Deformation Characteristics of Cement Modified Soft Clay Soil for Shallow Foundation Using Finite Element Method

Abstract

The larger area of the world is covered with soft clay; the soil type known for its high susceptibility to a shear failure, unexpected differential settlement, and experiencing low bearing capacity which makes it be categorized as unsuitable soil for variety of engineering use. Yet, it remained cumbersome to suitably use soft clay soil because of its high vulnerability to the subsequent foundation failures; which is a headache to construction stakeholders especially in the contemporary engineering world. Similarly, majority of Jimma town’s land cover is predominantly known for its deposit of soft clay soil which is conventionally excavated up to a certain depth and discarded ahead of actual commencement of construction projects due to its stability concern. The usage of soft clay soil as foundation of different engineering structures is excavated unless its intrinsic properties are enhanced through application of appropriate improvement mechanisms among which the cement stabilization approach is one. Hence, the study aimed at studying deformation analysis of cement modified soft clay by using finite element method. The soil samples were collected from three different pits located in Jimma town and laboratory tests were conducted to determine index properties, unconfined compressive strength, one-dimensional consolidation characteristics and shear strength parameters of the soil samples. To improve these engineering properties of the clay soil a varying percentage of cement in the mix by 9 %, 12 %, and 15 % were applied. Besides, the deformation analysis of the soil was assessed by using Plaxis 2D software which operates with the principle of Finite Element Method. Therefore from finite element analysis the vertical displacement encountered in untreated soft clay was 124 mm and the displacement of 15% of cement treated of soil is 26.77 mm. It is observed that the displacement is improved when soft clay soil is modified with 15% of cement. There was a high difference in the magnitude of untreated and treated soft soils this is a result of soil cement reaction and effect of curing period of the specimen.