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;

Abstract: 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.

Key words: red-stratum landslide; characteristic minerals; water-rock interaction; formation mechanism; illite; albite;