Experimental study on vertical and lateral behaviour of open caisson foundations in clay

摘要

A programme of centrifuge model tests (100 g) was conducted to examine the vertical and lateral bearing behaviour of open caissons in clay. The dimensions of the model caisson were 0.52 m in length, 0.43 m in width and 0.28 m in height, and the soil was referred to as Malaysian kaolin clay. Soil and pore pressure cells were installed on the caisson skirt to enable detailed inspection into the soil-structure behaviour in addition to the load-displacement response. The normalised vertical penetration resistance on the model caisson during installation demonstrated satisfactory agreement with the data collected from parallel tests conducted in the field. Explicit equations were developed to quantify the soil plug coefficient, thus facilitating reliable assessment of the penetration resistance. The historical cyclic loading was found to have a significant enhancing effect on the lateral bearing behaviour of open caissons, which was demonstrated by the load-displacement response as well as the development of soil and pore pressures. After a resting period of about 14 days in prototype, the stiffness of the open caisson foundation was about four times that prior to previous lateral cyclic loading.