Abstract

Type of deformation in expansive soil is lateral and vertical Laboratory expansion tests are often performed on rings with restrained, lateral movement so that horizontal, swelling deformation will not occur. The road damage in the highway between Purwodadi – Semarang (Begel village, Purwodadi) was identified because the soil is expansive. Therefore, this study was conducted to identify characteristics of its soil expansion, specifically the influence of pressure of membrane restraints on expansion of expansive soil. The expansion test was conducted on modified test tools. The axial expansion strain was measured using the dial gauge which was installed in parallel, vertical position while the lateral strain was measured using the caliper digital in order to identify any change in the diameter of sample with the variations of initial water content (wo), vertical pressure (pv) and membrane’s thickness (t). The test result show that the greater the (horizontal) lateral strain is, the greater the restraint pressure in the membranes will be. The restraint pressure in the membranes (ph) is closely related to factors that influence the expansion possibility such as vertical pressure (pv), initial height of test object (ho), initial water content (wo), and membrane’s thickness (t).