Experimental Study on Soil Deformation during Sampler Penetration

Abstract

Disturbance at the stage of penetration during soil sampling induces the deformation of samples, causing unreliable results on the determination of soil properties. In order to minimize the disturbance on soil during the penetration process, the displacement field around the tube sampling and influence factors on disturbance are investigated widely. However, there is a lack of effective observation on the development of soil movement at axis and on cross sections with the increase in the penetration depth, which should be studied individually at a certain penetration depth. This paper presents the effect of different sampler penetration depths on the development of soil at central axis and on cross sections through a series of 1-g physical model tests using the particle image velocimetry (PIV) technique. Results show that with the increase in the penetration depth, the correlation between the maximum compression deformation at central axis and the depth corresponding location may be approximated a hyperbola. Moreover, the surface of clay presents the downward compression deformation while that of sand presents the upward deformation. Furthermore, the disturbance influence depth of soil at central axis increases approximately linearly with the increase in the penetration depth. For the sand, the correlation between sensitivity on cross sections and depth presents approximately a line while that of clay presents a hyperbola. These deformation correlations provide useful references for detail predicting the overall deformation curve at a certain penetration depth, which helps to further develop and validate analytical or numerical solutions for this problem.