【作者】 王崇涛；

【导师】 王秉纲；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2010， 博士

【摘要】 路桥过渡段差异沉降的存在会降低道路的行车速度,同时也直接影响行车的舒适性与安全性,成为影响道路正常运营的关键技术难题之一。论文对路桥过渡段的差异沉降及其动力响应进行系统分析,分别基于行车舒适性和安全性提出路桥过渡段差异沉降的控制标准,并对路桥过渡段路面结构的动力响应进行分析,从而为及时提出路桥过渡段的养护维修对策,并为合理设计路桥过渡段路面结构提供理论依据。论文采用最大沉降量与最大纵坡变化值作为路桥过渡段差异沉降的控制指标,以人体承受振动的瞬时加权加速度均方根值作为舒适性评价指标。通过采用问卷调查与压电式加速度传感器测量相结合的方式,分别从主观与客观两方面评价车辆通过路桥过渡段时的人体舒适性。回归得出小轿车座椅加权加速度均方根值与路桥过渡段最大沉降量和最大纵坡变化值的相关关系,以小轿车为测试评价车型,基于人体感觉“有些不舒适”提出路桥过渡段不同行车速度下的差异沉降控制标准。建立人车路垂向振动系统,编制MATLAB程序,分析五自由度车辆模型通过路桥过渡段时承受的动力响应,得到车辆速度、载重、错台高度、搭板长度、搭板纵坡变化值、汽车轴距等参数对车辆承受振动的影响规律。提出采用动荷载系数作为评价路桥过渡段车辆承受动载的评价指标,并计算得出行驶车辆作用于路桥过渡段时受到的附加动荷载和动荷载系数,基于大客车行车安全性提出路桥过渡段差异沉降的控制标准。建立路桥过渡段三维有限元模型,分别计算了冲击荷载作用下,未设和设搭板两种情况路桥过渡段路面结构的动态响应,根据计算结果引入沥青路面动载弯沉修正系数、动载基层和底基层层底拉应力修正系数和动载路基顶面压应变修正系数,以充分考虑车辆动荷载对路桥过渡段路面结构的影响,从而完善路桥过渡段路面结构设计方法。更多还原

【Abstract】 The differential settlement at bridge-subgrade transition section will reduce the running speed of the road, and also affect its comfort properties and safety directly. So it turns to be one of the key technical problems to affect the normal operation of the road. The paper analyzed the differential settlement at bridge-subgrade transition section and its dynamic response, proposed the differential settlement control criterion based on running comfort and safety, and also analyzed the dynamic response of the pavement structure at bridge-subgrade transition section. The research results can provide theoretical basis for timely maintenance and rational design of pavement of the bridge-subgrade transition section.The maximum settlement value and the maximum change value in longitudinal slope were proposed as the differential settlement control indexes at bridge-subgrade transition section, and the root mean square of the transient weighting acceleration of vibration was proposed as the comfort evaluation index. Combined with questionnaire survey and piezoelectric acceleration sensor measuring, the human comfort was evaluated when the vehicle go through a bridge-subgrade transition section from the subjective and objective way respectively. The correlation equations between the root mean square of weighting acceleration of the seat of the car and the maximum settlement value and the maximum change value in longitudinal slope at bridge-subgrade transition section were gained. Using cars as evaluation models, based on the human feeling of "somewhat uncomfortable", the differential settlement control criterion at bridge-subgrade transition section under different running speed was proposed. The vertical vibration system combined with the feeling of human, the vehicles and the road was established, and the dynamic response of 5-DOF vehicle model when going through the bridge-subgrade transition section were analyzed with the compiled MATLAB program. The models’ change laws influenced by the parameters of running speed, load, setting height, the length of the approach slab, longitudinal slope change ratio, wheelbase, etc. were analyzed. The dynamic load factor was proposed as the index to evaluate the capability of the bridge-subgrade transition section to withstand the dynamic load, and the additional dynamic load and dynamic load factor when the vehicle running through the bridge-subgrade transition section were calculated. Based on the running safety of the bus, the differential settlement control criterion in bridge-subgrade transition section was put forward. In order to make a full consideration of the influence caused by the vehicles’ dynamic loading and improve the pavement structural design method of the bridge-subgrade transition section, the three-dimensional finite element models for the bridge-subgrade transition section were built, and the dynamic response of the pavement with or without approach slab under the impact loading was calculated. Based on the calculation results, the dynamic load modified coefficients of the deflection on the asphalt pavement surface, the tensile stress at the base and subbase bottom, and the compressive strain on the subground surface were introduced.更多还原