Analysis of Shotcrete Lining and Estimation of Support Pressure of Sardar Sarovar Underground Powerhouse Cavern

The present paper deals with the finite element analysis of shotcrete lining of Sardar Sarovar project cavern intercepted by a shear zone. The shotcrete has been modelled using a single layer of 20-noded isoparametric brick element. A layer of joint elements has been added above the layer of brick elements to simulate the influence of surrounding rock mass. Following the concept of the substructure technique, the displacements obtained from the analysis of the cavern have been applied on to the outer surface of the joint elements (surface other than that in contact with the shotcrete) in order to obtain the displacements, support pressure and the stresses in the shotcrete. The support pressures obtained from numerical analysis have been compared with those obtained on the basis of conventional approaches. The long-term support pressures computed in the present study are in good agreement with those obtained using Norwegian Geotechnical Institute criterion even near the shear zone. However, wall support pressures away from the shear zone are negligible due to lower stiffness of shotcrete in the horizontal direction.