THE EFFECT OF VERTICAL GEO MEMBRANE DRAIN ON LIQUEFACTION

Abstract

Liquefaction of saturated cohesionless soils has often been the main cause of the catastrophic damage to structures resulting in loss of life and property. To alleviate the chances of liquefaction(geo membrane drains can be provided in soil stratum as geo synthetic materials have good permeability and tensile strength. In t-he present study the effect of various parameters on the performance of drain has been investigated for the design of C~eo membrane drain. Samples have been prepared using sand (SOLANI) and the intial relative density was of the order of 45%. Tests have been conducted on shake table using different diameter geo membrene drains ranging from 15mm to 140mm filled with K1, K2, and K3 type free draining material in. combination. It has been found that these drains are effective in reducing the dynamic pore water pressures. This re~'uction in dynamic pore water pressure increases with increase in permeability of free draining material and with diameter of drain. It has also been shown that the reduction gradient is sharp up to a distance equal to two times the diameter of drain and flattened after the distance equal to three times the diameter of drain. For a desired percentage of reduction in dynamic pore water pressure the spacing and diameter of the geo membrane drain can be obtained from the design curve given in this dissertation.