| At present,static pile-driving is widely employed in practical slope engineering and the application of pile-driving adjacent to slope is common in city construction,subgrade treatment,bridge engineering and port engineering.Previous research shew that piles could have a positive impact on slope stability due to their anti-slide effect in some certain conditions.In such conditions,the research focus turns to the effect of anti-slide piles on slope stability.Hence the issue of slope stability under the effects of pile-driving and anti-slide piles’ reinforcement needs to be researched systematically and thoroughly.At present related calculation theorem and research results are far from perfect.In this dissertation,based on satisfied failure mechanisms,the slope stability under effects of pile-driving and anti-slide piles’ reinforcement is investigated using upper-bound limit analysis and related parameter analysis is carried out.The main contents and results are as follows:(1)Two-dimensional and three-dimensional slope failure mechanisms are established to investigate the dynamic stability of slope during the process of pile-driving and to evaluate the influence of related parameters.The pile driving leads to a decrease of the safety factor during the earlier stage of pile driving and the safety factor significantly increases after the end of pile reaching the sliding surface.Pile diameter,slope angle and pile location have significant influence on the dynamic stability of slope.(2)The failure mechanisms are extended to three types by introducing new geometrical parameters,by which the upper-bound solution of safety factor is optimized further.Using such extended mechanisms,the stability analysis of reinforced slope is carried out,meanwhile the mechanism type and sliding surface shape of slopes under different parameter conditions are emphatically analyzed.The results show that such kind of extension of failure mechanism is meaningful.The stability of reinforced slope increases and then decreases with the pile location moving from slope toe to slope crest.There is an optimal pile location at which the slope stability is the highest.Also,the closer the pile location is to the slope crest,the closer the failure surface is to the slope face and the more the curvature is.In addition,with increasing pile space and slope width,slope stability decreases and the failure mechanism becomes thicker.(3)The stability of reinforced slope is also analyzed considering thenonhomogeneity and anisotropy of soil.The nonhomogeneity and anisotropy of soil nearly has no effect on the optimal location.The slope stability increases as the nonhomogeneous factor rises and the anisotropic factor drops.Beside,with a smaller frictional angle of soil,the slope stability is influenced by nonhomogeneity less and by anisotropy more,as well as less sensitive to the pile location,while the optimal pile location is closer to the slope crest.(4)The reinforced slope stability under effects of water drawdown is studied at last,as well as the stability change during the drawdown process.The water in the reservoir adjacent to the slope reinforces the slope and the decline of its level has a negative impact on slope stability.Meanwhile,The water in the slope impairs the slope and the decline of its level has a positive impact.Slow drawdown is more beneficial for the maintaining of slope stability compared with rapid drawdown.During the water drawdown in the reservoir,the optimal pile location becomes farther from slope crest and slope stability turns less sensitive to pile location.During the subsequent drawdown after the reservoir is fully drained,the optimal pile location remains almost unchanged. |
