【作者】 张春霞；

【导师】 刘忠玉；

【作者基本信息】 郑州大学 ， 道路与铁道工程， 2013， 硕士

【摘要】 郑州到民权的一段高速公路兼作飞机的跑道,其路基为粉土或粉砂土,路堤主要用粉土填筑。考虑到粉土路基在地震荷载和交通荷载作用下可能出现不均匀沉降、车辙、裂缝、路基的液化等工程隐患,本文采用FLAC3D软件对该段路基建立三维数值分析模型,分别研究了地震荷载、车辆荷载、飞机荷载作用下该段路基的动力稳定性,得到的主要结论如下：(1)当采用摩尔库仑模型描述路基粉土时,地震过程中不会发生液化,但在路基坡脚处会出现瞬时屈服现象。当采用Byrne液化模型描述路基粉土的动力响应时,随着烈度的增大,屈服范围增大,路面沉降和边坡位移增大,路基内孔压累积现象显著,液化可能性增大。特别地,当加速度峰值为0.1g时,坡面和坡底将发生拉裂破坏,路基有液化的可能,加速度峰值达到0.2g时,路面、坡面和坡底均发生拉裂破坏,路基下将有较大范围的液化。(2)在车辆荷载作用下,路基中存在孔压累积的现象。随着加载频率的增大,孔压累积值增大,且当频率较小(1Hz和2Hz)时,随着加载次数的增大,孔压累积值逐渐趋于稳定,但频率为5Hz时,随着加载次数的增大,孔压累积值一直增大,路堤坡面局部会出现拉裂破坏,路基有发生液化的可能。这说明车流量过大对路堤边坡稳定性有很大影响。(3)飞机荷载作用下的各种规律与车辆荷载作用时相似,随频率增大和加载次数的增加,孔压累积值增大,且明显大于汽车荷载作用时。更多还原

【Abstract】 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.更多还原