地下水控采条件下上海土层变形特征研究  

Effect on land subsidence of controlling groundwater extraction in Shanghai

作　　者：李明霞[1] 张云[1] 

机构地区：[1]南京大学地球科学与工程学院,江苏南京210023

出　　处：《上海国土资源》2014年第4期17-20,共4页Shanghai Land & Resources

摘　　要：根据上海地区分层标和水位孔的实测资料，分析了2001~2012年间地下水控采条件下地下水位变化及土层变形特征。上海地区潜水层和第一承压含水层水位基本保持不变，第二至第五承压含水层水位都呈现出明显的回升趋势。三个软土层仍在发生压缩变形，其中第三软土层随着水位的回升变形得到了控制，部分地区已出现回弹趋势。在水位全面回升情况下，第一到第四承压含水层表现为明显的塑性和蠕变变形，当水位持续回升时土层仍有沉降，且变形滞后于水位变化；而第五承压含水层主要以弹性变形为主，当水位不断回升时，含水砂层也随之持续回弹，滞后不明显。将上海地区近年来含水层与水位变化关系归纳出四种模式。砂性土单向蠕变试验的结果表明，双屈服流变模型可以较好地反映砂土蠕变变形特征。Long-term and excessive extraction of groundwater has led to serious regional land subsidence in Shanghai. Using ifeld data obtained from extensometer groups and observation wel s, the changes in groundwater levels in aquifer units and the characteristics of soil deformation were analyzed for the period 2001-2012. The water level in the phreatic aquifer and the ifrst conifned aquifer remained approximately stable, while the water level in the second to iffth conifned aquifers fol owed an obvious rising trend over the study period. Moreover, three soft layers remained under compression, but the deformation of the third soft layer was effectively control ed and rebound occurred in some areas. Under the condition of overall recovery of groundwater, the ifrst to fourth conifned aquifers showed clear plastic and creep deformation. The deformation of the aquifer sand lags behind the variation in the water level. With the groundwater level rising continuously, the soil layer was stil compacting, while the iffth conifned aquifer behaved primarily as an elastic material, and the sand layer rebounded constantly, although the lag was not as obvious. Four modes were classiifed based on the relationship between the deformation and the groundwater level of the aquifer under the pumping conditions between 2001 and 2012. The results of the laboratory creep test showed that the newly developed double-yielding viscoelastic-plastic model is able to simulate the deformation characteristics of saturated sand.

关 键 词：地面沉降 地下水控采 砂土蠕变 变形特征 本构模型 

分 类 号：P642.26[天文地球—工程地质学]