摘要
河塘淤泥具有含水率高、孔隙比大、压缩性高和强度低等不良特性,工程上常常将其挖除并换填为性质良好的石灰/水泥混合土.但挖除换填法的处理周期长,淤泥堆积占用大量良田,且波特兰水泥生产过程中耗能高、温室气体排放严重,强度增长缓慢.基于此,提出了采用MgO-CO2碳化技术进行河塘淤泥的现场处理,介绍了该技术的固化改良机理,开展了河塘淤泥的单点试验和现场处理试验.结合温度监测和轻型动力触探,得出通气最大半径宜为60 cm,通气支管间距宜为1 m,气体压力为500 kPa;采取通气1 h暂停0.5 h的间断式通气方法,累计通气3 h可基本完成碳化.结合单点试验,对现场河塘进行分区碳化处理,并进行了动力触探和动回弹模量测试.结果表明:碳化处理后淤泥场地的承载力达到140kPa以上,动回弹模量达到20 MPa,满足了路基工程的处理要求.研究结果为通气支管布设和大面积整体碳化施工提供重要参考.
There existed the bad engineering characteristics such as high moisture content,large void ratio,low strength and high compressibility for the pond mud,which was often removed and replaced by the lime/PC-admixed soils with good properties.However,it took too much time to treat for dredging and replacement-filling method,the accumulation of mud occupied a large number of good farmland,and there was larger consumption of energy,serious emissions of greenhouse gas during the PC production,as well as the slow strength growth in application.Under the background,the MgO-CO2 carbonization technology was put forward to treat the pond mud,and the stabilization and improvement mechanism was introduced.The single-point test and the field treatment test were carried out.According to the temperature monitoring and light dynamic probing,it was concluded that the maximum ventilation radius should be 60 cm,the ventilation branch tube spacing should be 1 m,and the gas pressure should be 500 kPa.The carbonation can be basically completed after 1 hour of intermittent ventilation with half an hour of suspension,and 3 hours of accumulated ventilation.Combined with the single point test,the carbonization treatment of the pond was carried out in the field,and the dynamic penetration and dynamic modulus modulus were tested.The results showed that the bearing capacity of the sludge field could reach over 140 kPa after the carbonation treatment,and the dynamic resilience modulus also reached 20 MPa,which met the engineering requirements of the subgrade treatment.The research results would provide an important reference for the layout of the ventilation pipe and the mass carbonation.
作者
蔡光华
王中
刘松玉
杜广印
张欣雅
秦川
CAI Guanghua;WANG Zhong;LIU Songyu;DU Guangyin;ZHANG Xinya;QIN Chuan(College of Civil Engineering,Nanjing Forestry University,Nanjing 210037,China;School of Transportation,Southeast University,Nanjing 211189,China)
出处
《河南大学学报（自然科学版）》
CAS
2020年第6期742-749,共8页
Journal of Henan University:Natural Science
基金
国家自然科学基金项目(41902286)
江苏省交通科学研究项目(2018T01)
大学生科研创新项目(201910298123Y)
关键词
活性氧化镁
碳化固化
河塘淤泥
单点试验
现场处理
reactive magnesia
carbonation-stabilization
pond mud
single-point test
field construction
作者简介
通信作者:蔡光华(1985-),男,河南洛阳人,博士,副教授,硕士生导师.研究方向:环境岩土和特殊土处理,E-mail:ghcai@njfu.edu.cn
