The treatment of contaminated soil is a crucial issue in geotechnical and environmental engineering.This study proposes to incorporate appropriate polypropylene fibers and cements as an effective method to treat heavy...The treatment of contaminated soil is a crucial issue in geotechnical and environmental engineering.This study proposes to incorporate appropriate polypropylene fibers and cements as an effective method to treat heavy metal contaminated soil(HMCS).The objective of this paper is to investigate the effects of fiber content,fiber length,cement content,curing time,heavy metal types and concentration on the mechanical properties of soils.To this end,a series of direct shear test,unconfined compression strength(UCS)test,dry-wet cycle and freeze-thaw cycle test are performed.The results confirm that the appropriate reinforcement of polypropylene fibers and cement is an effective way to recycle HMCS as substitutable fillers in roadbed,which exhibits benefits in environment and economy development.展开更多
煤矿复垦区在施工过程中受机械碾压和扰动影响,土壤原有结构和剖面层次遭到破坏,重构土壤生产力难以恢复至原状土壤水平,常出现植被恢复初期良好而后期退化的问题。大孔隙是土壤水分和空气流通的重要通道,对土壤的物理、化学和生物过程...煤矿复垦区在施工过程中受机械碾压和扰动影响,土壤原有结构和剖面层次遭到破坏,重构土壤生产力难以恢复至原状土壤水平,常出现植被恢复初期良好而后期退化的问题。大孔隙是土壤水分和空气流通的重要通道,对土壤的物理、化学和生物过程具有显著影响。通过定性与定量相结合的方法分析复垦区不同重构层次基质大孔隙特征,有助于识别重构土壤关键层,优化复垦工艺设计。本研究采用工业CT扫描技术,对潘一矿不同重构层次土壤样品进行三维成像,以原状土壤为对照,结合VG Studio Max软件开展数字图像定量分析。研究结果表明:不同重构层中大孔隙的主要分布范围较为一致,但在?>10 mm的孔径范围内,覆土和煤矸石层的孔隙贡献率分别达90.83%和97.80%,显著高于原状土和泥矸混合土。覆土层在植被根系和外界环境作用下形成孔隙-裂隙网络,入渗条件改善,但比表面积降低使得持水与固土效应受限。泥矸混合土层孔隙结构分布均匀、比表面积适中,具备良好的蓄水能力,是复垦剖面中的典型蓄水功能层;煤矸石层因含有大量碎块物质,孔隙集中分布,连通性强但比表面积较小,整体蓄水性能较差。建议煤矸石充填前应充分破碎,提高孔隙结构均匀性;在表层优先种植浅根型草本植物增强稳固性,并避开汛期开展种植作业,降低水蚀风险。研究成果可为煤矸石复垦区土壤结构优化与施工工艺改进提供技术支撑。展开更多
基金Projects(51778386,51708377,51608059)supported by the National Natural Science Foundation of ChinaProject(BK20170339)supported by Natural Science Foundation of Jiangsu Province,China+2 种基金Project(17KJB560008)supported by Natural Science Fund for Colleges and Universities in Jiangsu Province,ChinaProjects(KFJ170106,KFJ180105)supported by Open Fund of National Engineering Laboratory of Highway Maintenance Technology(Changsha University of Science&Technology),ChinaProjects(2016ZD18,2017ZD002)supported by Jiangsu Provincial Department of Housing,Urban-Rural Development,China。
文摘The treatment of contaminated soil is a crucial issue in geotechnical and environmental engineering.This study proposes to incorporate appropriate polypropylene fibers and cements as an effective method to treat heavy metal contaminated soil(HMCS).The objective of this paper is to investigate the effects of fiber content,fiber length,cement content,curing time,heavy metal types and concentration on the mechanical properties of soils.To this end,a series of direct shear test,unconfined compression strength(UCS)test,dry-wet cycle and freeze-thaw cycle test are performed.The results confirm that the appropriate reinforcement of polypropylene fibers and cement is an effective way to recycle HMCS as substitutable fillers in roadbed,which exhibits benefits in environment and economy development.
文摘煤矿复垦区在施工过程中受机械碾压和扰动影响,土壤原有结构和剖面层次遭到破坏,重构土壤生产力难以恢复至原状土壤水平,常出现植被恢复初期良好而后期退化的问题。大孔隙是土壤水分和空气流通的重要通道,对土壤的物理、化学和生物过程具有显著影响。通过定性与定量相结合的方法分析复垦区不同重构层次基质大孔隙特征,有助于识别重构土壤关键层,优化复垦工艺设计。本研究采用工业CT扫描技术,对潘一矿不同重构层次土壤样品进行三维成像,以原状土壤为对照,结合VG Studio Max软件开展数字图像定量分析。研究结果表明:不同重构层中大孔隙的主要分布范围较为一致,但在?>10 mm的孔径范围内,覆土和煤矸石层的孔隙贡献率分别达90.83%和97.80%,显著高于原状土和泥矸混合土。覆土层在植被根系和外界环境作用下形成孔隙-裂隙网络,入渗条件改善,但比表面积降低使得持水与固土效应受限。泥矸混合土层孔隙结构分布均匀、比表面积适中,具备良好的蓄水能力,是复垦剖面中的典型蓄水功能层;煤矸石层因含有大量碎块物质,孔隙集中分布,连通性强但比表面积较小,整体蓄水性能较差。建议煤矸石充填前应充分破碎,提高孔隙结构均匀性;在表层优先种植浅根型草本植物增强稳固性,并避开汛期开展种植作业,降低水蚀风险。研究成果可为煤矸石复垦区土壤结构优化与施工工艺改进提供技术支撑。
