COMPUTER AIDED ANALYSIS WITH GRAPHICS PACKAGE FOR SOIL SLOPES

Abstract

Cuts and embankments are constructed for many purposes such as highways, railways, earthdains etc. one of the principal requirements of a satisfactory design of earth embankments is to ensure an adequate factor of safety against failure by shear. There are number of methods available for computing the factor of safety of the slopes and it is found by different investigators that Bishop's simplified method is fairly accurate for analysis of homogenious slopes having constant soil properties throughout the soil mass. The Bishop's simplified method was modified to take into account the effect of earthquake loading and computer programs for stability and back analysis of slopes were developed and extensively used for tackling actual field problems (Singh and iamasamy, 1979). These programs nave been modified to take into account the effect of tension crack, pore water pressure and surcharge load (Misra,1988) In the present investigation, graphics packages for stability analysis of slopes and back analysis of slopes have been developed to present the results of analysis in more impressive way. The"Graph X"library of graphics subroutines is used to develop the graphics packages. The graphics packages are essentially interactive in nature. Variety of commands selected from on screen menu may be given for generating corresponding graphics response on the screen or on dot matrix printer in the form of critical slip circles or 0-0 graph etc. (iv) The computer programs with graphics packages are used to analyse some actual slopes and in optimisation of cuttings. The stability of Koteshwar dam reservoir slope was analysed and the results of a typical slope showing critical slip circles and factor of safety are presented in the graphical form. A typical problem of stabilising a slope by cutting is solved and a method of optimising the cutting using the graphics package is illustrated. It has been observed that with the use of graphics packages: the designer gets a physical feel of the ground profile and the critical slip circles. The results presented in the form of graphs (directly from the computer during execution of program) give to the designer a better feel of the