多年冻土地区路基纵向裂缝形成机理研究

多年冻土地区路基纵向裂缝呈现裂缝数量多、规模大、久治不愈的特点.在野外调查纵向裂缝变形特点和多年冻土上限变化规律分析的基础上,发现导致多年冻土地区纵向裂缝产生的原因是路基边坡坡脚下存在不稳定的融化区域,并提出机理分析模型.通过弹塑性有限元分析,研究了路基中的位移、应变变化规律,提出了纵向裂缝形成过程的3个阶段:初始变形阶段、强度破坏阶段和变形失稳阶段;相应于这3个阶段,路基及地基中呈现了三个性状不同的区域:发育区、抑制区和诱发区.为纵向裂缝防治对策的提出提供了依据.

Forming Mechanism of Embankment Longitudinal Cracks in Permafrost Regions

There are many longitudinal cracks in the embankments in permafrost regions,which are widespread and difficult to control.In this paper,on the basis of investigation,together with analyses of deformation characteristics and embankment temperature regimes,the main reasons for forming longitudinal crack are attributed to the unstable area under the slope foot of an embankment,and a new model for analyzing the mechanism is presented.Through an analysis with FEM of elastic-plastic theory,the deformation and strain variations in an embankment are studied,and then three phases of the forming course are puts forward,i.e.,the initial deformation phase,strength decrease phase and a phase of failure in stability.Corresponsively,there are three zones with different characteristics within the embankment and roadbed,i.e.,developing zone,restraint zone and inducement zone.Study of the mechanism of longitudinal cracks is helpful to take measures against the cracks.