一维向上渗流作用下多层地基有效应力性状研究

研究了一维向上渗流作用下多层地基有效应力的计算问题，推导了有效应力的计算公式，讨论了有效应力性状。定义了渗流有效应力的概念。渗流作用下土层有效应力由两部分组成：一部分是自重有效应力，它由重力引起，体现了静水压力的影响；另一部分是渗透有效应力，由土层水头差产生，体现超静水压力的影响。一维向上渗流作用使土层的有效应力减小。一维向上渗流作用下多层地基有效应力沿土层厚度呈线性分布，在土层层面处发生转折。多层地基有效应力计算的关键是确定土层层面处的有效应力，而确定土层层面处的有效应力的关键是计算各土层的水头差。文后给出了实例计算。

Research on characteristics of effective stress for a layered ground under one-dimensional upward seepage

An analytical solution is given to the problem of calculation of effective stress for a layered ground under one-dimensional upward seepage. The formulas for computing the effective stress are derived. Based on the formulas, the characteristics of effective stress are discussed. The effective stress of seepage has been defined. The effective stress for a layered ground under one-dimensional upward seepage is divided into two parts of both effective stress of weight and effective stress of seepage, the former embodying the effect of hydrostatical pressure is brought about by the weight, and the latter embodying the effect of super hydrostatical pressure is given rise to by the seepage. The effective stress of soil layer is decreased by one-dimensional upward seepage. The effective stress distribution along longitudinal section for a layered ground under one-dimensional upward seepage is linear, and has a turning point on the bedding surface of soil layer. The key to analyzing effective stress for a layered ground under one-dimensional upward seepage is to calculate the effective stress on the bedding surface of soil layer and the head loss of soil layer. an example is given to illustrate the analytical procedure.