【作者】 刘龙飞；

【导师】 屈畅姿； 刘正才；

【作者基本信息】 湘潭大学 ， 测绘工程， 2019， 硕士

【摘要】 近年来,高速铁路凭借着安全、平稳、舒适、便捷、高效等优势,得到了快速发展。但随着列车速度和线路使用年限的不断提高,随之而来的大周次列车荷载作用下路基的累积沉降变形问题也越发突出。本文依托国家自然科学基金项目,以武广线沿线地区级配碎石(B组料)高铁路基填料为研究对象,开展了循环动载作用下路基填料变形监测试验研究,分析了不同工况下路基填料长期累积变形发展规律。基于“混合模型法”建立了大周次循环动载作用下高铁路基的累积塑性变形计算模型,并将计算模型应用到高速铁路工程中,预测和分析了高铁路基在实际行车荷载作用下基床底层和整体路基结构的长期累积变形。主要研究工作及成果如下:(1)对变形监测过程中采用的位移传感器、加速度传感器和土压力传感器分别进行标定试验研究。结果表明:相同位移行程条件下位移传感器测量值均大于千分表;保护措施会导致振动加速度幅值衰减;标定介质不同土压力传感器标定系数会有明显差异。(2)开展循环动载作用下路基填料变形监测试验,分析了不同位置处竖向弹性变形、竖向累积塑性变形及侧向累积塑性变形随荷载作用次数、荷载水平、荷载频率及深度的变化规律。结果表明:竖向弹性变形随荷载水平增加而增大,近似呈线性变化关系;竖向弹性变形随荷载频率增加而减小;竖向累积塑性变形随着荷载作用次数增加而增大,随荷载水平增加呈现明显的发展趋势;竖向各测点弹、塑性变形与侧向各测点塑性变形沿深度方向变化规律基本一致。(3)基于“混合模型法”建立了考虑荷载作用次数及荷载水平的级配碎石基床填料路基长期累积变形计算模型,通过对实测变形数据回归分析和填土模型的仿真计算确定了模型计算参数。以武广线为研究对象,建立三维有限差分模型,模拟高速铁路无砟轨道路基面实际行车荷载,结合计算模型对实际行车条件下基床底层及整体路基的长期累积塑性变形进行预测分析。更多还原

【Abstract】 In recent years,with the advantages of safety,stability,comfort,convenience and efficiency,high-speed railway has developed rapidly.However,with the continuous improvement of train speed and service life of railway lines,the cumulative settlement and deformation of Subgrade under large-cycle train loads become more and more prominent.Based on the project of National Natural Science Foundation of China(No.51508489),this paper takes graded gravel(B-aggregate)high-speed roadbed filler along the WuhanGuangzhou high-speed railway as the research object,carries out the deformation monitoring test of roadbed filler under cyclic dynamic load,and analyses the long-term cumulative deformation development law of roadbed filler under different working conditions.Based on the "mixed model method",the cumulative plastic deformation calculation model of high-speed railway subgrade under large cycle dynamic load is established,and the calculation model is applied to high-speed railway engineering.The long-term cumulative deformation of the subgrade and the whole subgrade structure under the actual driving load is predicted and analyzed.The main research work and results are as follows:(1)Calibration experiments of displacement sensor,acceleration sensor and earth pressure sensor used in deformation monitoring are carried out respectively.The results show that the measured values of displacement sensors are larger than those of micrometers under the same displacement stroke conditions;the amplitude of vibration acceleration will be attenuated by protective measures;and the calibration coefficients of different earth pressure sensors in calibration media will be significantly different.(2)The deformation monitoring test of subgrade filling under cyclic dynamic load is carried out,and the variation laws of vertical elastic deformation,vertical cumulative plastic deformation and lateral cumulative plastic deformation with load number,load level,load frequency and depth at different locations are analyzed.The results show that the vertical elastic deformation increases with the increase of load level,and the relationship is approximately linear;the vertical elastic deformation decreases with the increase of load frequency;the vertical cumulative plastic deformation increases with the increase of load number,and shows obvious development trend with the increase of load level;the elastic and plastic deformation of vertical measuring points and the plastic deformation of lateral measuring points change along the depth direction.The law is basically the same.(3)Based on the mixed model method,a long-term cumulative deformation calculation model of Graded Macadam Subgrade Filling Subgrade Considering the number and level of loading is established.The model parameters are determined by regression analysis of measured deformation data and simulation calculation of filling model.Taking the Wuhan-Guangzhou high-speed railway as the research object,a three-dimensional finite difference model is established to simulate the actual driving load on the Ballastless Track Subgrade of high-speed railway.The long-term cumulative plastic deformation of the subgrade and the whole subgrade under the actual driving conditions is predicted and analyzed with the calculation model.更多还原