降雨影响下的海堤非稳定渗流分析

Sea Dike Unsteady Seepage Flow Analysis under the Condition of Rainfall

海堤的稳定关乎到其保护范围内的生命财产安全,渗压是评判海堤安全的重要指标,潮水位长期作用于海堤,是影响其渗压分布的主要因素,而降雨是影响渗压的重要因素。在潮位和降雨作用下,海堤长期处于饱和-非饱和非稳定渗流状态,易导致海堤失稳和滑坡。为及时掌握海堤渗流场分布,有效监控、分析特殊工作环境下海堤的安全稳定,采用合理的降雨入渗模式,输入实际的动态潮位,利用ANSYS热分析模块,模拟计算海堤渗流场分布。根据前次有限元迭代计算结果调整自由面、溢出点,并由基质吸力修正非饱和区渗透系数,使用ANSYS参数化设计语言编写海堤非稳定渗流场分析程序。先不考虑研究时段内降雨入渗对渗压分布的影响,而后进行潮位和降雨共同作用下海堤渗流场的模拟分析,结果与实测数据吻合度良好,为进一步分析海堤稳定性提供依据。

The security of sea dike is related to its protection against life and property safety. Seepage pressure is important for determining sea dike security. Tide level is the permanent load for sea dike. Meanwhile rainfall is another important factor affecting sea dike safety. Under the action of tide and rainfall, sea dike is always in saturated-unsaturated seepage state, and it often leads to slope failure and landslide. To master the seepage field distribution timely, and to monitor the security of sea dike effectively under the special working environment, a given rainfall infiltration model was used, a series of reasonable dynamic tide level was set up. After that, the distribution of seepage field was calculated by ANSYS thermal analysis module. According to the previous iteration computation, the free surface and overflow point were adjusted, and the unsaturated permeability parameters were modified with matrix suction. ANSYS parameter design language was used to write the program, which can simulate the distribution of unsteady seepage field. Firstly, the influence of rainfall infiltration was ignored, then, the seepage field was analyzed under the function of tide and rainfall. The simulated values tended to be identical to the measured data, which provided the basis for further analyses of sea dike stability.