车路耦合条件下沥青混凝土路面变形特性时域分析

Analysis on Asphalt Concrete Pavement Deformation Characteristics Time-domain Considering Vehicle-pavement Coupling Effect

考虑路面不平整度激励下车路耦合振动的研究主要是在频域范畴内利用线弹性模型进行。利用有限元方法建立了考虑路面不平整度因素的车路耦合非线性数值模型,分别研究了不同路面不平整度、不同车辆行驶速度、不同车辆载重和不同路基强度等影响因素下的道路结构振动响应情况。考虑道路结构本身的复杂性,每一结构层对振动的响应均会表现不同,为了突出和便于比较影响因素下的变化趋势,故取路表位移响应作为研究对象。研究发现:无论在何种路面条件下行驶,道路位移响应都可以明显地分为3个阶段,暂称为:车辆临近、车辆进行和车辆离去;路面平整度越差,路面结构位移也越大,C级路面下的最大位移量是A级路面的1.31倍;路面响应的最大位移峰值主要受车辆自重影响,而在车辆进行阶段出现的一些小的位移振动峰值主要受路面不平整而引起的随机振动影响,而且这些小的振动峰值随着路面不平整度的变差而增大,随着车辆行驶速度的增大,路面最大位移量变小,但是最大位移量的变化幅度很小,趋势不是很明显;车辆超载后,路面最大位移量增大明显,超载比例达到100%情况下,路面变形增大幅度在50%~109%之间;路基强度降低后,路面最大位移量明显增大,路基强度降低28%后,路面变形增大幅度在15%左右。

The study of the vehicle-pavement coupling vibration excitation is mainly based on the linear elastic model in frequency domain. The nonlinear numerical model for vehicle-pavement coupled system considering pavement roughness is established using finite element method. Using the model, the vibration response of road structure under the conditions of different pavement roughnesses, different vehicle speeds, different vehicle loads and different subgrade strengths are studied. The road structure itself is complex and each structural layer will respond differently to vibrations. In order to highlight and facilitate the comparison of the change trend under these influencing factors, the road surface displacement response is taken as a research object. It is found that （ 1 ） no matter driving on what kind of road, road displacement response can be clearly divided into 3 stages which are temporarily referred to as： vehicles approaching, vehicles entering and vehicles leaving; （2） the worse the pavement roughness, the larger the deformation of the pavement, The max deformation of the level C pavement roughness is 1.31 times as large as that of the level A pavement roughness ; （3） the maximum displacement peak of pavement response is mainly affected by vehicle＇s own weight, some of the small displacement vibration peaks that occur during the vehicles entering stage are mainly affected by the random vibration caused by uneven road surface, and these small vibration peaks increase with the being worse of pavement roughness; （4） with the faster of the vehicle speed, the max deformation of pavement is smaller, but the change extent is not obviously; （5） the max deformation of pavement increased obviously for overload, the deformation ratio increased by 50% - 109% when the overload ratio reached 100% ; （6） the max pavement deformation increased obviously for the subgrade strength reduction, and the pavement deformation increased by about 15% when the subgrade strength is reduced by 28%.