The Dynamic Stability Analysis Of Silty Soil Roadbed

A section of Zhengzhou to Minquan highway is the of the runway of plane at the same time,its roadbed is floury soil or silty soil,the embankment mainly used silty soil to fill.Considering that floury soil embankment under earthquake load and traffic load may appear engineering hidden danger such as uneven settlement, rut, crevice and liquefied subgrade,this article used FLAC3D to set up a three-dimensional numerical analysis model of this segment of subgrade,it respectively to study the the dynamic stability of floury soil subgrade under the seismic load and vehicle load, the plane load,the main conclusions are as follows:(1) When using Mohr coulomb model to describe embankment silt, liquefaction will not occur in the process of earthquake,but instantaneous yield phenomenon will appear in subgrade and the base pf slope.When using Byrne liquefaction model to describe the dynamic response of roadbed silt,with the increase of earthquake intensity, yield range increased,the road surface settlement and displacement of the slope increased,the pore pressure accumulation phenomenon of roadbed is obvious,possibility of liquefaction increased. In particular,when the peak acceleration is0.1g,slope and bottom riped to destroy,possibility of liquefaction exist in the roadbed,when peak acceleration reach to0.2g,the road surface, slope and bottom riped to destroy all,there will a wide range of liquefaction in the subgrade.(2) When the vehicle load, impact,there is a pore pressure accumulation phenomenon in the subgrade.With the increase of loading frequency,quantitative value of pore pressure accumulation increased,and when the frequency is smaller (1hertz and2hertz),with the increase of loading number,quantitative value of pore pressure accumulation tends to be stable gradually,but when the frequency is5hertz,with the increase of loading number,quantitative value of pore pressure accumulation has been increasing,embankment slope local riped to destroy,there is a possibility of liquefaction in the roadbed.It seems that too much traffic has very big effect on embankment slope stability. (3) The various law of plane loads is similar to the vehicle load,with the increase of load frequency and the increase of loading times,quantitative value of pore pressure accumulation increased,when the frequency is same,various variables under plane loads is larger than the car load.