Sand Compaction Pile (SCP) method is constructed in the soft ground by feeding sand into the ground through a casing pipe and is compacted by vibrating compaction technique. The SCP method has been commonly applied on soft clay ground to assure stability and to reduce ground settlement.
Observed field behaviors are frequently different from the behaviors predicted in the design due to several uncertainties involved in soil properties, numerical modeling, and error of measuring system, even though a sophisticated numerical analysis technique is applied to solve the settlement behavior of SCP composite ground.
In this study, the reliable and simple analysis method was proposed to predict the settlement characteristic of composite ground in stage of design and construction of SCP. Model parameters could be obtained by the optimization process based on genetic algorithm. In order to examine the proposed method, laboratory consolidation tests on the settlement characteristic of SCP composite ground were performed in various replacement ratios of sand such as 0(no replacement), 20, 36, and 56%. The proposed method showed very good agreements with measured data in relationship of void ratio-log scaled stress and time?compression for each replacement ratio.
Example analyses of multi-layered SCP composite ground were performed to examine the applicability of proposed back-analysis method.
Furthermore, case analyses of in-situ measured data of SCP composite ground were performed to examine the applicability by comparing proposed method and traditional method.
Utilizing the proposed method, one might be able to appropriately predict the subsequent settlement behavior from the measured data in an early stage of settlement of SCP composite ground.
Proposed back-analysis method is possible to change the construction due to changes in the ground conditions, construction period, and efficient settlement management techniques.