桩靴贯入黏土层时邻近群桩相互作用分析

为研究钻井船插桩对邻近平台群桩相互作用的影响,采用耦合欧拉拉格朗日(CEL)方法对桩靴贯入黏土层时邻近群桩中各桩荷载分担比、桩头附加位移及两桩相互作用系数进行了分析。首先通过对缩尺模型试验的数值分析,验证了CEL方法的可行性;然后进一步分析了桩靴贯入黏土层时对邻近群桩相互作用的影响;最后探讨了净间距、桩间距对群桩相互作用的影响。结果表明,在桩靴贯入中,前桩的荷载分担比大于后桩,且桩靴贯入至一定深度后,当净间距越小或桩间距越大时,前桩的荷载分担比越大、后桩的荷载分担比越小,但各桩的荷载分担比随桩靴贯入深度增加时的变化规律不变;净间距越大,桩头附加位移及相互作用系数越小;在桩靴贯入时,由于受群桩遮拦效应的影响,桩头附加位移及相互作用系数随桩间距的变化规律同插桩前有所不同,当桩间距大于3倍桩径时,随桩间距的增加而减小,当桩间距小于3倍桩径时,随桩间距的增加而增大。

Interaction analysis of adjacent pile groups during spudcan penetration in clay layer

The purpose of this study is to study the effect of spudcan insertion of drilling vessel on pile-group interaction of adjacent platforms. In this paper, the load sharing ratio, pile head additional displacement and interaction coefficient of each pile in the adjacent pile group when spudcans are inserted into the clay layer are analyzed with the CEL (coupled-Eulerian-Lagrangian) method. Firstly, the feasibility of the CEL method is verified by numerical simulation of scale model test. Then the influence of spudcan penetration into the clay layer on the interaction of adjacent piles is further analyzed. Finally, the effect of net spacing and pile spacing on pile group interaction is discussed. The results show that the load sharing ratio of the front pile is greater than that of the rear pile in the spudcan penetration, and when the net spacing is smaller or the pile spacing is larger, the load sharing ratio of the front pile is larger and the load sharing ratio of the back pile is smaller, but the change rule of the load sharing ratio of each pile remains unchanged with the increase of the penetration depth of the spudcans. The greater the net spacing, the smaller the additional displacement and interaction coefficient of the pile head. In the process of spudcan penetration, due to the influence of pile group blocking effect, the change rule of the pile head additional displacement and the interaction coefficient with pile spacing is different from that before pile insertion. When the pile spacing is greater than 3 times of pile diameter, it decreases with the increase of pile spacing, and when the pile spacing is less than 3 times of pile diameter, it increases with the increase of pile spacing.