Ricerc@Sapienza

Ground displacements caused by underground excavations in densely urbanised areas often requires the adoption of protective techniques to prevent damage to existing buildings. When the tunnel passes to the side of a potentially affected building, tunnelling-induced settlements can be reduced pre-installing a protective barrier between the tunnel and the building. Usually, this mitigation technique is implemented in practice based on empirical knowledge rather than as a result of a rational design process.

An experimental study has been carried out to investigate the effects of soil partial saturation on the behaviour of laterally loaded piles. The proposed study has been conducted by means of centrifuge tests at 100×g, where a single vertical pile has been subjected to a combination of static horizontal load and bending moment. The study has been conducted on a silty soil characterized with laboratory testing under saturated and unsaturated conditions. During flight, two different positions of water table have been explored.

This note presents the preliminary outcomes of a numerical investigation on the influence of soil partial saturation on the behaviour of laterally loaded piles. The modified Cam clay model extended to unsaturated conditions and formulated in terms of Bishop’s effective stress has been used to analyse the results of centrifuge tests designed to address this topic. The model, calibrated on laboratory tests, well reproduces the main aspects of the soil-pile interaction.