黄土的湿陷性及其评价准则

COLLAPSIBILITY OF LOESS AND ITS DISCRIMINATION CRITERIA

针对法国高速列车沿线黄土区域内部分站台周围雨季出现多处落水洞问题,对黄土路基土的地质及岩土特征、特别是黄土的湿陷性展开研究。在阐述法国北部黄土基本特征的基础上,对巴黎以北140km处高速列车沿线原状黄土的湿陷性进行了试验研究,探讨了初始含水量对黄土湿陷性的影响,以期能对现场条件下季节性含水量变化对黄土湿陷性的影响进行预测判断。结果表明,初始含水量的变化对湿陷性的影响很明显,并且随着含水量的增加,湿陷量会线性地降低,这表明在湿陷准则中必须考虑初始含水量的影响。最后依据试验结果,分析探讨了几种湿陷性判别准则的适用性。

Considering some sinkholes found in loess area along the high speed railway（TGV） in France, which affect the foundations of TGV during the very rainy periods, the geological and geotechnical properties, especially the collapsibility of loess have been analyzed. Based on the geological presentation of loess deposits in northern France, tests on the collapsibility of loess located at the place 140 km north to Paris along the TGV have been carried out. The effects of initial water contents on the magnitude of collapse are also examined to find out the effects of seasonal change of water content on the loess collapsibility. Test results show that the effects of water content change on the magnitude of collapsibility are significant. The collapsibility linearly decreases with the increase of initial water content. So, the criteria for collapsibility should include the initial water content. The evaluation of various criteria for collapsibility are discussed according to the testing results obtained.