地下水临界开采水位的识别方法研究

The depression cone and its extent expansion formed by over-exploitation of deep groundwater were the main causes inducing a series of geological disasters such as land subsidence, ground fissures, seawater intrusion etc. in many large and medium-sized cities. The land subsidence and related disasters caused by groundwater over-exploitation are a kind of geological hazard that the people face globally and that mark one of serious geo-environmental disasters in China. This kind of disaster becomes more and more serious, and is characteristic of progressivity, difficult treatment and great harm. It has caused the heavy economic damage and needs to be solved urgently. Restriction on groundwater exploitation within the critical ground water table can allow the exploitation of partial groundwater and slow down the rapid development of land subsidence and its disasters; the study shows that once the groundwater table recovers within the critical exploitation groundwater table, the rapid land subsidence can be remitted significantly. How to identify the critical exploitation level of groundwater that does not cause the rapid development of land subsidence and the related disasters is of great significance for prevention and control of the geological disasters caused by groundwater exploitation and is the important subject which needs to be studied urgently. .The study was conducted with Tianjin and Cangzhou in the North China as the research sites and with the soilmass within the range of influence extent of exploitation deep groundwater as the study object. Based on the summary of the geological environment survey, the existing geological data, long-term observation data of land subsidence, with the multi-disciplinary theory including engineering geology, soil mechanics, and numerical geology as the basis, and through the comparison between the experimental results of soil mechanics test and in-situ simulation experiment and long-term observation data of land subsidence, the transmitting rule of stress function of water level fluctuation in the soil layer and the variation laws of the soil structure, strength, physical mechanics, pore water seepage parameters were analyzed, the effect of the groundwater table fluctuation on the deformation of soilmass and response on regional geological environment as well as the necessary link between the whole soilmass deformation and hierarchical soilmass deformation were studied systematically, the common mechanism of groundwater seepage field and stress-strain field was probed, how to use the features of regional geological structure, groundwater flow field and hierarchical soilmass to determine the critical points of the slow deformation and rapid deformation for groundwater exploitation table was revealed. It is in order to provide a scientific basis for preventing and controlling land subsidence and related disasters.

超采深层地下水引起的地面沉降灾害是一种全球性的地质灾害，也是我国比较严重环境灾害之一，正在发展之中，它具有累进性、难治理、危害大等特点。限制地下水在临界水位内开采或者恢复地下水位到临界水位，对预防与治理因开采地下水引起的地面沉降等灾害具有重要意义，识别地下水临界水位是地学工作者需要迫切研究的课题。.本研究拟选取华北典型地面沉降边缘区地下水开采影响深度内的土体为研究对象，以工程地质学、水文地质学、土力学等多学科理论为基础，通过室内土力学试验、现场模拟实验等综合实验成果与研究区地下水位动态与地面沉降长期观测数据资料对比研究方法，分析地下水开采应力对土层结构、强度、物理力学性质、孔隙水渗流等参数的影响，探索地下水位升降过程对各土层变形及区域地质环境的响应，研究地下水渗流场、土体的应力-应变场共同作用机理，揭示不同地层组合条件下地下水临界水位的识别方法，为预防和治理地面沉降及相关灾害提供科学依据。

本项目在项目组全体人员的共同努力下，已经顺利完成项目的计划书的目标任务。.研究区主要为华北地区，第四系含水岩系埋深在624-1700m范围内，自上而下约每埋深100米存在一个含水岩组，由于地表水缺乏、第一层浅层水储量有限、水质差、埋深100m～350m内的水咸等问题，主要开采埋深350米以下的深层地下水，持续的深层地下水开采形成了一定范围的地下水开采漏斗区，并引起天津、沧州等地面沉降、地裂缝等灾害，该灾害也是我国比较严重环境灾害之一，正在发展之中，它具有难治理、危害大等特点。限制地下水在临界水位内开采或者恢复地下水位到临界水位，对预防与治理因开采地下水引起的地面沉降等灾害具有重要意义。. 项目选取华北典型地面沉降边缘区地下水开采影响深度内的土体为研究对象，以工程地质学、水文地质学、土力学等多学科理论为基础，通过室内土力学试验、现场模拟实验等综合成果与研究区地下水位动态与地面沉降长期观测数据资料对比研究方法，分析地下水开采应力对土层结构、物理力学特征等的影响，探索地下水位升降过程对各土层变形及区域地质环境的响应，研究地下水渗流场、土体的应力-应变场共同作用机理，揭示不同地层组合条件下地下水临界水位的识别方法，为预防和治理地面沉降及相关灾害提供科学依据。. 借助于以往研究基础、实测资料、正在执行的地质调查项目研究成果及本项目的补充的现场试验室内试验等多方研究工作，浅层地下水流场、深层深地下水流场、水文地质参数以及人类活动对地下水流场影响更深入认识，在此基础上研究了水位变动作用应力在土体中的分布、时效规律，分析了地下水渗流-土体的应力与土体变形耦合机理，探讨了地下水临界开采水位识别方法，并建立地下水流、地面沉降三维可视化模型。.通过项目研究，以项目名义以本项目名义论文发表5篇(其中SCI1篇、EI 1篇CPCI 1篇)，专著一部、实用新型专利3项、研究生毕业论文3项、培养研究生5名、参加国内外相关学术交流13 次。