地震液化条件下重力式码头的变形破坏机理

现场调查发现在神户地震期间重力式码头破坏时都发生了相当大的侧向位移，因此，阐明挡土墙有变形机理对于改善抗震设计具有十分重要的意义。为此，根据相似原理设计了重力式码头的地基模型，进行了一系列的振动台试验。试验结果表明：基底土的强度降低和局部液化是挡土墙变形破坏的主导因素。墙后动土压力的增加为挡土墙的运动提供了条件。在液化条件下重力式码头地基的运动以侧向位移为主。重力作用是地基侧向运动的主要影响因素。减少作用于挡土墙上的动土压力和充分填实基底下的砂土是增加重力式码头抗震稳定性的重要措施。

MECHANISM OF DEFORMATION AND FAILURE OF GRAVITY-TYPE QUAY WALLS UNDER EARTHQUAKE LIQUEFACTION

The field investigation found that seismic damage to gravity-type quay walls during Kobe earthquake consisted of tremendous lateral displacement of retaining walls. It is very important to clarify the mechanism of the wall displacement in order to improve the aseismatic design. For this purpose, a model of gravity-type quay wall ground based on the principle of similitude was designed and a series of shaking table tests are carried out in present study. The test results indicate that the strength decrease and local liquefaction of subsoil are the leading factors in the deformation and failure of retaining walls. The increase of dynamic earth pressure in the back of structure provides the movement condition for the structure. While the movement of the ground mainly manifest as the lateral displacement under liquefaction and the gravity is the leading factor in the lateral movement. It is very significant that the dynamic earth pressure is decreased and the foundation sand is fully compacted to increase the stability of gravity quay walls during future earthquakes.