低黏土矿物含量原状泥岩膨胀力试验研究

Experimental study on swelling force of undisturbed mudstone with low clay mineral

以兰新铁路第二双线某典型原状泥岩为对象,采用平衡加荷法,进行了3组不同膨胀特性土体在初始含水量分别为2%,6%,10%,14%和18%时原状泥岩试验,以研究土体自身膨胀特性和初始含水量对原状泥岩膨胀力的影响。试验结果表明:膨胀力时程曲线变化与土体渗水速度相关;膨胀力随初始含水量增大逐渐减小,膨胀力增量随含水量增量增长变化规律为先增后减;膨胀力与土体蒙脱石含量有关,低初始含水量时,膨胀性矿物颗粒含量对土体膨胀力影响显著;高初始含水量时,膨胀性矿物颗粒含量对土体膨胀力影响减弱。通过对试验数据的进一步分析,拟合了土体等效蒙脱石含量和初始含水量两种工况下环刀样膨胀力经验式,试验结果与计算结果相吻合,为膨胀泥岩地区工程建设提供了一定的理论支撑。

In order to study the influence of the swelling characteristics of soil and initial water content on the undisturbed mudstone swelling force,taking one typical area of undisturbed mudstone of the Second Double-Track Railway as the study object,three undisturbed mudstone tests have been carried out on the soils with different swelling characteristics when the initial water content is respectively at 2%,6%,10%,14%,and 18%.The experimental results show that the time-history curve change of the swelling force is related to the seepage rate of the soil.The swelling force decreases with the increase of the initial water content,and the increment of the swelling force increases first and then decreases with the increase of the water content increment.The swelling force of soil is subject to content of montmorillonite in soil.When the initial water content is low,the effect of swelling mineral content on soil swelling force is significant.When the initial water content is high,the effect of swelling mineral content on soil swelling force is weakened.Based on the further analysis of the experimental data,the empirical formula of the swelling force of the soil samples under the two kinds of working conditions is matched.The experimental results are in agreement with the calculated results,which provide a certain theoretical support to the engineering construction work in swelling mudstone areas.