张先伟, 孔令伟, 李宏程, 翟路平, 王占高, 刘新宇. 2018: 津巴布韦泥岩残积土的工程地质特性及其微观机制. 工程地质学报, 26(6): 1424-1432. DOI: 10.13544/j.cnki.jeg.2017-429
    引用本文: 张先伟, 孔令伟, 李宏程, 翟路平, 王占高, 刘新宇. 2018: 津巴布韦泥岩残积土的工程地质特性及其微观机制. 工程地质学报, 26(6): 1424-1432. DOI: 10.13544/j.cnki.jeg.2017-429
    ZHANG Xianwei, KONG Lingwei, LI Hongcheng, ZHAI Luping, WANG Zhangao, LIU Xinyu. 2018: ENGINEERING GEOLOGICAL PROPERTIES AND MICRO-MECHANISM OF RESIDUAL SOILS DERIVED FROM MUDSTONE IN HARARE, ZIMBABWE. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1424-1432. DOI: 10.13544/j.cnki.jeg.2017-429
    Citation: ZHANG Xianwei, KONG Lingwei, LI Hongcheng, ZHAI Luping, WANG Zhangao, LIU Xinyu. 2018: ENGINEERING GEOLOGICAL PROPERTIES AND MICRO-MECHANISM OF RESIDUAL SOILS DERIVED FROM MUDSTONE IN HARARE, ZIMBABWE. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1424-1432. DOI: 10.13544/j.cnki.jeg.2017-429

    津巴布韦泥岩残积土的工程地质特性及其微观机制

    ENGINEERING GEOLOGICAL PROPERTIES AND MICRO-MECHANISM OF RESIDUAL SOILS DERIVED FROM MUDSTONE IN HARARE, ZIMBABWE

    • 摘要: 津巴布韦泥岩残积土是一种性质特殊的风化土,系统地评价这类问题土的工程地质特性对于推动我国海外的工程建设具有重要指导意义。通过室内物理与力学试验,评价泥岩残积土的工程特性,并通过矿物组成、化学成分和微观结构论述其特殊性质的机理。结果表明,该土可定义为坚硬的非饱和黏性土,具有较弱膨胀性和较差的压实性;天然状态下,由于含有母岩残留的结构强度,表现出偏高的强度特征,但泡水后土的黏聚力明显减低,干湿循环作用也会导致内摩擦角的降低,但浸水过程不会出现明显的湿陷沉降;强烈的水敏性也导致该土浸水后产生强烈的泥化崩解,因此,雨季施工中应重点关注降雨引发的工程灾害。研究还表明,津巴布韦泥岩残积土的工程特性受控于土的物化成分与结构特性,该土的黏土矿物主要是伊利石-高岭石型,微观结构主要是含有高定向性的高岭石团与大裂隙的团粒结构,团粒间的铁质胶结是导致土的较高强度的根本原因。

       

      Abstract: From a geotechnical perspective, residual soil derived from the mudstone in Zimbabwe is often viewed as a regional problematic soil, indicating that their behavior can deviate from traditional rules of soil behavior. Thus it appears especially important to accurately assess its engineering characteristics, which can provide theoretical guidance to engineering investigation and construction. In this study, a laboratory study is conducted to investigate the physical and mechanical properties of the soils, and then the special characteristics in mechanics are explained from the aspects of mineral composition, chemical components, and microstructures. The results show that this residual soil is termed hard clayey soil with low expansibility and compaction. For undisturbed soil, it is unsaturated and possessed the high strength because of structural strength inherited from parent rock. The soil shows an aggregate structure which contains a highly orientated kaolin aggregation and many fissures according to the result of SEM. In addition, the ferrous cementing effect can result in a high strength between the aggregations, which is monitored. Because of strong water sensitivity and disintegration, the cohesion can be remarkably reduced after soaking and the internal friction angle can also be reduced under wetting and drying cycle. The high collapsible deformation is not founded. Therefore, geotechnical engineers should pay close attention to engineering disasters due to meteoric water.

       

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