Publications (2)0 Total impact
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ABSTRACT: An elasto-static thermal stress model of the earth is presented for estimating crustal stresses considering the variation of elastic constants, density and thermal expansion coefficient through the crust and mantle. The stresses obtained from the model are shown to be an average fit to stress measurement data. The factor responsible for causing higher values of the horizontal-to-vertical stress ratio k nearer to the surface is shown to be the earth's curvature. The model and its one variation which considers transverse isotropy indicate that the horizontal stress depends on the elastic modulus measured in the horizontal direction. An equation is proposed for obtaining the horizontal stress in soft, jointed or generally weaker formations when stress measurement is carried out in competent rocks at the same location. It is shown that stress values measured in one rock cannot be extrapolated to other rocks in the same area if their elastic moduli are different. The dependence of horizontal stress on elastic modulus is corroborated by 46 published stress measurement data and average prediction equations for horizontal stress and k are proposed in terms of the elastic modulus.International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts.
Article: An approximate analysis of floor heave occurring in roadways behind advancing longwall faces[show abstract] [hide abstract]
ABSTRACT: Floor heave occurring in a roadway behind a longwall advancing face has been analysed and analytical predictions have been compared with observed field results. The heave analysis consists of first obtaining the ribside and goaf loading on the floor, for which a method to estimate the zone of ribside crushing and abutment pressure distribution has been given. The method of face element stress analysis has been used for obtaining the stresses resulting from the loading on the floor. The zone of failure in the floor can be then determined from safety factor contours. The correspondence principle of linear viscoelasticity was applied to the broken rock to give the time-dependent variation of floor lift with face advance. The final floor heave picture was obtained after superposing an apparent increase in the floor rock volume due to breaking. The influence of roadside pack width, load and face length on the extent of floor fracturing has also been studied.International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts.