Study On The Influence Of Water On The Work Effect Of The Supporting Structure

Mountain torrents,debris flow,landslips and translational failure are the most common kinds of natural disasters in the Qin Mountains.Mountain area of Shaan xi Province In recent years,the probability of occurrence on extreme climates has rose and with the scope of human activities expanding,people often have to face disasters brought great threat,such as landslide and translational failure.Among them,the effect of rainfall and groundwater on risk of landslips has been common accepted and proved by the most.landslide disaster prevention under dynamic water environment is hard to prevention for it's short duration,and it can make spread effect.In recent years,as a special kind of anti-slide pile,the micro piles have rapidly application for its economical and work efficiency,and it causes less disturbance in unstable area.The piles distribution is flexible and they can offer an effective retaining structure.This paper firstly introduce the character of the loose accumulative formation,landslip effect based on rainfall and the force analysis of micro piles,the experiments would site in an simulation model casing,and adopt three different kinds of intensity when imitating raining and one situation of simulated groundwater effect,these studies would help in analysis on the behavior of micro piles,the three rows of piles site in parallel and row-to-row distance is 10D(D means diameter of the model piles),the deep of the pile anchorage is 2/5L(L means the length of the model piles),the loading increase gradually and averagely,about 80kg per time.The experiment findings are:1.the water content under the load condition is positively related to the pile end,during the tests,when the water content of loose accumulative formation is 6%--22%,considering the pile end displacement,the support system is on normal operating conditions.2.when using stronger intensity of rainfall(quantity of rainfall 1000mL/min),the loose face of the accumulative formation rapid changes into liquefaction,the strength of earth mass intermediate piles decrease as well,and then its surface subsides,forming lateral and longitudinal crevices.When the water content of earth mass in the active region is 17%,upper gliding mass has been changed into discrete,the mass stress changed from extrusion into break off and isolated,during the changing state,the pressure trend acting on the piles changes from increase to decrease then increase sharply when the isolated part underriding.3.The effect of rainfall increases the bending moment of pile because friction force of soil around the pile is increased.under the effect of rainfall,the maximum bending moment of piles fixed end can reach 3 to 4 times value of the sliding end,easily lead to groundwater soil anchor end softening occurs leading to the landslide displacement increases,anti-sliding section increases the angle in the process of displacement,eventually lead to pile soil with soil loose and pile out of body.Therefore,the existence of groundwater has an adverse effect on the support structure.