基于非均布荷载的柔性基层沥青路面纵向开裂分析
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摘要
为研究柔性基层沥青路面纵向裂缝的产生机理和发展规律,实测了子午线货车轮胎在不同轴重和胎压下的接地印迹与应力。借助实测的子午线轮胎接地面积和简化的非均布轮载应力,建立了轮胎-路面非均布条形荷载力学计算模型,对不同沥青层厚度的柔性基层沥青路面结构进行了三维有限元分析,计算超载和设计轴载工况下2种路面结构最大拉应力和最大剪应力值及其发生位置,并依托级配碎石基层沥青路面足尺试验路进行了加速加载破坏试验,得到了中低温环境下沥青层开裂类型、发生位置和发展变化规律,提出以轮胎胎纹间隙处的最大剪应力作为沥青路面自顶向下开裂的力学指标;基于力学分析指标和足尺试验路疲劳破坏作用次数,构建沥青路面自顶向下疲劳开裂预估模型。研究结果表明:柔性基层沥青路面最大拉应力远离轮迹带,其应力值远小于沥青混合料的容许拉应力,对沥青层自顶向下扩展的纵向开裂无影响;最大剪应力发生在路表或距路表一定深度范围内,轴载越大,最大剪应力越接近路表,水平力越大,最大剪应力越靠近轮底中心;当轮载水平力系数由0增加至0.5时,最大剪应力由轮底边缘移至子午线轮胎第2条凸纹与第3条凸纹间隙处。足尺试验路重轴载加速加载破坏试验时,柔性基层沥青路面最先发生了位于轮底中心、源自路表自顶向下扩展的间断纵向裂缝,随重复轮载作用纵向裂缝逐渐连通,裂缝的扩展方向与轮胎胎纹走向一致,印证了纵向开裂源于轮底轮胎胎纹间隙处的理论分析结果,明晰了柔性基层沥青路面自顶向下开裂的关键破坏源。
To study the mechanism of longitudinal cracks in asphalt pavement with a flexible base course and the law of crack development, the grounding impression and stress of truck tires under different axle loads and tire pressures were measured.With the help of the measured tire grounding area and simplified non-uniform distributed contact stress from the radial tires, a mechanical calculation model of tire-pavement under a non-uniform distributed strip load was established. A 3 D finite element analysis was developed for flexible base asphalt pavement structures with different asphalt layer thicknesses. Through the analysis, the maximum tensile stress and maximum shear stress and their acting positions on the two pavement structures were calculated under the overload conditions and the designed axle load conditions. An accelerated loading failure test was also conducted on a full-scale test road of graded crushed stone base asphalt pavement to obtain the type, location and development law of asphalt layer cracks in medium-and low-temperature environments. The maximum shear stress at the gap between the patterned ribs of the tire tread was proposed as the mechanical index of the top-down cracking of asphalt pavement. Then, based on the mechanical analysis and fatigue failure times of the test road, a top-down fatigue cracking prediction model of asphalt pavement was established. The results show that the maximum tensile stress of flexible base asphalt pavement is far away from the wheel track zone, and its value is far less than the allowable tensile stress of asphalt mixture, which has no effect on the top-down longitudinal cracks. The maximum horizontal shear stress occurs on the pavement surface or within a certain depth from the pavement surface, and the greater the axle load, the closer the maximum shear stress. In addition, the greater the horizontal force, the closer the maximum shear stress is to the center of the wheel bottom, and when the coefficient of horizontal force increases from 0 to 0.5, the maximum shear stress moves from the edge of the wheel bottom to the gap between the second and third patterned ribs of the radial tire. During the accelerated loading failure test with a heavy axle load on the full-scale test road, the flexible base asphalt pavement first has short top-down longitudinal cracks originating from the pavement surface. With the action of the wheel load, these short cracks are connected to each other and are located at the center of the bottom of the wheel. In addition, the direction of their propagation is consistent with that of the patterned ribs, which supports the theoretical analysis results, and indicating that longitudinal cracking originates from the gap between the patterned ribs of the bottom of the wheel.
To study the mechanism of longitudinal cracks in asphalt pavement with a flexible base course and the law of crack development, the grounding impression and stress of truck tires under different axle loads and tire pressures were measured.With the help of the measured tire grounding area and simplified non-uniform distributed contact stress from the radial tires, a mechanical calculation model of tire-pavement under a non-uniform distributed strip load was established. A 3 D finite element analysis was developed for flexible base asphalt pavement structures with different asphalt layer thicknesses. Through the analysis, the maximum tensile stress and maximum shear stress and their acting positions on the two pavement structures were calculated under the overload conditions and the designed axle load conditions. An accelerated loading failure test was also conducted on a full-scale test road of graded crushed stone base asphalt pavement to obtain the type, location and development law of asphalt layer cracks in medium-and low-temperature environments. The maximum shear stress at the gap between the patterned ribs of the tire tread was proposed as the mechanical index of the top-down cracking of asphalt pavement. Then, based on the mechanical analysis and fatigue failure times of the test road, a top-down fatigue cracking prediction model of asphalt pavement was established. The results show that the maximum tensile stress of flexible base asphalt pavement is far away from the wheel track zone, and its value is far less than the allowable tensile stress of asphalt mixture, which has no effect on the top-down longitudinal cracks. The maximum horizontal shear stress occurs on the pavement surface or within a certain depth from the pavement surface, and the greater the axle load, the closer the maximum shear stress. In addition, the greater the horizontal force, the closer the maximum shear stress is to the center of the wheel bottom, and when the coefficient of horizontal force increases from 0 to 0.5, the maximum shear stress moves from the edge of the wheel bottom to the gap between the second and third patterned ribs of the radial tire. During the accelerated loading failure test with a heavy axle load on the full-scale test road, the flexible base asphalt pavement first has short top-down longitudinal cracks originating from the pavement surface. With the action of the wheel load, these short cracks are connected to each other and are located at the center of the bottom of the wheel. In addition, the direction of their propagation is consistent with that of the patterned ribs, which supports the theoretical analysis results, and indicating that longitudinal cracking originates from the gap between the patterned ribs of the bottom of the wheel.
引文
[1] 管志光,庄传仪,林明星.足尺沥青混凝土路面加速加载动力响应[J].交通运输工程学报,2012,12(2):24-31. GUAN Zhi-guang,ZHUANG Chuan-yi,LIN Ming-xing.Accelerated loading dynamic response of full-scale asphalt concrete pavement[J].Journal of Traffic and Transportation Engineering,2012,12(2):24-31.
[2] 周亮,凌建明,林小平.考虑环境因素的沥青路面疲劳开裂预估模型[J].中国公路学报,2013,26(6):47-52. ZHOU Liang,LING Jian-ming,LIN Xiao-ping.Prediction model for fatigue crack of asphalt pavement with environmental factors considered[J].China Journal of Highway and Transport,2013,26(6):47-52.
[3] TAHREER M F,JANET M L.Experimental investigation of crack propagation and crack branching in lightly reinforced concrete beams using digital image correlation[J].Engineering Fracture Mechanics,2017,182:487-505.
[4] ZHANG Chen,WANG Hai-nian,YOU Zhan-ping,et al.Sensitivity analysis of longitudinal cracking on asphalt pavement using MEPDG in permafrost region[J].Journal of Traffic and Transportation Engineering:English Edition,2015,2(1):40-47.
[5] 韦金城,庄传仪,高雪池,等.基于疲劳损伤的沥青路面设计温度及预估模型研究[J].公路交通科技,2010,27(5):6-10. WEI Jin-cheng,ZHUANG Chuan-yi,GAO Xue-chi,et al.Design temperature and its prediction model for asphalt pavement based on fatigue failure[J].Journal of Highway and Transportation Research and Development,2010,27(5):6-10.
[6] GU F,LUO X,RANDY C W,et al.Energy-based crack initiation model for load-related top-down cracking in asphalt pavement[J].Construction and Building Materials,2017,159:587-597.
[7] 胡朋,庄传仪.基于加速加载实验的柔性沥青路面疲劳模型研究[J].武汉理工大学学报:交通科学与工程版,2015,39(5):958-962. HU Peng,ZHUANG Chuan-yi.Flexible pavement fatigue prediction model research based on accelerating pavement tests[J].Journal of Wuhan University of Technology:Transportation Science & Engineering,2015,39(5):958-962.
[8] 叶亚丽,庄传仪,王林,等.基于加速加载试验的柔性基层沥青混凝土路面动力响应[J].公路,2013(11):1-7. YE Ya-li,ZHUANG Chuan-yi,WANG Lin,et al.Dynamic response of flexible base asphalt pavement based on accelerated pavement testing[J].Highway,2013(11):1-7.
[9] NCHRP 1-37,Guide for mechanistic-empirical design of new and rehabilitated pavement structures[S].
[10] MA Ze-xin,LIU Li-ping,SUN Li-jun.Investigation of top-down cracking performance of in-situ asphalt mixtures based on accelerated pavement testing and laboratory tests[J].Construction and Building Materials,2018,179:277-284.
[11] MYERS L A,ROQUE R.Evaluation of top-down crack in thick asphalt concrete pavements and the implications for pavements design[J].Transportation Research Circular,2001(503):79-87.
[12] 李清富,杨泽涛,王鹏.半刚性路面TDC成因的有限元分析[J].郑州大学学报:工学版,2007,28(3):37-39. LI Qing-fu,YANG Ze-tao,WANG Peng.Finite element analysis of top-down cracking in semi-rigid pavement[J].Journal of Zhengzhou University:Engineering Science,2007,28(3):37-39.
[13] 李峰,孙立军.沥青路面Top-Down开裂成因的有限元分析[J].公路交通科技,2006,23(6):1-4. LI Feng,SUN Li-jun.Finite element analysis of top-down cracking in asphalt pavement[J].Journal of Highway and Transportation Research and Development,2006,23(6):1-4.
[14] 徐欧明,郝培文.厚沥青路面Top-Down裂缝分析及对路面设计的启示[J].中外公路,2006,26(5):133-137. XU Ou-ming,HAO Pei-wen.Top-down cracking and inspiration for pavement design of thick asphalt pavement[J].Journal of China & Foreign Highway,2006,26(5):133-137.
[15] 赵延庆,王抒红,周长红.沥青路面Top-Down裂缝的断裂力学分析[J].同济大学学报:自然科学版,2010,38(2):219-223. ZHAO Yan-qing,WANG Shu-hong,ZHOU Chang-hong.Analysis of top-down cracking of asphalt pavements based on fracture mechanics approach[J].Journal of Tongji University:Natural Science,2010,38(2):219-223.
[16] JTG D50—2017,公路沥青路面设计规范[S]. JTG D50—2017,Specifications for design of highway asphalt pavement[S].
[17] HU Xiao-di,WALUBITA L F.Modeling mechanistic responses in asphalt pavements under three-dimensional tire-pavement contact pressure[J].Journal of Central South University of Technology,2011,18(1):250-258.
[18] BEER M D,FISHER C.Stress-in-motion (SIM) system for capturing tri-axial tyre-road interaction in the contact patch[J].Measurement,2013,46(7):2155-2173.
[19] GUERCIO M C,MEHTA Y,MCCARTHY L M.Evaluation of fatigue cracking performance of asphalt mixtures under heavy static and dynamic aircraft loads[J].Construction and Building Materials,2015,95:813-819.
[20] 胡小弟,陶雄,白桃.考虑实测轮载及各向异性的沥青路面力学响应[J].武汉工程大学学报,2015,37(4):40-44. HU Xiao-di,TAO Xiong,BAI Tao.Mechanical response of asphalt pavement based on measured load and anisotropic properties[J].Journal of Wuhan Institute of Technology,2015,37(4):40-44.
[21] 张金喜,孔静静,黄颂昌,等.不同类型沥青路面吸声性能及机理的实验研究[J].北京工业大学学报,2010,36(8):1084-1090. ZHANG Jin-xi,KONG Jing-jing,HUANG Song-chang,et al.Experimental study on sound absorption of asphalt pavement with different types[J].Journal of Beijing University of Technology,2010,36(8):1084-1090.
[22] 庄传仪,叶亚丽,王林.级配碎石基层沥青路面FWD反算模量换算系数[J].重庆大学学报,2014,37(4):100-107. ZHUANG Chuan-yi,YE Ya-li,WANG Lin.Conversion coefficient for backcalculated modulus of unbound aggregate base asphalt pavement[J].Journal of Chongqing University,2014,37(4):100-107.
[23] 毕玉峰,孙立军.沥青混合料抗剪试验方法研究[J].同济大学学报:自然科学版,2005,33(8):1036-1040. BI Yu-feng,SUN Li-jun.Research on test method of asphalt mixture’s shearing properties[J].Journal of Tongji University:Natural Science,2005,33(8):1036-1040.
[24] 许严,孙立军.沥青路面沥青层剪应力变化简化模型研究[J].同济大学学报:自然科学版,2012,40(2):211-216. XU Yan,SUN Li-jun.Research on simplified model for variation of shear stress of asphalt layers in asphalt pavements[J].Journal of Tongji University:Natural Science,2012,40(2):211-216.
[25] 陈少幸,张肖宁,孟书涛,等.基于ALF 加速加载试验的沥青层疲劳损伤[J].公路交通科技,2012,29(1):18-22. CHEN Shao-xing,ZHANG Xiao-ning,MENG Shu-tao,et al.Fatigue damage in asphalt layer based on ALF accelerated loading test[J].Journal of Highway and Transportation Research and Development,2012,29(1):18-22.
[26] 胡斌,张肖宁.动水作用下沥青混合料疲劳性能变化[J].哈尔滨工业大学学报,2016,48(3):120-124. HU Bin,ZHANG Xiao-ning.Reduction of asphalt concrete anti-fatigue performance under hydrodynamic effect[J].Journal of Harbin Institute of Technology,2016,48(3):120-124.
[27] MODARRES A,SHABANI H.Investigating the effect of aircraft impact loading on the longitudinal top-down crack propagation parameters in asphalt runway pavement using fracture mechanics[J].Engineering Fracture Mechanics,2015(150):28-46.
[28] 肖川,邱延峻,艾长发,等.行车荷载作用下沥青路面动力特性试验[J].长安大学学报:自然科学版,2016,36(2):26-34. XIAO Chuan,QIU Yan-jun,AI Chang-fa,et al.Experiment on dynamic characteristics of asphalt pavement under vehicle load[J].Journal of Chang’an University:Natural Science Edition,2016,36(2):26-34.
[2] 周亮,凌建明,林小平.考虑环境因素的沥青路面疲劳开裂预估模型[J].中国公路学报,2013,26(6):47-52. ZHOU Liang,LING Jian-ming,LIN Xiao-ping.Prediction model for fatigue crack of asphalt pavement with environmental factors considered[J].China Journal of Highway and Transport,2013,26(6):47-52.
[3] TAHREER M F,JANET M L.Experimental investigation of crack propagation and crack branching in lightly reinforced concrete beams using digital image correlation[J].Engineering Fracture Mechanics,2017,182:487-505.
[4] ZHANG Chen,WANG Hai-nian,YOU Zhan-ping,et al.Sensitivity analysis of longitudinal cracking on asphalt pavement using MEPDG in permafrost region[J].Journal of Traffic and Transportation Engineering:English Edition,2015,2(1):40-47.
[5] 韦金城,庄传仪,高雪池,等.基于疲劳损伤的沥青路面设计温度及预估模型研究[J].公路交通科技,2010,27(5):6-10. WEI Jin-cheng,ZHUANG Chuan-yi,GAO Xue-chi,et al.Design temperature and its prediction model for asphalt pavement based on fatigue failure[J].Journal of Highway and Transportation Research and Development,2010,27(5):6-10.
[6] GU F,LUO X,RANDY C W,et al.Energy-based crack initiation model for load-related top-down cracking in asphalt pavement[J].Construction and Building Materials,2017,159:587-597.
[7] 胡朋,庄传仪.基于加速加载实验的柔性沥青路面疲劳模型研究[J].武汉理工大学学报:交通科学与工程版,2015,39(5):958-962. HU Peng,ZHUANG Chuan-yi.Flexible pavement fatigue prediction model research based on accelerating pavement tests[J].Journal of Wuhan University of Technology:Transportation Science & Engineering,2015,39(5):958-962.
[8] 叶亚丽,庄传仪,王林,等.基于加速加载试验的柔性基层沥青混凝土路面动力响应[J].公路,2013(11):1-7. YE Ya-li,ZHUANG Chuan-yi,WANG Lin,et al.Dynamic response of flexible base asphalt pavement based on accelerated pavement testing[J].Highway,2013(11):1-7.
[9] NCHRP 1-37,Guide for mechanistic-empirical design of new and rehabilitated pavement structures[S].
[10] MA Ze-xin,LIU Li-ping,SUN Li-jun.Investigation of top-down cracking performance of in-situ asphalt mixtures based on accelerated pavement testing and laboratory tests[J].Construction and Building Materials,2018,179:277-284.
[11] MYERS L A,ROQUE R.Evaluation of top-down crack in thick asphalt concrete pavements and the implications for pavements design[J].Transportation Research Circular,2001(503):79-87.
[12] 李清富,杨泽涛,王鹏.半刚性路面TDC成因的有限元分析[J].郑州大学学报:工学版,2007,28(3):37-39. LI Qing-fu,YANG Ze-tao,WANG Peng.Finite element analysis of top-down cracking in semi-rigid pavement[J].Journal of Zhengzhou University:Engineering Science,2007,28(3):37-39.
[13] 李峰,孙立军.沥青路面Top-Down开裂成因的有限元分析[J].公路交通科技,2006,23(6):1-4. LI Feng,SUN Li-jun.Finite element analysis of top-down cracking in asphalt pavement[J].Journal of Highway and Transportation Research and Development,2006,23(6):1-4.
[14] 徐欧明,郝培文.厚沥青路面Top-Down裂缝分析及对路面设计的启示[J].中外公路,2006,26(5):133-137. XU Ou-ming,HAO Pei-wen.Top-down cracking and inspiration for pavement design of thick asphalt pavement[J].Journal of China & Foreign Highway,2006,26(5):133-137.
[15] 赵延庆,王抒红,周长红.沥青路面Top-Down裂缝的断裂力学分析[J].同济大学学报:自然科学版,2010,38(2):219-223. ZHAO Yan-qing,WANG Shu-hong,ZHOU Chang-hong.Analysis of top-down cracking of asphalt pavements based on fracture mechanics approach[J].Journal of Tongji University:Natural Science,2010,38(2):219-223.
[16] JTG D50—2017,公路沥青路面设计规范[S]. JTG D50—2017,Specifications for design of highway asphalt pavement[S].
[17] HU Xiao-di,WALUBITA L F.Modeling mechanistic responses in asphalt pavements under three-dimensional tire-pavement contact pressure[J].Journal of Central South University of Technology,2011,18(1):250-258.
[18] BEER M D,FISHER C.Stress-in-motion (SIM) system for capturing tri-axial tyre-road interaction in the contact patch[J].Measurement,2013,46(7):2155-2173.
[19] GUERCIO M C,MEHTA Y,MCCARTHY L M.Evaluation of fatigue cracking performance of asphalt mixtures under heavy static and dynamic aircraft loads[J].Construction and Building Materials,2015,95:813-819.
[20] 胡小弟,陶雄,白桃.考虑实测轮载及各向异性的沥青路面力学响应[J].武汉工程大学学报,2015,37(4):40-44. HU Xiao-di,TAO Xiong,BAI Tao.Mechanical response of asphalt pavement based on measured load and anisotropic properties[J].Journal of Wuhan Institute of Technology,2015,37(4):40-44.
[21] 张金喜,孔静静,黄颂昌,等.不同类型沥青路面吸声性能及机理的实验研究[J].北京工业大学学报,2010,36(8):1084-1090. ZHANG Jin-xi,KONG Jing-jing,HUANG Song-chang,et al.Experimental study on sound absorption of asphalt pavement with different types[J].Journal of Beijing University of Technology,2010,36(8):1084-1090.
[22] 庄传仪,叶亚丽,王林.级配碎石基层沥青路面FWD反算模量换算系数[J].重庆大学学报,2014,37(4):100-107. ZHUANG Chuan-yi,YE Ya-li,WANG Lin.Conversion coefficient for backcalculated modulus of unbound aggregate base asphalt pavement[J].Journal of Chongqing University,2014,37(4):100-107.
[23] 毕玉峰,孙立军.沥青混合料抗剪试验方法研究[J].同济大学学报:自然科学版,2005,33(8):1036-1040. BI Yu-feng,SUN Li-jun.Research on test method of asphalt mixture’s shearing properties[J].Journal of Tongji University:Natural Science,2005,33(8):1036-1040.
[24] 许严,孙立军.沥青路面沥青层剪应力变化简化模型研究[J].同济大学学报:自然科学版,2012,40(2):211-216. XU Yan,SUN Li-jun.Research on simplified model for variation of shear stress of asphalt layers in asphalt pavements[J].Journal of Tongji University:Natural Science,2012,40(2):211-216.
[25] 陈少幸,张肖宁,孟书涛,等.基于ALF 加速加载试验的沥青层疲劳损伤[J].公路交通科技,2012,29(1):18-22. CHEN Shao-xing,ZHANG Xiao-ning,MENG Shu-tao,et al.Fatigue damage in asphalt layer based on ALF accelerated loading test[J].Journal of Highway and Transportation Research and Development,2012,29(1):18-22.
[26] 胡斌,张肖宁.动水作用下沥青混合料疲劳性能变化[J].哈尔滨工业大学学报,2016,48(3):120-124. HU Bin,ZHANG Xiao-ning.Reduction of asphalt concrete anti-fatigue performance under hydrodynamic effect[J].Journal of Harbin Institute of Technology,2016,48(3):120-124.
[27] MODARRES A,SHABANI H.Investigating the effect of aircraft impact loading on the longitudinal top-down crack propagation parameters in asphalt runway pavement using fracture mechanics[J].Engineering Fracture Mechanics,2015(150):28-46.
[28] 肖川,邱延峻,艾长发,等.行车荷载作用下沥青路面动力特性试验[J].长安大学学报:自然科学版,2016,36(2):26-34. XIAO Chuan,QIU Yan-jun,AI Chang-fa,et al.Experiment on dynamic characteristics of asphalt pavement under vehicle load[J].Journal of Chang’an University:Natural Science Edition,2016,36(2):26-34.