Estimating Land Subsidence Induced by Groundwater Extraction in Gassy Soil with Anisotropic Permeability

Extraction and utilization of groundwater is essential for meeting the demand of drinking water, agricultural irrigation, and industrial processes. Nevertheless, groundwater extraction frequently leads to land subsidence and damage to nearby facilities. The groundwater extraction process would be more complex in coastal areas, where gassy soils rich in discrete gas bubbles are widely distributed. This paper introduces a newly developed method to examine the land subsidence process induced by groundwater extraction. Considering the impact of gas bubbles on the compressibility and deposition process on anisotropic permeability of gassy soil, a new seepage equation is developed. With the aid of the integral-transform method and extended precise integration method, a precise solution is obtained. Extensive parametric investigations were conducted to compare the deformation behavior in gassy and saturated soils and further to explore the effects of saturation degree and anisotropic permeability on land subsidence processes. This paper presents a fundamental solution for analyzing the deformation behavior of gassy soil induced by groundwater extraction, which can be further treated as a kernel function of the boundary element method or finite-element method to evaluate the service process of structures built on gassy soils. The findings shed a new light on prevention and control of extracting groundwater.