考虑降雨作用的海堤渗流场模拟及监控模型研究

发布时间：2018-10-10 06:14

【摘要】：海堤的安全稳定关乎到其保护范围内的生命财产安全,为了掌握海堤工程的实时安全状态,建立科学有效的监测模型具有重要意义。在众多影响海堤安全稳定的因素中,渗压是评判海堤安全的重要指标。海堤工程始终受到潮水位的作用,潮水位是影响渗压分布的主要因素;同时,海堤还经常遭受降雨的作用,因此降雨是影响渗压分布的重要因素。在潮水位和降雨的共同作用下,海堤堤身内长期处于饱和—非饱和非稳定渗流状态,十分容易导致海堤的渗透破坏和岸坡失稳。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,本文首先在分析、总结前人研究的基础上,提出了一种形式简单、精度较好的降雨入渗模式。其次,利用ANSYS热分析模块,以潮水位和降雨分别作为水头边界条件和流量边界条件,模拟计算海堤渗流场分布。利用ANSYS参数化设计语言编写海堤非稳定渗流场分析程序,分析过程中,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。再次,分别进行了不考虑研究时段内降雨入渗时渗压计算、考虑潮水位和降雨共同作用下海堤渗流场的模拟分析,结果显示:采用本文所述的降雨入渗模式时,有限元计算结果与实测数据吻合度良好。此外,在进行海堤非稳定渗流场分析过程中发现,当采用不同时期的潮水位时,模拟渗流场逼近真实渗流场的速度差异较为明显,因此,本文也对四类不同时期的初始潮水位对模拟渗流场逼近真实渗流场的速度进行了分析研究。最后,根据监测点处渗压有限元计算,提取相应的水头渗压分量有限元结果和降雨渗压分量有限元结果,以前期潮水位的幂函数作为水头渗压分量的结构形式,以多段前期降雨量和作为降雨渗压分量的结构形式,再分别计算两个分量表达式的各个参数,将水头渗压分量和降雨渗压分量调整系数,同时效分量一起进行参数估计,从而建立起渗压确定性模型,为可靠预报海堤安全状态提供参考。
[Abstract]:The safety and stability of the seawall is related to the safety of life and property within the scope of its protection. In order to grasp the real-time safety state of the seawall project, it is of great significance to establish a scientific and effective monitoring model. Among the factors influencing the safety and stability of seawall, seepage pressure is an important index to evaluate the safety of seawall. The seawall works are always affected by the tidal level, which is the main factor affecting the distribution of osmotic pressure, and at the same time, the seawall is often affected by rainfall, so rainfall is an important factor affecting the distribution of osmotic pressure. Under the combined action of tidal level and rainfall, the embankment is in a saturated-unsaturated unsteady seepage state for a long time, which can easily lead to seepage failure and bank slope instability of the seawall. In order to grasp the seepage field distribution of seawall, monitor effectively and analyze the safety and stability of seawall under special working environment, this paper firstly puts forward a rainfall infiltration model with simple form and good precision on the basis of analyzing and summarizing the previous research. Secondly, the ANSYS thermal analysis module is used to simulate and calculate the seepage field distribution of seawall with tidal level and rainfall as head boundary condition and discharge boundary condition respectively. The analysis program of unsteady seepage field of seawall is compiled by ANSYS parametric design language. In the process of analysis, the free surface and overflow point are adjusted according to the results of the previous finite element iteration, and the permeability coefficient of unsaturated zone is modified by matrix suction. Thirdly, the seepage field of seawall under the influence of tide level and rainfall is simulated and analyzed separately without considering the rainfall infiltration in the study period. The results show that: when the rainfall infiltration model described in this paper is adopted, the seepage field of seawall is simulated and analyzed. The results of finite element method are in good agreement with the measured data. In addition, during the analysis of the unsteady seepage field of the seawall, it is found that the velocity difference between the simulated seepage field and the real seepage field is obvious when the tide level is used in different periods. In this paper, the velocity of the simulated seepage field approaching to the real seepage field by the initial tidal level in four different periods is also analyzed and studied. Finally, according to the finite element calculation of the seepage pressure at the monitoring point, the corresponding finite element results of the seepage pressure component of the head and the finite element result of the seepage pressure component of the rainfall are extracted, and the power function of the pre-tide level is taken as the structural form of the seepage pressure component of the water head. Based on the structural form of rainfall in the early stage and as the component of rainfall osmotic pressure, the parameters of the expression of the two components are calculated, and the adjustment coefficients of the water head component and the rainfall osmotic component are adjusted, and the parameters are estimated together with the effect component. Thus, the deterministic model of seawall pressure is established, which provides a reference for reliable prediction of seawall safety state.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U656.314

【参考文献】