Design of vibro-replacement stone column for foundation of multipurpose utility tunnels in Dalian

The efficiency of end bearing vibro-replacement stone columns in reducing the settlement of a multipurpose utility tunnels foundation system is designed in this paper. The foundation system is designed to consist of a large number of regularly spaced vibro-replacement stone columns of unequal length installed in a weak soil layer ( stratum includes plain fill, silty clay including mire, clay, cobble, stone and bedrock ) and supporting a rigid mat. At first, the analysis summarizes the influence of such factors as the column spacing, the weak soil properties, properties of the granular medium used in constructing the column, the in situ stresses caused by the installation technique, the depth of the bedrock relative to the tip of the columns and the magnitude of the uniformly distributed load carried by the supported raft foundation. The second, the paper examines the s-p, s-lg t curve of the single piles, the plane load of soil between piles, the composite foundation of the multi-pile. This paper is concluded by presenting a number of design parameter that was used in the construction of such a foundation scheme.