Analysis Of Stress And Strain Characteristic Of Site Slope At Gaixia Hydroelectric Dam In Yunyang City Of Chongqing

The slope landforms take more than 73% area of land around the world. It's one of the widest topography in nature world, and is the most common and basic nature environment for human beings and projects. The deformation and failure of slope seriously threatens production and living of human. It's one of the biggest nature hazards which human face with. The losses caused by slope destroy reaches tens of billion dollars and hundreds of casualties. China is one of the most damaging countries affected by slope disasters. Especially in recent years, a number of natural and artificial slope instability accidents happened, causing huge losses and seriously affecting people's production and living. Study on slope stability is a global study.Slope in its formation and operation of the process changes the stress distribution, by the role of force field such as gravity, work force, water pressure and stratum pressure. When the strength of the rock of slope can not adapt to this stress distribution, it is necessary to produce deformation and damage, caused an accident or disaster. Therefore, the study of slope rock Characteristic of re-distribution stress is the basis of analysis of stability.There are many methods, such as finite element method, discrete element method, boundary element method, FLAC and so on that can be used to study the internal stress-strain characteristics of the slope. The finite element method as the most widespread application method has been developed more mature in dealing with complex structures, complex boundary and loading conditions, nonlinear problems that shows the effectiveness of a unique.It can be easily used to solve elastic-plastic theory to analyze rock and soil as a result of the non-uniform, non-continuity in slope engineering problems caused by the non-linear features, to get the stress field, strain field and displacement field of the slope, to show a very intuitive simulation of the deformation and damage process, to determine the slope of plastic zone or rupture zones and the initial damage to the site and so on in accordance with destruction criteria of rock and soil.Paper firstly summarized the recent research of rock slope deformation and failure, followed by analysis of the relationship between stress and strain, and summed up slope internal stress distribution and failure mode of deformation. And then based on the system study of geological and rock mechanics environment of site slope on the right bank at Gaixia hydropower dam in Yunyang city of Chongqing, the process of the stress re-distribution and the deformation and damage of slope under the natural stress state and abutment load state has been successful simulated, and stability on potential sliding surface in slope has been analyzed in accordance with finite element calculate results. Research results in the above system study are as follows:1. Whether in natural or abutment stress load, the result of stress re-distribution is that, in the vicinity of overhead rock close to the stress state in a one-dimension, a gradual inward transition to three-dimension stress state. Principal stress trace of slope occur significant deflection. The more close to the overhead surface, the more nearly the maximum principal stress parallel to the overhead surface, the minimum principal stress plane orthogonal with the overhead. The principal stress gradually returns to the initial stress state inward slope.2. Maximum and minimum principal stress is mainly affected by the impact of self-stress. Generally, they decrease gradually from the surface of slope to internal. Affected by the shape of the slope, the nature of rock, weathering level and structural characteristics and so on, the stress distribution of the slope can be changed and appears the phenomenon of stress concentration.3. Shear stress gradually decreases from the surface to internal of the slope, and appear the stress concentration near the foot and inflection point of the slope.4. Because the principal stress trace occur deflection, the trace of largest shear stress will become concave curved surface to the shape of the invading. Its maximum is located in the most internal of slope.5. Beside the slope shoulder, under certain conditions, the radial stress in the vicinity and tangential stress on the top of the slope can be converted to tensile stress with the formation of tensile stress. More steep slope, the greater the scope of this belt. So, the shoulder of slope is nearly the most vulnerable to rupture damage.6. Generally speaking, the law of the slope displacement is that, the upper part of rock distort to the lower right corner away from the surface of slope, and the lower part of rock distort to the lower left corner. The maximum of horizontal deformation locate at the lower surface of slope, and the vertical at the top.7. The impact of abutment load on the slope: 1) About stress, principal stress increased at the inflection point and the foot of the slope, the direction of principal stress rotation was counter-clockwise, so that the shear stress reduced at the regional from abutment to the foot of the slope; 2)About deformation, for the horizontal of deformation, the horizontal displacement of rock mass is reduced at the mid-lower slope, and the upper part is increased. For the vertical deformation, the deposition of front slope is increased and the back top decreased.3) About tensile stress zone, the tensile stress distribution is still near the abutment, but the region decreased slightly.8. By the result of finite element method, the rock mass stability which have potential slip surface in slope can be calculated. The factor of stability to the potential slip surfaces of B1-B1, B2-B2, B3-B3 profile are more than 1.4, so the slopes are stable.