基于特征矿物的红层滑坡形成机理分析  

Analysis on formation mechanism of red-stratum landslide based on characteristic mineral

作　　者：蒋宇 赵宇[1] JIANG Yu;ZHAO Yu(Institute of Mountain Hazards and Environment,Chinese Academy of Science,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院水利部成都山地灾害与环境研究所,四川成都610041 [2]中国科学院大学,北京100049

出　　处：《人民长江》2021年第6期82-87,共6页Yangtze River

基　　金：国家自然科学基金项目(41671116)。

摘　　要：矿物成分是岩土体物理化学性质的主控因素,从矿物成分角度能更加深入地理解红层滑坡形成机理。以四川省五家坟滑坡为例,通过矿物分析、微观结构表征、强度测试等方法确定滑带土特征矿物,并从水岩相互作用角度量化分析特征矿物对滑坡形成的影响。结果表明:滑带土特征矿物为伊利石,含量高达41.9%,并且碎屑矿物散布于伊利石中,不起骨架作用;五家坟滑坡是在长期水岩相互作用下形成的,钠长石转化为伊利石,使滑带中伊利石含量增高,导致滑带土凝聚力增大而内摩擦角下降;矿物颗粒和胶结物在酸性地下水环境中发生溶蚀作用,破坏土体微观结构,导致滑带土强度显著降低;伊利石与碎屑矿物差异性膨胀使坡内土体发生崩解破坏,产生大量崩解裂隙,增强坡体安全系数对雨强的敏感性。The mineral composition is the main controlling factor for the physical and chemical properties of rock and soil mass,which is helpful to further understand the formation mechanism of red-stratum landslide.Taking the Wujiafen landslide in Sichuan Province as an example,the characteristic minerals of slip zone soil are determined by mineral analysis,micro-structure characterization and strength test.And the influence of characteristic minerals on the formation of the landslide is analyzed quantitatively from the perspective of water-rock interaction.The results show that illite is the characteristic mineral of slip zone soil with content up to 41.9%.Clastic minerals are scattered in illite,not playing a skeleton role.The Wujiafen landslide is formed under the long-term water-rock interaction.The transformation of albite into illite increases the content of illite in the slip zone,which leads to the increase of cohesion and the decrease of the internal friction angle of the slip zone soil.Mineral particles and cementation dissolve in the acid underground water environment,destroying the soil micro-structure and reducing the strength of the sliding zone soil.The differential expansion of illite and clastic minerals causes the disintegration and failure of the soil in the slope and develops a large number of disintegrated fissures,which enhances the sensitivity of slope safety coefficient to rainfall intensity.

关 键 词：红层滑坡 特征矿物 水岩相互作用 形成机理 伊利石 钠长石 

分 类 号：P694[天文地球—地质学]