摘要:
降雨是导致边坡失稳的主要因素。目前,使用有限元强度折减法进行降雨滑坡计算时,过程比较复杂,计算工作量大。同时,对降雨边界的处理更加大了计算的复杂性,从而影响了强度折减法在降雨滑坡计算中的推广应用。为了更加准确、高效地将有限元强度折减法应用于降雨滑坡计算,首先基于Geostudio软件采用迭代算法对降雨入渗边界进行处理,通过计算得到每一时刻边坡内的水压分布,然后利用Fortran编制程序将水压转化为等效结点力并导入ABAQUS中,之后结合“基于场变量的有限元强度折减法”对ABAQUS进行二次开发,最终建立降雨条件下边坡有限元强度折减法计算平台。该平台利用Geostudio考虑了降雨入渗边界的复杂性,克服了ABAQUS软件中不能准确模拟降雨边界的问题。同时采用ABAQUS软件提供的场变量,对有限元强度折减法的计算过程进行简化,提高了计算效率,经过一次计算即可求得每一降雨时刻的边坡稳定系数。通过与传统极限平衡法进行比较,发现两者得出的结果具有较好的一致性,表明该计算平台是稳定、可靠的。最后采用该平台对降雨滑坡机理进行研究,研究结果可为边坡防减灾提供参考。
Abstract:
Rainfall is a major cause for slope failures. At present, rainfall-induced slope failure analysis using shear strength reduction method is a complex and time consuming work. Meanwhile, the complexity of rainfall boundary makes such analysis more complex. As a result, the application of shear strength reduction method for slope stability analysis under rainfall conditions is limited. In order to perform such analysis more efficient, Geostudio software was adopted to obtain the pore water pressure within the slope which was then converted to equivalent node forces and passed into ABAQUS software for slope stability analysis. Combined with ‘Field variable based strength reduction FEM’, a secondary development on ABAQUS software was conducted, and a computing platform for slope stability analysis under rainfall conditions using shear strength reduction FEM was developed. This computing platform overcome the limitation of ABAQUS in simulating rainfall boundary by using Geostudio software, and promotes computational efficiency based on the field variable provided by ABAQUS software. To investigate the feasibility of the computing platform, a comparing study was performed. It was found that the results from the computing platform are in good agreement with that from the traditional limit equivalent method. This indicates the reliability of the computing platform. The study on the mechanism of rainfall-induced slope failure was then performed using the proposed computing platform.
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