The behavior of laterally loaded piles subjected to scour in marine environment

Pile foundations are used to transmit both vertical and horizontal loads. Many of offshore and coastal structures are founded on piles and these piles are subjected to significant amounts of lateral loads due to wind, wave and currents. Piles in shallow water regions are subjected to scour and there can be loss of soil support around these pile foundations. Bending moments and deflections are increased due to scour. In this investigation, it has been brought out that the lateral capacity of foundation is reduced due to scour. Tests on model piles of PVC and Aluminum embedded in soft marine clay bed formed at different consistency indices and load eccentricity ratios were conducted with and without scour. These pile materials are chosen such that there is a good variation in the rigidity of piles. From the model tests, it is noticed that scour results in the reduction in lateral capacity and increase in bending moments. In the second set of tests, cyclic loading is applied on PVC and Aluminum piles for a time period of 12 seconds. This time period represents the time period of storm wave in across the Indian seas. Considerable increase in deflection occurred due to scour in cyclic load tests for different consistency conditions of soil.