Joint bearing mechanism of structure and foundation for gravity anchor block of suspension bridge
-
摘要: 基于普宣高速公路宣威岸重力式锚碇工程, 设计了不回填无预应力、不回填有预应力和回填有预应力3种计算工况, 利用数值仿真试验分析了重力式锚碇和地基的力学机制和破坏模式。承载机制表明: 8倍设计荷载之前没有塑性变形, 为弹性工作状态, 最大变形在锚岩界面, 摩擦效应居主导, 基底拉应力区可控, 锚碇结构抗滑移和抗倾覆性均处于稳定可控状态; 12倍设计荷载之后塑性区逐步扩展, 达到20倍设计荷载时全部贯通, 基底塑性变形明显, 锚碇结构变形显著, 基底夹持岩体剪切破坏, 夹持效应居主导, 基底拉应力区不可控, 锚碇结构抗滑移和抗倾覆性均处于不可控状态; 锚碇施加的预应力只在结构-岩基协调变形之前起作用, 之后影响不大; 回填可以极大地改善基底应力状态与结构扭转变形、抗滑移和抗倾覆稳定性, 可在容许变形范围内适当考虑增强效应。可见, 重力式锚碇结构-地基协调变形与联合承载机制, 表现为摩擦效应、夹持效应和回填效应的综合作用。监测结果显示: 通过基底拉应力和压应力监控结构与地基接触面安全性, 监测值小于地基容许承载力3MPa; 通过基底变位和地基深部水平位移监控结构抗滑移稳定性, 实际工程监测值小于1mm; 通过角点不均匀沉降监控锚碇抗倾覆稳定性, 倾斜值小于0.006;通过大体积混凝土温控监测可知, 内部最高温度小于60℃, 进出水温差小于15℃, 内表温差小于20℃, 峰后降温速率小于3℃·d-1; 锚束锁固荷载监测变化幅值不超过设计值的5%。Abstract: Based on the gravity anchor block engineering in Xuanwei Bank of Puxuan Highway, three kinds of computing schemes such as no backfilling & no pretension, no backfilling & pretension and backfilling & pretension were designed, and the mechanical mechanisms and fail modes of gravity anchor block and foundation were analyzed on basis of numerical test.Bearing mechanism presents that when the loads are less than 8 times of design load, plastic deformationcan't occur, the working situation is elastic, the maximum of deformation locates on the interface of structure and foundation, the friction effect is dominant, the tensile stress zone under foundation is controllable, and the anti-slipping and anti-overturning stability of anchor block is stable or controllable.When the loads are larger than 12 times of design load, the plastic zone expands step by step, and until to 20 times of design load, the plastic zone is cut-through.The plastic strain under the structure and the structure deformation of anchor block aspect are observable.The rock mass clamped by structure is broken.The clamping effect is dominant.The tensile stress zone under foundation is uncontrollable.The anti-slipping and anti-overturning stability of anchor block is unstable or uncontrollable.The prestress of anchor block acts only before the compatible deformation of structure and foundation, and the action fades away after the compatible deformation.Backfilling can greatly improves foundation's stress state and structure's torsional deflection, anti-slipping and anti-overturning stability, so the enhancement effect can be considered within the scope of allowable deformation.The joint deformation and bearing mechanisms of gravity anchor block and foundation are comprehensively performed by friction effect, clamping effect and backfilling effect.Monitoring result denotes that the interface safety of anchor block and foundation can be controlled by monitoring the tensile and compressive stress of base bottom, and the monitoring data are less than 3 MPa that is allowable bearing capacity of foundation.The anti-slipping stability of the structure is monitored by using the deflection and the deeply horizontal displacement of foundation, and the practical monitoring values are less than 1 mm.The anti-overturning stability of structure is monitored by using the uneven sedimentation of structure corners, and the inclined value is less than 0.006.The inner maximum monitored temperature of mass concrete is less than 60℃, the temperature difference of input and output water is less than 15 ℃, the temperature difference of anchor block's inner and surface is less than 20℃, and the post-peak cooling rate is less than 3 ℃·d-1.The changing amplitudes of stresses of anchor cables are less than 5% of design stress.
-
Key words:
- suspension bridge /
- gravity anchor block /
- deformation mechanism /
- fail mode /
- joint bearing mechanism
-
图 14 轴线剖面塑性区扩展与加载关系曲线
Figure 14. Relation curve of plastic zone expansion and load for axis section
图 15 重力式锚碇极限状态塑性区
Figure 15. Plastic zones of gravity anchor block under ultimate bearing condition
-
[1] HAN Yan, CHEN Zheng-qing, LUO Shi-dong, et al. Calculation method on shape finding of self-anchored suspension bridge with spatial cables[J]. Frontiers of Structural and Civil Engineering, 2009, 3 (2): 165-172. [2] ZHANG Zhe, WANG Hui-li, QIN Shi-feng, et al. Limit span of self-anchored cable-stayed suspension cooperation system bridge based on strength[J]. Frontiers of Structural and Civil Engineering, 2009, 3 (3): 286-291. [3] LI Jian-hui, FENG Dong-ming, LI Ai-qun, et al. Determination of reasonable finished state of self-anchored suspension bridges[J]. Journal of Central South University, 2016, 23 (1): 209-219. doi: 10.1007/s11771-016-3064-6 [4] LEES H, LEE H H, PAIK I, et al. Evaluation of load and resistance factors for the reliability-based design of the main cables of earth-anchored suspension bridges[J]. KSCE Journal of Civil Engineering, 2016, 20 (6): 2457-2468. doi: 10.1007/s12205-015-1442-5 [5] KIM H K, LEE M J, CHANG S P. Non-linear shape-finding analysis of a self-anchored suspension bridge[J]. Engineering Structures, 2002, 24 (12): 1547-1559. doi: 10.1016/S0141-0296(02)00097-4 [6] SHINS U, JUNG M R, PARK J, et al. A deflection theory and its validation of earth-anchored suspension bridges under live loads[J]. KSCE Journal of Civil Engineering, 2015, 19 (1): 200-212. doi: 10.1007/s12205-014-0641-9 [7] ZHANG Qi-hua, LI Yu-jie, YU Mei-wan, et al. Study of the rock foundation stability of the Aizhai suspension bridge over a deep canyon area in China[J]. Engineering Geology, 2015, 198: 65-77. doi: 10.1016/j.enggeo.2015.09.012 [8] ADANUR S, GNAYDIN M, ALTUNISIK A C, et al. Construction stage analysis of Humber Suspension Bridge[J]. Applied Mathematical Modelling, 2012, 36 (11): 5492-5505. doi: 10.1016/j.apm.2012.01.011 [9] BHALLAS, YANG Y W, ZHAO J, et al. Structural health monitoring of underground facilities—technological issues and challenges[J]. Tunnelling and Underground Space Technology, 2005, 20 (5): 487-500. doi: 10.1016/j.tust.2005.03.003 [10] TAYLOR R J. Interaction of anchors with soil and anchor design[R]. California: Naval Civil Engineering Lab, 1982. [11] US Navy. US Navy Salvage Engineer's Handbook[M]. Washington DC: US Navy, 2000. [12] 范菊. 悬索桥锚旋系统及接触摩擦问题的研究[D]. 大连: 大连理工大学, 2011.FAN Ju. The study of suspension bridge anchorage system and the question of contact friction[D]. Dalian: Dalian University of Technology, 2011. (in Chinese). [13] 赵启林, 陈斌, 卓家寿. 悬索桥锚碇及地基基础中的力学问题研究动态[J]. 水利水电科技进展, 2001, 21 (1): 22-26. doi: 10.3880/j.issn.1006-7647.2001.01.008ZHAO Qi-lin, CHEN Bin, ZHUO Jia-shou. Developments in mechanical analysis of suspension bridges'anchorage and foundation[J]. Advances in Science and Technology of Water Resources, 2001, 21 (1): 22-26. (in Chinese). doi: 10.3880/j.issn.1006-7647.2001.01.008 [14] 吉林, 眭峰, 王保田. 润扬大桥锚碇基岩摩阻力试验研究[J]. 岩石力学与工程学报, 2003, 23 (2): 256-260. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200402015.htmJI Lin, XU Feng, WANG Bao-tian. Testing study on base resistance of the anchors at Runyang Yangtze Bridge[J]. Chinese Journal of Rock Mechanics and Engineering, 2003, 23 (2): 256-260. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200402015.htm [15] 陈志坚, 董学武, 谢和平. 复杂受力条件下重力式结构基底应力的实测研究[J]. 河海大学学报: 自然科学版, 2004, 32 (1): 46-50. doi: 10.3321/j.issn:1000-1980.2004.01.011CHEN Zhi-jian, DONG Xue-wu, XIE He-ping. Monitoring data-based study on foundation stress of gravity structures under complex loading conditions[J]. Journal of Hohai University: Natural Sciences, 2004, 32 (1): 46-50. (in Chinese). doi: 10.3321/j.issn:1000-1980.2004.01.011 [16] 吉林, 冯兆祥, 周世忠. 江阴大桥北锚沉井基础变位过程实测研究[J]. 公路交通科技, 2001, 18 (3): 33-35. doi: 10.3969/j.issn.1002-0268.2001.03.009JI Lin, FENG Zhao-xiang, ZHOU Shi-zhong. Study on Jiangying Bridge north anchoring sunk shaft foundation displacement process[J]. Journal of Highway and Transportation Research and Development, 2001, 18 (3): 33-35. (in Chinese). doi: 10.3969/j.issn.1002-0268.2001.03.009 [17] 陈志坚, 周世忠, 卓家寿. 大跨径悬索桥地基基础安全监控模型的研究思路及技术路线[J]. 中国工程科学, 2002, 4 (6): 20-24. doi: 10.3969/j.issn.1009-1742.2002.06.006CHEN Zhi-jian, ZHOU Shi-zhong, ZHUO Jia-shou. Technical methods to make safety monitoring and forecast models for the foundation of long suspension bridges[J]. Engineering Science, 2002, 4 (6): 20-24. (in Chinese). doi: 10.3969/j.issn.1009-1742.2002.06.006 [18] 周磊. 悬索桥锚碇结构长期安全监测合理测点布置技术研究[D]. 重庆: 重庆交通大学, 2012.ZHOU Lei. Reasonable arrangement technology of measuring points research of long term safety monitoring for suspension bridge anchorage[D]. Chongqing: Chongqing Jiaotong University, 2012. (in Chinese). [19] 卢江, 朱晓文, 赵启林. 悬索桥锚碇基础的计算与安全监控技术进展[J]. 贵州工业大学学报: 自然科学版, 2008, 37 (4): 240-244. https://www.cnki.com.cn/Article/CJFDTOTAL-GZGX200804057.htmLU Jiang, ZHU Xiao-wen, ZHAO Qi-lin. Development of safety monitoring and control of suspension bridge's anchorage foundation based on design and calculation[J]. Journal of Guizhou University of Technology: Natural Science Edition, 2008, 37 (4): 240-244. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GZGX200804057.htm [20] 李家平, 张子新, 黄宏伟, 等. 宁波庆丰大桥锚碇室内相似模型试验研究[J]. 同济大学学报: 自然科学版, 2005, 33 (8): 1011-1016. doi: 10.3321/j.issn:0253-374X.2005.08.004LI Jia-ping, ZHANG Zi-xin, HUANG Hong-wei, et al. Research on similarity model test of anchorage of Qingfeng Suspension Bridge in Ningbo[J]. Journal of Tongji University: Natural Science, 2005, 33 (8): 1011-1016. (in Chinese). doi: 10.3321/j.issn:0253-374X.2005.08.004 [21] 李永盛. 江阴长江公路大桥北锚碇模型试验研究[J]. 同济大学学报, 1995, 23 (2): 134-140. https://www.cnki.com.cn/Article/CJFDTOTAL-TJDZ502.004.htmLI Yong-sheng. Experimental study on thenorth anchorage of the Jiangyin Yangtze Bridge[J]. Journal of Tongji University, 1995, 23 (2): 134-140. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-TJDZ502.004.htm [22] 黄奶清, 李亚平, 程利鹏, 等. 悬索桥重力式混凝土锚碇稳定性验算与数值分析[J]. 河南城建学院学报, 2014, 23 (3): 5-8, 49. doi: 10.3969/j.issn.1674-7046.2014.03.002HUANG Nai-qing, LI Ya-ping, CHENG Li-peng, et al. Stability calculation and numerical analysis on anchorage of suspension bridge with gravity concrete[J]. Journal of Henan University of Urban Construction, 2014, 23 (3): 5-8, 49. (in Chinese). doi: 10.3969/j.issn.1674-7046.2014.03.002 [23] 吴国光, 张永健, 陈国平, 等. 矮寨大桥重力式锚碇应力分析[J]. 桥梁建设, 2013, 43 (6): 40-44. https://www.cnki.com.cn/Article/CJFDTOTAL-QLJS201306007.htmWU Guo-guang, ZHANG Yong-jian, CHEN Guo-ping, et al. Stress analysis of gravity anchorage of Aizai Bridge[J]. Bridge Construction, 2013, 43 (6): 40-44. https://www.cnki.com.cn/Article/CJFDTOTAL-QLJS201306007.htm [24] 李家平, 李永盛, 王如路. 悬索桥重力式锚碇结构变位规律研究[J]. 岩上力学, 2007, 28 (1): 145-150. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200701028.htmLI Jia-ping, LI Yong-sheng, WANG Ru-lu. Research on Displacement of anchorage of suspension bridge[J]. Rock and Soil Mechanics, 2007, 28 (1): 145-150. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200701028.htm [25] 游晓敏, 黄宏伟. 悬索桥锚碇剪切滑移的机理及试验初探[J]. 岩土力学, 2007, 28 (2): 336-342. doi: 10.3969/j.issn.1000-7598.2007.02.025YOU Xiao-min. HUANG Hong-wei. Test study on mechanism of shear-slip of anchorage in suspension bridge[J]. Rock and Soil Mechanics, 2007, 28 (2): 336-342. (in Chinese). doi: 10.3969/j.issn.1000-7598.2007.02.025 [26] 邵国建, 苏静波, 胡强. 润扬大桥悬索桥北锚碇基础接触应力仿真分析[J]. 中国工程科学, 2006, 8 (6): 28-34. https://www.cnki.com.cn/Article/CJFDTOTAL-GCKX200606004.htmSHAO Guo-jian, SU Jing-bo, HU Qiang. Numerical simulation of contact stresses under north anchorage foundation of Runyang Suspension Bridge[J]. Engineering Science, 2006, 8 (6): 28-34. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GCKX200606004.htm -
下载:
点击查看大图
图(24) / 表(2)
计量
- 文章访问数: 793
- HTML全文浏览量: 155
- PDF下载量: 440
- 被引次数: 0
