【作者】 卢正；

【导师】 姚海林； 葛修润；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 工程力学， 2009， 博士

【摘要】 交通动荷载作用下公路结构的响应特性与静态情况有很大不同,而目前国内实际工程中的分析方法和设计理论仍是基于静荷载假设。本文以理论推导、数值分析和模型试验相结合的手段,对交通荷载作用下公路结构的动力响应进行了较为系统的研究,同时提出了确定路基填土高度和模量的动力设计方法。首先,考虑车辆荷载的多轮性质,利用三角级数、Fourier变换及叠加原理等方法推导获得了粘弹性地基上连续配筋混凝土路面在多轮荷载作用下的稳态响应解;另外考虑基底剪切阻尼作用,详细分析了荷载参数、路面参数和地基参数对路面动力响应的影响。利用不平整路面的实测资料,提出了适合公路路面的不平整数学模型,通过对车辆荷载的简化,建立了不平整路面和车辆的耦合振动模式,并采用数值计算探讨了荷载速度、路面不平整波长和路面不平整幅值等对路面响应的影响规律。其次,考虑更符合实际的连续介质地基模型,将地基看成是层状弹性介质和层状饱和多孔介质,应用弹性动力学原理和Biot波动理论分别考虑了刚性路面和柔性路面的情况,利用矩阵传递法推导获得了置于刚性基岩上的层状地基和分层半无限地基的刚度矩阵,并采用Lame对位移场的分解理论和积分变换方法求得了路面-层状地基系统在交通荷载作用下的三维振动解。在此基础上,以路面-弹性层-饱和层系统为例,利用数值计算详细讨论了荷载速度、振动频率、饱和土层渗透系数、弹性土层厚度和以及弹性土层和饱和土层刚度比对地表位移和孔隙水压力分布的影响规律。第三,基于线性热弹性理论,对Biot波动方程进行修正,建立了考虑温度效应的饱和多孔地基在简谐荷载作用下的动力响应控制方程。通过对控制方程的求解,获得了热流固耦合地基动力响应问题的温度场、应力场、位移场和孔压场在时域内的积分形式解答。并对按热流固耦合动力理论(THMD)、饱和多孔弹性动力理论(HMD)和热弹性动力理论(TMD)得到的响应结果进行了比较。第四,开展了公路结构在交通荷载作用下的室内模型试验研究。根据高速公路结构的实际分层特性,分别建立了以全风化花岗岩和全风化花岗岩水泥稳定土为路基填料的室内公路结构模型,通过模型试验详细研究了各结构层的动应力、动弹性变形和累积塑性变形随不同交通荷载大小、荷载作用次数的变化规律。并将理论分析结果与模型试验结果进行了比较,验证了利用三维分层理论来计算公路结构动力响应的正确性和合理性。还探讨了公路结构面层的模量和厚度对动力响应结果的影响。最后,结合三维分层理论和模型试验成果以及室内动三轴试验得到的软土累积塑性变形经验公式,建立了软土地区公路结构由交通荷载引起的长期沉降计算模式,分析了公路各结构层性质对长期沉降的影响规律。考虑路面路基的变形协调,提出了一种基于动变形控制的确定路基填土高度和模量的动力设计方法,并以三种典型沥青公路结构为例,进行了路基动变形控制设计。更多还原

【Abstract】 The characteristics of highway structure layers under traffic loads are different from the static mechanical conditions.However,the traffic loads are always considered as static in present theoretical analysis and design of highway.To understand and master the influence of traffic loads on the highway structure layers so as to provide some technical supports for the design of the pavement and the subgrade, in this dissertation,the dynamic responses of highway structure layers are studied systematically based on the combination of theoretical analysis,numerical calculations and the full size model experiment.The main conclusions are as follows:Firstly,the dynamic response of Continuously Reinforced Concrete Pavement (CRCP) resting on viscoelastic Winkler foundation is investigated,and the analytical solutions of CRCP under multiple-wheel loads are obtained by using the trigonometric series,Fourier transform and the superposition method.Numerical results are derived when the horizontal resistance at the foundation’s bottom is considered,and the influence of various parameters such as the loads,pavement and foundation parameters on the dynamic responses is performed.To evaluate the dynamic responses of rough pavement subjected to traffic loads,research is focused on the geometric roughness of pavement,and by regarding the pavement roughness as sine function and simplifying the quarter vehicle to a two DOF vibration system,the analytical and numerical results of pavement are obtained and used to analyze the influence of moving load velocity,rough pavement parameters and foundation parameters on the dynamic displacement responses.Secondly,the three dimensional multiple layered ground model are established based on the elastic dynamic theory and Biot’s dynamic equation.Dynamic responses of rigid pavement and flexible pavement resting on the layered ground are studied respectively.By employing transfer matrix method,the integrated rigid matrix of multiple layered ground is obtained.The vehicle loads are considered as rectangular harmonic moving loads,and the analytical solution of the pavement and layered ground interaction is deduced with Lame decomposition theorem of displacement field and Fourier transform method.By employing IFFT,the influence law is studied using numerical analysis which concerns the influence of the factors(velocity, frequency of moving loads,permeability coefficient,the depth of elastic soil layer and the rigidity ratio between elastic single-phase layer and saturated layer) to the distribution of the foundation’s vertical displacement and pore pressure.Thirdly,the thermodynamic responses of porous elastic medium subjected to time harmonic loads are investigated analytically in the context of the theory of linear thermoelastic.The material of foundation,obeying Biot’s dynamic poroelastic theory, is idealized as a uniform,fully saturated poroelastic half-space stratum.The coupling thermo-hydro-mechanical dynamic governing equations are derived by employing Biot’s dynamic poroelastic theory and linear thermoelastic theory.The analytical solutions in the form of integral of stress,displacement,temperature distribution and excess pore water pressure are obtained by using Fourier transform.Numerical results are obtained to analyze the differences among coupling thermo-hydro-mechanical dynamic theory(THMD),coupling hydro-mechanical dynamic theory(HMD) and thermo-elastic dynamic theory(TMD).Fourthly,full size laboratory model experiment is conducted based on the construction of highway.The variation of the dynamic stress and strain and total deformation of highway structure layers is discussed under the condition of two subgrade soil including full weathering granite and cement stable soil.The results of laboratory model experiment are consistent with that of theoretical analysis.Further discussion is performed on the effect of the modulus and depth of pavement to the dynamic responses.Finally,combining the theoretical analysis,laboratory model experiment and the accumulative deformation model established though the cyclic triaxial tests on soft clay,an approach is presented to calculate the long-term settlements of soft ground induced by traffic loadings.Numerical results are obtained to analyze the influence of the characteristics of highway structure layers on long-term settlements.Moreover,a new method for design of highway subgrade is proposed to fit the depth and dynamic strength of subgrade considering compatibility of deformation between pavement and subgrade and three typical pavement structure are designed for illustration using this method.更多还原