飞机移动荷载下层状路基应力路径特性研究

Study on Characteristic of Stress Path of Layered Pavement under Aircraft Moving Loads

为研究飞机移动荷载作用下跑道地基受力特性及土体单元经历的应力路径,采用积分变换和传递矩阵法推导了层状地基各应力分量的半解析解,将道路面层-基层-地基视作多层跑道结构体系,将飞机荷载考虑为作用于跑道上的多个移动轮载的叠加,分析了不同移动轮组荷载组合形式下地基内部土单元的偏应力大小、主应力方向的变化规律,揭示了偏应力路径的基本特性;进一步探讨了跑道不同功能区土单元应力路径的差异性,发现不同功能区域土单元应力路径曲线有显著差异,呈现为全心形-上半心形及下半心形的形态,并开展动态空心扭剪试验观察了三种应力路径下土体累计变形的差异性,从而揭示了跑道差异沉降产生的内在机理。

This work aims to investigate the mechanical characteristics of the runway foundation and the stress paths of soil elements subjected to aircraft moving loads. A semi-analytical solution to stress in layered soils was developed using integral transforms and the transfer matrix method. The pavement is considered as a three-dimensional surface course-base course-subgrade system. The aircraft moving loading is equivalent to the sum of a number of wheel loads. The basic characteristic of stress path including the magnitude of deviatoric stress as well as the rotation of principal stress has been demonstrated. The stress paths at the different functional areas of the runway have been found and displayed as heart-shape,upper semi-heart-shape and lower semi-heart-shape. A series of dynamic torsion shear tests have performed to show the different accumulative deformation under three stress paths,and essentially illustrate the basic mechanism of differential settlement in the runway.