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碎石化的旧水泥路面上水泥混凝土加铺层脱空预估研究
Research on the Void Prediction of Cement Concrete Overly on Old Cement Pavement after Rubblization
【作者】 于恒峰;
【导师】 张洪亮;
【作者基本信息】 长安大学 , 道路与铁道工程, 2011, 硕士
【摘要】 MHB碎石化是一种旧水泥路面原位再生利用技术,该技术具有节约资源、降低工程造价等优点。旧水泥路面经该技术处理后一般可以作为新路的基层,其上的加铺层可以采用沥青混凝土或水泥混凝土。水泥路面在我国有很大的使用优势,但我国水泥路面冲刷脱空普遍严重,因此,本文针对旧水泥路面碎石化后水泥加铺层冲刷脱空展开研究。论文首先结合水泥混凝土的凝结过程,对面层与基层接触界面的破坏过程进行分析,提出以三种基本破坏形式为基础的碎石化层材料冲刷机理;分析碎石化层材料的冲刷性能,提出碎石化层材料冲刷性能的评价指标—冲刷系数。旧水泥路面碎石化后分三个层次,论文以咬合嵌挤理论为基础,分析各层次的强度形成机理。为进一步认识碎石化层冲刷的原理,论文采用动态荷载,并以现代多孔介质理论为基础,应用有限元软件ABAQUS对荷载-水耦合作用下的水泥路面进行数值模拟,计算结果表明:动载作用下板底孔隙水压力具有波动性,且产生正、负逆转。探讨材料参数变化对孔隙水压力的影响;结合试验路,对动载作用下不同路面结构的板底孔隙水压力进行对比分析,得出冲刷性能较好的路面结构;最后,推荐55KPa作为碎石化层材料室内冲刷实验的动水压力。对路面板底脱空形状和高度进行分析;考虑基层材料冲刷性能,定量分析荷载作用次数与基层材料冲刷损失的关系,计算出水泥路面板角和板纵缝下的脱空预估模型。引入天气修正系数,对脱空预估模型进行修正,分析脱空开始出现的时间。综合以上分析,系统提出旧水泥路面碎石化后水泥加铺层脱空预估方法;最后,提出设置层间隔离层的新型抗冲刷路面结构等防治脱空措施。
【Abstract】 MHB rubblization is a technology used to make old cement concrete pavement recycled as a part of new pavement in road reconstruction. This technology can conserve resources and reduce project cost. Generally, old cement concrete pavement could be used as base course after being rubbilized, and the overlay over the road base can be build with asphalt concrete or cement concrete. Cement concrete pavement has great advantages in our country. However, the erosion and cavity of the plain concrete pavement is common serious. This dissertation study the cement concrete overlay on rubblized old cement concrete pavement.Combined with the condensation process of cement concrete first, the dissertation analyzed the destroying process interface between the surface and road base from the angle of fracture mechanics. The new mechanism of the rubblization layer material being scoured based on three basic destroyed modes were provided; and the erosion performance of it had been analyzed. Also the erosion coefficient of the rubblization layer material was put forward.For further understanding of the scouring principle of rubblization layers, the dynamic load is used, and based on the theories of porous media, finite elements software ABAQUS was used to simulate concrete pavement under the coupled vehicle-water loading action. Calculation results indicated that pore water pressure was variable beneath slab of concrete pavement under the dynamic load action and there was a reversion between positive and negative pore pressure. The influences of materials on the pore water pressure were discussed. With test roads, the dissertation comparatively analyzes the pore water pressure on the top of different pavement structures under the dynamic load action, and the pavement structure with good anti-erosion performance was designed. Finally,55KPa was recommended as the dynamic water pressure of materials of rubblized layer in the laboratory scour tests.The shape and height of void was analyzed. According to rainfall and the anti-erosion performance of the base course materials, the relationship between the times of load function and the lost of materials caused by erosion was analyzed quantificationally. Reduction formula for scouring times of axle load and the correction factor for precipitation days within the life expectancy were provided. Then the prediction models of voids beneath slab corner and along longitudinal joint edge were established.By introducing the precipitation weather correction coefficient, the cavity predicion model is corrected. Taking into account the analysis above, the cavity precipitation method is firstly and systemly proposed. At last, the new measures prevent pavement structure from scoured such as setting isolating course between layers is given.
【Key words】 old cement concrete pavement; rubblization; base erosion; pore water pressure; void beneath slab; prediction model; design method;
- 【网络出版投稿人】 长安大学 【网络出版年期】2012年 01期
- 【分类号】U414
- 【下载频次】142