重金屬污染土物理性質(zhì) 強(qiáng)度定量關(guān)系試驗研究

王婧 牟聰 趙含瑞 丁建文

摘 要： 通過室內(nèi)試驗研究土體孔隙液中重金屬離子影響土體物理 力學(xué)性狀的機(jī)理，采用不同濃度的重金屬Cu2+、Zn2+、Pb2+摻入高嶺土、伊利石類黏土和鈉基膨潤土，研究土體界限含液率、不排水抗剪強(qiáng)度隨重金屬離子濃度的變化規(guī)律。試驗結(jié)果表明：以高嶺石、伊利石為主要黏土礦物的低活性土的液限、塑性指數(shù)隨離子濃度的增加而增大，鈉基膨潤土則表現(xiàn)出相反的變化規(guī)律;低活性黏土的不排水抗剪強(qiáng)度隨離子濃度增加而增大，高活性黏土強(qiáng)度則隨之減小;基于已有的無污染土體物理 力學(xué)性狀定量聯(lián)系，分析重金屬污染土的不排水抗剪強(qiáng)度與液性指數(shù)的定量關(guān)系，發(fā)現(xiàn)重金屬離子引起的不排水抗剪強(qiáng)度的變化可以歸結(jié)于重金屬離子引起的液塑限變化，表明重金屬Cu2+、Zn2+、Pb2+污染過程基本沒有產(chǎn)生化學(xué)反應(yīng)，其物理 力學(xué)定量關(guān)系與已有的無污染土經(jīng)驗關(guān)系式一致。

關(guān)鍵詞： 黏土礦物;重金屬;界限含液率;不排水抗剪強(qiáng)度

中圖分類號：TU411.2;TU411.3? ? 文獻(xiàn)標(biāo)志碼：A? ?文章編號：2096-6717（2020）02-0030-07

Experimental study on quantitative physical-strength relationship of heavy-metal-contaminated soils

Wang Jing， Mou Cong， Zhao Hanrui， Ding Jianwen

（School of Transportation， Southeast University， Nanjing 210096， P.R.China）

Abstract：? This study performed a series of laboratory tests for understanding the role of heavy metal ions in the physical-mechanical behaviour.Different kinds of soils， including kaolinite， illite clays and sodium bentonite， were mixed with different concentrations of heavy metals Cu2+， Zn2+， Pb2+ to measure the changes in the Atterberg limits and the undrained shear strength.The testing results show that： the liquid limit and plasticity index of low active soils increase with the ion concentration， but sodium bentonite shows the opposite trend; the undrained shear strength of low-active soils increases with the ion concentration， but conversely for the high-active soils; based on the existing quantitative correlation between physical and mechanical properties of non-polluted soils， the quantitative relationship between the undrained shear strength and liquidity index of contaminated soils is investigated.It is found that the changes of undrained shear strength caused by adding heavy metal ions can be attributed to the corresponding changes in liquid limit and plastic limit.Such a result indicates that there is almost no chemical reaction caused by heavy metal pollution.The physical-mechanical quantitative relationship of heavy-metal-contaminated soils is consistent with the existing empirical relationship of non-polluted soils.

Keywords： clay mineral; heavy metal; Atterberg limit; undrained shear strength

近20年來，中國城市化進(jìn)程的加快促進(jìn)了區(qū)域經(jīng)濟(jì)的快速發(fā)展，但也導(dǎo)致城市環(huán)境污染嚴(yán)重。2014年環(huán)境保護(hù)部和國土資源部發(fā)布了《全國土壤污染狀況調(diào)查公報》，其中明確指出，長江三角洲、珠江三角洲和東北老工業(yè)基地等部分區(qū)域由于控制不嚴(yán)格、排放無序，以重金屬為典型代表的無機(jī)污染物嚴(yán)重超標(biāo)[1]。

重金屬不僅污染土水體環(huán)境，嚴(yán)重危害人民身心健康，還會引起土體工程性質(zhì)改變。……