Subsurface Characterization of Malaysian Hemic Peat and Soft Clays Using CPTu and MASW

Abstract

Geotechnical engineers practice a variety of in-situ investigation techniques to comprehensively characterize peat soil properties. Peat soil is a challenging soil characterized by its high water content, organic content, and low strength, making its geotechnical properties difficult to assess accurately. High water saturation and the presence of fresh fibres in peat also risk sample disturbance in collecting undisturbed peat soil samples which causes underestimation. An In-situ test known as the Cone penetration test with pore pressure measurement (CPTu) was investigated to measure the cone resistance (qc), sleeve friction (fs), and pore water pressure (u2) at various depths. In parallel, multichannel analysis of surface waves (MASW) was employed to determine the shear wave velocity (Vs) profile of the peat soil. The findings revealed that CPTu and MASW data were able to delineate the soil stratigraphy and estimate the peat thickness. However, the presence of fresh fibres in peat causes overestimation of the qc and fs values, causing difficulties in accurately determining the peat strength. Overall, the combination of CPTu and MASW data offered a comprehensive understanding of the peat's geotechnical and dynamic characteristics. The findings have significant implications for engineering practices and ultimately contribute to safer and more resilient construction projects in challenging peat soil environments.