Current methods for groundwater level testing could not accurately reflect the actual variation of the groundwater level under vacuum pre-loading

and thus their limitations were comprehensively analyzed in this paper. A new testing method

namely closed piezometric testing method-laser testing method

was described in detail. Moreover

field tests were conducted to verify the rationality of the developed method. The results show that some restrictions are found in the existing closed piezometric testing method. On the one hand

the employed devices are very complex and challenging to install. On the other hand

experimental results are affected by many factors

which indicates that the results could not truly represent the ground level under vacuum pre-loading condition. However

the proposed new testing method has merits of easy

low-cost and intuitive results

owning to its principle of laser ranging. The field testing results show that during vacuum pre-loading

the groundwater level falls with the subsidence of ground foundation. In addition

the overall decline is slightly greater than the consolidation settlement of the foundation. Therefore

the new method can accurately reflect the actual variation of the groundwater level

and is useful to evaluate and analyse the effect of vacuum pre-loading.