基于LBM-DEM细观数值模拟的水力诱导覆盖型岩溶地面塌陷发育过程分析  

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

作　　者：陶小虎 叶明[3] 龚建师[1,2] 王赫生 胡晓雨[4] TAO Xiaohu;YE Ming;GONG Jianshi;WANG Hesheng;HU Xiaoyu(Nanjing Center,China Geology Survey,Nanjing,Jiangsu 210016,China;Key Laboratory of Watershed Eco-Geological Processes,Ministry of Natural Resources,Nanjing Jiangsu 210016,China;Department of Earth,Ocean and Atmospheric Science,Florida State University,Tallahassee,FL 32306,USA;Water Resources Service Center of Jiangsu Province,Nanjing,Jiangsu 210029,China)

机构地区：[1]中国地质调查局南京地质调查中心,江苏南京210016 [2]自然资源部流域生态地质过程重点实验室,江苏南京210016 [3]佛罗里达州立大学地球、海洋与大气科学学院,佛罗里达州塔拉哈西32306 [4]江苏省水资源服务中心,江苏南京210029

出　　处：《中国地质灾害与防治学报》2024年第1期124-131,共8页The Chinese Journal of Geological Hazard and Control

基　　金：中国地质调查局地质调查项目(DD20221756,DD20230079)。

摘　　要：文章以水力驱动的覆盖型岩溶地面塌陷为背景,基于离散元方法和格子Boltzmann方法,采用Bouzidi插值反弹边界格式和动量交换法,建立一种可以从细观角度模拟覆盖型岩溶塌陷的二维格子Boltzmann方法—离散元方法流固耦合模型。在此基础上对承压水下降引起的覆盖型岩溶塌陷数值模拟开展了探索性研究。模拟结果表明:承压水位下降工况中地下水主要对隔水层岩溶开口处的颗粒产生影响,对土洞周围土体产生向下的作用力;土体颗粒的剥落容易造成土颗粒原位置和上方位置处水压的陡降,从而造成较强的水力坡降,使得地下水对内部颗粒作用力陡增,容易引起上方颗粒在地下水作用力和重力作用下失稳,导致从土体颗粒失稳至土层塌陷逐渐加速。研究成果对进一步从细观尺度进行水力驱动的覆盖型岩溶地面塌陷的发育过程与特征研究具有理论及实际意义。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 a significant increase in the hydraulic gradient,causing the groundwater force on internal particles to sharply increase as well.As a result,the upper particles lose stability due to the combined force of groundwater dragging and gravitational force,which can lead to a gradual acceleration process of collapse.The research results provide valuable insights into the understanding of covered karst ground collapse formation induced by the groundwater changes.

关 键 词：覆盖型岩溶 地面塌陷 地下水 数值模拟 LBM-DEM方法 细观尺度 

分 类 号：P642.26[天文地球—工程地质学]