公路路基施工中，常会碰到路线通过水井、垃穴、坑塘、地下室、坑道等。这些地方的路基，如果处理不好，将会造成路基局部沉陷，直接影响工程质量。我们的实践证明，用水压法能压实这些特殊条件F的填土。以水井为例。路基通过某一水井，先用L（最好用沙或沙性土）将水井填满， Highway subgrade construction, often encounter the route through the wells, cave, pit pond, basement, tunnel and so on. The subgrade in these places, if not handled well, will cause partial subsidence of the roadbed and directly affect the quality of the project. Our practice has proved that the hydrostatic method can be used to compact the fill of these special conditions. Take water well for example. Subgrade through a well, first with L (preferably sand or sandy soil) to fill the well,