交通荷载作用下公路软土地基长期沉降的计算

合理预测公路软土地基在交通荷载作用下产生的长期沉降，对公路的设计有着重要的指导作用。基于以往试验规律的分析，提出了一个较为合理地描述软土在长期重复荷载作用下残余变形发展过程的经验模型。通过对上海软土的循环三轴试验的模拟，初步验证了模型的合理性。对于工程边值问题，首先，根据拟静力法将交通荷载视为长期重复作用的静分布力；其次，采用弹性层状体系理论计算交通荷载在地基中引起的附加动应力；最后，将提出的模型用于计算各土层的残余应变，并沿深度对应变积分得到沉降。以日本Saga机场公路为例，说明了公路软土地基沉降的简化计算方法的有效性。

A simple method to predict traffic-load-induced permanent settlement of road on soft subsoil

Excessive settlement of road on soft subsoil induced by traffic load is the main reason leading to pavement failure. To predict this part of settlement correctly is very important for road design. A simple empirical model for predicting residual strain under repeated load suitable for soft clays is proposed based on test results. The validity of the model is verified by cyclic triaxial test results of Shanghai soft clays. For practical boundary value problems, the traffic-load-induced dynamic stress is calculated by multilayer elastic theory; the residual strain distribution of subsoil induced by traffic load is calculated by the proposed model; and then the settlement can be given by integrating the residual strain along depth. A practical problem, Saga Airport Road, is analyzed to illustrate the proposed prediction method.