Through analyzing the achievement of the direct shear rheological tests of brown mudstone muddy intercalation, the paper shows linear relationship between normal stress and shear stress in the brown mudstone muddy intercalation, and it exists unitive ultimate strain value of rheological character model of coming creep acceleration stage. This paper establishes rheological mechanical model suitable to rheological character of weak layer based on theory of obsolescence. It gets long-term strength equation based on ultimate strain value of coming creep acceleration stage, It presents the equation of slope safety coefficient and creep acceleration, thereby provides the reliable evidence for slope deformation analysis and long-term landslide forecast.


Rock engineers need to know the long-term in situ strength and rheological character of a rock for the design and construction of excavations in the rock for mines, tunnels, underground storage facilities and nuclear waste repositories [1]. The rheological character will greatly advance the understanding of the creep mechanisms involved in the process of damage accumulation leading to failure under long-term loading. In addition, it will be used to further define the relationship between of the stress at volumetric strain reversal and the long-term in situ strength of a rock [1, 2, 3, 4, 5]. The deformation and sliding of north wall slope of Fushun west open-pit mine is controlled by brown mudstone muddy siltized intercalation of creep character, now open-air mining has been completed, The fluctuations in water pressure during the rainy season can approximately thinks the stress changes slow. This paper adopts obsolescence model to establish rheological model of siltized intercalation and research into the relationship between rheological character and slope stability.

Rheological test method and theoryequation of siltized intercalation

Firstly test of consolidation and fast shear on weak layer is to get shear stress values ó i and i ô, then determines normal stress and sheer load class gradient relative to rheological test. The normal stress is operated by four classes, stress ó i is 100kPa, 200kPa, 300kPa, 400kPa respectively. Shear stress is imposed up gradually, the anterior should be increased properly, the latter should be imposed densely, and each class keeps one week. Daily creep deformation gets the relationship between shear creep deformation i ã and time t based on i ó and 0i ô of each class, then four groups relation data t i ã − are available. The data 0i ô must be adjusted during the test according to the real condition of deformation. Generally we should increase the class in order to attain gradually damaged relationship of t i ã − till the last class 0i ô

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