波浪作用下临海基坑超孔压响应试验研究

以港珠澳大桥拱北隧道明挖段基坑工程为背景，根据相似比尺理论，确定具体的试验模型，利用多功能波浪流水槽系统，研究了波浪作用下黏质粉土基坑周围的超孔压响应规律，研究发现，临海基坑周围的超孔压由振荡超孔压和累积超孔压两部分组成；振荡超孔压幅值沿着从坑外主动区到坑内被动区的渗流路径逐渐衰减，同时伴随着波动相位的滞后，且振荡超孔压幅值衰减值越大，相位滞后也就越明显；基坑主动区的超孔压以随着时间逐渐减小的速率累积，判断临海基坑周围某一位置处的超孔压累积情况，应该从该处的排水条件好坏及由波浪荷载产生的动应力大小两方面分析，排水条件越差或由波浪荷载产生的动应力越大，就越有利于该处超孔压的累积；基坑被动区的振荡超孔压及累积超孔压均相对较小。

Experiment research on response of excess pore pressure to wave around near-sea excavation

Model test of coastal excavations is based on the excavation of Gongbei tunnel located in the Ling-ding Ocean, which is a part of the famous Hong Kong-Zhuhai-Macao Bridge project. The physical size of the testing model is determined by theory of similar scale. A series of model tests are carried out in the multifunctional wave-current flume to study the pore pressure response to wave around clayey silt excavation. This study shows that the excess pore pressure around near-sea excavation consists of oscillatory and accumulated excess pore pressure. For the oscillatory excess pore pressure, the amplitude decreases and the lagging phase increases gradually along the seepage path from the active zone to the passive zone of the excavation; and the more amplitude attenuated, the more phase lagged. Excess pore pressure accumulates at a rate decreasing with time. The worse of the drainage condition or the larger of the dynamic stress generated by the wave load, the easier for the excess pore pressure to accumulate. The oscillatory and accumulated excess pore pressures are all relatively small in the passive zone of the excavation.