【作者】 冉涛；

【导师】 罗强；

【作者基本信息】 西南交通大学 ， 交通运输工程， 2011， 硕士

【摘要】 本文通过调研振动压实技术的相关文献,分析了路基的振动压实的原理；采用试验手段,在实验室针对小型冲击夯进行了室内模型填筑压实试验；在京沪高速铁路高资路桥过渡段工点,采用冲击夯和振动压路机,开展了现场碾压过程的动应力测试。通过对数据的处理和分析,得到了以下试验结论：(1)振动压路机在桥台台背附近进行碾压,振动压路机的振幅对桥台台背承受的动应力及分布规律有重要影响,表现出随振动轮与桥台距离的增大而呈减小的趋势；振动压路机沿桥台台背横向碾压施工,振动轮侧缘距桥台台背大于1.5m后,桥台台背承受的动应力较小；振动压路机在台背附近沿线路纵向碾压施工,振动轮前缘距桥台台背大于1m后,振动荷载对桥台台背基本没有影响。(2)振动压路机的振动状态对路基碾压土层内的动应力分布有显著影响。试验中YZ18JC型振动压路机在强振作用下的最大动应力约为静压的1.8倍；振动压路机在对路基的压实过程中,路基土层中的动应力在振动轮下最大,在测试范围内0.3m-1.2m衰减均超过90%,其竖向影响深度约为1.2m,横向振动轮左右0.5m。振动压路机的碾压速度对路基碾压土层内的动应力分布影响不大。(3)小型冲击夯在桥台台背附近进行压实作业,桥台台背H=0.3m处所承受的动应力最大值为32.5 kPa与YZ18JC型振动压路机在桥台台背附近横向强振碾压测试的最大值31.1kPa相当；小型冲击夯在路基进行压实作业,其在H=0.3m深度处,动应力最大值已经达到106.06 kPa,约为YZ18JC型振动压路机在强振工况下的1/3,故其采用其压实时,宜采用较薄的压实摊铺厚度；小型冲击夯对高速铁路基床填料(级配碎石)能够进行有效的压实,通过控制级配碎石的分层填筑厚度20cm和最佳含水率5.27%,最大的干密度可达2.42g/cm3,灌砂法检测压实系数≥0.97,K30地基系数为278-384 MPa/m。其压实效果完全达到高速铁路设计规范中对基床填料的压实规定。(4)将振动压路机对路基的作用力简化为线荷载,将路基简化为半无限空间体,采用Boussinesq计算路基碾压土层中的动应力。在静碾工况下,将测试值进行曲线拟合发现,动应力大致呈对数衰减规律,实测碾压土层内动应力分布曲线的趋势和形态与Boussinesq计算结果大致相同；在振动工况下,由于忽略了路基的刚度和阻尼,计算结果大于实测结果,实测值约为计算值的75%倍,其衰减规律与Boussinesq解一致。更多还原

【Abstract】 This dissertation dicuss the mechanism of vibratory compaction by the research of relevant documents of vibratory compaction technology. We made two experiments:a model of soil filling test is made by vibration plates indoor and dynamic vibrational stress test in field compaction on gaozi site of Beijing-Shanghai high-speed railway. Though data processing and analysis, conclusions are made below.(1)When the vibratory roller is rolling on the bridge back, its working condition can change the distribution of dynamic stress of bridge back. The dynamic stress decrease when the distance between the vibration wheel and bridge back increase.when using transverse rolling construction, the sphere of influence is mainly the distance between lateral margin of the vibration wheel and bridge back,that is about 0-1.5m.while using Longitudinal rolling, the sphere of influence is mainly the distance between lateral margin of the vibration wheel and bridge back,that is below lm.(2)The different working conditions of vibratory roller have a strong influence on the distribution of dynamic stress of subgrade. The maximum dynamic stress under the condition of YZ18JC strong vibration is about 1.8 times that under static pressure. In the compaction process, under the vibration wheel is the largest distribution of dynamic stress. The sphere of influence of the vibration wheel on the vertical orientation is 0-1.2m, on the horizontal orientation is 0.5m.(3)When the vibration plates is making a vibration compaction on the bridge back, the maximum dynamic stress the bridge back bear (H=0.3m,the dynamic stress is 32.5 kPa) is as much as that of the YZ18JC vibratory roller test value, when the vibration plates is making a vibration compaction on the subgrade, the maximum dynamic stress under 0.3m can reach 106.06 kPa, is about a third of the value under the condition of weak vibration. The compaction paving thickness can’t be too large, small vibration plates can compact bedding packing (graded broken stone) effectively.By the control of the filling layer thickness 20cm and the optimum water content 5.27%, the compaction factor will be greater than 0.97,the maximum dry density will reach 2.42 g/cms3,and the foundation coefficient will be 278-384 MPa/m. The Compaction effect totally reach the specified value on the bedding packing compaction of the Design of high-speed railway.(4)Simplify the force vibratory roller to the foundation to a line load and use Boussinesq.J to calculate the additional stress. Compare the calculated value with the measured value, and make a curve match. A conclusion is made; When the vibration roller static passes on the subgrade, the dynamic stress is about Logarithmic attenuation. The distribution of dynamic stress of subgrade match the Boussinesq calculate results. When the vibration roller vibratory passes on the subgrade. as ignoring the stiffness and damping of the subgrade, the measured value is about 75% of the calculate results, the dynamic stress’s attenuation match the calculated value.更多还原