交通荷载作用下冻土路基动力响应分析

季节冻土区路基在交通荷载作用下的冻胀翻浆病害是一个复杂的热、力相互作用过程,又是一个急需解决的实际工程难题.运用传热学及Biot固结理论建立季节冻土区公路路基的动力分析模型,以季节冻土区典型冻胀翻浆路基为例,分析其工程处理前、后的动力反应特性.结果表明:1)路基温度场的研究表明修筑路基后,在路基及其下部地基中将会产生大片的力学性质极不稳定的高温冻土层;2)路基运营期当交通荷载刚驶入或离开路基计算断面时,路基内的加速度、速度、位移、应力、孔隙水压力均振荡剧烈.但与普通路基相比,防冻胀翻浆路基的碎石层大大削弱了汽车动荷载的冲击振动作用;3)防冻胀翻浆路基中间存在透水层(碎石),减小了路基内的孔隙水压力,与普通路基相比,防冻胀翻浆路基的最大孔隙水压力比减小达30%左右,这对延缓、消除路基病害产生有很大作用.计算理论以及分析结果可为季节冻土区道路的安全运营以及维修提供参考依据.

Dynamic Response of Embankment in Permafrost Regions under Traffic Load

Frost heave and frost boiling is a complicated interaction course between heat and force on embankment under traffic loading in seasonally frozen ground regions,and is also an engineering problem which is badly in need of solving.Heat transfer theory and Biot consolidation theory are applied to develop dynamic analysis model for embankment in seasonally frozen ground regions.Taking a typical embankment as an example,the characteristics of the dynamic response were calculated and analyzed for an embankment before and after engineering handling.The research conclusions indicate:1)A block of high temperature frozen ground takes place inside the embankment,where ground mechanical property becomes unstable;2)In the operation life cycle,when traffic load drive into or depart from the calculating cross-section,acceleration,velocity,displacement,stress and pore water pressure inside the embankment vibrate severely.However,comparing with ordinary embankment,the vibration and shock due to motor vehicle dynamic load are greatly weakened by the macadam inside the embankment of preventing frost heaving pumping;3)Pore water pressure inside the embankment of preventing frost heaving pumping decreases,as compared with ordinary embankment,with a maximum reducing extent of 31.4%.Thus,it greatly brings about delaying or eliminating embankment disease.The conclusions are useful for disease controlling and theoretical research.