土石坝非稳定渗流场和应力场耦合分析方法

Coupling analysis method of unsteady seepage field and stress field for earth-rockfill dams

开展饱和/非饱和土的非稳定渗流场和应力场的耦合分析方法研究,考虑土石坝施工过程的初次蓄水变形、运行期考虑降雨和库水位升降导致的坝体变形对坝体安全的影响,对科学客观地评价坝体安全性具有重要意义。在对分析对象做出合理假定的基础上,推导了非稳定渗流场和应力场耦合的等价积分方程,对其进行了空间域和时间域的有限单元离散,并用Fortran 90编制了相应的求解该耦合问题的非线性有限元程序。对一土柱非饱和固结问题的计算分析和一均质坝考虑施工过程和蓄水过程的应力应变计算分析表明,提出的针对土石坝的非稳定渗流场和应力场耦合分析方法是合理的,可以应用于实际工程。

It is of great importance to carry out the coupling analysis on unsaturated unsteady seepage field and stress field for earth-rockfill dams. To evaluate dam safety, it is essential to perform stress and strain analysis which takes construction process and initial reservoir impoundment process into consideration. In operation, it is also necessary to implement soil-water coupled analysis considering periodical fluctuation of reservoir water level and rainfall within dam area. Based on an assumption for the earth-rockfill dam, the equivalent integral equations are derived for the unsteady flow field coupled with stress field. Finite element discretization in spatial domain and time domain is made and the correspond- ing computer program is developed with Fortran 90 to solve the coupling issues. By calculation on the consolidation for an unsaturated soil column as well as analysis on the deformation and stress for a homogeneous earth-rockfill dam considering the construction and initial reservoir impoundment process, conclusion is gotten that the proposed coupling analysis method for earth-rockfill dam is reasonable, correct and reliable. It can be applied to the coupling analysis of seepage field and stress field for an actual project.