Influence of joints on rock modulus

196A 875190 Reliability" of cyclic load deformation models for cohesive soils Ejezie. S U; Harrop-Williams, K Soil Dynam Earthq Engng V6. N2. April 1987, P108-117 The reliability of some of the models developed to describe the deformation of cohesive soils has been examined using the concepts of probability and structural reliability theory. Quantitative measures of reliability are defined and evaluated as a series of indices, which, suitably interpreted, reveal useful information on the relative effectiveness and limitations of the models as descriptors of dynamic stress strain behaviour. Results show the models examined fall into three different groups, defined by their relative degrees of conservation in predicting failure strain. 875191 Formation compaction associated with thermal cooling in geothermal reservoirs Garg, S K Proc 3rd International Symposium on Land Subsidence, Venice, 19-25 March 1984 Pl17-126. Publ Wallingford: IAHS Constitutive relationships for thermoplastic fluid saturated porous media are developed using concepts from the theory of interacting continua. The relationship between porosity and confining pressure and temperature is established. Uniaxial compression due to fluid withdrawal from a reservoir is evaluated in terms of fluid pressure and temperature, and, from this, formation compaction due to cooling is derived. 875192 Analysis of rock behaviours for safe excavation of mine pillars Lee, H K; Mizuta, Y Proc International Symposium on Large Rock Carerns, Helsinki, 25-28 August 1986 V1. P681-692. Publ Oxford." Pergamon Press, 1986 Numerical solutions and the boundary element method are used to calculate the vertical displacements around the roof of a disc shaped opening. If the analytical method uses a fine enough mesh, the results are almost coincident. This method, which has comparatively low computing costs, may thus be applied to similar problems. It is used to model six stages of pillar extraction in an underground mine, and to examine stresses in the remaining pillars and the surrounding rock. In this case it is seen that, after the fourth stage of extraction, stress levels in the permanent pillars are such that remedial measures will be required. 875193 Ice rheolgy finite element models Brown, T G; Cheung. M S; Bercha, F G Proc 5th (1986) lnternationtd. Offshore 34echanics and Arctic Engineering (OMZ4E) Symposium, Tokyo, 13-18 April 1986 V4, P583-588. Publ .VY: ASME. 1986 The development of an ice finite element model which is capable of representing a variety of triaxial failure surfaces for ice is described. The coding also includes the modelling of cracks through tension weakening and has built-in strain rate dependence. The current knowledge of failure theories for ice and the effect of strain rate on the failure surface are discussed in detail. The implementation of the rheology and the assumptions used are discussed in general terms. Examples of the use of the coding are presented with other solutions and results. Model limitations are discussed and recommendations for further development are given. Auth.

875194 Influence of joints on rock modulus Wei, Z Q; Hudson. J A Proc International Symposium on Engineering in Complex Rock Formations, Be~iing, 3-7 :Vorember, 1986 P54-62. Pub! Beijing: Science Press. 1986 The initial shear stiffness and normal stiffness are discussed together with their interrelation. The compliance matrix for a jointed rock mass is developed and a method for calculating the limiting values and directions of modulus is recommended. Auth.

Design methods See also: 875213 875195 Computer-aided planning and management of surface coal mines Chugh, Y P; Caudle, R D Min Sci Technol V4, N3. March 1987. P279-290 Computer programs available for surface mine planning and management in the areas of surveying and mapping, orebody modelling and mine evaluation,hydrological modelling and impact analysis, mine planning and feasibility analysis, and management information systems are referred to. Case studies of computer based research in the following fields are presented: integrated mining/reclamation planning, reclamation management; feasibility of terrace pit mining operations: selection of pit configurations for moderately pitching seams; and thin seam miner/trench mining feasibility.

Rock Breakage and Excavation Drilling See also. 875036, 875141, 875158, 875159, 875224 875196 Quiet, efficient, sophisticated. Diamond drilling has come a long way Rogers, B Can Min J V108, N3, March 1987, P13-18 Benefits due to improved hydraulics and drill bits have resulted in diamond drilling, particularly wireline drilling, largely replacing traditional mechanical drilling for exploration drilling for gold in northern Ontario and Quebec, Canada. The deflection drilling technique, which allows a large volume to be explored from a single drill hole is described. 875197 Ultra small diameter drilling (USDD) for onshore oil and gas. Mineral exploration equipment for minor reservoirs Geodrilling N42, Feb 1987. PC)-/I The conventional oilfield drill rig is heavy, labour intensive, requires considerable site preparation and can only be economically justified for large reservoirs. New slimhole technology has been developed to drill holes of 50ram final diameter. The rigs can reach remote sites and economically explore small reservoirs. The slimfield drill rig is described, which includes

~-~ 1987 Pergamon Journals Ltd. Reproduction not permitted