A surrounding rock grading system and grading method suitable for a boom roadheader construction

Abstract

The application discloses a surrounding rock grading system and grading method suitable for cantilever heading machine construction, and the method comprises the following steps: S1, grading the stratum influencing factor indexes of the cantilever heading machine according to the preliminary geological exploration results; S2, summing up the scores of the indexes by using the sum and difference method, obtaining the adaptability total score, and grading the stratum adaptability of the cantilever heading machine; S3, introducing a surrounding rock drilling and excavating index RPI, and grading the drivability of the cantilever heading construction; and S4, comprehensively grading the surrounding rock stratum geology in combination with the adaptability grading and the drivability grading. The method can save the tunnel excavation cost and improve the construction efficiency of the cantilever heading machine by considering the key factors influencing the cantilever heading machine construction, establishing the adaptability grading and the drivability grading of the surrounding rock of the cantilever heading machine construction, and establishing the surrounding rock grading system of the cantilever heading machine construction based on the heading performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underground engineering rock mass classification, and particularly relates to a surrounding rock classification system and method suitable for cantilever excavator construction. BACKGROUND

[0002] In recent years, with the acceleration of urbanization process in China, in order to solve the problem of urban public transportation, the subway engineering is booming. In the construction of subway engineering in mountainous towns, the station and the interval tunnel are inevitably adjacent to or pass through the densely populated downtown area. The accident rate of blasting excavation engineering is high, and the shield method and TBM are also difficult to apply in poor geology. Therefore, the cantilever excavator technology emerges as the times require. The determination of surrounding rock classification and its mechanical parameters is the basis for the design and construction of underground space engineering. The current specifications such as “Railway Tunnel Design Specification” TB10003-2016, “Engineering Rock Mass Classification Standard” GB / T50218-2014 and “Urban Rail Transit Geotechnical Engineering Investigation Specification” GB50307-2012 stipulate that the current railway tunnel surrounding rock classification adopts the classification method based on the stability of surrounding rock. These surrounding rock classification methods are all based on the traditional blasting excavation method, while the principle of cantilever excavator and traditional mine drilling and blasting excavation is completely different. The existing surrounding rock classification method is not suitable for the construction needs of cantilever excavator excavation. Therefore, it is necessary to study a surrounding rock classification method for cantilever excavator construction.

[0003] Most of the existing and current tunnel surrounding rock classification methods are based on the drilling and blasting method for tunnel construction, and are proposed around the stability of rock. However, there are essential differences between the cantilever excavator construction and the blasting method. The complexity of the interaction between the machine and the rock mass, the uncertainty of the construction process (such as the reduction of rock breaking efficiency caused by tool wear, abnormal downtime caused by adverse geological conditions, etc.), and the uncertainty of the rock mass conditions determine that the traditional rock mass quality classification system for guiding rock blasting method construction cannot be used to design support and guide the construction of cantilever excavator. Therefore, the surrounding rock classification for cantilever excavator construction should be divided according to the rock-machine interaction and the stratum applicability of cantilever excavator, and a more effective surrounding rock classification system should be established.

[0004] However, in the prior art, there is no surrounding rock classification system suitable for the construction of cantilever excavator, and there is no corresponding classification method for adaptively classifying and excavating the surrounding rock during the construction of cantilever excavator. This seriously affects the construction efficiency of cantilever excavator. Therefore, it is urgent to design a surrounding rock classification method suitable for cantilever excavator construction to classify the surrounding rock. SUMMARY

[0005] In view of the above problems, the present application aims to provide a surrounding rock grading system and method suitable for cantilever heading machine construction, which can save tunnel excavation cost and improve the construction efficiency of the cantilever heading machine by considering the key factors affecting the cantilever heading machine construction, establishing adaptability grading and drivability grading of the surrounding rock of the cantilever heading machine construction respectively, and finally establishing a surrounding rock grading system of the cantilever heading machine construction based on the driving performance, and has the characteristics of clear surrounding rock grade division, effective saving of tunnel excavation cost and improvement of the driving efficiency of the cantilever heading machine.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A surrounding rock grading method suitable for cantilever heading machine construction, comprising

[0008] Step S1. Preliminary investigation is performed on the surrounding rock stratum geology of the tunnel, and according to the preliminary geological prospecting result, the stratum influencing factor index grading of the cantilever heading machine is performed;

[0009] Step S2. The sum of the scores of each index is calculated by using the sum-difference method, and the adaptability total score is calculated, and the stratum adaptability grading of the cantilever heading machine is performed;

[0010] Step S3. The surrounding rock drilling index RPI is introduced, and the drivability grading of the cantilever heading machine construction is performed;

[0011] Step S4. The surrounding rock stratum geology is comprehensively graded in combination with the adaptability grading and the drivability grading.

[0012] Preferably, the process of the stratum influencing factor index grading of the cantilever heading machine in step S1 comprises:

[0013] Step S101. Taking the uniaxial compressive strength R c of rock as the index, the utilization rate of the heading machine is divided according to the hardness of the rock;

[0014] Step S102. Taking the rock mass integrity coefficient K v as the index, the utilization rate of the heading machine is divided according to the integrity of the rock mass;

[0015] Step S103. The utilization rate of the heading machine is divided according to the angle between the main structural plane of the rock mass and the tunnel axis;

[0016] Step S104. The utilization rate of the heading machine is divided according to the groundwater state;

[0017] Step S105. The utilization rate of the heading machine is divided according to the initial ground stress state of the surrounding rock.

[0018] Preferably, the process of the stratum adaptability grading of the cantilever heading machine in step S2 comprises:

[0019] Step S201. The scores of each index are summed by using the sum-difference method, i.e.:

[0020] A = A1 + A2 + A3 + A4 + A5

[0021] wherein A is the total score of the adaptability classification, A1 is the score considering the hardness of the rock, A2 is the score considering the completeness of the rock, A3 is the score considering the angle between the structural plane and the tunnel axis, A4 is the score considering the groundwater of the rock, and A5 is the score considering the ground stress;

[0022] Step S202. According to the calculation result of the adaptability total score, the stratum adaptability classification of the boom tunneling machine is determined, taking the average utilization rate of the boom tunneling machine working for 24 hours as 23% as the standard.

[0023] Preferably, the process of the boom tunneling machine drivability classification in step S3 comprises:

[0024] Step S301. Considering the rock-machine interaction, the drilling and tunneling index RPI is introduced, which is defined as P / R c , i.e. the ratio of the power of the boom tunneling machine to the uniaxial compressive strength of the rock mass:

[0025] RPI = 72.23exp(-0.007×[BQ]) (R 2 = 0.88)

[0026] wherein BQ is the basic quality index value of the engineering rock mass:

[0027] [BQ] = (90 + 3R c + 250K v ) - 100(K1 + K2 + K3)

[0028] wherein R c is the saturated compressive strength of the rock, K v is the rock mass integrity coefficient, K1 is the groundwater state of the surrounding rock, K2 is the initial ground stress state of the surrounding rock, and K3 is the combination relationship of the tunnel axis and the occurrence of the structural plane. When R c > 90K v + 30, R c = 90K v + 30 and K v are substituted to calculate the BQ value; when K v > 0.04R c + 0.4, K v = 0.04R c + 0.4 and R c are substituted to calculate the BQ value.

[0029] Step S302. According to the above formula, it can be further transformed as:

[0030] RPI = 72.23exp(0.7(K1+K2+K3))-(0.063+0.021R c +1.75K v );

[0031] Step S303. Establish the rock mass drivability classification standard with the RPI value as the classification index.

[0032] Preferably, the specific classification process of the comprehensive classification of the surrounding rock stratum geology in step S4 comprises:

[0033] Step S401. According to the stratum adaptability classification and the rock mass drivability classification standard divided in steps 202 and 303, and based on the combination of RPI and the influence of the adaptability classification on the cantilever heading machine driving, the surrounding rock construction comprehensive classification is performed by referring to the risk level matrix division principle.

[0034] Step S402. Obtain the surrounding rock stratum geology comprehensive classification table.

[0035] Preferably, the surrounding rock classification system after the stratum geology of the tunnel surrounding rock is classified based on the above-mentioned surrounding rock classification method suitable for the cantilever heading machine construction comprises:

[0036] The first-class surrounding rock has good cantilever heading machine construction conditions.

[0037] The second-class surrounding rock has better cantilever heading machine construction conditions.

[0038] The third-class surrounding rock has general cantilever heading machine construction conditions.

[0039] The fourth-class surrounding rock has poor cantilever heading machine construction conditions.

[0040] The beneficial effects of the present application are as follows: the present application discloses a surrounding rock classification system and method suitable for cantilever heading machine construction, and compared with the prior art, the improvement of the present application is that:

[0041] The present application proposes a surrounding rock classification method suitable for cantilever heading machine construction on the basis of considering the key factors affecting the cantilever heading machine construction, the method establishes the adaptability classification and the drivability classification of the surrounding rock of the cantilever heading machine construction respectively, and finally establishes the surrounding rock classification system of the cantilever heading machine construction based on the driving performance, which guides the cantilever heading machine construction, solves the problem that the existing surrounding rock classification method does not consider the rock mass-machine interaction, saves the tunnel excavation cost, improves the driving efficiency of the cantilever heading machine, and has the advantages of clear surrounding rock grade division, effective saving of tunnel excavation cost, and improvement of the driving efficiency of the cantilever heading machine. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Flow chart of the surrounding rock classification method suitable for the construction of the boom tunneling machine.

[0043] Figure 2 RPI and [BQ] correlation analysis chart of the present application. DETAILED DESCRIPTION

[0044] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions of the present application are further described below in combination with the drawings and examples.

[0045] Example 1: refer to the surrounding rock classification method suitable for the construction of the boom tunneling machine shown in the accompanying drawings, which comprises Figures 1-2 The surrounding rock classification method suitable for the construction of the boom tunneling machine shown in the accompanying drawings, which comprises

[0046] Step S1. Preliminary survey of the surrounding rock stratum geology of the tunnel, according to the preliminary geological survey results, the stratum influencing factor index of the boom tunneling machine is classified

[0047] Specifically, the geological factors affecting the construction of the boom tunneling machine explained in the “Engineering Rock Mass Classification Standard” GB / T50218-2014 are comprehensively considered, the hardness of the rock, the integrity of the rock mass, the groundwater state, the initial ground stress, and the angle between the structural plane and the tunnel axis are introduced into the scoring classification to analyze the influence of the factors on the utilization rate

[0048] Step S101. The uniaxial compressive strength of the rock is taken as an index to classify the utilization rate of the tunneling machine according to the hardness of the rock, and the classification score is shown in Table 1:

[0049] Table 1: Uniaxial compressive strength of rock

[0050]

[0051] In detail, the design mechanism of the boom tunneling machine is that the tensile strength and shear strength of the rock are significantly lower than its compressive strength, so the uniaxial compressive strength of the rock is an important index; according to a large number of studies, R c The larger the value, the harder the rock mass, the more difficult the excavation, and when the R c value is too high, the cutting tooth is severely damaged, which also causes the reduction of the excavation speed; but when the R c value is too low, the machine may have difficulty in self-stabilization, which increases the amount of initial support and reduces the utilization rate of the machine; therefore, only when the uniaxial compressive strength of the surrounding rock is within a reasonable range, the boom tunneling machine can realize self-stabilization and improve the utilization rate;

[0052] Step S102. Take the rock mass integrity coefficient K v as an index to classify the utilization rate of the tunneling machine according to the integrity of the rock mass, and the classification score is shown in Table 2:

[0053] Table 2: Rock mass integrity score table

[0054]

[0055] In detail, another important geological factor affecting the utilization rate of the boom tunneling machine is the development degree of the rock mass structure surface, which is represented by the rock mass integrity coefficient K v , generally speaking, the larger the value of K v , the more complete the rock mass, the higher the difficulty of excavation, when K v value is too large, the pick consumption is large, and the replacement of the pick reduces the utilization rate of the machine; when K v value is too low, the surrounding rock does not have enough time to self-stabilize after the end of the tunneling machine construction, at this time the primary support amount is large, which also has a large impact on the utilization rate; therefore, when K v value is in the middle range, the utilization rate of the machine is the highest;

[0056] Step S103. According to the angle between the main structure surface of the rock mass and the tunnel axis, the utilization rate of the tunneling machine is divided, and the division score is shown in Table 3:

[0057] Table 3: Angle between structure surface and tunnel axis score table

[0058]

[0059] In detail, when the angle between the structure surface and the tunnel axis is 50-70°, it has almost no effect on the utilization rate, when the angle is 40-50°, 70-80° or other, the existence of unstable wedge increases the support amount, thereby affecting the utilization rate of the machine;

[0060] Step S104. According to the state of groundwater, the utilization rate of the tunneling machine is divided, and the division score is shown in Table 4:

[0061] Table 4: Water content state score table of rock mass

[0062]

[0063] In detail, there are generally the following states of groundwater outflow: dry, wet, seepage, dripping, linear flow, stock flow, and tubular gushing; when dry, the dust content in the hole is large, which affects the effective play of the ventilation system and increases the machine failure rate; the wet-seepage state is beneficial to the construction of the boom tunneling machine; dripping has little effect on construction; linear flow brings some difficulty to the surrounding rock reinforcement, and the strength of the advanced support and primary support needs to be increased, which reduces the utilization rate of the machine; stock flow has a greater impact on construction, and advanced strong support measures such as advanced pipe shed and grouting need to be taken; tubular gushing seriously affects construction, and needs to be stopped for gushing treatment;

[0064] Step S105. According to the initial ground stress state of the surrounding rock, the utilization rate of the tunneling machine is divided, and the division score is shown in Table 5:

[0065] Table 5: Initial ground stress state score table of surrounding rock

[0066]

[0067] In detail, when there is no high ground stress, there is no impact on construction; when in a high stress state, soft rock will deform by extrusion, and timely support is needed, hard rock is prone to slight rock burst, increasing the difficulty of support; when in an extremely high ground stress state, soft rock is prone to large-area collapse, causing machine jamming or even causing the boom tunneling machine to stop working, which threatens the safety of construction personnel, at this time, the machine needs to be stopped for ground stress release to prevent catastrophic accidents, which has a great impact on machine utilization;

[0068] Step S2. The sum of the scores of each index is calculated by using the sum-difference method to obtain the total adaptive score, and the boom tunneling machine stratum adaptability classification is performed

[0069] Step S201. The sum of the scores of each index is calculated by using the sum-difference method, that is:

[0070] A = A1 + A2 + A3 + A4 + A5

[0071] Wherein, A is the total score of the adaptability classification, A1 is the score considering the degree of rock hardness, A2 is the score considering the degree of rock integrity, A3 is the score considering the angle between the structural plane and the tunnel axis, A4 is the score considering the underground water of rock, and A5 is the score considering the ground stress;

[0072] Step S202. According to the actual tunneling record, the boom tunneling machine working 24h average utilization rate is taken as 23% as the standard, according to the calculation result of the total adaptive score, the boom tunneling machine stratum adaptability classification is determined, and the total adaptive score is shown in Table 6:

[0073] Table 6: Adaptive classification and boom tunneling machine utilization rate table

[0074]

[0075] Step S3. The surrounding rock drilling and tunneling index RPI is introduced to perform boom tunneling construction drivability classification

[0076] Step S301. Considering the interaction between rock and machine, the drilling and tunneling index RPI is introduced, which is defined as P / R c , that is, the ratio of the power of the boom tunneling machine to the uniaxial compressive strength of the rock mass, and the correlation analysis of the RPI value and the [BQ] value is performed by using the engineering measured data as shown in Figure 1 , and the index fitting formula of the two is:

[0077] RPI = 72.23exp(-0.007 x [BQ]) (R 2 = 0.88)

[0078] Wherein, BQ is the basic quality index value of engineering rock mass:

[0079] [BQ] = (90 + 3R c + 250K v )- 100(K1+K2+K3)

[0080] Wherein, R c is the saturated compressive strength of rock, K v is the integrity coefficient of rock mass, K1 is the groundwater state of surrounding rock, K2 is the initial ground stress state of surrounding rock, and K3 is the combination relationship of tunnel axis and structure surface occurrence; in order to avoid taking too high R C value and taking too high K v value when the rock mass is broken, when R c > 90K v + 30, R c = 90K v + 30 and K v are substituted to calculate BQ value; when K v > 0.04R c + 0.4, K v = 0.04R c + 0.4 and R c are substituted to calculate BQ value;

[0081] Step S302. According to the above formula, the following transformation can be further obtained:

[0082] RPI = 72.23exp(0.7(K1+K2+K3))-(0.063+0.021R c + 1.75K v );

[0083] Step S303. Taking RPI value as the classification index, the rock mass drivability classification standard is established, as shown in Table 7, taking the commonly used BQ classification as reference, the surrounding rock is classified into 6 grades:

[0084] Table 7: drivability classification table

[0085]

[0086] Step S4. The surrounding rock stratum geology is comprehensively classified combining with the adaptability classification and the drivability classification

[0087] Step S401. In combination with the adaptability classification in Table 6, the utilization table of the boom tunneling machine, and the excavatability classification table in Table 7, the surrounding rock construction comprehensive classification is performed based on the combination of the influence of the RPI and the adaptability classification on the boom tunneling machine excavation, and the principle of the risk level matrix division.

[0088] Step S402. The surrounding rock classification is divided according to the surrounding rock comprehensive classification table shown in Table 8:

[0089] Table 8: Surrounding rock comprehensive classification table

[0090]

[0091] In combination with the adaptability classification and the excavatability classification, the surrounding rock is finally divided into four levels, as shown in Table 8: the first level of surrounding rock has good boom tunneling machine construction conditions; the second level of surrounding rock has better boom tunneling machine construction conditions; the third level of surrounding rock has general boom tunneling machine construction conditions; and the fourth level of surrounding rock has poor boom tunneling machine construction conditions.

[0092] Example 2: The scheme described in the present application has been successfully applied to the actual construction of Guiyang Metro Line 1. Taking the north extension interval YDK22+169.76-YDK22+731.27 and the Huosha interval YDK26+309.03-YDK26+728.69 of Guiyang Rail Transit Line 1 as examples:

[0093] The tunnel site area of the proposed interval tunnel is a soluble rock distribution area, and the karst landform is relatively developed, belonging to a medium karst development area. The hydrogeological conditions of the engineering area are complex, and the water-bearing properties of different sections are quite different. In particular, in the karst area, groundwater is controlled by structural joints, karst caves, and pipelines, with uneven distribution and poor regularity. In particular, in the cave development section, the karst pipeline water is relatively abundant, and the field collected data are as follows:

[0094] Table 9: Engineering geological data

[0095]

[0096] Table 10: Tunnel surrounding rock parameters

[0097]

[0098]

[0099]

[0100] According to Tables 1 to 8 of the above steps S1 to S4, the drivable classification of the final northward extension interval is 5, the adaptability classification is 4, the drivable classification of the Huosha interval is 3, and the adaptability classification is 2, so the comprehensive classification of the surrounding rock of the northward extension interval is grade IV, and the construction condition of the boom roadheader is poor; the comprehensive classification of the surrounding rock of the Huosha interval is grade II, and the construction condition of the boom roadheader is better; according to the field measured data Table 11, the monthly footage of the northward extension interval is 17.5 m, and the monthly footage of the Huosha interval is 55.5 m, which is consistent with the comprehensive classification table of the surrounding rock, indicating that the above-mentioned surrounding rock classification method is reasonable and effective;

[0101] Table 11: Construction monthly progress table

[0102]

[0103] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for classifying surrounding rock suitable for cantilever tunneling machine construction, characterized in that: include Step S1. Conduct a preliminary geological survey of the surrounding rock strata of the tunnel, and classify the influencing factors of the strata on the cantilever tunneling machine based on the preliminary geological survey results; The process of classifying the geological influencing factors of the tunnel boring machine as described in step S1 includes: Step S101. Using the uniaxial compressive strength R of the rock c The utilization rate of tunneling machines is categorized based on the hardness of the rock. Step S102. Using the rock mass integrity coefficient K v Using the integrity of the rock mass as an indicator, the utilization rate of tunneling machines is divided into categories. Step S103. Classify the utilization rate of the tunnel boring machine according to the angle between the main structural plane of the rock mass and the tunnel axis; Step S104. Classify the utilization rate of the tunneling machine according to the groundwater conditions; Step S105. Classify the utilization rate of the tunnel boring machine according to the initial geostress state of the surrounding rock; Step S2. Use the sum-difference method to sum the scores of each indicator, calculate the total adaptability score, and classify the formation adaptability of the cantilever tunneling machine. The process of geological adaptability classification for cantilever tunneling machines described in step S2 includes: Step S201. Sum the scores of each indicator using the sum-difference method, that is: ； Where A is the total score of the adaptability classification, A1 is the score considering the rock hardness, A2 is the score considering the rock integrity, A3 is the score considering the angle between the structural surface and the tunnel axis, A4 is the score considering the rock groundwater, and A5 is the score considering the ground stress. Step S202. Based on the standard that the average utilization rate of the tunnel boring machine is 23% after 24 hours of operation, determine the geological adaptability classification of the tunnel boring machine according to the calculation results of the total adaptability score; Step S3. Introduce the surrounding rock drilling index (RPI) to classify the tunnelability of cantilever excavation. The process of classifying the excavability of cantilever tunneling as described in step S3 includes: Step S301. Considering the rock-machine interaction, introduce the drilling index RPI, defined as P / R c This refers to the ratio of the power of the tunnel boring machine to the uniaxial compressive strength of the rock mass. ； Wherein, BQ represents the basic quality index value of the engineering rock mass: ； Among them, R c K represents the saturated compressive strength of the rock. v K1 is the rock mass integrity coefficient, K2 is the groundwater state of the surrounding rock, K3 is the initial in-situ stress state of the surrounding rock, and K4 is the combination relationship between the tunnel axis and the orientation of the structural plane. c >90K v At +30, with R c =90K v +30 and K v Substitute into the calculation of BQ value; when K v >0.04R c When +0.4, with K v =0.04R c +0.4 and R c Substitute into the formula to calculate the BQ value; Step S302. Based on the above formula, we can further transform it to obtain: ； Step S303. Establish a rock mass excavability classification standard using RPI value as the classification index; Step S4. Perform a comprehensive classification of the geological strata of the surrounding rock strata by combining adaptability classification and tunnelability classification; The specific classification process for comprehensively classifying the geological strata of the surrounding rock strata as described in step S4 includes: Step S401. Based on the stratum adaptability classification and rock mass tunnelability classification standards of the cantilever tunneling machine divided in steps 202 and 303, and drawing on the risk level matrix classification principle, a comprehensive classification of surrounding rock construction is carried out based on the combination of the influence of RPI and adaptability classification on cantilever tunneling. Step S402. Obtain the comprehensive geological classification table of the surrounding rock strata.

2. The surrounding rock classification method applicable to cantilever tunneling machine construction according to claim 1, characterized in that: Based on the above-mentioned rock strata classification method applicable to cantilever tunneling machine construction, the rock strata classification system for tunnel surrounding rock after classifying the geological strata includes: Class I surrounding rock provides favorable conditions for cantilever tunneling machine construction. Class II surrounding rock provides favorable conditions for cantilever tunneling machine construction. Class III surrounding rock, the construction conditions for cantilever tunneling machines are generally poor; Class IV surrounding rock presents poor construction conditions for cantilever tunneling machines.

Images