Laboratory and Field Simulations on the Compression Behavior of Reinforced Soil-Cement Pile for Deep Ground Improvement Application

Abstract

Deep Mixing Method (DMM) is an effective ground improvement technique which improves the geotechnical properties of thick deposit of weak soils by introducing some cementitious materials into and within the soil deposit. This paper proposes a new soil improvement method that employs reinforced deep mixing method (RDMM). In the RDMM, the deep mixing pile is reinforced in a manner similar to a spirally reinforced concrete column or pile. This paper aims to evaluate the effectiveness of RDMM on improving the strength and deformation properties of a non-plastic soil. The study comprises of four (4) experimental phases, namely: 1) physical property tests of the base soil, (2) Unconfined Compression (UC) tests on unreinforced cement-admixed soil specimens, (3) UC Tests on reinforced cement-admixed soil specimens, and (4) construction and load testing of full-scale RDMM pile. Results of UC tests on reinforced cement-admixed soil revealed that the cement content (Aw), number of longitudinal bars (nb) and spacing of spiral (SS) reinforcement have significant contributions on the strength gain of reinforced cement-admixed non-plastic soil. The results of UC tests further revealed that the influence of longitudinal bars on the unconfined compressive strength of reinforced cement-admixed non-plastic soil is pronounced at lower cement contents. Furthermore, static load test conducted on the full-scale RDMM pile revealed the load-settlement behavior of single RDMM pile.