考虑主应力轴偏转角影响的饱和软粘土路基长期沉降分析

Long-term settlement calculation of saturated soft clay bedroad considering the influence of deflection angle of the principal stress axis

基于循环三轴试验基础上的交通荷载路基沉降计算模型未能反映主应力轴偏转现象,而建立在不同围压的饱和软粘土恒定主应力轴偏转角的不排水循环加载试验基础上的循环累应变显式模型、累积孔压显式模型能考虑主应力轴偏转的现象。基于拟静力有限元计算、恒定主应力轴偏转角循环累积塑性变形及累积孔压显式模型相结合的思路,提出了考虑主应力轴偏转角影响的交通荷载作用下软土地基长期运营沉降的实用分析方法,并应用于高速公路工程的长期沉降预测。

The method for calculating long-term bedroad settlement established based on cyclic tri-axial test does not reflect the principal stress axial deflection. A series of the tri-axial undrained tri-axial cyclic loading tests of saturated soft clay in Shanghai are performed. A revised cyclic accumulative pore pressure explicit model is proposed. The validity of the model is verified based on undrained cyclic tri-axial tests of consolidated soft clay in Shanghai. A practical method is proposed to calculate the long-term settlements of soft roadbed subject to traffic loading. The long-term settlements of S32 highway in Shanghai is calculated with the proposed method. Because of the combination of the pseudo-static finite element, cyclic accumulative plastic stain explicit model and cyclic accumulative pore pressure explicit model, the parameters used in the proposed method are easy to obtain and is simply employed. The method can provide a reference for the long-term settlement prediction of soft soil subway roadbed subject to cyclic loading.