GB/T 50218-2014 English PDFUS$2099.00 · In stock
Delivery: <= 13 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 50218-2014: Standard for engineering classification of rock masses Status: Valid GB/T 50218: Historical versions
Basic dataStandard ID: GB/T 50218-2014 (GB/T50218-2014)Description (Translated English): Standard for engineering classification of rock masses Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: P10 Classification of International Standard: 93.020 Word Count Estimation: 95,982 Date of Implementation: 5/1/2015 Older Standard (superseded by this standard): GB/T 50218-1994 Regulation (derived from): People's Republic of China Housing and Urban-Rural Development Ministry Bulletin No. 531 Issuing agency(ies): Ministry of Housing and Urban-Rural Development of the People's Republic of China; General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Summary: This Standard applies to all types of rock mass classification of rock engineering. GB/T 50218-2014: Standard for engineering classification of rock masses---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.1 General 1.0.1 This standard is formulated to unify the classification method of engineering rock mass and provide basic basis for rock engineering survey, design, construction and operation. 1.0.2 This standard is applicable to rock mass classification of various types of rock engineering. 1.0.3 The grading of engineering rock mass shall adopt the method of combining qualitative and quantitative methods, and shall be carried out in two steps. Firstly, the basic quality of rock mass shall be determined, and then the grade of engineering rock mass shall be determined in combination with the characteristics of specific projects. 1.0.4 The grading of engineering rock masses shall not only comply with this standard, but also comply with the current relevant national standards. 2 Terms and symbols 2.1 Terminology 2.1.1 rock engineering rock engineering The engineering that uses rock mass as the foundation or environment of engineering buildings and excavates or reinforces it mainly includes rock underground engineering, rock slope engineering and rock foundation engineering. 2.1.2 Engineering rock mass engineering rock mass Rock mass within the sphere of influence of rock engineering. 2.1.3 rock mass basic quality The most basic property inherent in rock mass that affects the stability of engineering rock mass. This standard stipulates that the basic quality of rock mass is determined by the hardness of rock and the integrity of rock mass. 2.1.4 Structural plane (discontinuity) The interior of the rock mass has a certain direction, a certain scale, a certain shape and characteristics of the surface, fracture, layer and band-shaped geological interface. 2.1.5 Intactness index of rock mass The square of the ratio of the elastic longitudinal wave velocity of the rock mass to the elastic longitudinal wave velocity of the rock. 2.1.6 volumetric joint count of rock mass The number of structural planes per cubic meter of rock mass volume. 2.1.7 point load strength index point load strength index The point load strength of a cylindrical specimen with a diameter of 50 mm when it is radially compressed. 2.1.8 initial geo-stress field The stress field in the rock mass in the natural state is also called the natural stress field. 2.1.9 Stand-up time of engineering rock mass The ability of engineered rock mass to maintain stability under unsupported or unreinforced conditions. 2.1.10 basic value of bearing capacity of rock foundation In rock foundation engineering, the load corresponding to the proportional limit or yield limit in the load-displacement curve of the rock mass. 2.2 Symbols γ—gravity density of rock mass; Rc - saturated uniaxial compressive strength of rock; Is(50)——rock point load strength index; E—deformation modulus of rock mass; μ—Poisson’s ratio of rock mass; φ——Inner friction angle of rock mass or structure; c—cohesion of rock mass or structural surface; Kv—rock mass integrity index; Jv—volume joint number of rock mass; K1——Correction coefficient for groundwater impact of underground engineering; K2——Correction coefficient for the influence of the occurrence of main structural planes in underground engineering; K3—the initial stress state influence correction coefficient; K4——correction coefficient for groundwater impact of slope engineering; K5——correction coefficient for the influence of the occurrence of the main structural plane of the slope engineering; λ——main structural surface type and extensibility correction coefficient of slope engineering; f0——Basic value of bearing capacity of bedrock of rock mass; BQ—basic quality index of rock mass; [BQ]——engineering rock mass quality index; H—the buried depth of rock underground engineering or the height of rock slope. 3 Grading factors of basic quality of rock mass3.1 Grading factors and their determination methods 3.1.1 The basic quality of rock mass shall be determined by two factors. rock hardness and rock mass integrity. 3.1.2 The degree of rock hardness and integrity of rock mass shall be determined by qualitative division and quantitative index. 3.2 Qualitative division of grading factors 3.2.1 The qualitative classification of rock hardness shall comply with the provisions in Table 3.2.1. Table 3.2.1 Qualitative classification of rock hardness 3.2.2 When qualitatively classifying rock hardness, its weathering degree shall be determined according to the provisions in Table 3.2.2. Table 3.2.2 Classification of rock weathering degree 3.2.3 The qualitative division of rock mass integrity shall comply with the provisions in Table 3.2.3. Table 3.2.3 Qualitative division of rock mass integrity Note. The average spacing refers to the average spacing of main structural planes. 3.2.4 The bonding degree of the structural surface shall be determined according to Table 3.2.4 according to the characteristics of the structural surface. Table 3.2.4 Classification of bonding degree of structural planes 3.3 Quantitative indicators of grading factors 3.3.1 The quantitative index of rock hardness shall be the saturated uniaxial compressive strength Rc of the rock. Rc should adopt the measured value. When the measured value is unconditionally obtained, the converted value of the measured rock point load strength index Is(50) can also be used, and converted according to the following formula. In the formula. Rc—rock saturated uniaxial compressive strength (MPa). 3.3.2 The quantitative index of rock mass integrity should use the rock mass integrity index Kv. Kv should adopt the measured value. When the actual measured value is unconditionally obtained, the rock mass volume joint number Jv can also be used, and the corresponding Kv value can be determined according to Table 3.3.2. Table 3.3.2 Correspondence between Jv and Kv 3.3.3 The corresponding relationship between saturated uniaxial compressive strength Rc and rock hardness can be determined according to Table 3.3.3. Table 3.3.3 Correspondence between Rc and rock hardness 3.3.4 The corresponding relationship between rock mass integrity index Kv and rock mass integrity degree can be determined according to Table 3.3.4. Table 3.3.4 Correspondence between Kv and integrity of rock mass 3.3.5 The test of quantitative indicators Rc and Is(50) shall comply with the provisions of Appendix A of this standard. 3.3.6 The test of quantitative indicators Kv and Jv should comply with the provisions of Appendix B of this standard.4 Basic quality classification of rock mass4.1 Determination of basic quality level 4.1.1 The basic quality classification of rock mass should be based on the combination of the qualitative characteristics of the basic quality of rock mass and the basic quality index BQ of rock mass, and should be determined according to Table 4.1.1. Table 4.1.1 Basic quality classification of rock mass 4.1.2 When the grades determined according to the qualitative characteristics of basic quality and the basic quality index BQ of rock mass are inconsistent, the basic quality grade of rock mass should be determined through comprehensive analysis of qualitative division and quantitative indicators. When the difference between the two grades reaches 1 grade or above, further supplementary tests should be performed. 4.1.3 The physical and mechanical parameters of rock masses of each basic quality level can be determined according to Table D.0.1 of this standard. The shear peak strength parameters of structural planes can be determined according to Table D.0.2 of this standard according to the hardness of the rocks on both sides and the bonding degree of structural planes. 4.2 Qualitative characteristics and basic quality indicators of basic quality 4.2.1 The qualitative characteristics of the basic quality of rock mass shall be determined by the combination of rock hardness and rock mass integrity determined in Table 3.2.1 and Table 3.2.3 of this standard. 4.2.2 The determination of basic quality indicators of rock mass shall meet the following requirements. 1 The basic quality index BQ of the rock mass should be calculated according to the MPa value and Kv of the quantitative index Rc of the grading factor according to the following formula. 2 When using the formula (4.2.2) for calculation, the following provisions shall be met. 1) When Rc >90Kv+30, Rc=90Kv+30 and Kv should be substituted to calculate BQ value; 2) When Kv >0.04Rc+0.4, Kv=0.04Rc+0.4 and Rc should be substituted to calculate BQ value.5 Determination of engineering rock mass grade5.1 General provisions 5.1.1 When preliminary grading of engineering rock mass, the basic quality level of rock mass determined in Table 4.1.1 of this standard should be used as the rock mass level. 5.1.2 When grading engineering rock mass in detail, it should be based on the basic quality classification of rock mass, combined with the characteristics of different types of projects, and according to the state of groundwater, initial stress state, orientation of project axis or project trend line and main structure Correction factors such as the combination relationship of surface occurrences are used to determine the quality indicators of various engineering rock masses. 5.1.3 The influence of the initial stress state of rock mass on the grade of underground engineering rock mass should be adjusted according to the strength-stress ratio determined by the corresponding initial stress and surrounding rock strength according to Table C.0.2 of this standard. 5.1.4 For the initial stress state of the rock mass, when there are actual measured stress results, the measured value should be used; Special geological phenomena such as core cake formation and rockburst during excavation shall be evaluated according to Appendix C of this standard. 5.1.5 For special rock types such as expansibility and easy solubility, the grade of engineering rock mass should be comprehensively determined according to its special deformation and failure characteristics, karst development degree and its influence on engineering rock mass. 5.2 Determination of rock mass grade in underground engineering 5.2.1 For the detailed grading of underground engineering rock mass, when one of the following situations occurs, the basic quality index BQ of the rock mass should be corrected, and the rock mass quality index value obtained after correction should be determined according to Table 4.1.1 of this standard. body level. 1 with groundwater; 2 The stability of rock mass is affected by structural planes, and one group plays a controlling role; 3 The engineering rock mass has an initial stress state characterized by the strength-stress ratio. 5.2.2 The rock mass quality index [BQ] of underground engineering can be calculated according to the following formula. The values of correction coefficients K1, K2 and K3 can be determined according to Table 5.2.2-1, Table 5.2.2-2 and Table 5.2.2-3 respectively. In the formula. [BQ]——underground engineering rock mass quality index; K1——Correction coefficient for groundwater impact of underground engineering; K2——Correction coefficient for the influence of the occurrence of main structural planes in underground engineering; K3—the initial stress state influence correction coefficient. Table 5.2.2-1 Correction coefficient K1 for groundwater impact of underground works Note. 1 p is the hydraulic pressure of cracks in the surrounding rock of underground engineering (MPa); 2 Q is the water yield per 10m of hole growth (L/min·10m). Table 5.2.2-2 Correction coefficient K2 for the influence of the occurrence of main structural planes in underground works Table 5.2.2-3 Initial stress state influence correction factor K3 5.2.3 For underground projects with a span not greater than 20m, the rock mass self-stabilization capacity can be determined according to Table E.0.1 in Appendix E of this standard. When its actual self-stabilization capacity does not match the self-stabilization capacity of the corresponding level in Table E.0.1 of this standard, the rock mass level should be adjusted accordingly. 5.2.4 For underground engineering rock masses with a span greater than 20m or special ones, in addition to determining the basic quality level according to this standard, when grading in detail, methods in other relevant standards can be used to conduct comparative analysis and comprehensively determine the rock mass level. 5.3 Determination of rock mass grade for slope engineering 5.3.1 When grading rock slope engineering in detail, it should be based on the influence factors such as the type and extensibility of the main structural surface controlling the stability of the slope, the degree of groundwater development in the slope, and the relationship between the occurrence of the structural surface and the slope surface. Correct the basic quality index BQ of the rock mass, and determine the grade of the rock mass according to Table 4.1.1 of this standard for the obtained engineering rock mass quality index value. 5.3.2 The rock mass quality index [BQ] of slope engineering can be calculated according to the following formula. The values of correction coefficients λ, K4 and K5 can be determined according to Table 5.3.2-1, Table 5.3.2-2 and Table 5.3.2-3 respectively. In the formula. λ——main structural surface type and extensibility correction coefficient of slope engineering; K4——correction coefficient for groundwater impact of slope engineering; K5——correction coefficient for the influence of the occurrence of the main structural plane of the slope engineering; F1—coefficient reflecting the influence of the relationship between the main structural surface inclination and slope inclination; F2—coefficient reflecting the influence of the inclination angle of the main structural plane; F3—coefficient reflecting the influence of the relationship between the slope angle and the main structure plane angle. Table 5.3.2-1 Main Structural Surface Types and Extensibility Correction Factor λ of Slope Engineering Table 5.3.2-2 Groundwater Impact Correction Factor K4 for Slope Engineering Note. 1 pw is the diving or confined water head in the slope (m); 2 H is the slope height (m). Table 5.3.2-3 Correction of influence of main structural planes of slope engineering Note. The negative value in the table means that the inclination angle of the structure plane is smaller than the inclination angle of the slope surface, and it is exposed on the slope surface. 5.3.3 For slope engineering rock mass with a height not greater than 60m, its self-stabilization capacity can be determined according to Table E.0.2 in Appendix E of this standard according to the determined grade. 5.3.4 For the rock mass with a height greater than 60m or special slope engineering, in addition to determining the [BQ] value according to Article 5.3.2 of this standard, special demonstrations should be carried out based on the influence of the slope height and combined with the project to comprehensively determine the rock mass grade. 5.4 Determination of rock mass grade for foundation engineering 5.4.1 The rock mass of foundation engineering shall be graded according to the basic quality grade of rock mass specified in Table 4.1.1 of this standard. 5.4.2 The basic value f0 of bedrock bearing capacity of rock mass of various grades in foundation engineering can be determined according to Table 5.4.2. 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