result is yes, the initial surrounding rock grade IV and V is modified to V and V, and if the judgment result is no, the next step is judged;

[0094] Step S233: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is less than 30%, if the judgment result is yes, no correction is made, and if the judgment result is no, the next step is judged;

[0095] Step S234: judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 30%, if the judgment result is yes, the initial surrounding rock grade IV and V are corrected to V and V.

[0096] The existing technology does not consider the influence of the complex layered rock mass structure combination type and the layer thickness ratio on the surrounding rock classification.

[0097] The application proposes a new surrounding rock classification correction method, which classifies and corrects the initial surrounding rock grade according to the complex layered rock mass structure combination type and the layer thickness ratio, reduces the subjective influence, and significantly improves the tunnel surrounding rock classification effect through the surrounding rock grade quantization.

[0098] For the tunnel section where the tunnel body section is located in the same type of dumped stratum, the basic surrounding rock classification is performed according to the specification, and the surrounding rock classification correction method based on the complex layered rock mass structure combination type and the layer thickness ratio is introduced to correct the basic surrounding rock grade, thereby playing a role in quantizing and standardizing the tunnel surrounding rock classification.

[0099] Referring to Figures 2-5 Another aspect of the application also provides a complex layered rock mass large underground cavern surrounding rock classification correction device for the above-mentioned method, which comprises:

[0100] An initial classification module is configured to perform basic surrounding rock classification on the tunnel section where the tunnel body section is located in the same type of dumped stratum, and obtain the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum.

[0101] A correction module is configured to judge the complex layered rock mass structure combination type and the layer thickness ratio of the tunnel section, and classify and correct the initial surrounding rock grade of the tunnel body located in Q1-Q4 stratum respectively, so as to obtain the corrected surrounding rock grade.

[0102] The initial surrounding rock grade of the tunnel body located in Q1 / Q2 stratum is II, III, IV and V.

[0103] The initial surrounding rock grade of the tunnel body located in Q3 stratum is III, IV and V.

[0104] The initial surrounding rock grade of the tunnel body located in Q4 stratum is IV and V.

[0105] Wherein, Q1 represents an undumped rock mass, Q2 represents a weak dumped rock mass, Q3 represents a strong dumped rock mass, and Q4 represents an extremely strong dumped rock mass.

[0106] Preferably, the correction module comprises:

[0107] The first Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0108] The second Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to III, IV, V and V, and if the judgment result is no, the next step is performed.

[0109] The third Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is less than 30%, if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0110] The fourth Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is 30% to 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to III, IV, V and V, and if the judgment result is no, the next step is performed.

[0111] The fifth Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to IV, IV, V and V.

[0112] Preferably, the correction module comprises:

[0113] The first Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed.

[0114] The second Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade III, IV and V is corrected to IV, IV and V, and if the judgment result is no, the next step is performed.

[0115] The third Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is less than 50%, and if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed;

[0116] The fourth Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is greater than 50%, and if the judgment result is yes, the initial surrounding rock grade III, IV and V is corrected to IV, V and V.

[0117] Preferably, the correction module comprises:

[0118] The first Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is less than 30%, and no correction is performed, and if the judgment result is no, the next step is performed;

[0119] The second Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is greater than 30%, and if the judgment result is yes, the initial surrounding rock grade IV and V is corrected to V and V, and if the judgment result is no, the next step is performed;

[0120] The third Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is less than 30%, and if the judgment result is yes, no correction is performed, and if the judgment result is no, the next step is performed;

[0121] The fourth Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is greater than 30%, and if the judgment result is yes, the initial surrounding rock grade IV and V is corrected to V and V.

[0122] The surrounding rock classification result is corrected by using the device, and the III grade surrounding rock is increased by 28.76%, and the IV and V grade surrounding rocks are correspondingly reduced. Through the quantification of the surrounding rock grade, the surrounding rock classification correction effect of the tunnel is remarkable.

[0123] Embodiment

[0124] The method used in the embodiment comprises the following steps:

[0125] Step 1: for the tunnel section where the tunnel body section is located in the same type of inclined stratum, the basic surrounding rock classification is performed by using the method provided in the relevant engineering specification of the “Hydropower Engineering Geological Exploration Specification (GB50287-2006)”;

[0126] The obtained initial surrounding rock grade is specifically:

[0127] For the tunnel body located in Q1 / Q2 stratum, the basic surrounding rock classification is obtained, and the initial surrounding rock grades are II, III, IV and V;

[0128] For the tunnel body located in Q3 stratum, the basic surrounding rock classification is obtained, and the initial surrounding rock grades are III, IV and V;

[0129] For the tunnel body located in Q4 stratum, the basic surrounding rock classification is obtained, and the initial surrounding rock grades are IV and V;

[0130] Wherein, Q1-Q4 represents the dumping degree of surrounding rock, Q1 represents no dumping (normal rock mass), Q2 represents weak dumping, Q3 represents strong dumping, and Q4 represents extremely strong dumping.

[0131] Step 2: For the initial surrounding rock grades II, III, IV and V of the tunnel body located in Q1 / Q2 stratum, the complex layered rock mass structure combination type and the layer thickness ratio are corrected;

[0132] For the initial surrounding rock grades III, IV and V of the tunnel body located in Q3 stratum, the complex layered rock mass structure combination type and the layer thickness ratio are corrected;

[0133] For the initial surrounding rock grades IV and V of the tunnel body located in Q4 stratum, the complex layered rock mass structure combination type and the layer thickness ratio are corrected.

[0134] Wherein, for the initial surrounding rock grades II, III, IV and V of the tunnel body located in Q1 and Q2 stratum, the complex layered rock mass structure combination type and the layer thickness ratio are corrected, and the specific correction is shown in Table 1:

[0135] (1) When the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, no correction is made, and the classification is still according to the initial surrounding rock grades II, III, IV and V;

[0136] (2) When the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, the initial surrounding rock grades II, III, IV and V are corrected to III, IV, V and V;

[0137] (3) When the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is less than 30%, no correction is made, and the classification is still according to the initial surrounding rock grades II, III, IV and V;

[0138] (4) When the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is 30% to 50%, the initial surrounding rock grades II, III, IV and V are corrected to III, IV, V and V;

[0139] (5) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the thickness ratio of soft rock layer is greater than 50%, the initial surrounding rock grade II, III, IV, V is modified to IV, IV, V, V.

[0140] Table 1 Q1 / Q2 stratum surrounding rock classification correction table

[0141]

[0142]

[0143] For the initial surrounding rock grade III, IV, V of the tunnel body located in Q3 stratum, the complex layered rock mass structure combination type and the layer thickness ratio are modified as shown in Table 2:

[0144] (1) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the thickness ratio of soft rock layer is less than 50%, no modification is made, and the initial surrounding rock grade III, IV, V is still classified;

[0145] (2) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the thickness ratio of soft rock layer is greater than 50%, the initial surrounding rock grade III, IV, V is modified to IV, IV, V;

[0146] (3) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the thickness ratio of soft rock layer is less than 50%, no modification is made, and the initial surrounding rock grade III, IV, V is still classified;

[0147] (4) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the thickness ratio of soft rock layer is greater than 50%, the initial surrounding rock grade III, IV, V is modified to IV, V, V.

[0148] Table 2 Q3 stratum surrounding rock classification correction table

[0149] Initial surrounding rock grade Ⅲ Ⅳ Ⅴ Hard-soft-hard, soft rock layer thickness ratio less than 50% Ⅲ Ⅳ Ⅴ Hard-soft-hard, soft rock layer thickness ratio greater than 50% Ⅳ Ⅳ Ⅴ Soft-hard-soft, soft rock layer thickness ratio less than 50% Ⅲ Ⅳ Ⅴ Soft-hard-soft, soft rock layer thickness ratio greater than 50% Ⅳ Ⅴ Ⅴ

[0150] For the initial surrounding rock grade IV, V of the tunnel body located in Q4 stratum, the complex layered rock mass structure combination type and the layer thickness ratio are modified as shown in Table 3:

[0151] (1) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the thickness ratio of soft rock layer is less than 30%, no modification is made, and the initial surrounding rock grade IV, V is still classified;

[0152] (2) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the thickness ratio of soft rock layer is greater than 30%, the initial surrounding rock grade IV and V are corrected to V and V;

[0153] (3) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the thickness ratio of soft rock layer is less than 30%, no correction is made, and the initial surrounding rock grade IV and V are still classified according to the initial surrounding rock grade IV and V;

[0154] (4) When the tunnel is of the same type as the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the thickness ratio of soft rock layer is greater than 30%, the initial surrounding rock grade IV and V are corrected to V and V.

[0155] Table 3 Q4 stratum surrounding rock classification correction table

[0156] Initial surrounding rock grade Ⅳ Ⅴ Hard-soft-hard, soft rock layer thickness ratio less than 30% Ⅳ Ⅴ Hard-soft-hard, soft rock layer thickness ratio greater than 30% Ⅴ Ⅴ Soft-hard-soft, soft rock layer thickness ratio less than 30% Ⅳ Ⅴ Soft-hard-soft, soft rock layer thickness ratio greater than 30% Ⅴ Ⅴ

[0157] In this embodiment, the initial classification results of the surrounding rock class of the underground cavern group of Gushui Hydropower Station are corrected by using the above method, and the comparison results before and after correction are shown in Table 4.

[0158] Table 4 Comparison of surrounding rock grade statistics before and after correction

[0159] Surrounding rock grade Before correction After correction Increase / decrease number Increase / decrease ratio Ⅱ 138 158 20 14.49％ Ⅲ 963 1240 277 28.76％ Ⅳ 565 422 -143 -25.31％ Ⅴ 734 580 -154 -20.98％ Total 2400 2400 — —

[0160] As can be seen from Table 4, by using the method provided in the present application to correct the surrounding rock grade, the III grade surrounding rock is increased by 28.76%, and the IV and V grade surrounding rocks are correspondingly reduced. Through the quantification of the surrounding rock grade, the surrounding rock classification correction effect is remarkable, the accuracy of the surrounding rock grade division can be effectively improved, the proportion of high-risk surrounding rock can be reduced, the classification results can be rationalized, waste can be effectively avoided, and safety can be considered.

[0161] As a second embodiment of the present application, a surrounding rock classification correction device based on the complex layered rock mass structure combination type and the layer thickness ratio is provided, which comprises a basic surrounding rock classification module and an initial surrounding rock correction module. The basic surrounding rock classification module is used to classify the basic surrounding rock of the tunnel section where the tunnel body section is located in the same type of dumping stratum by using the method specified in the specification, to obtain the initial surrounding rock grade. The initial surrounding rock correction module is used to classify and correct the initial surrounding rock grade according to the complex layered rock mass structure combination type and the layer thickness ratio, to obtain the corrected surrounding rock grade.

[0162] Further, the basic surrounding rock classification module classifies the basic surrounding rock of the tunnel section where the tunnel body section is located in the same type of dumping stratum by using the method specified in the specification, to obtain the initial surrounding rock grade, which is specifically:

[0163] For the tunnel body located in Q1 / Q2 stratum, the initial surrounding rock classification is II, III, IV and V; for the tunnel body located in Q3 stratum, the initial surrounding rock classification is III, IV and V; for the tunnel body located in Q4 stratum, the initial surrounding rock classification is IV and V; wherein, Q1-Q4 represents the dumping degree of surrounding rock, Q1 represents no dumping (normal rock mass), Q2 represents weak dumping, Q3 represents strong dumping, and Q4 represents extremely strong dumping.

[0164] Further, the initial surrounding rock correction module corrects the initial surrounding rock classification according to the complex layered rock mass structure combination type and the layer thickness proportion, and obtains the corrected surrounding rock classification, which is: the initial surrounding rock classification II, III, IV and V of the tunnel body located in Q1 / Q2 stratum is corrected according to the complex layered rock mass structure combination type and the layer thickness proportion; the initial surrounding rock classification III, IV and V of the tunnel body located in Q3 stratum is corrected according to the complex layered rock mass structure combination type and the layer thickness proportion; the initial surrounding rock classification IV and V of the tunnel body located in Q4 stratum is corrected according to the complex layered rock mass structure combination type and the layer thickness proportion.

[0165] The correction of the initial surrounding rock classification II, III, IV and V of the tunnel body located in Q1 / Q2 stratum according to the complex layered rock mass structure combination type and the layer thickness proportion is: (1) when the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness proportion is less than 50%, no correction is made, and the classification is still according to the initial surrounding rock classification II, III, IV and V; (2) when the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness proportion is greater than 50%, the initial surrounding rock classification II, III, IV and V is corrected to III, IV, V and V; (3) when the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness proportion is less than 30%, no correction is made, and the classification is still according to the initial surrounding rock classification II, III, IV and V; (4) when the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness proportion is 30%-50%, the initial surrounding rock classification II, III, IV and V is corrected to III, IV, V and V; (5) when the tunnel is of the same type of dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness proportion is greater than 50%, the initial surrounding rock classification II, III, IV and V is corrected to IV, IV, V and V.

[0166] When the initial surrounding rock grade of the tunnel body located in Q3 stratum is III, IV, V, the initial surrounding rock grade is modified according to the complex layered rock mass structure combination type and the layer thickness ratio, and the modification is as follows: (1) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, no modification is made, and the initial surrounding rock grade III, IV, V is still used for grading; (2) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, the initial surrounding rock grade III, IV, V is modified to IV, IV, V; (3) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is less than 50%, no modification is made, and the initial surrounding rock grade III, IV, V is still used for grading; (4) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is greater than 50%, the initial surrounding rock grade III, IV, V is modified to IV, V, V.

[0167] When the initial surrounding rock grade of the tunnel body located in Q4 stratum is IV, V, the initial surrounding rock grade is modified according to the complex layered rock mass structure combination type and the layer thickness ratio, and the modification is as follows: (1) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is less than 30%, no modification is made, and the initial surrounding rock grade IV, V is still used for grading; (2) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is hard-soft-hard, and the soft rock layer thickness ratio is greater than 30%, the initial surrounding rock grade IV, V is modified to V, V; (3) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is less than 30%, no modification is made, and the initial surrounding rock grade IV, V is still used for grading; (4) when the tunnel is of the same type and is located in the dumping tunnel section, the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is greater than 30%, the initial surrounding rock grade IV, V is modified to V, V.

[0168] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some of the technical features, and 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 modifying the classification of surrounding rock of a large underground cavern in a complex stratified rock mass, characterized in that, Comprising the following steps: Step S1: For the tunnel section where the tunnel body is located in the same type of dumping stratum, the basic surrounding rock classification is carried out, and the initial surrounding rock grade of the tunnel body located in Q1~4 stratum is obtained; Step S2: Determine the complex layered rock mass structure combination type and layer thickness ratio of the tunnel section, and respectively classify and correct the initial surrounding rock grade of the tunnel body located in Q1~4 stratum to obtain the corrected surrounding rock grade; The initial surrounding rock grade includes: The initial surrounding rock grade of the tunnel body located in Q1 / Q2 stratum is II, III, IV, V; The initial surrounding rock grade of the tunnel body located in Q3 stratum is III, IV, V; The initial surrounding rock grade of the tunnel body located in Q4 stratum is IV, V; Wherein, Q1 represents undumped rock mass, Q2 represents weakly dumped rock mass, Q3 represents strongly dumped rock mass, and Q4 represents extremely strongly dumped rock mass; The initial surrounding rock grade of the tunnel body located in Q1 / Q2 stratum is corrected as follows: Step S211: Determine whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no correction is made, and if the judgment result is no, the next step is determined; Step S212: Determine whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV, V is corrected to III, IV, V, V, and if the judgment result is no, the next step is determined; Step S213: Determine whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is less than 30%, if the judgment result is yes, no correction is made, and if the judgment result is no, the next step is determined; Step S214: Determine whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is 30%~50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV, V is corrected to III, IV, V, V, and if the judgment result is no, the next step is determined; Step S215: Determine whether the complex layered rock mass structure combination type is soft-hard-soft, and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade II, III, IV, V is corrected to IV, IV, V, V; The initial surrounding rock grade of the tunnel body located in Q3 stratum is corrected as follows: Step S221: Determine whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no correction is made, and if the judgment result is no, the next step is determined; Step S222: Determine whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the soft rock layer thickness ratio is greater than 50%, if the judgment result is yes, the initial surrounding rock grade III, IV, V is corrected to IV, IV, V, and if the judgment result is no, the next step is determined; Step S223: Determine whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the soft rock layer thickness ratio is less than 50%, if the judgment result is yes, no correction is made, and if the judgment result is no, the next step is determined; Step S224: If the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the thickness ratio of soft rock layer is greater than 50%, the initial surrounding rock grade III, IV and V is corrected to IV, V and V respectively. The initial surrounding rock grade of the tunnel body located in Q4 stratum is corrected according to the following steps: Step S231: If the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the thickness ratio of soft rock layer is less than 30%, no correction is made, and the next step is performed if the result is false. Step S232: If the complex layered rock mass structure combination type is hard-soft-hard, and the thickness ratio of soft rock layer is greater than 30%, the initial surrounding rock grade IV and V is corrected to V and V respectively if the result is true, and the next step is performed if the result is false. Step S233: If the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the thickness ratio of soft rock layer is less than 30%, no correction is made if the result is true, and the next step is performed if the result is false. Step S234: If the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the thickness ratio of soft rock layer is greater than 30%, the initial surrounding rock grade IV and V is corrected to V and V respectively if the result is true.

2. A device for the correction of the classification of the surrounding rock of large underground caverns of complex layered rock mass, according to the method of claim 1, characterized in that, Comprise: An initial grading module for grading the basic surrounding rock of the tunnel section located in the same type of tilted stratum to obtain the initial surrounding rock grade of the tunnel body located in Q1~4 stratum; A correction module for judging the complex layered rock mass structure combination type and the layer thickness ratio of the tunnel section, and correcting the initial surrounding rock grade of the tunnel body located in Q1~4 stratum respectively to obtain the corrected surrounding rock grade; the initial surrounding rock grade comprises: The initial surrounding rock grade of the tunnel body located in Q1 / Q2 stratum is II, III, IV and V; The initial surrounding rock grade of the tunnel body located in Q3 stratum is III, IV and V; The initial surrounding rock grade of the tunnel body located in Q4 stratum is IV and V; Wherein, Q1 represents an un-tilted rock mass, Q2 represents a weakly tilted rock mass, Q3 represents a strongly tilted rock mass, and Q4 represents an extremely strongly tilted rock mass; The correction module comprises: A first Q1 / Q2 stratum judgment correction module for judging whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the thickness ratio of soft rock layer is less than 50%, and no correction is made if the result is true, and the next step is performed if the result is false; A second Q1 / Q2 stratum judgment correction module for judging whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard, and the thickness ratio of soft rock layer is greater than 50%, and the initial surrounding rock grade II, III, IV and V is corrected to III, IV, V and V respectively if the result is true, and the next step is performed if the result is false; A third Q1 / Q2 stratum judgment correction module for judging whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft, and the thickness ratio of soft rock layer is less than 30%, and no correction is made if the result is true, and the next step is performed if the result is false; The fourth Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is 30% to 50%. If the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to III, IV, V and V. If the judgment result is no, the next step is performed. The fifth Q1 / Q2 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 50%. If the judgment result is yes, the initial surrounding rock grade II, III, IV and V is corrected to IV, IV, V and V. The correction module comprises: The first Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is less than 50%. If the judgment result is yes, no correction is performed. If the judgment result is no, the next step is performed. The second Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is hard-soft-hard and the soft rock layer thickness ratio is greater than 50%. If the judgment result is yes, the initial surrounding rock grade III, IV and V is corrected to IV, IV and V. If the judgment result is no, the next step is performed. The third Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is less than 50%. If the judgment result is yes, no correction is performed. If the judgment result is no, the next step is performed. The fourth Q3 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type of the tunnel section is soft-hard-soft and the soft rock layer thickness ratio is greater than 50%. If the judgment result is yes, the initial surrounding rock grade III, IV and V is corrected to IV, V and V. The correction module comprises: The first Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is hard-soft-hard and the soft rock layer thickness ratio is less than 30%. If the judgment result is yes, no correction is performed. If the judgment result is no, the next step is performed. The second Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is hard-soft-hard and the soft rock layer thickness ratio is greater than 30%. If the judgment result is yes, the initial surrounding rock grade IV and V is corrected to V and V. If the judgment result is no, the next step is performed. The third Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is soft-hard-soft and the soft rock layer thickness ratio is less than 30%. If the judgment result is yes, no correction is performed. If the judgment result is no, the next step is performed. The fourth Q4 stratum judgment correction module is configured to judge whether the complex layered rock mass structure combination type is soft-hard-soft and the soft rock layer thickness ratio is greater than 30%. If the judgment result is yes, the initial surrounding rock grade IV and V is corrected to V and V.

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