Slope Stability Study On Strength Reduction And Gravity Increase Method And Its Engineering Application

Recently numerical analysis technique of slope stability has made great progress; It has still been an intractable problem on how to evaluate the critical failure state of slope engineering stability. On the law of landslide deformation failure, this paper presents the failure evaluation criterion of slope stability. Applying strength reduction method and gravity increase method for finite difference analysis, the stability of some rock slope engineering is made a comprehensive evaluation to provide a foundation for engineering design and construction. The research achievements are as follows:1. According to the origin and deformation observation data analysis of typical landsides, such as Xintan landside, Jiming temple landside and Huangci landside, in which the deformation failure mechanism is summarized, and then is applied to slope stability analysis as the failure evaluation criterion by adopting strength reduction method and gravity increase method. By classical instances, various factors effecting computable accuracy are also analyzed, and at the same time, the reliability and stability of previous methods are demonstrated. The result indicates that the failure evaluation criterion has a clear concept, special physical meaning and distinct definition for slope stability analysis, and the precision and reliability on basis of strength reduction method are better. At the same time, the reason of the error which is introduced by gravity increase method is discussed in detail.2. Through considering the effect of rainfall infiltration, unsaturated seepage field of the excavation slope is analyzed on Guangdong to Jiangxi expressway typical slope section. And then the variation law of the slope stability is researched applying general limit equilibrium slices method based on unsaturated geomechanics in course of rainfall. The safety factor reducing extent of the excavation slope is up to 11.7% before reinforcement, and it reaches 27% after reinforcement. It makes clear that rainfall has a great effect on the slope stability. Considering with the effect of rainfall infiltration, reinforcement measure, seismic load and substep excavation on slope stability, the excavation slope stability analysis of Guangdong to Jiangxi expressway typical sections is carried out. By comparing the results of general limit equilibrium slices method, strength reduction method, gravity increase method, the stability of former slope engineering is evaluated comprehensively. The result indicates that the former slope could happen to slip on rainfall condition before reinforcement, however on otherscondition it would preserve stable. So drainage arrangement and protection measure on sloping surfaces should be specially paid attention to prevent slipping during the course of construction in rainy season.3. By applying strength reduction method and gravity increase method to stability analysis in 3D high slope of the Tiger Leaping Gorge hydroelectric station, the potential failure 3D-sliding block is obtained in this paper. Compared with the results of the gen eralized wedge method, the stability of the slope is evaluated, and then the reliability of 3D slope stability analysis is verified in accordance with strength reduction method and gravity increase method. The slope has enough stability on natural condition; however, it is difficult to satisfy stability demand and should be reinforced specially when locating in seismic load condition.Through the analysis of the slope engineering instances, when the deformation variance tendency of slope engineering is adopted as failure evaluation criterion, the precision and reliability on basis of strength reduction method are better in making an analysis of the slope stability. However, gravity increase method is a kind of effective path in solving the problem of slope stability, which has still been further investigated in order to improve the computable precision and reliability of slope stability analysis. The research results in this paper have been applied to design and construction in the slop...