Site Classification using Multichannel Analysis of Surface Wave (MASW) Method for Evaluation Foundation Costruction Planning of The Meureudu Hydropower Tunnel

Abstract

A critical component in the development of the Meureudu Hydropower Plant (PLTA) in Aceh Province is the construction of a tunnel to channel water from the reservoir to the power generation unit. Accurate site classification is essential to support foundation design and ensure long-term structural stability. This study applies the Multichannel Analysis of Surface Waves (MASW) method, supported by geological sample data, to classify the site conditions. The dataset comprises seismic measurements from seven survey lines and 124 geological rock samples. MASW data were processed by utilizing the dispersion properties of Rayleigh waves to generate shear wave velocity (Vs) profiles for each line. The velocity models were then interpreted using non-linear Least Squares Inversion to obtain the Vs–depth profile. Based on the shear wave velocity interpretation, the subsur-face layers are classified into three categories: stiff soil (SC) at depths of 0–20 meters, rock (SB) at around 20–40 meters, and bedrock (SA) at 40–45 meters depth. Lithological interpretation indicates that the rock layers consist of sand-stone and shale. For tunnel foundation design, in elevation 197 masl is recom-mended to reach the bedrock layer.