Response of Single Pile Due to Deep Excavation and Underground Openings

One of the important issues of excavation and tunneling in urban areas is the assessment of its impact on foundations of neighboring structures due to ground movements in particular on pile foundations. Excavation and tunneling operations cause lateral soil movements which induce additional lateral loads on piles and they are known as passive piles. They are subjected to additional bending moment and shear force which can lead to serviceability problems or even failure of piles itself. The present study focuses on 1 g model tests to determine the response of single pile adjacent to a tunnel and a combined effect of excavation and tunneling. The effect of various parameters related to the pile, tunnel, and soil on the response of pile to passive loading was analyzed in this study. The following parameters viz. pile length to diameter ratio, distance between pile and retaining wall, distance between pile and tunnel springline, position of pile with respect to retaining wall and tunnel are varied to understand the response of piles and also to identify the factor which influences the response most. The lateral deflection of pile head was measured. Analysis of the test results showed that the shorter pile (L/d = 10) deflects more when compared to a long pile (L/d = 20) in case of excavation, tunneling and combined case.