如何正确评价原位饱和砂土的抗液化强度

How to properly evaluate the in-situ liquefaction resistance of saturated sand strata

依据剪切波速与抗液化强度相关性的原理,首先对某工程场地砂土地层进行了原位剪切波速测试和相应原状土样的室内剪切波速实验;然后以剪切波速为反映土体结构性的指标,定量评价了取样对抗液化强度的影响程度。剪切波速的对比实验表明,对于可液化深度范围内的砂土地层,室内测试剪切波速结果一般偏大,最大相差达40.7%,与此对应的饱和砂土的抗液化强度会增大到真实值的200%。因此不考虑取样过程的扰动而进行的原位饱和砂土地层抗液化强度的评价方法存在巨大误差。解决此问题的方法是以原位剪切波速为控制指标,在室内重现原位土层的抗液化强度。

According saturated sand, the separately, by which The result show, the at the most within the to the dependence between shear wave shear wave velocity the effect of sample shear wave velocity o depth of 20m under of in-situ stratum velocity and liquefaction resistance of and undisturbed soil sample is tested disturbance on liquefaction resistance is quantitatively studied. btained in lab is 40.7 percent higher than that of in-situ value the ground surface. Correspondingly, the liquefaction resistance of undisturbed soil sample can be lOOpercent higher than the in situ liquefaction resistance. So great discrepancy exist if the sample disturbance is ignored during liquefaction evaluation of saturated sand stratum. The suggestion to this problem is to reproduce the in-situ liquefaction resistance by recover the in-situ shear wave velocity in lab.