EFFECTS OF SAMPLE DISTURBANCE ON SMALL STRAIN CHARACTERISTICS AND LIQUEFACTION PROPERTIES OF HOLOCENE AND PLEISTOCENE SANDY SOILS
EFFECTS OF SAMPLE DISTURBANCE ON SMALL STRAIN CHARACTERISTICS AND LIQUEFACTION PROPERTIES OF HOLOCENE AND PLEISTOCENE SANDY SOILS
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DOI：
10.3208/sandf.49.509
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发表时间：
2009-08
影响因子：
3.7
通讯作者：
T. Kiyota;J. Koseki;Takeshi Sato;Y. Tsutsumi
中科院分区：
文献类型：
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作者：
T. Kiyota;J. Koseki;Takeshi Sato;Y. Tsutsumi
为了研究砂土的液化特性，通常进行不排水循环加载试验。然而，即使采用原位冻结技术，被测样品也会受到干扰，因此很难通过实验室试验完全模拟土壤的实际行为。采用全新世和更新世沉积物中的3种原位冻结砂土及其重建样品，在30 kPa和98 kPa的围压条件下，测量了冻结和解冻过程中砂土的体积变化特性。为了研究可能的试样扰动对液化阻力的影响，还测量了反映土结构的小应变特性。当围压低于原位覆盖层应力时，全新世岩样的小应变特征和液化阻力均有所降低。另一方面，对于更新世岩样，解冻过程中围压对小应变特性和液化阻力的影响较小。全新世与更新世样品的这种对比特征可能与其自然老化作用类型的不同有关。
To investigate liquefaction properties of sandy soils, undrained cyclic loading tests are usually performed. However, it would be difficult to simulate fully the actual soil behaviour through the laboratory tests because the tested sample can be disturbed even though it is taken by in-situ freezing technique. In this study, by using three kinds of in-situ frozen sandy soils which were taken from Holocene and Pleistocene deposits and their reconstituted samples, their volume change properties were measured during freeze and thaw processes at different confining pressures of 30 kPa and 98 kPa. In order to investigate the effects of the possible sample disturbance on the liquefaction resistance, small strain characteristics were measured as well, which would reflect the soil structure. Decreases in the small strain characteristics and the liquefaction resistance were observed in case of the Holocene specimens that were thawed at the confining pressure that was lower than the in-situ overburden stress. On the other hand, in case of the Pleistocene specimens, the effects of the confining pressure during the thaw process on the small strain characteristics and the liquefaction resistance were small. Such contrastive feature between the Holocene and the Pleistocene samples could be linked with the difference in the types of their natural aging effects.