Rock mass classification

About: Rock mass classification is a research topic. Over the lifetime, 14144 publications have been published within this topic receiving 179750 citations.

Engineering classification of rock masses for the design of tunnel support

Abstract: An analysis of some 200 tunnel case records has revealed a useful correlation between the amount and type of permanent support and the rock mass qualityQ, with respect to tunnel stability. The numerical value ofQ ranges from 0.001 (for exceptionally poor quality squeezing-ground) up to 1000 (for exceptionally good quality rock which is practically unjointed). The rock mass qualityQ is a function of six parameters, each of which has a rating of importance, which can be estimated from surface mapping and can be updated during subsequent excavation. The six parameters are as follows; theRQD index, the number of joint sets, the roughness of the weakest joints, the degree of alteration or filling along the weakest joints, and two further parameters which account for the rock load and water inflow. In combination these parameters represent the rock block-size, the interblock shear strength, and the active stress. The proposed classification is illustrated by means of field examples and selected case records. Detailed analysis of the rock mass quality and corresponding support practice has shown that suitable permanent support can be estimated for the whole spectrum of rock qualities. This estimate is based on the rock mass quality Q, the support pressure, and the dimensions and purpose of the excavation. The support pressure appears to be a function ofQ, the joint roughness, and the number of joint sets. The latter two determine the dilatency and the degree of freedom of the rock mass. Detailed recommendations for support measures include various combinations of shotcrete, bolting, and cast concrete arches together with the appropriate bolt spacings and lengths, and the requisite thickness of shotcrete or concrete. The boundary between self supporting tunnels and those requiring some form of permanent support can be determined from the rock mass qualityQ.

Underground excavations in rock

Abstract: This book deals with the geotechnical aspects of the design of underground openings for mining and civil engineering purposes. It contains a number of worked examples to assist the reader in applying the techniques described to his or her own problems. The data are presented under the following chapter headings: (1) planning considerations; (2) classification of rock masses; (3) geological data collection; (4) graphical presentation of geological data; (5) stresses around underground excavations; (6) strength of rock and rock masses; (7) underground excavation failure mechanisms; (8) underground excavation support design; (9) rockbolts, shotcrete and mesh; (10) blasting in underground excavations; (11) instrumentation. Several appendices deal with: isometric drawing charts, stresses around single openings, two-dimensional boundary element stress analysis, determination of material constants, underground wedge analysis, and conversion factors. A very extensive bibliography is included.

Engineering rock mass classifications

Abstract: Keywords: Classification ; Caracterisation Reference Record created on 2004-09-07, modified on 2016-08-08

Rock slope engineering

Abstract: This book is concerned with the stability of rock slopes, with methods for assessing this stability and with techniques for improving the stability of slopes which are potentially dangerous. The geotechnical problems of rock slope design are discussed for the mining or civil engineer who is not a specialist in rock or soil mechanics; many work examples are included to assist in relating the techniques described to his own slope problems. Methods for the collection and interpretation of geological and groundwater information are presented and tests for the determination of relevant mechanical properties of rock are described.