水泥土拌合均匀度量化方法及其试验研究

The Quantification Method and Verification Tests of the Mixing Uniformity of Cement Soil

水泥土的拌合均匀度是影响水泥土强度的重要因素之一,目前尚无有效的量化方法及其测试手段,且无法做到拌合后的即时检测。本文通过X射线荧光光谱仪(XRF)对水泥土中钙元素含量进行测量,基于钙元素分布特征提出了一种水泥土拌合均匀度的实时评价方法。以拌合均匀度为对象,开展了不同水泥掺量、含水率和养护龄期条件下的水泥土强度响应分析,研究拌合均匀度对水泥土强度的影响规律。试验结果表明:拌合均匀度、水泥掺量、含水率及养护龄期均是影响水泥土强度的重要参数;水泥土强度随拌合不均匀系数(UY)的增大而降低,且UY值对水泥土强度的影响随着水泥掺量和养护龄期的增长而增大;在相同水泥掺量和UY值的情况下,液限附近的水泥土所对应的强度最大。此外,引入均匀度修正系数α,提出了考虑均匀度的水泥土无侧限抗压强度(UCS)计算公式,并开展了室内和现场试验验证,结果发现,当UY<0.4时计算结果与试验数据较为吻合。

The mixing uniformity of cement soil is one of the important factors affecting the strength of cement soil.At present,there is no effective quantitative method and testing method,and it is impossible to achieve real-time detection after mixing.In this paper,X-ray fluorescence spectrometer(XRF)was used to measure the content of calcium in cement soil,and a real-time evaluation method for the mixing uniformity of cement soil was proposed based on the distribution characteristics of calcium.Taking mixing uniformity as the object,the strength response analysis of cement soil under the conditions of different cement content,moisture content and curing age was carried out,and the influence of mixing uniformity on the strength of cement soil was studied.The test results showed that:mixing uniformity,cement content,moisture content and curing age were all important parameters affecting the strength of cement soil;the strength of cement soil decreased with increasing mixing unevenness coefficient(UY)value,and the effect of UY value on the strength of cement soil increased with increasing cement content and curing age;the cement soil near the liquid limit corresponded to the highest strength with the same cement content and UY value.In addition,the calculation formula of the unconfined compressive strength(UCS)of cement soil considering the uniformity was proposed by introducing the uniformity correction coefficientα.Indoor and field tests were carried out to verify the formula,and the results found that when UY value was less than 0.4,the calculated results were more consistent with the experimental data.