季冻区路基土回弹模量影响因素分析

Influencing Factor Analysis of Subgrade Resilience in the Seasonal Freezing Region

通过对黑龙江省内3条试验路段进行路基含水率调查,并选取黏性土、粉质土和砂性土3种有代表性的路基土,采用承载板法对所选土样进行室内回弹模量试验,分析其和含水率、压实度及冻融循环次数之间的关系。结果表明:3条试验路段路基平均含水率均大于最佳含水率;3种土样的回弹模量对含水率变化的敏感性非常大,都随含水率的升高而降低;土样回弹模量随压实度的降低而降低;冻融作用对土样回弹模量有衰减作用,但6次冻融之后,回弹模量值趋于稳定;3种变量对砂性土回弹模量的影响较黏性土和粉性土小。基于以上结论,建议对在用道路的排水设施及时进行检测及养护;在季冻区路面结构设计时,建议选取6次冻融之后的回弹模量作为路基强度设计值。

Through surveying the subgrade moisture content of three test roads in Heilongjiang province,and selecting three representative subgrade soils including cohesive soil, silty soil and sandy soil, resilient modulus of the soils are tseted using bearing plate method. The realationship between resilent modulus and moisture content, degree of compaction, freeze-thaw cycling times are analysed. It is shown that the subgrade moisture content of three test roads is bigger than optimum moisture content, and the resilient modulus of three soils are influenced by the change of the moisture cotent seriously reducing with the rising of moisture content, it also reduces when the degree compaction reduces. Freeze-thaw cycling to the soil sample resilience modulus have attenuation effect, but resilient modulus tends to be stable after 6 times freeze-thaw cycling. The infulence of three variables to the resilient modulus of sandy soil is smaller than cohesive soil and silty soil. Based on the above conclusions, drainage facilities of the roads in service should be detected and maintained timely, and should select resilient modulus after 6 times freeze-thaw cycling as subgrade strength design value when the pavement structure in the seasonal freezing region is designed.