Investigation of groundwater status for deep underground construction

In deep underground construction, if a Confined aquifer exists under a clay layer, excavation of the clay layer may occur serious ground heaving due to the unbalanced groundwater pressure. The accurate measurement of the groundwater is very important for the ground safety analysis and the excavation design. The buoyancy of groundwater is often taken into account in designing underground works. More accurate estimation of the buoyant force can lead to a more reasonable design to improve the economical feasibility. The result of field pumping test contributes to solve geological problems. When the geological conditions are very complicated, such as in the vicinity of a fault, it is difficult to determine a geological section from the drilling logs only. Considering the aquifer as a key layer, we can get a clearer geological image by tracing the aquifer. From the viewpoint mentioned above, the authors examined three results of groundwater surveys and discuss the complex groundwater conditions and other related problems.