Research On The High-filled Loess Slope In Deformation Mechanism

With the rapid development of economic construction,large loess high filled engineering has become an integral part of all kinds of infrastructure construction projects.However,loess high-filled slope instability has become one of the most dangerous geological activity,which seriously affect the loess area of economic construction and urbanization.Regard a SanMenxia high-filled loess slope as the study site,combined with early survey data,field investigation and laboratory test,master fill soil engineering properties,high fill slope geological numerical model is established.Based on the deformation characteristics and deformation monitoring information accurate analysis,through theoretical analysis of anti slide pile,the deformation mechanism of the piles,temperature,atmosphere,rainfall infiltration of unfavorable factors reveal the influence law of high-filled loess slope stability,analysis the supporting mechanism of interaction between the structure and slope.Finally,determine the high-filled loess slope deformation occurs when all the critical threshold,thus analysis the loess high-filled slope instability mechanism further.Through the above work,the main research results are as follows:(1)Combined with the actual deformation characteristics of the research region supporting structure of and deformation development process,the crack evolution and embankment fill loading height of the generalized model is established.Utilize the IBIS-L slight monitoring system to monitor the deformation process of the full range of real-time deformation.Through the two stage nearly three months of monitoring data analysis,draw the monitoring data and the deformation tendency is consistent;generate displacement nephogram to reflect the fill slope retaining structure showed obvious regional characteristics;(2)Combined with the IBIS-L system monitoring and temperature monitoring,it can be concluded that the deformation displacement and the temperature change correlation exists.Displacement deformation curves and temperature have the same changing trend.Finite element method is used in the calculation theory and that anti slide pile on a point,consider that the temperature change under the condition of different temperature deformation is proporal to explain the concrete phenomenon of heat expansion and cold contraction;combine with the site test and temperature and atmospheric,conclude that atmospheric pressure fluctuations in the reverse,namely daily high temperature period corresponding atmospheric low tide,low temperature periods corresponding atmospheric tides;and the soil strength and high pressure fluctuation trend of the same in low atmospheric tides,corresponding the day's high temperature period,at this time the soil shear strength is the lowest;(3)Based on the field monitoring,the site test and the finite element numerical simulation of coupled calculation,draw the rainfall infiltration process,the slope will be emerge formation of transient saturated zone,when on surface of slope development have a certain depth of the crack,the saturation region will be extended down,and concentrated in the distance on the slope surface of 4 to 8 m depth.At the same time with the increase of slope soil saturation and the cohesion of the values degreed obviously,the friction angle degreed mildly;(4)According to the monitoring data,regression analysis and the slope seepage simulation,obtained the displacement of slope caused by rainfall infiltration tends to lag in rainfall,and the presence of the cumulative effect of rainfall.Slope displacement increment by more than a dozen hours after the initial rainfall began to grow,after that the the rainfall in the three to four genius began to grow,the distribution of pore water pressure also from the conversion of the overall negative on the grounds to a state of negative,positive and negative.At the same time,we calculate the slope deformation by the creep sliding stage into slip phase,and then to collapse sliding stage of critical speed and the critical acceleration.