一种砂类土的环刀取样技术及试验验证

A sampling technique with cutting ring for sandy soil and its experimental verification

为解决砂类土取样困难且易受扰动的问题,本文设计加工了一套砂类土环刀取样装置;采用福建标准砂构筑长600mm、宽600mm、高400mm的室内小型砂箱模型,针对干密度为1.45g/cm^3和目标含水率分别为3%、6%、9%的三组砂样模型,使用该装置进行了分层取样试验,以砂样干密度作为评价指标,对砂类土环刀取样技术的可靠性进行了验证。试验表明:对砂箱模型中具有较好均匀性的同一水平层砂土进行取样得到的干密度差值在0.03g/cm^3以内,平均差值不大于0.02g/cm^3,一致性较好且满足规范要求;同样,取样得到的干密度沿深度变化趋势能较好地反映砂箱模型分层击实制备过程中不同深度砂土层的干密度逐渐增大的基本特征。

In order to solve the problems of sampling difficulty and disturbance for sandy soil,a set of cutting ring sampling device is designed and a small indoor sand-box model（ 600 mm × 600 mm × 400mm）is built by using Fujian standard sand. Based on three groups of sample models whose dry density is 1. 45g/cm^3 and the target water content is 3%,6% and 9% respectively,the device is used for the stratified sampling test. The dry density of samples is used as the evaluation index and the reliability of cutting ring sampling technique is verified. The results show that： for the same horizontal layer of sand with a good uniformity in the sand-box model,the difference value of sampling is within 0. 03g/cm^3 and the average difference value is not greater than 0. 02g/cm^3,thus the results have the good consistency and meet the code requirements; similarly,the variation trend of sampling results along depth is the better measurement to track the basic feature of dry density increasing along depth in the preparation process of hierarchical compaction system in the sand box.