摘要
土中有机质的存在对土-金属界面黏附有显著影响,但其影响规律及机制尚缺乏系统研究。通过在蒙脱石、伊利石和高岭土中添加泥炭,配置了不同矿质、有机质含量的黏性土样。利用MC-100型拉力试验机测试了不同含水率土-金属界面黏附力。试验结果表明:在塑限至液限含水率范围内,黏附力F与含水率w的关系曲线为典型的“钟型”;有机质含量wu增大会导致F-w曲线由高陡变扁平;土样峰值黏附力Fmax随有机质含量wu变化可分为3个阶段:波动或缓慢下降(上升)阶段、急剧下降阶段和趋于稳定阶段。利用傅积平法测试了3种黏土矿物对有机质的饱和吸附量,从而明确了有机质在土中赋存形态随有机质含量变化的过程。机理分析表明:除了有机质含量外,有机质在土中的赋存形态对土样宏观黏附力也有显著影响。最后对分布于昆明地铁5号线沿线的天然泥炭土-金属界面黏附力进行了测试,得出其黏附力较小、黏附风险较小的结论,盾构机穿越泥炭土层没出现严重黏附刀盘或堵塞现象验证了该结论。
The presence of organic matter in soil has a significant effect on the soil-metal interface adhesion,but its influencing law and mechanism have not been systematically studied.By adding peat to montmorillonite,illite and kaolin,three groups of clay samples with different mineral and organic matter contents are prepared.The adhesion between the soil-metal interfaces with different moisture contents is tested by using the MC-100 tensile testing machine.The test results show that the relation curve between the adhesion force F and water content w is a typical"bell-shape"in the range from the plastic limit to the liquid limit water content.With the increase of the organic matter content wu,the curve of F-w changes from high to flat.With the increase of the organic matter content wu,the change of peak adhesion Fmax can be divided into three stages:fluctuation or slow decline(or ascending)stage,significant decline stage,and stable stage.The saturation adsorption of the organic matter with three kinds of clay minerals is measured by the Fu`s method,and the occurrence forms of the organic matter in soil change with the content of the organic matter.The mechanism analysis shows that in addition to the content of the organic matter,the form of the organic matter in soil also has a significant effect on the macroscopic adhesion of soil samples.Finally,the adhesion force of the natural peat soil-metal interface distributed along Line 5 of Kunming Metro is tested,and it is concluded that the adhesion force is small,and the risk of adhesion is also small,which is verified by the fact that the shield machine traversing through the peat layer does not show any serious adhesion to the cutter plate or clogging phenomenon.
作者
朱俊宇
裴利华
桂跃
ZHU Junyu;PEI Lihua;GUI Yue(Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming 650500,China;China Railway Fourth Academy Group Southwest Survey and Design Co.,Ltd.,Kunming 650504,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2024年第3期605-615,共11页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(52068039)
中铁第四勘察设计院集团有限公司科技研发计划项目(院科2020K145)。
关键词
黏附力
黏土矿物
拉力试验
稠度指数
有机质含量
adhesion
clay mineral
pull-out test
consistency index
organic matter content
