基于两尺度模型的CRCP第二阶段冲断机理与预估研究

发布时间：2018-05-28 19:10

本文选题：第二阶段冲断 + 两尺度模型　；参考：《长安大学》2015年博士论文

【摘要】：冲断是指由两个间距很小(小于0.6m)的横向裂缝与短的纵向裂缝和路面边缘(或纵向接缝)所围成的区域。冲断是CRCP的主要病害形式,在冲断形成初期,路面状况良好,对行车舒适性及安全性影响不大。但在外界环境及车辆荷载的反复作用下,冲断区域开始出现后续开裂及剥落,严重影响行车舒适性及安全性,需对路面进行修复。基于此,本文提出以纵向裂缝的形成时刻为界将冲断的发展过程分成两个阶段,第一阶段是纵向裂缝的形成阶段,第二阶段是由横向裂缝、纵向裂缝和路面边缘(或纵向接缝)形成区域的退化。尽管国内外对于CRCP冲断病害已经进行了大量的研究,并取得了丰硕的成果,但多从宏观尺度对CRCP第一阶段冲断展开研究,在基于两尺度模型的第二阶段冲断区域退化和维修标准方面缺乏研究。CRCP是高等级路面的重要形式之一,为了适应我国高等级公路发展的需要,对CRCP的第二阶段冲断展开研究具有十分重要的工程意义。本文基于数值模拟试验和室内试验研究,从宏观、细观两尺度出发对第二阶段冲断区域退化和维修标准进行研究。主要研究内容如下:首先,考虑冲断区域路面的振动,建立冲断区域车辆振动模型,进行冲断区域人-车-路耦合振动分析,获得冲击荷载和乘客的加速度时程曲线,并进行参数敏感性分析。冲击荷载将用于冲断区域后续开裂和裂缝处混凝土剥落机理研究,乘客加速度将用于第二阶段冲断区域维修标准的研究。其次,考虑水泥混凝土在细观尺度上是由集料、胶凝材料及其界面组成,利用离散元软件从细观尺度上进行水泥混凝土抗压强度、弯拉强度和抗剪强度数值模拟试验,对混凝土强度形成及破坏机理进行研究,得到混凝土的抗压强度、弹性模量、弯拉强度和抗剪强度;考虑冲断区域特点,结合所得弹性模量,建立CRCP有限元宏观模型,对车辆荷载、温度梯度和湿度梯度作用下的冲断区域进行宏观受力分析;结合混凝土细观研究所得弯拉强度,对冲断区域后续开裂进行研究,并分析混凝土细观组成参数和宏观影响因素对冲断区域的后续开裂的影响。再次,在混凝土剥落形成原因分析的基础上,将剥落分为剪切剥落和分层剥落,并建立分层剥落数学模型;考虑冲断区域特点,利用有限元软件建立CRCP宏观力学分析模型,对车辆荷载、温度梯度和湿度梯度作用下的冲断区域裂缝处的剪应力和分层处的弯拉应力进行分析;结合混凝土细观模拟试验所得抗剪强度和弯拉强度,对冲断区域混凝土的剥落进行研究,并分析混凝土细观组成参数和宏观影响因素对冲断区域混凝土剥落的影响。然后,考虑冲断区域边缘裂缝对混凝土性能的影响,基于加速加载试验、干湿循环试验和冻融循环试验,对冲断区域混凝土的退化进行试验研究;在冲断区域后续开裂和剥落两尺度研究及混凝土退化试验研究的基础上,结合混凝土弯拉强度、抗剪强度分析及水泥混凝土细观模型试验,对第二阶段冲断区域退化机理进行研究,给出第二阶段冲断区域退化预估方法。最后,提出冲断区域台阶高度的概念,考虑车辆通过单个冲断区域引起的振动属于瞬态振动,参考最大瞬态振动值(MTVV)的概念,以MTVV作为行车舒适性评价指标,通过对瞬态振动行车舒适性评价标准的研究,结合行车舒适性影响因素分析,给出冲断区域维修标准的确定方法和步骤。同时,基于冲断区域退化机理的研究成果,在室内试验研究的基础上对第二阶段冲断区域退化延缓措施进行研究。
[Abstract]:Flushing refers to the area enclosed by two small (less than 0.6m) transverse cracks and short longitudinal cracks and road edges (or longitudinal joints). The thrust is the main form of CRCP disease. In the early stages of the formation, the road condition is good, and it has little effect on the comfort and safety of the vehicle, but the external environment and the repeated action of the vehicle load On the other hand, the following cracking and exfoliation began to occur in the thrust area, which seriously affected the comfort and safety of driving, and the road was repaired. Based on this, the development process of the longitudinal fracture was divided into two stages, the first stage was the formation stage of the longitudinal crack and the second stage was the transverse and longitudinal fissure. Fracture and pavement edge (or longitudinal joint) degenerate. Although a lot of research has been carried out on CRCP breakage at home and abroad, and great achievements have been made, the first stage of CRCP flushing from the macro scale is studied, and the lack of research on the degradation and maintenance standards of the two scale model based on the second stage of the scour zone and the maintenance standards. .CRCP is one of the important forms of the high grade road. In order to meet the needs of the development of the high grade highway in China, it is of great significance to study the second stage thrust of the CRCP. Based on the numerical simulation test and the laboratory test, the degradation and maintenance standard of the second stages of the thrust zone are made from the macroscopic and the fine two feet degree. The main research contents are as follows: first, the vibration of the pavement in the thrust area is considered, the vehicle vibration model of the thrust zone is established, the coupling vibration analysis of the man car road in the thrust zone is analyzed, the impact load and the passenger acceleration time history curve are obtained, and the parameter sensitivity analysis is carried out. The impact load will be used for the subsequent cracking of the thrust zone and the subsequent cracking of the thrust zone. Research on the mechanism of concrete exfoliation at cracks, passenger acceleration will be used in the study of the second stage maintenance standard. Secondly, the cement concrete is composed of aggregate, cementitious material and its interface on the meso scale, and the compressive strength, flexural strength and shear strength of the concrete are carried out from the meso scale using the discrete element software. The compressive strength, modulus of elasticity, flexural strength and shear strength of concrete are obtained by numerical simulation test. Considering the characteristics of the thrust area and the elastic modulus of the concrete, the CRCP finite element macro model is established, and the thrust area under the action of vehicle load, temperature gradient and humidity gradient is carried out. Macro stress analysis, combined with the tensile strength of the concrete meso study, to study the subsequent cracking of the broken area, and analyze the influence of the concrete meso component parameters and macro influence factors on the subsequent cracking of the broken zone. Thirdly, on the basis of the analysis of the reasons for the formation of concrete, the peeling is divided into shear peeling and stratified stripping. At the same time, a mathematical model of stratified stripping is set up. Considering the characteristics of the punching and breaking area, the CRCP macro mechanical analysis model is established by using the finite element software. The shear stress and the bending stress at the fracture zone at the breaking zone under the action of the vehicle load, the temperature gradient and the humidity gradient are analyzed, and the shear strength is obtained by the concrete meso simulation test. And the flexural strength, the exfoliation of the concrete in the hedge area is studied, and the influence of the concrete meso component parameters and macro factors on the concrete exfoliation in the broken zone is analyzed. Then, the effect of the edge cracks on the concrete performance is considered. Based on the accelerated loading test, the dry and wet cycle test and the freeze-thaw cycle test, the hedging break are taken. The degradation of regional concrete is studied. On the basis of two scale research and concrete degradation test of subsequent cracking and peeling in the thrust area, combined with concrete flexural strength, shear strength analysis and cement concrete meso model test, the degradation mechanism of the second stage of punching zone is studied, and the second stage punching zone is given. In the end, the concept of step height is put forward. Considering the vibration of a vehicle passing through a single thrust area, the vibration belongs to the transient vibration, and the concept of the maximum transient vibration value (MTVV) is used as the evaluation index of the driving comfort, and the comfort evaluation standard of the transient vibration driving is studied, and the comfort of the vehicle is combined with the comfort of the driving. In the analysis of the factors of sexual influence, the methods and steps for determining the maintenance standards of the punching zone are given. At the same time, based on the research results of the degradation mechanism of the thrust zone, the second stage degradation delay measures are studied on the basis of the laboratory test.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U418.6

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