Flume Test Study On Movement Characteristics Of Flow Slide Landslide

Flow slide landslide refers to a type of landslide that has the characteristics of transforming from a solid state to a fluid state during the movement of the landslide body.It often has the characteristics of complex starting mechanism,sudden failure,and fast and far fluidized movement.This thesis divides it into two stages of landslide initiation and fluidization process to conduct research.In the landslide incubation and initiation stage,what are the influences of factors such as internal water level rise,pore water pressure change,and particle migration on the precursors of slope initiation? In the process of fluidization,how does the movement shape and flow velocity of the slope change? It is the key point of this paper.Through the analysis of the basic characteristics of flow slide landslide,the loose accumulations and tailings pond materials after the earthquake were selected as test soil materials,and the simulation test of fluidized landslide flume under the catchment condition of the trailing edge was carried out to explore the interior of the slope during the initiation of flow slide landslide.Changes in related factors and related characteristics of the fluidization movement process of the slope.The main findings are as follows:(1)In terms of experimental phenomena,the downstream landslide under the catchment condition at the rear edge mainly goes through three stages;(1)the bottom of the slope saturated settlement stage(gestation stage),with the infiltration of water at the back edge,the infiltration line expands,the slope gradually saturated;In the process of seepage,fine particles inside the slope are taken away,resulting in small slope subsidence.(2)In the sliding stage of the landslide body,the slope body expands with the internal erosion and the infiltration line of the slope body,the soil at the bottom of the slope body is saturated,and the potential sliding surface appears inside the slope body;Under the action of gravity and the driving force of seepage,the slope body moves suddenly.(3)In the process of fluidization movement,the top of the slope begins to sink and destroy first,then the whole fluidization movement,finally decelerate and stop deposition,until the solid state is stationary.(2)Due to the differences in permeability,particle grading and structure of the two test materials,instability occurred when the infiltration line of the tailings slope body expanded to the third part of the slope toe,lasting 16 min.However,instability occurred after the infiltration line of the loose accumulation body expanded to the slope toe,lasting less than 1 min.It shows that the initiation of fluidized landslide is closely related to the geological conditions on site.(3)In the fluidization initiation stage of the slope,the tailings slope and the postearthquake loose accumulation slope have the same characteristics.The slope starts suddenly and the velocity of fluidization movement is extremely large.At the beginning moment,the pore water pressure at the bottom of the landslide suddenly surges and then drops sharply,resulting in excess pore pressure.A large amount of energy is released,and the microseismic signal produces intensive acceleration signal,and the corresponding acoustic emission also produces a large number of amplitude signal.Slope sliding drives the internal displacements meter ball to produce a displacement of 0.3m.(4)Based on the PIV particle imaging technology,the slope morphology and movement velocity variation rule of the flow landslide movement process were analyzed.It was found that at the beginning of starting,the slope body showed obvious sliding zone with slow movement speed,and the soil near the sliding zone showed fluid movement,driving the whole upper soil to slide.Then,the movement speed increases and flows forward in the shape of a whole fluid.At this stage,the movement speed of the faucet at the front edge of the slope reaches the maximum.In the final stop stage,due to the movement of particles inside the slope,impact and friction,the slope movement speed begins to slow down,gradually changing from fluid motion to quasisolid motion,until solid static.(5)Fluid-type landslide movement is generally a solid-liquid transformation mechanism,and the slope movement process presents a mutual transition form from quasi-solid state to quasi-liquid state and then to quasi-solid state.