STABILITY ANALYSIS OF SLOPES AROUND NAGALAND PAPER MILL COMPLEX

Abstract

The present study aims at analysis and design of slopes with particular reference to the slopes of NAGALAND PULP & PAPER MILL COMPLEX at TULI,NAGALAMD, which is located at a hill top.Four major slope slides took place at the site during the earthquake of August 6 ,1988 which measure 7.0 on Richter scale. The problem has been analysed by two methods, namely the Slip Circle Method and Finite Element method.The FEM analysis was carried out assuming plane strain condition. The cross-sections of the hill slopes show that the existing slope angles vary, in general, from 250 to 33°. The site is located in a highly seismic zone and high precipitation area in Nagaland The geology of the site consists of clay sequences with small bands of friable sand rocks. The properties of soil which have been supplied vary over a wide range which was thought to be untenable to cope with. The slopes existing prior to earthquake have been analysed for stability under the following conditions : a) Factor of safety has been assumed to be 1.0 under static and pseudo static conditions, b) Pore pressures have been varied from zero to 20% of the weight of material, c) Saturated density of soil has been used, d) Horizontal seismic coefficient has been varied from 0.0 to 0.1.