The Influence of Soil Saturation on the Geotechnical Test Results

The consistency limits are important properties of soil. The fall cone test method has a good repeatability, and the operator's judgement has little effect on the results. This paper presents a new sample preparation method, in which the sedimentation method and consolidation test are combined, to prepare the saturated specimens for fall cone test for determining the consistency limits, and the sample prepared by this new method can be considered completely saturated. For the specimens prepared by the previous sample preparation method, the decrease in the water content leads to a decrease in the degree of saturation of soil. The test results show that the specimens prepared by this new method can reach a low water content, and the minimum penetration depths are as low as 2 mm, and the plastic limit could be obtained directly. In addition, the van shear test results show that the unsaturated specimens have larger values of undrained shear strength than the saturated specimens at the same water content, which could explain the difference of consistency limits obtained from different specimen preparation methods.

Automated summary

This paper presents a new method of preparing soil samples for fall cone tests to determine consistency limits, which combines the sedimentation method and consolidation test. The results show that the specimens prepared by this method can reach low water content and obtain plastic limit directly. Additionally, the un saturated specimens have larger undrained shear strength than the saturated specimens, which explains the difference in consistency limits obtained from different sample preparation methods.