The appendix J engineering geology classification of surrounding rock J.0.1 The engineering geologic classification of surrounding rock can be divided into preliminary classification and deta
iled classification. The classification results can be used to evaluate the stability of surrounding rock and as the basis of support type. Classification of surrounding rock shall conform to table 0.1.J
Table J.0.1 Surrounding Rock type Ⅰ
Engineering geology classification of surrounding rock
Stability evaluation of surrounding rock Support type No need supporting or use anchor at some place or filling with concrete. Big span, shotcrete, system anchoring bolt and steel mesh.
Stability: stable for a long time Stable on the whole, the overall stability of surrounding rock, won't produce plastic
deformation and local combination block instability may be produced. Stability is poor at Some place: the strengt h of surrounding rock is insufficient, plasti
Shotcrete, system anchoring bolt and steel m esh, for the big span case, it should be stren gthen the flexible and rigid supporting.
c deformation, may produce at some place, landslides or deformation may be produce d when there is not supporting. The intact soft rock may be short-term instability Unstable: the stability of surrounding rock is
short-time, larger deformation and damage can occur. Very poor stability: the surrounding rock
Shotcrete, system anchoring bolt and steel m esh, for the big span case,strengthen the flexi ble and rigid supporting or pour concrete lining.
can't keep stability at short-term. deformation and failure will occur seriously.
J.0.2 A preliminary classification of surrounding rock is mainly on the basis of rock type and rock mass structure type or the integrite degree, rock mass is suitable for the planning and preliminary feasibility study phase, and should be in accordance with the table below.
Table J.0.2 Preliminary classification of surrounding rock
Rock types structural types of rock mass The integrate structure or the thick layered structure Blocky structure Submissive structure In thick bedded or middle-thick layered structure relative integrity Interbreeding structure Hard rock lamellar structure Integrity mosaic structure poor is Ⅲ Ⅳ Relatively Broken rock Fragmental or fragment structure The integrate structure or the thick layered structure blocky structure thick Soft rock bedded or middle-thick layered structure or interbreeding structure lamellar structure structure or blocky Integrity poor Relatively Cataclastic texture broken rock Ⅳ、Ⅴ is Ⅳ、Ⅴ when 15>Rb>5 soft and no groundwater; Ⅳclass structure or submissive relative integrity When there is no groundwater, Ⅳ、Ⅴ Ⅳclass; when it has groundwater, Ⅴ class broken completely when integrity Ⅲ、Ⅳ 30>Rb>15 and no groundwater is Ⅲ class. when it has groundwater, Ⅳclass. when 15>Rb>5 Soft, Ⅳ class Ⅴ Ⅳ、Ⅴ Ⅲ、Ⅳ Ⅲ、Ⅳ degree of rock integrity integrity preliminary classification of surrounding rock classes Ⅰ、Ⅱ Ⅱ、Ⅲ Ⅱ、Ⅲ Ⅱ、Ⅲ The hard rock(Rb>60) is Ⅱ, (when 60>Rb>30) is Ⅲ. instruction The hard rock(Rb>60) isⅠ, (when 60>Rb>30) is Ⅱ
Axis hole less than 30 degree Angle with the strike of the strata, 4 class. when rock is homogeneous,and there is no weak interlayer, Ⅲ class ----When there are groundwater, Ⅴ class ---
Block crack structure Cataclastic structure
J.0.3 The determination of rock types, should comply with the table J.0.3. Table J.0.3 The classification of rock types
rock types Saturated uniaxial compressive strength of rock Rc(Mpa) Rc>60 60≥Rc>30 30≥Rc>15 15≥Rc>5 Hard Rock Hard Rock Mid Hard Rock Soft Rock Little Soft Rock Soft Rock
J.0.4 The determination of rockmass integral degree, should comply with the table J.0.4 Table J.0.4 The determination of rockmass integral degree
Integral degree of rock mass Group Number of structural development Structural spacing The development degree of structure plane No plane >100 100~50 slightly -developed 50~30 Mediumdeveloped 30~10 relatively developed <10 <10 High developed plane 1~2 1~2 2~3 2~3 2~3 >3 disorderly Integral Relatively integral Low integral Little crush Crush
Note: Structural plane spacing means the average value J.0.5 The determination of rock mass structural type should comply with appendix N. J.0.6 Detailed classification of surrounding rock should be to control the rock strength, rock mass integrity of the surrounding rock, structure state, groundwater, and main structural plane occurrence overall rating of the sum of the five factors are divided into basic criterion, it is mainly used for feasibility study, detail design stage, bidding and construction and shall comply with the provisions of the table . Table J.0.6 Detailed classification of surrounding rock of underground cavern
Overall rating of Surrounding rock type Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ surrounding rock T T>85 85≥T>65 65≥T>45 45≥T>25 T≤25 Stress ratio of surrounding rock strength S >4 >4 >2 >2 -
Note:For Ⅰ、Ⅱ、Ⅲ、Ⅳ types, when the stress ratio is less than the above, then the rock type corresponding lower level . J.0.7 The strength-stress ratio, S, may be obtained by the following equation (J.0.7):
Where: Rb—Saturated uniaxial compression strength of rock (MPa); Kv—Integrity coefficient of rock mass, i.e.: square of ratio of longitudinal wave velocity of rock mass to that of rock therein; σm—max. principle stress of surrounding rock (MPa), if there is no measured data available , it may be replaced by self-weight stress. J.0.8 The ratings of five factors in the detailed classification shall comply with the following stipulations. 1. The ratings of rock strength shall comply with Table J.0.8-1. Table J.0.8-1 Rating of rock strength
Rock strength type Saturated uniaxial compression strength Rb (MPa) Rating (A) Hard rock Stiff Rb > 60 30~20 Moderately stiff 60≥Rb>30 20~10 Soft Rock Moderately weak 30≥Rb>15 10~5 Weak 15≥Rb>5 5~0
Notes: (1) For rock with saturated uniaxial compression strength of greater than 100MPa, the rating of strength shall be 30. (2) When the sum of the ratings of rock integrity and structural plane conditions is less than 5, the rating of rock strength shall be taken as 20 in the case that it is greater than 20. 2. The rating of rock mass integrity shall comply with Table J.0.8-2. Table J.0.8-2 Rating of rock mass integrity
Rock mass integrity Integral Relatively integral 0.75≥KV >0.5 5 30~22 19~14 Poorly integral Relatively crushed 0.35≥KV >0.1 5 14~6 9~4 Crushed
Integrity coefficient of rock mass KV Rating (B) Hard rock Soft rock
Notes: (1) If 60MPa≥Rb>30MPa, and the sum of ratings of integrity and structural plane conditions is greater than 65, the rating shall be taken as 65; (2) If 30MPa≥Rb>15MPa, and the sum of ratings of integrity and structural plane conditions is greater than 55, the rating shall be taken as 55; (3) If 15MPa≥Rb>5MPa, and the sum of ratings of integrity and structural plane conditions is greater than 40, the rating shall be taken as 40; (4) For very soft rock with Rb≤5MPa, integrity of rock mass and structural plane
conditions will not be involved in rating.
3. The rating of structural plane conditions shall comply with Table J.0.8-3. Table J.0.8-3 Rating of Structural Planes Conditions
Opening W(mm) Filling material Structural planes conditions Rolling and rough conditions Rolling and rough Straight and smooth Rolling and rough Closed W<0.5 -None Rolling and smooth or straight and rough Hard rock Rating (C) Relatively soft rock Soft rock 27 21 24 21 15 21 Straight and smooth Rolling and rough Slight open 0.5W<5.0 Rock debris Rolling and smooth or straight and rough 17 12 15 Straight and smooth Rolling and rough Mud Rolling and smooth or straight and rough 12 9 12 6 Straight and smooth --Open W5.0 Rock debris Mud
Note: (1) For a structural plane with an extended length of less than 3m, the ratings of structural plane conditions for hard and relatively soft rocks shall be added by 3 respectively, and rating for soft rock added by 2; for a structural plane with an extended length of greater than 10m, the ratings of hard and relatively soft rocks shall be cut down by 3, and rating for soft rock cut down by 2. (2) For a structural plane with an opening of greater than 10mm and with no filling material, the rating of structural plane conditions shall be zero. 4. The rating of ground water conditions shall comply with Table J.0.8-4 Table J.0.8-4 Rating of ground water conditions
Regime Dry to seep drip Linear running water Water gushing
Discharge q (L/min· 10m cavern length) or pressure head H(m) T’>85 Rating of basic factors (T') 85≥T’>65 65≥T’>45 45≥T’>25 T’≤25 Rating of ground water (D)
q≤25 or H≤10 0 0 ~ -2 -2 ~ -6 -6 ~ -10 -10 ~ -14
25<q≤125 or 10< H≤100 0 ~ -2 -2 ~ -6 -6 ~ -10 -10 ~ -14 -14 ~ -18
q>125 or H>100 -2 ~ -6 -6 ~ -10 -10 ~ -14 -14 ~ -18 -18 ~ -20
Note: The rating of basic factors T refers to the sum of the above ratings A, B and C. 5. The rating of occurrence of main structural plane shall comply with Table J.0.8-5. Table J.0.8-5 Rating of occurrence of main structural plane
Including angle of structural plane strike with axis of cavern Dip of structural plane Roof Side walls 70° >70° ~ 45° 0 -2 -2 -5 <45° ~ 20° -5 -2 70° <20° >70° ~ 45° -10 0 -2 -5 -5 -10 <45° ~ 20° -10 -2 70° <20° >70° ~ 45° -12 0 -5 -10 -10 -12 <45° ~ 20° -12 -5 90°~ 60° <60°~ 30° <30°
Note: For surrounding rocks that are determined to be poorly integral, relatively crushed and crushed according to rock mass integrity, the rating adjustment for occurrence of main structural plane will not be conducted. J.0.9 This classification of surrounding rocks is not applicable to underground caverns with a buried depth of less than 2 times the diameter or span and caverns in special soil stratum and developed Karst cave region. For the classification of surrounding rocks in very high stress and very soft rock areas (Rb≤5MPa), a special study may need to be carried out according to the actual conditions of a project. J.0.10 The classification of surrounding rocks around large span caverns, in addition to this
classification, shall yet comply with other relevant state standards for synthetically assessment, and current international classification such as Q system may be used for comparison and check.