基于SPH的边坡稳定性计算中失稳判据研究

在用强度折减法进行边坡稳定性分析时,失稳判据的选择对安全系数有着直接的关系。光滑粒子流体动力学法(SPH)是一种新型的无网格法,由于其在大变形等领域的优势而逐渐发展起来,并扩展至边坡稳定性分析领域。然而,目前对于该方法在边坡稳定性分析中失稳判据的研究尚未见报道。首先通过Fortan语言编写了基于SPH强度折减法的边坡稳定性分析程序,然后通过一个经典边坡案例,讨论了不同失稳判据对安全系数的影响,并提出了一种新的位移变化失稳判定方法。结果表明,在基于SPH的边坡稳定性分析中,以塑性区贯通或以位移变化为判定准则时各有优劣,但得到的安全系数均与极限平衡法及有限元法得到的安全系数十分接近,均可作为失稳判据。而当采用位移变化准则进行分析时,采用"两步走"的方法即可以减小计算量,又可以得到较准确的安全系数,是一种值得推荐的方法。

Failure criteria based on SPH slope stability analysis

When the strength reduction method is used to solve the problem of slope stability, the failure criteria have direct relationship with the safety factor. The smoothed particle hydrodynamics (SPH) method is a new mesh-less method, which is developed recently due to its advantages in the field of large deformation, is also applied to slope stability analysis. However, no discussions about the failure criteria of slope stability analysis based on SPH are available until now. Firstly, the slope stability analysis procedure based on SPH is written in Fortran language. Then, the influences of different failure criteria on the safety factor are discussed through a typical slope case, and a new displacement change failure criterion is proposed. The case shows that in the slope stability analysis based on SPH method, the plastic zone criterion and the displacement change criterion have their own advantages and disadvantages, but the safety factor obtained by the two criteria are quite close to the safety factor obtained by the limit equilibrium method or finite-element method, and both of the two methods can be failure criteria. When using the displacement change criterion, the two-step method can be used to reduce the computation time and to obtain more accurate safety factor, and it is worth recommending.