A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geotechnical and Earth Resources Engineering

Thesis (M. Sc.) - Asian Institute of Technology, 2024

This thesis investigates the integration of Electrical Resistivity Imaging (ERI) and Multichannel Analysis of Surface Waves (MASW) to improve slope stability models, specifically addressing an embankment failure case in the soft clay of Ayutthaya, Thailand. The primary objectives are to obtain detailed subsurface characteristics and properties of the embankment using ERI and MASW techniques and to determine the failure mechanisms through enhanced slope stability modeling informed by data from these geophysical methods. Through comprehensive field investigations and geophysical surveys, ERI is utilized to map subsurface characteristics, providing valuable insights into site conditions. MASW is employed to obtain Young's modulus, crucial for numerical modeling using MIDAS GTS NX software. The research demonstrates that incorporating geophysical data, particularly Young's modulus from MASW, significantly improves the accuracy of numerical modeling. By integrating MASW-derived Young's modulus with reconstructed geometries, the final slope stability models exhibit enhanced predictive capabilities. This integration cnables a more comprehensive understanding of failure mechanisms and facilitates more accurate assessment of slope stability.The findings underscore the efficacy of ERI and MASW in characterizing subsurface properties and their importance in improving slope stability modeling accuracy. This research contributes to advancing geotechnical engineering practices, particularly in regions prone to embankment failures, by providing a robust methodology for integrating geophysical and geotechnical data to enhance slope stability assessments.