International Journal of Advance Civil Engineering and Technology ISSN: 3107-7374 (Online)

Authors:- Sampreeth B S, Pushparaj A Naik, Sundhip Shenoy

Abstract:- Slopes and retaining walls are widely used for roads, railways, river training works, canal works, dams etc. The economy and safety of these earth-retaining structures can be accomplished by adopting proper methods of design, construction and maintenance. The failure of these structures is likely to result in huge loss of life and damage to property. In the present work, an attempt has been made to estimate the permanent displacement of the slopes and retaining walls from pseudo static approach. MATLAB is used as a tool and programs are developed. To evaluate permanent displacement of slopes and retaining walls considering factors such as height of slope, inclination of slope, cohesion of soil and density of soil. Newmark's method, the popular method of analysis has been used and parametric studies have been carried out. To calculate permanent displacement of retaining walls, Richards-Elms method has been adopted. In addition, Newmark's method has been modified to suit the requirements of retaining walls. The present work has been carried out in three stages. In the first stage, a program has been developed in MATLAB to evaluate the permanent displacement of slopes using Newmark's approach. For this purpose, pseudostatic analysis has been carried out considering the effect of height of slope, inclination of slope, cohesion of soil, density of soil on the yield acceleration. The effect of input motion on the permanent displacement has been brought out by considering different earthquake motions, In the second stage of work, importance is given to the development of a computer program for the evaluation of permanent displacement of retaining walls using Richards-Elms approach. For this purpose, yield acceleration that develops under the given soil properties, mobilized earth pressure and geometry of retaining wall were determined by iterative procedure. A parametric study has been made to consider the effect of various factors influencing the permanent displacement of retaining walls such as geometry of wall, properties of backfill soil, condition of soil and soil and wall interaction angle In the last stage, an attempt has been made to modify the Newmark's approach to suit the retaining wall problem. For this purpose, a combination of analysis using Richards-Elms method to calculate yield acceleration and Newmark's method to estimate permanent displacement from the data of earthquake motion and yield acceleration as in the analysis of slopes has been incorporated. A comparison is made with Richards-Elms approach. From the present work, it has been brought out that Newmark's method gives more realistic results as Richards -Elms approach is an empirical relation and Newmark's approach considers the region of the earthquake motion above the yield acceleration more accurately.

Keywords-: slopes; retaining walls; Earth-retaining structures; Design; Displacement; Pseudostatic approach; MATLAB;   Program   development;   Newmark's method; Richards-Elms method; Yield acceleration; Cohesion of soil Earthquake motions.