Abstract: This paper used the coupled euler-lagrangian (CEL) method to establish three models, including a single-pile model, a single-pile model with pre-drilled hole, and a double-piles model with an isolated pile, aiming to study the soil displacement distribution around the pile and to investigate the control effect of pre-drilled hole and isolated pile on soil squeezing deformation. Results show that during the penetration process of pipe pile, the horizontal displacement distribution of soil along the depth varies with the penetration depth of pile, and the maximum displacement occurs near the depth of the pile tip. Furthermore, the soil under the depth of 6~7d (d is the pile diameter) below pile tip is not affected by the pile penetration. When the pile penetration depth is larger than 8d, the uplift deformation of ground surface caused by the yield failure of the deep soil gradually disappear. After the pile is fully penetrated, the horizontal displacement decreases exponentially as the distance from the pile increases. In addition, as the depth of pre-drilled hole increases, the control effect of pre-drilled hole on soil squeezing deformation becomes more effective. The isolated pile can significantly reduce the horizontal displacement of soil on the back side of the isolated pile, and can transfer the position of soil depth where occures maximum horizontal displacement from near the pile tip to a depth of 0.5L (L is the pile length). The CEL approach is well suited to study the influences of pile penetration on the surrounding soil, and can be widely applied to the researches of geotechnical problems involving the large deformations, such as pile installation and spudcan penetration.

Key words: coupled eulerian-lagrangian method, soil squeezing effect, numerical analysis, pre-drilled hole, isolated pile