王来贵, 丁盛鹏, 何慧娟, 杨建林. 2018: 冻融循环作用下含结核砂岩风化特征实验研究. 工程地质学报, 26(3): 611-619. DOI: 10.13544/j.cnki.jeg.2017-143
    引用本文: 王来贵, 丁盛鹏, 何慧娟, 杨建林. 2018: 冻融循环作用下含结核砂岩风化特征实验研究. 工程地质学报, 26(3): 611-619. DOI: 10.13544/j.cnki.jeg.2017-143
    WANG Laigui, DING Shengpeng, HE Huijuan, YANG Jianlin. 2018: EXPERIMENTAL STUDY ON CRACKING CHARACTERISTICS OF CONCRETION SANDSTONE WITH FREEZING-THAWING CYCLES. JOURNAL OF ENGINEERING GEOLOGY, 26(3): 611-619. DOI: 10.13544/j.cnki.jeg.2017-143
    Citation: WANG Laigui, DING Shengpeng, HE Huijuan, YANG Jianlin. 2018: EXPERIMENTAL STUDY ON CRACKING CHARACTERISTICS OF CONCRETION SANDSTONE WITH FREEZING-THAWING CYCLES. JOURNAL OF ENGINEERING GEOLOGY, 26(3): 611-619. DOI: 10.13544/j.cnki.jeg.2017-143

    冻融循环作用下含结核砂岩风化特征实验研究

    EXPERIMENTAL STUDY ON CRACKING CHARACTERISTICS OF CONCRETION SANDSTONE WITH FREEZING-THAWING CYCLES

    • 摘要: 为研究云冈石窟砂岩孔状风化现象的形成机理,对现场选取的含结核砂岩进行冻融循环实验,利用激光共聚焦显微镜对砂岩结核、砂岩基质、以及结核与基质交界面进行观测,分析冻融条件下含结核砂岩裂隙扩展规律,建立了含结核砂岩冻融破坏力学模型。研究表明:随冻融循环周期增加,结核与基质交界面、结核中心、砂岩基质先后出现裂隙。各区域裂隙宽度随冻融循环周期增多均呈增长趋势,但3个位置裂隙发展过程存在差异,交界面的裂隙沿交界面延伸;结核中心产生新裂隙,同时早期裂隙扩展、延伸、汇交形成裂隙网络;砂岩基质裂隙发展缓慢。结核的存在改变了砂岩物理力学性质,显著增强了砂岩的非均质性,建立的含结核砂岩冻融破坏模型,揭示了裂隙一般易发育于交界面的特点。砂岩的非均质性是云冈石窟砂岩形成孔状风化的内在因素。

       

      Abstract: In order to study the formation mechanism of sandstone pore weathering in Yungang Grottoes, three kinds of typical regions of sandstone concretion, sandstone matrix and sandstone matrix interface were observed by laser confocal microscopy. The crack propagation law of the concretion sandstone is analyzed, and the freezing and thawing failure model of the concretion sandstone is established. The results show that with the increase of freeze-thaw cycle, the cracks at the interface between concretion and rock matrix, at the concretion center and at the sandstone matrix appeared successively. The crack width of each region increases with the increase of freeze-thaw cycle, but there are differences in the development process of the three positions, and the cracks at the interface extend along the interface. The new cracks are produced in the concretion center, and the early cracks are extended, producing crack network. Sandstone matrix crack was developed slowly. Concretion changed the physical and mechanical properties, and significantly enhanced the heterogeneity of sandstone. The model of freeze-thaw damage of concretion sandstone revealed that the crack was generally developed at the interface. The heterogeneity of sandstone is the internal reason for the formation of pore weathering in Yungang Grottoes.

       

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