Evaluation of Land Subsidence Based on Distributed Monitoring and SEM Analysis

Abstract

A better understanding on the relationship between macro compression behavior and microstructure of soil is essential in order to evaluate the trend of land subsidence. In this paper, distributed fiber optic sensing (DFOS) technology was applied in a borehole located in Guangming Village, Wuxi, China, to obtain the deformation of soil layers after the prohibition of deep groundwater withdrawal in this area. DFOS provided detailed information on the movement of soil layer within any depth range. The microstructure of undisturbed soil samples from the borehole was analyzed using SEM images. With the application of Particle/Pore and Crack Analysis System (PCAS), the micro porosity of samples were characterized by two statistical parameters called area probability distribution index and fractal dimension. Area probability distribution index described the distributions of micro-porosities and fractal dimension described the shape of pores in nature regardless of complexity. Good correlations between the deformation of soil layers and the two parameters about the microstructure characteristics were illustrated.