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Numerical simulation method is adopted to analysis the stability of tailings dam under the fluid-solid coupled interaction. Using the full-coupled analysis function, stress field 、seepage field and their coupled model are studied in this paper. Finally, the critical sliding surface of the tailings dam is searched. Results show that the safety factor after coupling is smaller than before. It illustrates that the fluid-solid coupling analysis has an important practical significance for the stability analysis of tailings dam.

The abutment slope at left bank in Dagangshan hydropower station has complex geological conditions with deep fractures, developed faults and unloading crack. The excavation will influence the stability of the slope. To evaluate the slope stability, the finite element model of this abutment slope was built in this paper to study the deformation, stress and plastic zone distribution of the slope during the excavation. The potential failure location of the slope is forecasted, some suggestions are proposed to be helpful to keep the stability of the slope.

The HBT(10)9 method for ODEs is expanded into HBT(10)9DAE for solving nonstiff and moderately stiff systems of fully implicit differential algebraic equations (DAEs) of arbitrarily high fixed index. A scheme to generate first-order derivatives at off-step points is combined with Pryce scheme which generates high order derivatives at step points. The stepsize is controlled by a local error estimator. HBT(10)9DAE uses only the first four derivatives of y instead of the first 10 required by Taylor's series method T10DAE of order 10. Dormand-Prince's DP(8,7)13M for ODEs is extended to DP(8,7)DAE for DAEs. HBT(10)9DAE wins over DP(8,7)DAE on several test problems on the basis of CPU time as a function of relative error at the end of the interval of integration. An index-5 problem is equally well solved by HBT(10)9DAE and T10DAE. On this problem, the error in the solution by DP(8,7)DAE increases as time increases.