Study On Instability Mechanism For The Reservoir Bank Accumulation Body-Slope Based On Rheological Characteristics Of Soil

In recent years,the rheological properties of soil have been paid more and more attention by the geotechnical engineering community,which makes the failure mechanism of slope considering the rheological characteristics of soil become the hotspot and focus of current research.For the slope in the reservoir or along the river,fluctuation of water is the most important factor affecting instability of bank slope.In this paper,author set the bank accumulation soil-Slope in the natural state as the subject of our research,and be devoted to building a coordination mechanism of bank slope safety factors,rheological strength of soil and fluctuation of water,which could reflect the instability mechanism of bank soil slope.The work and results of this paper mainly includes the following aspects:(1)Through a systematic study of basic theory of soil rheology,a comparison of characteristics and combination principle of soil-rheological element model and grasping the recognition methods of rheological param eters,author found Nishimoto Masao element model and Burgers element model are excellent in simulation of slope soil rheological behavoir.(2)Author used the Nishimoto Masao element mode and combined the rheological control theory of landslide to establish the displacement criterion of slope the slope stability considering the strength criterion of slope.Through the displacement criterion of slope and ed the slope and a simple model,created the function of the relationship between slope safety coefficient and time.This paper uses the Patton criterion and the Nishimoto Masao rheological model to identified the rheological parameters of soil in sliding zone.Through the collection of a soil slope in Three Gorges Reservoir Area rheological parameters,the curve of relationship between slope deformation and parameters of soil in sliding zone was built.(3)Through the soil indoor shearing rheological experiment about slip-zone soil in Three Gorges Reservoir Area,author found the law of rheolog ical characteristics of slip-zone soil and long-term strength of slip-zone soil.According to the experimental data,author used Burgers rheological model to identify rheological parameters of slip-zone soil,and get the rheological equation of slip-zone soil of kank slope,and demonstrated the relationship between rheological characteristics of soil and slope instability.(4)In order to take influence of reservoir water and the relationship between soil rheology and bank slope instability into joint consideraion,author deduced the relevant formula in unsaturated soil mechanics.Author established the curve relationship between matric suction and soil water content by Measurement method of filter paper.Author found that with the increase of water content of unsaturated soil,the matric suction decreases;with the decrease of soil matric suction,the shear strength of sliding zone soil decreases.(5)In this paper,author used FLac3 D finite difference numerical simulation software to establish the calculation model of bank slope.Through the calculation model of bank slope,author get the corresponding relationship between the bank slope safety factor and reservoir water level under the condition of fluctuation of reservoir water.By using the nonlinear dynamic model of slope evolution,the corresponding relationship between the rheological strength of reservoir soil and the water level of reservoir was found,and the criterion for evaluating the rheological strength of bank soil was established.Author built a linkage coordination mechanism among three factors,namely,bank slope safety factor,reservoir water fluctuation and bank soil rheological strength,which could be developed to reflect the slope failure mechanism of reservoir bank slope.It is found that with the rapidly decrease of reservoir water level,the rheological strength of the slope soil medium increases,the safety of the bank slope decreases.(6)Finally,through the analysis of an engineering example,the rationality of the linkage coordination mechanism of the bank slope safety factor-reservoir water fluctuation-bank soil rheological strength is proved.