【摘要】 建筑基坑的降水、防渗和支护工作需要了解地下水渗流场的分布、补给与排泄等规律,以便于作出有针对性的处理。温度是地下水运动的天然示踪剂,正常地层温度的分布是连续且规律的,在季节气温影响点(如钻孔温度曲线上的拐点)以下深部地层的温度将随着深度的增加而上升。但由于地下水的运动影响,会产生温度分布的异常现象。分析了钻孔中由于地下水流动对温度曲线的影响,根据地层中温度的异常变化判定地层渗流的分布情况,利用温深曲线的异常来提取地下水渗流场的有关信息,如确定地层的渗透性,强渗漏带,集中渗漏通道以及地下水的补给关系等。对南京地铁三山街站基坑进行了地下水温度示踪探测分析,发现地下连续墙深度不够,存在裂缝,隔水效果差,是基坑渗水的主要原因,由此造成了基坑周围地面的沉降,并提出了相应的处理措施。更多还原

【Abstract】 During the construction of foundation pit,some characteristic factors about groundwater seepage field,should be investigated for the dewatering,antiseepage and supporting works. Temperature is a natural tracer of groundwater movement. Normal temperature distribution of strata is continuous and regular. Under the influence point of seasonal temperature,strata temperature will increase with depth,but groundwater movement will bring abnormality to this distribution. This abnormality of temperature curve can be used to study the permeability of strata and locate the concentrated leakage passage. Related information about groundwater seepage field is provided by the abnormality of the curve of temperature vs. depth,such as the location of strong leakage layer and the relation of groundwater recharge. As an example,ground water temperature tracer detection is performed in the foundation pit of Sanshanjie Subway Station in Nanjing. The case study shows that the major reason of leakage of foundation pit is the inadequate depth of underground continuous wall and the existence of faults on the wall. Deep confined water is drained out and then this will cause the ground settlement around the foundation pit. Corresponding countermeases are proposed accordingly.更多还原