煤矸石粉改良膨胀土的试验  

Experimental Study on Improved Expansive Soil of Coal Gangue Powder

作　　者：马缤辉[1,2] 曾星 郭佳乐 胡志勇 贺成斌 Ma Binhui;Zeng Xing;Guo Jiale;Hu Zhiyong;He Ghengbin(School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Hunan Provincial Key Laboratory of Geotechnical Engineering for Stability Control and Health Monitoring,Xiangtan 411201,China)

机构地区：[1]湖南科技大学土木工程学院,湖南湘潭411201 [2]岩土工程稳定控制与健康监测湖南省重点实验室,湖南湘潭411201

出　　处：《矿业工程研究》2019年第3期66-72,共7页Mineral Engineering Research

基　　金：国家自然科学基金资助项目(51778227;51308208;41372303);湖南省科技创新平台与人才计划资助项目(2016RS3032);湖南省自然科学基金资助项目(2015JJ3069);湖南省教育厅科研资助项目(10C0669)

摘　　要：针对南方地区广泛存在的膨胀土路基病害处置及煤矸石资源化利用需求,采用煤矸石粉改良膨胀土的胀缩特性.通过现有的公路工程土工试验规程中的室内试验方法,利用击实试验确定最佳含水率和最大干密度,再进行直接剪切试验和无荷载膨胀率试验,研究分析在掺入6%,8%,10%,12%煤矸石粉下膨胀土的黏聚力c,内摩擦角和无荷载膨胀率的变化规律,比较素膨胀土和改良土的效果,并通过扫描电镜试验分析膨胀土的改良机理.结果表明:随着煤矸石粉掺量的增加,膨胀土的抗剪强度提高,无荷载膨胀率减小,黏聚力和内摩擦角均有提高,煤矸石粉能够有效地降低膨胀土的胀缩性和改良膨胀土的抗剪强度,得出了改良膨胀土的物理化学机理及微观结构机理,并且确定了煤矸石粉的最佳掺量为8%,为有效改良膨胀土路基、资源化利用煤矸石提供科学依据和有效改良方法.Aiming at the widespread disease disposal of expansive soil subgrade and the demand of coal gangue resource utilization in the southern region,the swelling and shrinkage characteristics of expansive soil are improved by coal gangue powder. Through the indoor test method in the existing geotechnical test rules of highway engineering,the optimum water content and maximum dry density are determined by the compaction test,and then the direct shear test and the non-load expansion rate test are carried out,and the variation law of cohesion,internal friction angle and non-load expansion rate of expansive soil under 6%,8%,10% and 12% coal gangue powder are studied,comparing the effect of vegetarian expansive soil and modified soil,and analyzing the improvement mechanism of expansive soil by scanning electron microscope test. Results show that with the increase of coal gangue powder content,the shear strength of expansive soil increases,the non-load expansion rate decreases,the adhesion force and internal friction angle are improved,the coal gangue powder can effectively reduce the swelling and shrinkage of expansive soil and improve the shear strength of expansive soil,and the physicochemical mechanism and microstructure mechanism of the modified expansive soil are obtained. It also determines that the optimum dosage of coal gangue powder is 8%,which provides a scientific basis and an effective improvement method for effective improvement of expansive soil subgrade and resource utilization of coal gangue.

关 键 词：膨胀土 煤矸石 抗剪强度 无荷载膨胀率 改良机理 

分 类 号：TU4111[建筑科学—岩土工程]