DefinePK

Abstract

A geotechnical investigation of cavity and settlement has been conducted at Besraya Highway, Jln Kuchai Lama due to pipe jacking works to determine subsurface condition at the proposed site and to identify the causes of settlement. In this research study, JKR Probe test and Electrical Resistivity Imaging (ERI) method were applied in order to achieve the objectives. Analyses of the settlement problem also were carried out based on soil parameters obtained from JKR Probe data using Two-Dimensional (2-D) finite element method (FEM) analyses with PLAXIS Finite Element Code. Based on JKR Probe test results, it is found that the soil layer is loose to medium dense for middle of line. While for line 1, the soil was found in fully saturated condition since there is an evidence of water pocket when the rod was pulled out from the ground. For ERI results, the soil layer was found very weak with presence of saturated condition. Besides that, there is an appearance of water pocket based on images of ERI resulting formation of cavities and voids which beneath the existing pavement structure. From the geo forensic stimulation, the development of excess pore water pressure and seepage in the loose unconsolidated deposit provide additional volume change to the material, causing excessive settlement. The results indicated that the groundwater seepage and dissipation is the main problem to the ground settlement issue with the contribution of pipe jacking work. Therefore, a mitigation step is a need in order to stop the major failure occur due to excessive settlement.