固化重金属污染土电阻率与强度特性试验研究

Experimental study on resistivity and strength properties of solidified heavy metal contaminated soil

为研究固化重金属污染土电阻率与强度关系特征,对稻壳灰-水泥固化镉污染土开展电阻率测试及无侧限抗压强度试验,通过单轴压缩-电阻率联合试验得到固化土单轴应力-应变-电阻率关系,分析了初始电阻率影响因素及其与强度的关联性,建立了基于电阻率的强度预测与力学损伤模型。研究结果表明:固化土应力-应变和电阻率-应变曲线呈一定负相关关系;初始电阻率随稻壳灰掺量增加而先升后降,在稻壳灰掺量为5%时初始电阻率达到峰值,水泥掺量较高时初始电阻率持续降低;固化土初始电阻率随其龄期增加而持续增加,随镉含量增加而波动式增大后减小,在镉含量为2000 mg/kg时降为最低;基于初始电阻率的强度预测模型可对固化土抗压强度进行预测;基于实时电阻率的力学损伤模型可对固化土单轴压缩过程中土体破坏前的损伤发展进行预测。

In order to study the relationship between resistivity and strength of solidified heavy metal contaminated soil,resistivity test and unconfined compressive strength of rice husk ash(RHA)-cement solidified cadmium(Cd)-contaminated soil were carried out.Uniaxial stress-strain-resistivity relationship of solidified soil was obtained by uniaxial compression-resistivity joint test,the influencing factors of initial resistivity and its correlation with strength were analyzed,and the models of strength prediction and mechanical damage based on resistivity were established.The results show that there is a negative correlation between the stress-strain and the resistivity-strain curves of solidified soil.The initial resistivity increases first and then decreases with the increase of RHA content,and reaches the peak when the RHA content is 5%,while the initial resistivity decreases continuously when the cement content is high.The initial resistivity of the solidified soil increases continuously with the increase of age,increases first and then decreases with the increase of Cd content,and reaches the lowest when the Cd content is 2000 mg/kg.The compressive strength of solidified soil can be predicted by the strength prediction model based on initial resistivity.The mechanical damage model based on real-time resistivity can be used to predict the damage development before soil failure during uniaxial compression of solidified soil.