Evaluation the impact of weak layer in layered soil media using MASW method

Detecting the subsurface anomaly and characteristics of the soil such as weak layer is one of the most important parts of an engineering project. In this paper, the multichannel analysis of surface wave (MASW) is used to identify the subsurface anomaly. The effect of weak layer between soil layers is evaluated by simulating in ABAQUS software. In this regard, the effect of changes in the depth and thickness of weak layer are compared with the results of a two-layer soil media. In examining of thickness parameter, the values of 2, 4, 6 and 8 meters are chosen for thickness of the weak layer. Also, in the investigation of the depth parameter, the location of the weak layer at the depths of 2, 4, 6 and 8 meters are selected. The results showed that the presence of the weak layer caused discontinuity and jump in phase velocity spectrum of Rayleigh wave. It was determined that the position of jump is moved from higher to lower frequencies by increasing the buried depth of the weak layer. In accordance to the increase in the thickness of the weak layer, the number of jumps are increased, and these jumps are inclined towards lower frequencies.