DESIGN OF TRENCH DRAIN FOR STRATIFIED SOIL USING FEM

Abstract

Large number of landslides occurs quite often during rainy seasons primarily owing to the development of substantial pore water pressure in a slope mass. Rainfall induced failures are the most common ones causing many landslides. There is a need for developing suitable methodology for examining the effectiveness of different stabilizing techniques to be adopted. By applying hydraulics and seepage analysis we can develop different measures for controlling the occurrences of most of the landslides. To prevent the occurrence of landslides, trench drains are widely used for draining out water from the soil and to reduce the pore water pressure to restore stability of the slope. Current project explains hazard ness of landslides, importance of hydraulics and seepage analysis in providing design guidelines of trench drains by numerical and statistical data. In this aspect we obtained variation of seepage velocities of the trench for various values of depth in a stratified soil medium by using FEM. In order to provide design guidelines for designing trench drains placed in a more common isotropic/anisotropic and stratified soil media, we need to investigate the performance of two dimensional steady state flow of water within a parallel rectangular trench drainage system and obtained pore water pressures by applying finite element method (FEM) and discussed the relationship between the piezometric head and various other factors separately and explained the variation of piezometric head between the drains along the drain and the discharge of water flowing within the drains. It helps to draw various diagrams taking account of depth, width and spacing of trench drains for determining the magnitude of piezometric head within the flow domain and the discharge of water flowing into the drains. Secondly in the hilly regions soil consists of strata’s. Trench drains are for shallow depths, so if we design them by considering top two layers are helpful to implement this concept in the field for stratified soils. Different combinations of layers are allotted for present analysis