Using the Cone Penetration Test to Divide the Soil Layer and Judge the Aquifer of Ultra-Soft Soil After Vacuum Preloading

Abstract

No sand cushion vacuum preloading method is widely used in China's coastal areas, as the detection technology of the surface-layer improvement of the ultra-soft soil is not yet mature. In this paper, using the cone penetration test (CPT) to detect the improved ultra-soft soil based on one case in Zhejiang province in China. The result shows that the cone resistance peaks and sleeve friction peaks are formed due to the effect of the surface crust layer and a thin sand layer, which can provide to determine the boundary of soil layer and the soil thickness in combination with drilling. The permittivity can be used to judge the dry zone, the unsaturated zone and the saturated zone of the ultra-soft soil.