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以青藏铁路那曲物流中心站场路基填料为研究对象,通过室内试验深入研究和分析了压实度、荷载以及冻融次数对土体融沉性质的影响规律。研究结果表明:第1次冻融过程中压实度大的试样的冻胀融沉量小,而经历多次冻融后压实度大的试样的冻胀融沉量则变大;多次冻融后较大压实度的试样表现为隆起变形,而较小压实度的试样则表现为压密变形,即不同压实度试样在经历多次冻融后压实度趋于某一定值;存在一临界压实度值,该值下多次冻融后试样高度不发生变化;荷载的压密作用在抑制冻胀变形的同时也加剧了试样的融沉变形,总体变形量随荷载的施加和增大而增大;补水条件下多次冻融后试样的含水率远远大于初始含水率,因此应做好防排水措施;外界水源补给量随冻融次数的增加而减小,并在经历3次冻融后达到稳定,且冻结过程中的补水量远远大于融化过程中的补水量;融沉系数随冻融次数的增加先增大而后减小并在经历5次冻融后趋于稳定,因此可将5次冻融后的融沉系数作为评价土体融沉性质的指标。
Taking the subgrade filling of Naqu logistics center of Qinghai-Tibet Railway as the research object, the influence laws of compaction degree, load and frequency of freeze-thaw on the thaw settlement property of soil were deeply studied and analyzed through laboratory experiments. The results show that in the first freeze-thaw process, the samples with high degree of compaction have a small amount of frost heaving and thawing, whereas the samples with large degrees of compaction after repeated freeze-thaw cycles increase the amount of frost heaving and thawing. After repeated freeze-thaw, the specimens with larger compaction degree showed uplift deformation, while the specimens with smaller compaction degree showed compact deformation, that is, the specimens with different compaction degrees were compacted Degree tends to a certain value; there is a critical compaction value, the value of the sample after repeated freeze-thaw does not change the height; load compaction in the suppression of frost heave deformation also exacerbated the sample thawing Deformation, the overall deformation increases with the load applied and increased; under the conditions of water supply after repeated freezing and thawing the moisture content of the sample is much larger than the initial moisture content, so should be good drainage measures; external water supply with frozen The number of melting decreases, and after three freeze-thaw cycles to reach a stable, and the amount of water during the freezing process is much larger than the amount of water during the melting process; thaw settlement coefficient increases with the increase in the number of freeze-thaw first and then reduced Small and stable after five freeze-thaw cycles, the thawing-thawing coefficient after five freeze-thaw cycles can be used as a criterion to evaluate the thawing settlement Indicators.