煤系固废协同固化盐渍土的力学特征与机理研究  

Mechanical properties and mechanism of co-curing saline soil with coal solid waste

作　　者：董晨曦 王念秦[1] 李江山[2] 陈新 闫旭升 马威 DONG Chenxi;WANG Nianqin;LI Jiangshan;CHEN Xin;YAN Xusheng;MA Wei(College of Geology and Environment,Xi’an University of Science and Technology,Xi’an 710054,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Science,Wuhan 430071,China)

机构地区：[1]西安科技大学地质与环境学院,陕西西安710054 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071

出　　处：《煤田地质与勘探》2023年第3期85-94,共10页Coal Geology & Exploration

基　　金：国家自然科学基金项目(42177163);冻土国家重点实验室开放基金项目(SKLFSE201806)。

摘　　要：以干旱半干旱地区固体废弃物资源化利用为研究背景,利用煤系固废煤矸石(CG)、煤系偏高岭土(CMK)联合干旱区易获取的固废材料电石渣(CS)协同普通硅酸盐水泥(OPC)开发一种新型固化材料,探讨其固化干旱半干旱区盐渍土的力学性能与微观变化机理。基于室内实验,对比100%OPC固化盐渍土,研究不同矿区产出的CG以及煤矸石-煤系偏高岭土-电石渣协同固化剂(CGCMK-CS)替代52%、60%、68%、72%、84%OPC后各龄期的无侧限抗压强度(UCS)特征,并取特征组进行有害阴离子(Cl^(-)、SO_(4)^(2-))浸出试验与微观测试,从微观角度对其强度变化机理进行探讨。结果表明,煤矸石–电石渣–煤系偏高岭土–普通硅酸盐水泥协同固化(CG-CMK-CS-OPC)体系具有良好的Cl^(-)与SO_(4)^(2-)结合能力,固化盐渍土后Cl^(-)与SO_(4)^(2-)浸出量是100%OPC的一半,其水化产物铝酸三钙能与盐渍土中的Cl^(-)与SO_(4)^(2-)生成AFm相产物,并使体系中的团粒内孔隙与团粒间孔隙向颗粒内与颗粒间孔隙转化,由此降低了盐渍土中盐分带来的危害。根据7 d UCS试验结果,使用山西运城CG固化体系的效果最佳,这与其活性钙质和铁铝质含量高、生物质含量低有关,榆林CG次之,咸阳CG性能最差。CG-CMK-CS在替代52%的OPC固化盐渍土后,部分试验组抗压强度qu超过了使用100%OPC固化盐渍土,即使在替代84%OPC之后,CG-CMK-CS-OPC依然满足公路底基层水泥粉煤灰材料的强度要求。因此,CG-CMK-CS-OPC可作为一种绿色、经济、环保低碳的固化材料,推广应用于干旱半干旱地区的盐渍土公路路基工程中。Under the research background of resource utilization of solid wastes in the arid and semiarid regions,a new curing material was developed with the coal wastes(such as the coal gangue(CG)and coal metakaolin(CMK)),the carbide slag(CS)that is a waste material readily available in the arid region,and the ordinary Portland cement(OPC).Besides,its mechanical properties and microscopic change mechanism in curing of saline soil in the arid and semi-arid regions were discussed.Based on the laboratory experiment,the unconfined compressive strength(UCS)characteristics of curing saline soil in different ages were studied by replacing 52%,60%,68%,72%and 84%OPC with CG from different mines and CG-CMK-CS,and comparison was made with the saline soil cured with 100%OPC.Then,the characteristic groups were taken for the leaching tests of harmful anions(Cl^(-)and SO_(4)^(2-))and microscopic tests to investigate the strength change mechanism from a microscopic perspective.The results show that the CG-CS-CMK-OPC system has a good ability of binding Cl^(-)and SO_(4)^(2-),with the leaching amount of Cl^(-)and SO_(4)^(2-)equivalent to only half of that cured by 100%OPC.Further,the hydration product tricalcium aluminate could form AFm with Cl^(-)and SO_(4)^(2-)in the saline soil,and thus the intra-agglomerate and inter-agglomerate pores in the system are transformed into intra-granular and intergranular pores,reducing the hazard caused by salt in saline soil.The results of the 7d UCS test show that Shanxi Yuncheng CG curing system has the best strength,which is related to its high content of active calcium and ferroaluminum,as well as the low content of biomass.Shaanxi Yulin CG takes the second place and Shaanxi Xianyang CG has the worst performance.After replacing 52%OPC for curing saline soil with CG-CMK-CS,the compression strength of some test groups qu exceeded that of curing saline soil with 100%OPC.Even after the replacement of 84%OPC,CGCMK-CS-OPC can still meet the strength requirements of cement and fly ash material for highway b

关 键 词：煤矸石 碱激发 盐渍土 微观机理 力学特征 固化材料 

分 类 号：P642.3[天文地球—工程地质学]