深水防波堤软土地基变形稳定性监测研究

Study on Deformation Stability Monitoring of Soft Soil Foundation of Deepwater Breakwater

摘要:

在深水防波堤的建设中，经常需要面对水下存在软弱土层的问题，而软土的变形问题与防波堤的稳定性息息相关。实时监测软土地基变形和孔隙水压力的变化，对控制抛填施工速度和防波堤地基稳定具有重大意义。以某海军基地防波堤为例，利用一套自动化水下测量和实时数据传输系统，分别对防波堤软土地基进行沉降、孔隙水压力、水平位移监测并分析其变化规律。监测结果表明：随着抛填层数的增加，软土地基的沉降变形特征发生改变，达到一定抛填层数后，基本不再发生瞬时沉降。抛填加载作用导致地基土体中产生超静孔隙水压力，需要控制抛石速度，防止出现超静孔隙水压力累积。地基土体的水平位移主要发生在抛填层以上的软土部分，并随土体深度的增加而不断减小，各监测断面中最大水平位移速率均低于10 mm/d，且基本不受台风天气影响。

Abstract:

In the construction of deepwater breakwater， we are often faced with the problem of weak soil layers under water， and the deformation of soft soil is closely related to the stability of breakwater. The real-time monitoring of the deformation of soft soil foundation and the variation of pore water pressure is of great significance to control the construction speed of riprap and the stability of breakwater foundation. Taking a breakwater of naval base as an example， a set of automatic underwater measurement and real-time data transmission system are used to monitor the settlement， pore water pressure and horizontal displacement of the soft soil foundation of breakwater， and to analyze its variable law respectively. The monitoring results show that the settlement and deformation characteristics of soft soil foundation change with the increase of the number of riprap layers. The instantaneous settlement no longer occurs when the number of riprap layers reaches a certain level. The riprap loading induces the excess pore water pressure in the foundation soil， thus it is necessary to control the riprap rate to prevent the accumulation of excess pore water pressure. The horizontal displacement of the foundation soil mainly occurs in the soft soil above the riprap layer， and decreases with the increase of soil depth. The maximum horizontal displacement rate of each monitored section is less than 10 mm/d， while basically unaffected by typhoon weather.