飞机动载下复合道面结构软土路基长期沉降研究

Taken the long-term settlement of the airport runway which is made of composite pavement on soft subgrade as engineering background, the project aims to explore the three main problems, including the load transfer law of the composite pavement subjected to repeated moving loading, the dynamic properties of soil under stress cyclic rotation condition, and the long-term settlement of the roadbed. By numerical simulation considering the roadbed-composite pavement structure-aircraft wheel load interaction and multi-layer theory analysis, the load transfer law of the composite pavement structure and the distribution and variation of dynamic stress in the subgrade are obtained. By employing the hollow cylinder shear test, the cumulative deformation and limit cyclic stress of over-consolidated soft clay under principle stress rotation are obtained, and the cumulative deformation of gravel are obtained from big cyclic triaxial tests and DEM analysis. The equivalent visco-plastic model considering the influence of cyclic stress rotation was proposed to describe the soft soil and gravel under large number of under dynamic load cycles, and then a calculation method for the long-term settlement of composite pavement on soft ground is proposed. The research results could provide theoretical supports for the deformation control of airport runway and ensure aviation safety.

以我国软土地区机场跑道复合道面结构路基长期沉降为工程背景，针对飞机荷载下复合道面结构荷载传递、主应力轴循环旋转下路基土动力特性及路基长期沉降等关键问题开展研究。基于飞机轮载-复合道面结构-路基相互作用的三维数值模拟及层状理论分析，获得飞机移动荷载下复合道面与路基层状体系的荷载传递规律及路基土体心形循环旋转应力路径；通过动态空心圆柱循环扭剪试验，研究心形循环旋转应力路径下超固结软黏土累积变形规律，并通过循环大三轴试验和离散元模拟获得砾石填料的循环累积变形特性；提出考虑心形应力路径循环旋转效应的大数目循环动载下软粘土及砾石填料的等效粘塑性模型，建立飞机荷载下复合道面结构软土路基长期沉降分析理论和计算方法，从而为软土地区机场跑道建设制定更经济合理的变形控制措施、保障航空安全提供理论支撑。

以我国软土地区机场跑道复合道面结构路基长期沉降为工程背景，针对飞机荷载下复合道面结构荷载传递、主应力轴循环旋转下路基土动力特性及路基长期沉降等关键问题开展研究。研究内容包括：飞机动载下复合道面结构软土路基动应力特性、循环动载下天然软黏土及砾石填料的累积变形、飞机循环动载下复合道面软土路基长期沉降。主要成果体现在：（1）建立飞机移动荷载下考虑飞机轮载-复合道面结构-路基相互作用的三维分析模型，揭示复合道面结构-路基层合体系的荷载传递机理，并获得飞机移动荷载下路基土体“心形”循环旋转应力路径；（2）利用先进的试验技术及细观土力学分析手段，获得大数目循环次数条件下软粘土及砾石填料累积变形的理论描述，获得心形循环旋转应力路径下土体的长期累计变形特性；（3）基于地基土体及砾石填料长期累计变形及分层总和法，建立了软土地区飞机荷载下复合道面结构路基的长期沉降分析理论和计算方法，从而为软土地区机场跑道建设制定更经济合理的变形控制措施、保障航空安全提供理论支撑。