Analysis of the formation process of the covered karst ground collapse induced by groundwater changes based on the coupled LBM-DEM numerical simulation at micro scale

• Published in: Zhongguo dizhi zaihai yu fangzhi xuebao Vol. 35; no. 1; pp. 124 - 131
• Main Authors: Xiaohu TAO, Ming YE, Jianshi GONG, Hesheng WANG, Xiaoyu HU
• Format: Journal Article
• Language: Chinese
• Published: Editorial Office of The Chinese Journal of Geological Hazard and Control 01.02.2024
• Subjects: covered karst ground collapse; groundwater; lbm-dem method; micro scale; numerical simulation
• ISSN: 1003-8035
• DOI: 10.16031/j.cnki.issn.1003-8035.202207027

To investigate the hydraulic characteristics and soil behaviors during the formation of covered karst ground collapse induced by the groundwater changes, a 2D fluid-solid coupling model was developed based on discrete element method and lattice Boltzmann method. This model utilizes the linearly interpolated bounce-back scheme of Bouzidi and the momentum exchange method, allowing for the simulation of the formation of covered karst ground collapse from a microscopic perspective. Using the fluid-solid coupling model, an exploratory study was conducted to simulate the formation of covered karst ground collapse induced by a decrease in the hydraulic head of confined aquifers. Simulation results indicate that when the water level of a confined aquifer declines, the groundwater flow mainly affects the particles located above a cave opening and produces a downward force on the surrounding soil. When soil particles spall, the hydraulic heads at the positions of the spalled soil particles drop sharply. This results in