ABSTRACT

This paper describes the detailed numerical analysis performed to study and observe the effect of toe cutting caused by anthropogenic activities like construction of new roads, widening of existing roads and by natural processes like undercutting and erosion by rivers and streams, on the stability of slopes. For this purpose, a slope showing the evidence of toe cutting caused by river erosion and undercutting is chosen for analysis. The slope selected for analysis is made up of a mixture of soil and debris material lying above the rigid hard bed rock foundation. The selected slope has been analysed using the Morgenstern – Price limit equilibrium method using the GeoStudio SLOPE/W software. In order to comprehend the behaviour of slope under different geotechnical, hydraulic and seismic conditions the analyses have been performed by taking into account a wide variation in these parameters. The behaviour of slope and its probability to failure is calculated on the bases of the evaluated strength reduction factor in different strength effecting conditions. In this study, the analyses are conducted in three different phases. In the first phase, simplified model of the slope is analysed under its own weight without any additional parameter. In the second phase, pseudo static analysis has been performed on the slope. In the third and last phase, hydraulic parameters were incorporated in the slope model and the results are generated. Results of the analysis are presented in easy to interpret graphical format and based on the analysis, results are interpreted for the critical horizontal limit of the vertical toe cutting of the slopes for the different types of slopes having varied geotechnical parameters.

INTRODUCTION

Toe cutting of hill slopes is a common slope destabilising phenomenon related to the routine work carried out on hill slopes in order to construct new roads or in widening of the existing roads or due to the erosion caused by undercutting of slopes by rivers. The road cutting as anthropogenic interference on hill slopes is the consequence of the advancement of the facilities and infrastructure due to rise in population and high demand of foreign resources in the hilly regions.

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