车辆荷载在挡土墙上引起的附加土压力研究
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摘要
为了研究路面车辆在挡土墙上引起附加土压力的分布规律,结合330国道莲都至缙云段改扩建工程中悬臂式挡土墙的施工,在挡土墙的底板上方和立板内侧埋设了一系列的土压力盒,以工地施工用30 t自卸式货车为荷载源,采用定点停车方式加载,测试了路面车辆荷载(静载)引起的附加竖向和侧向土压力,并将测试结果与规范均匀分布法和弹性力学Boussinesq解进行了对比分析。结果表明:实测附加侧向土压力沿墙高呈非线性分布,峰值出现墙高的中部,峰值随车辆停车位置距挡土墙距离的增加而减小;底板上的附加竖向土压力在横断面方向上也为非线性分布;附加土压力实测值与现行公路设计规范采用的均匀分布法计算结果有较大的差异;若采用均匀分布法确定车辆荷载引起的附加侧向土压力,附加侧向土压力引起的弯矩或倾覆力矩可能被低估,使挡土墙下部的抗弯拉能力和抗倾覆能力不足,同时对于变截面挡土墙(墙身截面尺寸随高度增加而减小),可能造成墙身中上部抗剪强度过小而发生剪切破坏;实测附加侧向土压力的分布规律与Boussinesq解基本一致,但竖向附加土压力较Boussinesq解要大。建议在挡土墙(特别是重载道路挡土墙)设计时采用多车道同时作用有标准车辆时的Boussinesq解作为挡土墙的车辆附加荷载。
In order to study the distribution of additional earth pressure on retaining wall caused by vehicle load,combining with the construction of a cantilever retaining wall in Liandu-Jinyun section of 330 National Highway expansion project,a series of soil pressure boxes are embedded above the floor of the retaining wall and inside the vertical plate. By using a 30 t dump truck for construction as the load source and stopping and loading at designated places,the additional vertical and lateral earth pressures caused by vehicle( static)load is tested,which is compared with the result calculated from standard uniform distribution method and the Boussinesq solution of elastic mechanics. The result shows that( 1) The measured additional lateral earth pressure shows a nonlinear distribution along the wall height,the maximum value appears in the middle of the wall height,and the peak value decreases as the distance of the truck from the retaining wall increases.(2)The additional vertical soil pressure above the floor in the direction of the cross-section also obeys a nonlinear distribution.( 3) There is a great difference between the measured value and the result obtained by the uniform distribution method used in current highway design code.(4) If the uniform distribution method isused to determine the additional lateral earth pressure caused by vehicle load,the bending moment or overturning moment caused by the additional lateral earth pressure may be underestimated,this will make the insufficient anti bending and anti overturning ability of the lower retaining wall. Meanwhile,for the variable section retaining wall( the area of the wall section decreases as the height of the wall increases),the shear strengths above the middle part of the wall may be too small and the shear failure may occur.( 5) The distribution of the measured additional lateral earth pressures is basically the same as the Boussinesq solution,but the vertical additional earth pressure is larger than the Boussinesq solution. It is suggested that when designing the retaining wall( especially heavy duty road retaining wall),the Boussinesq solution with multiple lanes and standard vehicle loadings at the same time will be used as the additional vehicle load on retaining wall.
In order to study the distribution of additional earth pressure on retaining wall caused by vehicle load,combining with the construction of a cantilever retaining wall in Liandu-Jinyun section of 330 National Highway expansion project,a series of soil pressure boxes are embedded above the floor of the retaining wall and inside the vertical plate. By using a 30 t dump truck for construction as the load source and stopping and loading at designated places,the additional vertical and lateral earth pressures caused by vehicle( static)load is tested,which is compared with the result calculated from standard uniform distribution method and the Boussinesq solution of elastic mechanics. The result shows that( 1) The measured additional lateral earth pressure shows a nonlinear distribution along the wall height,the maximum value appears in the middle of the wall height,and the peak value decreases as the distance of the truck from the retaining wall increases.(2)The additional vertical soil pressure above the floor in the direction of the cross-section also obeys a nonlinear distribution.( 3) There is a great difference between the measured value and the result obtained by the uniform distribution method used in current highway design code.(4) If the uniform distribution method isused to determine the additional lateral earth pressure caused by vehicle load,the bending moment or overturning moment caused by the additional lateral earth pressure may be underestimated,this will make the insufficient anti bending and anti overturning ability of the lower retaining wall. Meanwhile,for the variable section retaining wall( the area of the wall section decreases as the height of the wall increases),the shear strengths above the middle part of the wall may be too small and the shear failure may occur.( 5) The distribution of the measured additional lateral earth pressures is basically the same as the Boussinesq solution,but the vertical additional earth pressure is larger than the Boussinesq solution. It is suggested that when designing the retaining wall( especially heavy duty road retaining wall),the Boussinesq solution with multiple lanes and standard vehicle loadings at the same time will be used as the additional vehicle load on retaining wall.
引文
[1]JTG D60—2015,公路桥涵设计通用规范[S].JTG D60—2015,General Code for Design of Highway Bridges and Culverts[S].
[2]JTG D30—2015,公路路基设计规范[S].JTG D30—2015,Specifications for Design of Highway Subgrades[S].
[3]李存宝,李元鑫,戴玉双,等.车辆荷载和静荷载对路肩式挡墙影响的研究[J].四川建筑科学研究,2011,37(4):130-132.LI Cun-bao,LI Yuan-xin,DAI Yu-shuang,et al.Comparative Research on the Effect of Vehicle Load and Static Load on Road Shoulder Type Retaining Wall[J].Sichuan Building Science,2011,37(4):130-132.
[4]于一凡,张宏博,宋修.重载交通下锚拉悬臂式挡土墙受力特性研究[J].公路,2015(7):1-6.YU Yi-fan,ZHANG Hong-bo,SONG Xiu.Research on Mechanics Characteristics of Anchor Cantilever Retaining Wall under Heavy Traffic[J].Highway,2015(7):1-6.
[5]乐金朝,邱洪志,张利军,等.交通荷载作用下桩锚支护结构动力响应分析[J].地下空间与工程学报,2013,9(6):1320-1325.YUE Jin-chao,QIU Hong-zhi,ZHANG Li-jun,et al.Analysis on Dynamic Response of the Foundation Pit Supporting Structure under Traffic Loads[J].Chinese Journal of Underground Space and Engineering,2013,9(6):1320-1325.
[6]李志勇,邓宗伟.预应力锚索桩板墙动态响应规律研究[J].岩土力学,2010,31(2):645-648.LI Zhi-yong,DENG Zong-wei.Study of Dynamic Response Rule of Prestressed Anchor Sheet-pile Wall[J].Rock and Soil Mechanics,2010,31(2):645-648.
[7]谭献良,邓宗伟,李志勇,等.交通荷载对预应力锚索桩板墙的土压力影响分析[J].中南大学学报:自然科学版,2010,41(3):1178-1185.TAN Xian-liang,DENG Zong-wei,LI Zhi-yong,et al.Dynamic Earth Pressure Effect Analysis on Pre-stressed Anchor Pile Plate Wall under Traffic Load[J].Journal of Central South University:Science and Technology Edition,2010,41(3):1178-1185.
[8]李昀.格宾加筋挡土墙动力特性试验研究及数值分析[D].长沙:中南大学,2010.LI Yun.Test Study and Numerical Analysis on Dynamic Characteristics of Gabion Reinforced Soil Retaining Walls[D].Changsha:Central South University,2010.
[9]李昀,杨果林,林宇亮.重复荷载作用下加筋格宾挡土墙动力特性[J].公路交通科技,2011,28(2):1-6.LI Yun,YANG Guo-lin,LIN Yu-liang.Dynamic Characteristics of Reinforced Gabion Walls Subjected to Cyclic Loading[J].Journal of Highway and Transportation Research and Development,2011,28(2):1-6.
[10]黄向京,许桂林,杨果林,等.加筋格宾新型组合支挡结构试验研究[J].公路交通科技,2011,28(2):7-13.HUANG Xiang-jing,XU Gui-lin,YANG Guo-lin,et al.Experimental Research on a New Kind of Compound Supporting and Retaining Structure with Reinforced Gabion Retaining Wall[J].Journal of Highway and Transportation Research and Development,2011,28(2):7-13.
[11]王怡,罗丹霞,杜雪芳,等.车辆荷载下土工格栅加筋挡土墙动力特性研究[J].西南科技大学学报,2014,29(2):37-40.WANG Yi,LUO Dan-xia,DU Xue-fang,et al.Research on Dynamic Characteristics of Geogrid Reinforced Retaining Walls under Vehicle Load[J].Journal of Southwest University of Science and Technology,2014,29(2):37-40.
[12]吴顺川,金爱兵,王金安.车辆荷载下路基挡土结构失稳机理数值模拟[J].岩土力学,2007,28(2):258-262.WU Shun-chuan,JIN Ai-bing,WANG Jin-an.Numerical Simulation of Failure Mechanism of Subgrade Retaining Structure under Vehicle Load[J].Rock and Soil Mechanics,2007,28(2):258-262.
[13]张波,陶连金,孟云伟,等.石笼挡墙在振压下破坏机理的颗粒流模拟研究[J].公路交通科技,2009,26(10):48-52.ZHANG Bo,TAO Lian-jin,MENG Yun-wei,et al.Study of Failure Mechanism of Gabion Retaining Wall under Vibrating Compaction Using PFC[J].Journal of Highway and Transportation Research and Development,2009,26(10):48-52.
[14]马晓芳.车辆荷载作用下深基坑支护结构计算方法研究[D].西安:西安建筑科技大学,2010.MA Xiao-fang.Study on Support Structure of Deep Foundation Pit under Vehicle load[D].Xi’an:Xi’an University of Architecture and Technology,2010.
[15]王洪亮,宋二祥,宋福渊.基坑周边荷载引起支护结构上土压力的分析[J].工业建筑,2012,42(9):90-96.WANG Hong-liang,SONG Er-xiang,SONG Fu-yuan.Analysis of Earth Pressure on the Retaining Structure due to Surcharge Near the Excavation[J].Industrial Construction,2012,42(9):90-96.
[16]张卓.超载作用下路肩挡墙附加主动土压力计算探讨[J].路基工程,2007(1):42-45.ZHANG Zhuo.Calculation of Additional Active Earth Pressure on Road Shoulder Retaining Wall under Overloading[J].Subgrade Engineering,2007(1):42-45.
[17]任有锋.大型车辆荷载在公路挡土墙设计中的换算[J].西北水电,2010(4):55-58.REN You-feng.Conversion of Large Vehicle Loads in Design of Access Road Retaining Wall[J].Northwest Hydropower,2010(4):55-58.
[18]赵成刚,白冰,王运霞.土力学原理[M].北京:清华大学出版社,2004.ZHAO Cheng-gang,BAI Bing,WANG Yun-xia.Principles of Soil Mechanics[M].Beijing:Tsinghua University Press,2004.
[2]JTG D30—2015,公路路基设计规范[S].JTG D30—2015,Specifications for Design of Highway Subgrades[S].
[3]李存宝,李元鑫,戴玉双,等.车辆荷载和静荷载对路肩式挡墙影响的研究[J].四川建筑科学研究,2011,37(4):130-132.LI Cun-bao,LI Yuan-xin,DAI Yu-shuang,et al.Comparative Research on the Effect of Vehicle Load and Static Load on Road Shoulder Type Retaining Wall[J].Sichuan Building Science,2011,37(4):130-132.
[4]于一凡,张宏博,宋修.重载交通下锚拉悬臂式挡土墙受力特性研究[J].公路,2015(7):1-6.YU Yi-fan,ZHANG Hong-bo,SONG Xiu.Research on Mechanics Characteristics of Anchor Cantilever Retaining Wall under Heavy Traffic[J].Highway,2015(7):1-6.
[5]乐金朝,邱洪志,张利军,等.交通荷载作用下桩锚支护结构动力响应分析[J].地下空间与工程学报,2013,9(6):1320-1325.YUE Jin-chao,QIU Hong-zhi,ZHANG Li-jun,et al.Analysis on Dynamic Response of the Foundation Pit Supporting Structure under Traffic Loads[J].Chinese Journal of Underground Space and Engineering,2013,9(6):1320-1325.
[6]李志勇,邓宗伟.预应力锚索桩板墙动态响应规律研究[J].岩土力学,2010,31(2):645-648.LI Zhi-yong,DENG Zong-wei.Study of Dynamic Response Rule of Prestressed Anchor Sheet-pile Wall[J].Rock and Soil Mechanics,2010,31(2):645-648.
[7]谭献良,邓宗伟,李志勇,等.交通荷载对预应力锚索桩板墙的土压力影响分析[J].中南大学学报:自然科学版,2010,41(3):1178-1185.TAN Xian-liang,DENG Zong-wei,LI Zhi-yong,et al.Dynamic Earth Pressure Effect Analysis on Pre-stressed Anchor Pile Plate Wall under Traffic Load[J].Journal of Central South University:Science and Technology Edition,2010,41(3):1178-1185.
[8]李昀.格宾加筋挡土墙动力特性试验研究及数值分析[D].长沙:中南大学,2010.LI Yun.Test Study and Numerical Analysis on Dynamic Characteristics of Gabion Reinforced Soil Retaining Walls[D].Changsha:Central South University,2010.
[9]李昀,杨果林,林宇亮.重复荷载作用下加筋格宾挡土墙动力特性[J].公路交通科技,2011,28(2):1-6.LI Yun,YANG Guo-lin,LIN Yu-liang.Dynamic Characteristics of Reinforced Gabion Walls Subjected to Cyclic Loading[J].Journal of Highway and Transportation Research and Development,2011,28(2):1-6.
[10]黄向京,许桂林,杨果林,等.加筋格宾新型组合支挡结构试验研究[J].公路交通科技,2011,28(2):7-13.HUANG Xiang-jing,XU Gui-lin,YANG Guo-lin,et al.Experimental Research on a New Kind of Compound Supporting and Retaining Structure with Reinforced Gabion Retaining Wall[J].Journal of Highway and Transportation Research and Development,2011,28(2):7-13.
[11]王怡,罗丹霞,杜雪芳,等.车辆荷载下土工格栅加筋挡土墙动力特性研究[J].西南科技大学学报,2014,29(2):37-40.WANG Yi,LUO Dan-xia,DU Xue-fang,et al.Research on Dynamic Characteristics of Geogrid Reinforced Retaining Walls under Vehicle Load[J].Journal of Southwest University of Science and Technology,2014,29(2):37-40.
[12]吴顺川,金爱兵,王金安.车辆荷载下路基挡土结构失稳机理数值模拟[J].岩土力学,2007,28(2):258-262.WU Shun-chuan,JIN Ai-bing,WANG Jin-an.Numerical Simulation of Failure Mechanism of Subgrade Retaining Structure under Vehicle Load[J].Rock and Soil Mechanics,2007,28(2):258-262.
[13]张波,陶连金,孟云伟,等.石笼挡墙在振压下破坏机理的颗粒流模拟研究[J].公路交通科技,2009,26(10):48-52.ZHANG Bo,TAO Lian-jin,MENG Yun-wei,et al.Study of Failure Mechanism of Gabion Retaining Wall under Vibrating Compaction Using PFC[J].Journal of Highway and Transportation Research and Development,2009,26(10):48-52.
[14]马晓芳.车辆荷载作用下深基坑支护结构计算方法研究[D].西安:西安建筑科技大学,2010.MA Xiao-fang.Study on Support Structure of Deep Foundation Pit under Vehicle load[D].Xi’an:Xi’an University of Architecture and Technology,2010.
[15]王洪亮,宋二祥,宋福渊.基坑周边荷载引起支护结构上土压力的分析[J].工业建筑,2012,42(9):90-96.WANG Hong-liang,SONG Er-xiang,SONG Fu-yuan.Analysis of Earth Pressure on the Retaining Structure due to Surcharge Near the Excavation[J].Industrial Construction,2012,42(9):90-96.
[16]张卓.超载作用下路肩挡墙附加主动土压力计算探讨[J].路基工程,2007(1):42-45.ZHANG Zhuo.Calculation of Additional Active Earth Pressure on Road Shoulder Retaining Wall under Overloading[J].Subgrade Engineering,2007(1):42-45.
[17]任有锋.大型车辆荷载在公路挡土墙设计中的换算[J].西北水电,2010(4):55-58.REN You-feng.Conversion of Large Vehicle Loads in Design of Access Road Retaining Wall[J].Northwest Hydropower,2010(4):55-58.
[18]赵成刚,白冰,王运霞.土力学原理[M].北京:清华大学出版社,2004.ZHAO Cheng-gang,BAI Bing,WANG Yun-xia.Principles of Soil Mechanics[M].Beijing:Tsinghua University Press,2004.