摘要
岩溶区抽取地下水导致水位被迫下降将诱发溶洞坍塌及地面沉降等灾害,其实质是流场和力场相互作用的结果。为精确评判溶洞稳定性和沉降风险性,需构建流-固耦模型模拟地下水抽取过程中的流场和力场的时空分布。基于连续介质力学推导给出流-固全耦合控制方程,结合渗透率关系、应力-应变关系等本构方程给出闭合数学描述,通过经典算例验证模型有效性后分析全耦与传统解耦计算的差异。以深圳市场地工程地质条件为背景,根据勘察参数,计算分析不同抽水速率、洞径、洞形等多个关键因素下孔压、应力和塑性区的时空分布,阐述多物理场作用下岩溶塌陷及地面沉降的力学破坏机制,并基于灰色理论对各影响因素敏感性大小进行分析。结果表明:在重点分析土体渗流时,耦合作用不可忽视;与勘察结果一致,水力压降造成的应力集中是形成地面沉降和溶洞坍塌的主要因素;地面沉降对抽水速率、洞径和洞形更为敏感,溶洞稳定性对抽水速率和洞径更为敏感。研究成果可为岩溶塌陷防治提供参考。
The collapse caused by groundwater extraction in karst area is caused by the interaction between fluid and mechanic field essentially.A fluid-solid coupling model is needed to quantify the settlement and the stress around the cave.The governing equation of fluid-solid fully coupled model is derived from the continuum mechanics.Combining with the constitutive equations such as permeability and stress-strain relation,the closed mathematic description was given.The effectiveness of the model was verified by comparing with classical example,and the difference between the fully coupled model and the semi-coupling model was analyzed.Based on the engineering conditions of karst collapse area in Shenzhen,the temporal-spatial distribution was computed under the different working conditions,such as pumping rate,hole diameter and hole shape etc.The mechanical mechanism of karst collapse and subsidence was expounded.Grey correlation matrix was established based on grey theory to determine the sensitivity of each influencing factor.The results show that the coupling effect should be considered when the seepage occur in soil.The stress concentration caused by hydraulic pressure drop is the main factor of ground settlement and cave collapse.The settlement is more sensitive to the pumping rate,diameter and the shape of the cave,and the stability of the cave is more sensitive to the pumping rate and the diameter.The research results can provide support for disaster prevention and control in karst area.
作者
梁文鹏
钱静
王明龙
LIANG Wen-peng;QIAN Jing;WANG Ming-long(Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518000,China;Development Research Center for Natural Resources and Real Estate Assessment,Shenzhen 518000,China;Shenzhen Geo-environmental Monitoring Center,Shenzhen 518000,China)
出处
《科学技术与工程》
北大核心
2024年第5期2026-2035,共10页
Science Technology and Engineering
基金
深圳市岩溶地区稳定性评价及岩溶塌陷防治对策研究专题(SZCG2021199770)
深圳市城市地质调查服务项目(SZCG2021199767)。
关键词
抽取地下水
数值模拟
溶洞稳定性
地面沉降
groundwater extraction
numerical simulation
cavern stability
land subsidence
