作 者：
吕伟华;杨帅;辛文青;孙信;张继周;薄冠中
单 位：
水能资源利用关键技术湖南省重点实验室;江苏交通控股有限公司;公路地质灾害防治工程技术研究中心;中交一公局第二工程有限公司;南京林业大学土木工程学院
关键词：
地面沉降;含水层;流固耦合;预测方法;线性趋势
摘 要：
过量抽取地下水是造成地面沉降的重要原因之一,要准确预测抽水地面沉降必须考虑含水层压密变形的影响,而已有研究中对含水层压密过程中的孔隙特征变化及渗透性改变的定量描述仍显不足。因此,利用在模型槽中模拟设立含水层和弱透水层交替的富含地下水的含水层系统,通过对贯穿至系统底部模拟的非完整井进行虹吸抽水与倒流回灌,研究抽水含水层水位降深及其压缩变形的时间效应。基于水位降深过程含水层孔隙比减小规律的定量表征,建立了考虑释水含水层水位降深条件下的含水层压缩量计算方法,并进行了合理性验证;同时,提出了一种简化流固耦合的抽水含水层压缩量线性预测方法,并基于多年的抽水沉降实测数据验证了其合理性。研究结果表明,试验抽水含水层储水系数数量级为10~(-2),其水位降深与压缩变形之间满足双线性关系,采用考虑耦合计算直线法预测值较非耦合算法更合理,在没有丰富的实测水位降深及沉降变形统计资料时,本研究方法可为局部抽水地面沉降的评估提供参考。
译 名：
Study on linear prediction method of pumped aquifer compression based on coupling process
作 者：
LYU Weihua;YANG Shuai;XIN Wenqing;SUN Xin;ZHANG Jizhou;BO Guanzhong;College of Civil Engineering,Nanjing Forestry University;Hunan Provincial Key Laboratory of Key Technology on Hydropower Development;Highway Geological Disaster Prevention and Control Engineering Technology Research Center;CCCC First Highway Two Engineering Co.Ltd.;Jiangsu Communications Holding Co.Ltd.;
关键词：
land subsidence;;aquifer;;coupling of seepage and consolidation;;prediction method;;linear trend
摘 要：
Land subsidence is one of the main manifestations of engineering geological disasters,which threatens the normal production and life of human beings all over the world. The increase of effective stress in soil layer caused by the excessive extraction of groundwater has been clearly identified as one of the main causes of land subsidence,and how to accurately calculate the land subsidence is a very tough challenge to engineers and policy making department. It is convinced that the compression contribution of aquifers plays a significant role in the composition of ground settlement.However,the quantitative characterization on the variation of permeability and void ratio of aquifer in the compaction process due to groundwater dropping was not fully considered. Therefore,a special model test was carried out to study the land subsidence in which an artificial simulated aquifer system was organized in a transparent plexiglass sink via pumping and water injection. Then,the time effect of water table dropdown and compression of the pumped aquifer was regularized by accumulated statistics analysis of the physical model test. In the physical model,a nonholonomic well was installed into the bottom aquifer to pump and recharge water with the inverted siphon principle method,and a quantitative characterization of pore reduction was also indicated in an expression to depict the changes of permeability coefficient after water release in aquifers. Finally,a linear prediction method of aquifer compression was proposed by coupling the process of seepage and consolidation under a simplified one-dimensional scale,and the effectiveness was well verified by the reasonable extension of the field measured data. Results show that the order of magnitude of storage coefficient of the pumped aquifer is 10~(-2) in the physical model test and is considered to be reasonable,a relationship between drawdown and compression deformation of pumping aquifer can be established and the turning point of the bilinear relation is the pre-consolidation pressure. The proposed prediction method based on the coupling process can characterize the variation of pore characteristic of sand strata due to the descending of groundwater table,and is more reasonable than the uncoupled method. Moreover,if there are not enough measured data of groundwater table and land subsidence in situ,the proposed method can provide a reference for the evaluation of land subsidence caused by local pumping,and,of course,more data is also needed to verify its applicability.
