Research On Progressive Failure Model Of Slope Under Solid-Fluid Coupling Effect

With the times developing,the scale and the quantity of projects in buiding infrastructure have been getting larger and larger.The amount of wading slopes(or landslides)caused by the impoundment of reservoirs with large magnitude of pondage and the number of artificial or natural wading slopes encountered during the construction of other projects has been unprecedentedly huge.The stability of wading slope is related to the benefits of various projects in the aspects of safety,economy and sociaty.However,the current method to analyzing the stability of wading slope needs to be explored more deeply.For the stability calculation of wading slopes,the research has been carried out systematically with the solid-fluid coupling taken as the focus of it,while the seepage field and stability calculation during progressive destruction of the slope taken as the main courses.What the research has mainly contained and obtained are listed as follows:(1)Seepage models of wading slopes are studied.The wading slopes is classified into two types: dam-type and the reservoir-bank-type.After having generalized and summarized the disadvantages of the current model,the calculation method of seepage flow in the dam-type wading slope is proposed based on conditions from the macroscopic boundary of geometry and boundary of seepage in the slope,while the calculation principle of which is elucidated.Without standard method about the seepage calculation of the reservoir-bank-type wading slopes found current,the calculation method about seepage flow in the reservoir-bank-type wading slope,that can consider the falling level of water in the reservoir,proposed by Academician Zheng Yingren,is quoted to calculate the seepage of the bank-type wading slopes.A set of practical seepage calculation models for common wading slopes have been established by combining the proposed method with the quoted method.(2)The progressive failure model of slopes is researched.The main failure modes of landslides are deeply studied.And according to the characteristics of typical crosssections of thrust-load-caused landslides and retrogressive landslides,the stability calculation method of thrust-type landslides is proposed to be applied into analyzing the stability of the topmost-sliding-mass(the first soil layer to be destroyed)of retrogressive landslides.With the progressive failure congsiderated,the evolution characteristics of the stress-strain relationship are summarized based on the mechanical failure mechanism of the thrust-load-caused landslide.Aiming at the shortcomings that the current slice methods have,a model that can characterize the softening relationship of shear stress-shear strain in the sliding surface is introduced.Then an innovated Swedish section method and an improved unbalanced thrust method are proposed to analyze the progressive destruction of thrust-load-caused landslides and the gradual change of soil mechanical characteristics.(3)The solid-fluid coupling models are studied.And the force caused by the interaction of water-soil in the wading slope is studied based on the analysis of seepage mechanics.For the limitations in the current model,that can only be combined with the arc slice methods for coupling calculation,an improved solid-fluid coupling model is proposed,while the coupled calculation principles of the improved coupling model combined with the innovated slice methods are elucidated.And considering the softening effect of groundwater on the soil and the solid-fluid coupling effect,the progressive failure model of slopes is proposed.(4)The engineering cases are analyzed.The established progressive failure model of the slope considering the solid-fluid coupling is applied into the specific cases of engineering for stability analysis.As indicated in what is obtained from the analysis,the proposed method can not only characterize the evolution of the stability and mechanical properties well,but also reflect the softening effect of seepage on the mass of wading slopes,with the progressiveness of slopes failure considerated,while providing an idea to reference for developing calculation method of wading slopes about stabilities.