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岩土工程中孔隙水的作用一直是工程安全稳定分析中不容忽视的问题。基于Viesca提出的考虑饱和孔隙水压力作用的孔隙弹塑性模型,推导其在满足D-P准则的理想弹塑性情况下的具体形式。对于不排水条件,饱水状态下材料强度参数被等效化,使得屈服面的形状发生改变,同时根据最近点投影法确定其在弹塑性计算中的本构积分策略。不排水孔隙水压力对岩土体的塑性响应的影响得以表达,而对结构的稳定性的影响通过基于过应力概念的不平衡力反映出来。基于该模型开发非线性有限元程序Pore Tfine,选取非均质边坡降雨入渗下的稳定问题作为算例验证其实用性,边坡随降雨作用的非平衡演化过程得到研究。Skempton系数的增大对连续降雨条件下边坡有弱化作用,对其稳定性不利。
The role of pore water in geotechnical engineering has always been a problem that can not be ignored in engineering safety and stability analysis. Based on the pore elastic-plastic model proposed by Viesca that takes into account the effect of saturated pore water pressure, the concrete form of the elastic-plastic elastic model that satisfies the D-P criterion is derived. For undrained condition, material strength parameters are equalized in saturated water, which changes the shape of yield surface. At the same time, according to the nearest point projection method, its constitutive integration strategy in elastoplastic calculation is determined. The effect of undrained pore water pressure on the plastic response of rock and soil mass is expressed, while the effect on the stability of the structure is reflected by the imbalance force based on the concept of over stress. Based on this model, the nonlinear finite element program Pore Tfine was developed. The stability of heterogeneous slope under rainfall infiltration was chosen as an example to verify its practicability. The slope was studied with the non-equilibrium evolution of rainfall. The increase of Skempton coefficient weakens the slope under continuous rainfall, which is unfavorable to its stability.