Study On The Formation Mechanism And Stability Of The Toppling-Thrusting Nappe-Sliding Geological Body

The paper systematically studied of a new type complex landslide—"Toppling-thrusting nappe-sliding geolodical body", about its formation mechanism, calculating parameters, stability, sliding stabiliazing principias, inspection monitoring methods and so on. The research achievements consummated and complemented the theory about landslide, and reinforced the complex landslide researching with more helpful for disaster prevention and mitigation, and also provided a reference of theoretical gist and research approach in researching and treating with the same and other similar geological body.It is indicated through the researching that the necessary conditions of the formation of "toppling-thrusting nappe-sliding geological body" included monoclinal strata texture and anisomerous intermontane gully and the peculiarly physiognomy in the bottom and side of the gully. The toppling-thrusting nappe-sliding geological body formed through a circularly process such as that "toppling, toppling bodies sliding and stopping, toppling again, toppling bodies thrusting the soft bed strata sliding and stopping,…,"and so on. It is a huge landslide repetitious complexed with toppling accumulations and thrusting nappe-sliding geological bodies. Toppling was the main dynamical factors of the displacement and deformation of thrusting nappe-sliding geological body, while the toppling rock strata were the key strata in the stabilization of the slope. When the free face strata were the soft bed strata, the surface retrogressive sliding came into being easily.The geological model of toppling-thrusting nappe-sliding geological body can be approximately made up of two elements which were toppling rock accumulations and thrusting nappe-sliding soft geological bodies. The geological model of toppling-thrusting nappe-sliding geological body can be approximately made up of two elements which were toppling rock accumulations and thrusting nappe-sliding soft geological bodies.The shear strength parameters c,φof geological body with complicated structure and different complex composing has been studied by the in-situ level-push shear test, and been validated from the prototype sliding medol.The methods of limit equilibrium and numerical analysis have been adopted to study the stability of toppling-thrusting nappe-sliding geological body. Evaluation results indicated that the whole slope is stable under the current conditions. Three-dimensional numerical simulation results showed that the distribution of rock strata plays a crucial control role in the deformation, stress distribution and stability of the langslide slope. Project constructing and building and stacking could not affect the whole stability of toppling-thrusting nappe-sliding geological body, but excavating and leveling up and filling and other human activities may bring part sliding into being.From the basic theory of disaster prevention and treatment that " taking as an integral part of architecture material to father the body of disasters, using the adverse geological process to control and transform its adverse geological processes", this paper puts forward the main principias to comply with in controlling the stability of toppling-thrusting nappe-sliding geological body, and the most critical contents in monitoring. The inspection monitored results show that the studied slope is overall steady, and the May. 12, 2008 Wenchuan(Sichuan) Mw8.0 earthquake did not affect the overall stability of the studied Geological body.This paper included 53 figures, 18 tables, 13 photos and 179 references.