摘要
过量开采地下水引发的“采水型”地裂缝灾害在国内外广泛存在。采水型地裂缝的发育是过量开采地下水与复杂的地质、水文地质条件共同作用的结果。含水层厚度突变型地裂缝是常见的一类采水型地裂缝。为了深入理解含水层厚度突变型地裂缝发育机制,文章基于这类地裂缝的概念模型设计了一个理想的地裂缝发育数值试验算例,应用有限元方法计算含水层连续性介质的应力应变分布,应用界面元方法计算非连续裂缝的发育。在此理想算例基础上,进一步应用Sobol全局敏感性分析方法评估含水层厚度比、孔隙水压力变化、压缩系数以及内聚力四个控制因子对地裂缝发育深度的影响。研究结果表明:开采地下水过程中,由于孔隙水压力降低,差异性沉降和剪切应力在含水层厚度突变处集中并不断增大,导致地面产生地裂缝,并进一步向下扩展。含水层厚度比是地裂缝发育最敏感的控制因子,孔隙水压力变化的敏感性次之,压缩系数敏感性弱,内聚力是不敏感控制因子。含水层厚度比和孔隙水压力变化之间有明显的交互作用,含水层厚度差异越大且孔隙水压力降低越大则地裂缝发育越深。
The“groundwater pumping type”earth fissure disasters caused by excessive exploitation of groundwater widely occur worldwide.Their developments are contributed by both excessive exploitation of groundwater and complex geological and hydrogeological conditions.The type of earth fissure in aquifer system with abrupt thickness change is a general type of earth fissures.In order to achieve a deeper understanding of the mechanism of this type of earth fissures,the paper designs a numerical experimental test in which earth fissure developes in an aquifer system with abrupt thickness change.Firstly,the finite element method is used to calculate the stress-strain distribution of the aquifer system,and the interface element method is used to calculate rupture development.Then the Sobol global sensitivity analysis method is applied to quantify the impact of four control factors,including aquifer thicknesses ratio,changes in pore water pressure,compression coefficient,and cohesion,on the depth of earth fissure development.The results of numerical test indicate that during the process of pumping groundwater,due to the decrease of pore water pressure,differential compaction and shear stress concentrate continuously increase at the location with abrupt changes in aquifer thickness,which leads to the formation of earth fissure on the ground and further downward expansion.The sensitivity analysis results indicate that the aquifer thicknesses ratio is the most sensitive control factor for the development of earth fissures,the sensitivity of pore water pressure changes is second,the sensitivity of compression coefficient is weak,and cohesion is an insensitive control factor.There is an obvious collaboration between the thicknesses ratio and the changes in pore water pressure.The greater the difference in thickness between aquifers,combined with the greater decrease in pore water pressure,the deeper the development of earth fissures.
作者
张火链
贺圣淋
张永伟
于德杰
龚绪龙
叶淑君
ZHANG Huolian;HE Shenlin;ZHANG Yongwei;YU Dejie;GONG Xulong;YE Shujun(Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources,School of Earth Science and Engineering,Nanjing University,Nanjing 210023,China;Shandong Provincial Territorial Spatial Ecological Restoration Center,Jinan 250014,China;Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources,Geological Survey of Jiangsu Province,Nanjing 210049,China)
出处
《高校地质学报》
CAS
CSCD
北大核心
2024年第4期442-450,共9页
Geological Journal of China Universities
基金
国家自然科学基金项目(41877180)资助。
关键词
地裂缝
厚度突变
敏感性分析
Sobol方法
数值模拟
Earth fissure
abrupt thickness change
sensitivity analysis
Sobol method
numerical simulation
