【摘要】 基于拟静力抗震设计概念,提出利用强度折减有限单元法分析土石坝的抗震稳定性,给出了两种确定地震惯性力的方法:(1)依据《水工建筑物抗震设计规范》[1],并结合有关土石坝动态分布系数计算了沿坝高分布的地震惯性力;(2)直接利用土石坝有限元地震动力反应分析得到的单元节点加速度反应,依据建议的方法确定坝体各单元节点的地震惯性力。将上述计算确定的地震惯性力与其他形式的外荷载共同作用到土石坝上,采用强度折减有限元法确定土石坝坝体的拟静力抗震安全系数。对于稳定渗流期,水位降落期等不同工况,或需要考虑振动孔隙水压力作用的饱和无黏性土填筑坝等不同计算条件,给出了使用折减强度有限元法分析坝体抗震稳定性的实现途径和方法。研究表明,有限元法对边界条件、复杂断面条件和材料分区及荷载组合均具有较强的适应能力,因此,使用有限元法分析土石坝抗震稳定性具有显著的优越性。更多还原

【Abstract】 An analysis procedure based on shear strength reduction finite element method for pseudo-static seismic stability calculation of earth and rockfill dam(ERFD) is presented.In the proposed procedure,two methods are proposed to determine the seism-induced inertia force:(1) the inertia forces are computed with the same method adopted in the pseudo-static limit equilibrium slices method;(2) with the absolute acceleration response of element nodes obtained from the finite element dynamic response analysis of the dam,the inertia forces corresponding to the node acceleration are computed with the proposed empirical method.With the inertia forces achieved above,the self-gravity,and/or the forces corresponding to the seepage force or dynamic pore water pressure,the elastoplastic finite element analysis is conducted to achieve the pseudo-static factor of safety of the dam by reducing the effective shear strength parameters of soil until the limit equilibrium is reached.Finally,numerical computations are conducted to illustrate the proposed analysis method;and the results are compared with those obtained from the pseudo-static limit equilibrium method.It is concluded that the utilization of the finite element method for aseismic stability analysis of ERFD is feasible.更多还原