移动荷载下冻土的损伤机理与振动波隔振方法

The damage machanism of frozen soil under train vibration load is complicated. As the rapid development of resource utilization in frozen zone, the railway system has had a great progress in recent decades.However, the track frozen soil foundation failure had led to great risk for train transportation system safety and its sustainable development. ..This proposal will focus on studying the frozen soil damage mechanism and disaster mitigation due to the train vibration. Firstly, a seismic array observation method is tested and set up to explore the track vibration propagation and its effects on the frozen soil damage. Based on this experiment, a model named movable stochastic load to discribe the train vibration load will be structured, and its attenuation relationship in forzen soil site is also built. Secondly, based on a simulation test, the dynamics parameters of frozen soil under moving train load will be studied to identify their relationship among these parameters and load characteristics. In the basis of the theories and methods of damage mechanics, seismology and soil dynamic, the forzen soil damage will be analyzed. Finally, a reliable vibration isolation system will be tested to reduce the vibration effection on frozen soil damage.. .The frozen soil damage under train load is a key problem for a sustainable development of transportation network system, however, there is little konwledge to stop its damage,this proposal will be able to find a new method to reduce damage risk of frozen soil and railway foundation.

寒区工程开发的首要问题是冻土资源合理保护和利用。本项目针对我国东北地区列车引起的冻土路基破坏和冻土环境的破坏现象，利用现场台阵观测技术、大型模型试验、室内试验和数值模拟技术，研究列车振动荷载在冻土中的传播规律、振动引起的冻土损伤机制和相应的振动控制措施。选择兴安岭牙林线铁路为研究基地，首先统计机车车辆类型及其运输参数和线路参数，得到主要机车相关参数、线路平整与平顺度等数据，结合台阵观测技术资料，将车辆动荷载模拟为移动随机荷载，利用波动理论建立相应的车辆振动波传播方程；然后利用室外冻土模型试验，观测和研究移动随机荷载作用下冻土的动力学参数变化规律和冻土损伤特征与机制；基于损伤力学与土动力学理论，分析冻土的动弹模和剪模、动阻尼比、动摩擦角在列车移动随机荷载作用下的变化特性，揭示列车动荷引起冻土破坏的基本规律；最后，提出列车振动隔振设计方法，并利用动力有限元方法和台阵观测试验检验隔振效果可靠性。

本研究主要针对轨道交通引起的振动对冻土和环境的破坏机制、相应的控制技术等两方面的问题开展了理论、实验和数值模拟研究。主要研究内容包括了：1）基于台阵观测技术和模型实验、理论分析，揭示了列车振动荷载在冻土中的传播特征和振动引起的冻土损伤机制，并提出了基于2.5D有限元模拟振动波的传播模型；2）利用室外冻土模型试验，观测和研究移动随机荷载作用下冻土的动力学参数变化规律和冻土损伤特征，分析冻土的动弹模和剪模、动阻尼比、动摩擦角在列车移动随机荷载作用下的变化特性，揭示列车动荷引起冻土破坏的基本规律；3）利用数值模拟技术和室内实验，提出了列车振动隔振设计方法，并利用动力有限元方法和台阵观测试验检验隔振效果可靠性。取得的重要成果：1）基于2.5D和三维有限元的振动波冻土中的传播规律；2）冻土动力损伤模型，包括了多场耦合的冻土动力损伤、动力作用下的融沉规律、长期强度评价方法；3）研发了3中隔振装置，高铁路基波阻板隔震、充填沟隔振和蜂窝状波阻块隔振三种隔振方法。通过上述研究，本文研发的隔振装置最大的隔振效果降低振动强度80%，对路基的设计提出了最优化的设计方法。上述研究成果对我国寒区轨道交通的设计和环境保护有很好的参考价值