取样扰动引起土层剪切波速变化的试验研究

STUDY ON VARIATION OF SHEAR WAVE VELOCITY CAUSED BY SAMPLING DISTURBANCE

对3个工程场地土层的原位剪切波速和相同场地原状土样的室内剪切波速进行了比较试验,研究结果表明,随土性的不同,剪切波速的变化程度也不同。对于粘性土,两者测试结果一般相差在11%以内,个别相差达到13%左右;对于砂性土,室内测试结果一般偏小,相差在14%以内,最大相差达到20%。这些结果为依据室内剪切波速测试资料比较客观地评价原位土层剪切波速提供了客观依据,同时,也为评价取样过程对土样的扰动程度提供了一个定量的参考指标。

In order to study the impact of sample disturbance on shear-wave velocity, a comparative survey was carried out both in situ and in laboratory. The results show that variation levels of shear-velocity differ according to the property of soil. For cohesive soil, the differences between the two sets of results are generally less than 11 percent with the utmost value about 13 percent. For sandy soil, the indoor shear-wave velocity is smaller than that of the in-situ test and the differences are generally under 14 percent with the utmost value of 20 percent. Such conclusion offers an objective reference to estimate the in-situ shear wave velocity through indoor test. The differences between the two sets of results provide useful reference parameters to evaluate the disturbance level during sampling.