瀑布沟心墙坝有效应力算法和总应力算法的对比分析

Comparative Analysis of Pubugou Dam with Total Stress and Effective Stress Methods

在总结土体总应力算法和有效应力算法区别的基础上,结合瀑布沟粘土心墙坝实际工程,分别运用两种方法,计算模拟施工填筑以及蓄水过程,得出各个时期坝体典型断面上各部分的变形、应力.计算结果表明,两种方法算得的变形、应力分布规律一致,只是由于有效应力算法考虑了土水相互作用以及孔隙压力消散的时间过程,以至于在各时期有效应力算法各变量极值均较总应力法为小.在大坝初次满蓄情况下,有效应力算法得出心墙上游面小主应力较竣工期有明显减小,而总应力法却不能反映这一典型现象,表明有效应力法更为符合实际,更能准确地判断心墙发生水力劈裂的可能性.

Combining with Pubugou clay core rockfill dam, deformations and stresses in typical sections of which could be yielded are calculated by applying total stress method and effective stress method during construction and impounding period. The results from two methods have the same distribution law except that from effective stress method has smaller extreme value than total stress method; because effective stress method considers soil-water interaction and the dissipation procedure of pore water pressure. At the stage of initial fullness of reservior impounding, the minor principal stress of the core upstream side sharp decreased comparing with the time of comparing, while the total stress method can not reflect this typical phenomenon. It turns out that effective stress method corresponds with the reality and can judge the possibility of the hydraulic fracturing.