【作者】 郑良飞；

【导师】 折学森；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2008， 博士

【摘要】 恩施地区修筑公路,常会遇到采用软岩填料填筑路基。该填料岩性较软,强度较低,稳定性较差。本文通过现场调查、室内外试验、理论分析及工后观测,以红官公路为依托工程,研究了恩施地区软岩(主要是泥质页岩及砂质页岩)路用性能。主要研究工作包括如下内容:1.对恩施地区软岩填料的化学成分、级配特征、破碎特性、表面特征、非均质和非连续特征、尺寸效应等基本物理性质进行了试验研究。通过击实、CBR、回弹模量、压缩、直剪及三轴等室内试验,研究了软岩填料不同粗颗粒含量、击实功、替换法对最大干密度的影响规律;研究了软岩填料不同粗颗粒含量、含水量及干密度对其压缩性、黏聚力及内摩擦角的影响规律;研究了软岩填料在不同粗颗粒含量、含水量及不同围压条件下的剪胀性。2.对软岩填料路基进行了动力有限元分析。结果表明:软岩填料路基变形对交通荷载变化很敏感。增大荷载,路基塑性变形及路基振动位移、速度、加速度幅值随之显著增加。行车速度对路面变形的影响同样不容忽视,行车速度越大,路面变形越小。随着软岩填料密度的增加,垂直位移分量、水平位移分量最大值、最大位移量、坡顶最大垂直位移分量(即路基表面最大沉降量)呈逐渐递减趋势。3.将Grey模型非等时距时间序列采用拉格朗日插值函数转变为等时距序列,引入高阶弱化算子对原始数据进行弱化。通过对几组数据的累加、均值生成、最小二乘估计,计算出系统发展系数和驱动系数,得出估计模型。引入了VerhuLst模型进行组合修正,建立路基沉降预测的最优组合模型。该模型预测值的预测偏差平方和(方差)最小,提高了预测值的准确、稳健性,优于单一的灰色预测模型和Verhulst模型,能更好地对路基沉降量进行预测。4.根据软岩填料强度的非线性,应用最小势能理论,建立了软岩填料路堤边坡稳定性计算方法。该方法不需要进行条块划分,通过分析边坡整体的势能变化进行求解。安全系数可以直接求解,不需要迭代,计算过程简单,结果精确,实用性强。5.本文综合考虑稳定性、抗冲刷性、经济性等因素,采用综合赋权多属性决策法对红官公路软岩填料路堤横断面的设计方案进行了优化分析。该方法对软岩填料高路堤横断面进行多指标系统评价不失为一种简单可行的方法,并能够减少主观因素的影响,为合理横断面形式的确定提供更加合理的依据。6.通过大量的资料调研和工程调查,同时结合红官公路试验段,提出了软岩填料路基施工机械选择及组合、现场摊铺和整平及施工压实工艺等施工技术。更多还原

【Abstract】 Expressway construction will meet soft rock materials which will be used to fill embankment in EN-SHI area of Hu-bei province. The soft rock materials have such characteristics as the soft property, the low strength and the bad stability. The engineering characteristics of soft rock material in EN-SHI area are studied after investigating in site and testing indoor, analyzing with theory and observing after construction, the HONG-GUAN expressway is typical. The main work includes followings:1. This paper analysis the basic properties of soft rocks in EN-Shi area, include the chemical and particle composition, gradation characteristic, broken characteristic, character of surface, non-isotropic and non-continual characteristic, size effect, etc. After the test of compaction, CBR, the snapping back module, compressive strength, The variation law of the maximum density of Soft Rock Filling Materials has been obtained when its effect factors as the coarse aggregate contents, the maximum grain sizes, compactive efforts, replace method, etc. shear tests for soft rock material are performed. The effect law between cohesion of the material with coarse aggregate contents, water contents and the maximum density are studied. The dilatancy of soft rock filling material under different confining pressure also studied.2. It is shows from dynamic finite element analysis of soft rock filling materials subgrade under traffic load that deformation of soft rock filling materials roadbed are sensitive to traffic loads, when the load increases, the plastic deformation, vibration displacement, velocity and acceleration increase significantly; strictly control overloading is conducive to reducing road settlement. Speed can not be ignored, when speed is greater, the deformation is smaller. With the increase of soft rock filling materials density, the settlement deformation of subgrade becomes small, which means vertical displacement weight, the maximum horizontal displacement components, the largest displacement and the maximum vertical displacement components slope become small.3. GM(2,1) model of sedimentation forecast was set up based on Grey theory .Anisochronous displacement was changed to isochronous serial with Lagrange function. Higher Order weakening operator are introduced into it to weaker the original data in the hope of lowering the sensitivity of outer factors and solving it convenience. The estimation model is set up .Then the Overhauls model is introduced to be used as a combination amendment, and the optimal combination model of subgrade settlement prediction is established. This model is used and the result shows that the predictive value square deviation (variance) is smallest. The model improved accurate and stable of predictive value, which is better than a single Grey prediction model and Verhulst model.4. According to the nonlinear of strength of soft rock filling materials ,the slope stability analysis method of soft rock filling Materials embankment is established. The method does not require bar division, through analysis of the overall slope of the potential changes to solve the problem. safety factor can be directly solved and the results are accurate, which doesn’t need numerical analysis and iterative calculation.5. Considered stability, anti-erosion, economic and other factors, this paper, using a comprehensive multi-attribute decision-making law, optimizes the cross section design plan of Soft Rock Filling Materials subgrade in order to select the most economic and stability method. It’s a simple and feasible method, which can reduce the impact of subjective factors and provide a more rational basis for determining a reasonable cross-section form.6. In the foundation of the information investigation engineer investigation, through the typical test section experiment in HONG-GUAN highway, this paper has raised some construction technologies such as the construction machinery choice and the combination, the scene spreads paving and the leveling-up, the construction compaction craft and so on.更多还原