Field test and analysis of vacuum pressure in vacuum drainage preloading

Based on the analysis of basic physical concept of vacuum, the up-to-date in-situ measurement techniques and applications were summarized for the vacuum drainage preloading in construction engineering. The laboratory tests and engineering practices demonstrated that the soft clay above groundwater level was still under saturation even with vacuum drainage preloading. Therefore, when vacuum data were measured above groundwater level, the reading of vacuum gauge reflected the water pressure in pore void space, whereas if vacuum pressure measurement was located under groundwater level, the reading of vacuum gauge was meaningless.