沉入式桶式基础防波堤抗倾覆稳定性计算

在波浪荷载作用下,沉入式桶式基础防波堤抗倾覆稳定性是其稳定性计算的一个重要部分。假设沉入较深土层的桶式基础防波堤极限状态下的稳定性主要由桶侧土压力、桶侧摩阻力、桶底土反力、桶底摩阻力维持,其工作原理与挡土墙类似。文中假定桶体绕转动中心转动,港侧为被动土压力,海侧为主动土压力,同时假定被动侧桶底土体达到极限状态。由于下桶内部有较多隔墙,假定下桶结构与桶内土体协同变形,即桶与桶内土体看作一个整体。基于上述假设,通过解析的方式,推导了桶壁土压力及摩阻力、桶底土反力及摩阻力的表达式,建立了沉入式桶式基础防波堤满足抗倾覆稳定性要求的三维计算方法。通过数值分析与离心机试验对比,验证了本文抗倾覆稳定性计算方法的可靠性。

A computation method for stability against overturning of embedded bucket foundation breakwater

The stability against overturning is an important part to calculate the stability of the embedded foundation breakwater under wave loading. In this article, it is assumed that the stability of a new embedded bucket breakwater mainly depends on the horizontal soil pressures on the wall and the bottom of the bucket, and the vertical shear force on the wall and the bottom of the bucket, and that such a breakwater works in a similar principle as a retaining wall. In this study, the supposition is made that the bucket rotates around the rotating centre, as a result, soil near the wall of the harbor side is in a passive state, and soil near the wall of the sea side is in an active state. At the same time, the supposition is also made that the soil mass of the passive side under the bucket reaches a limit state. Because of the partitions in the lower bucket, it is assumed that the bucket and the soil mass in the bucket deform together, i.e. the bucket and the soil mass in the bucket are regarded as an entirety. Based on the above-mentioned hypothesis, by means of derivation and analysis, the expression of soil pressure and the friction on the bucket wall, the reaction and the friction under the bucket are deduced. A three-dimensional computation method for stability of the new embedded bucket foundation breakwater is thus developed. Finally, by analyzing the numerical model and comparing of the centrifugal tests, it is found that the computation method for the stability against overturning is reliable.