冻土区天然斜坡冻胀及融沉滑移变形模拟

Analytical simulation of the deformation and frost heave of frozen soil slope

对土坡的一个单位宽度土条进行简要受力分析,进行分层计算土体冻胀变形量。根据平面应变假定求解斜坡坡土应力分量,考虑温度效应对土体先期固结压力的影响对沈珠江水滴形屈服面进行修正,通过拟定坡土滑移速度与黏塑性应变率的关系,得出坡土滑移变形速度;再通过修正经冻融循环后的土体强度和黏滞性参数以提高模型的模拟精度。实例计算表明,冻胀变形和滑移变形量的计算值与现场实测数据结果较为一致。

First, stress analysis of a unit soil slice of the slope was given to calculate the frost heaveamount by layering the soil. Secondly,element stress of slope soil was derived from stress equilibrium dif-ferential equations under the plane strain condition. The water-drop type yield surface function was modified with the consideration of temperature effect on the preconsolidation pressure of soil. Visco- plasticitymodel was used between velocity and the visco-plastic strain of the slope soil. The explicit expression ofthe deformation rate with the depth of slope soil was thus derived. Simulation accuracy was improved bymodifying the soil strength and viscosity after freeze-thaw cycles with the depth of slope soil. Finally,numerical example was given in comparison with the field measured data and a good agreement is achieved.