Early refreezing law of large-diameter cast-in-place piles in permafrost regions
Article Text (Baidu Translation)
-
摘要: 基于多年冻土区桩基混凝土的设计与施工, 研究了多年冻土区大直径钻孔灌注桩的早期回冻规律, 通过桩基现场试验并结合数值仿真模型分析了桩周混凝土水化热和桩周冻土回冻规律。分析结果表明: 在灌注完成后25 d内桩侧温度在1℃以上, 在灌注完成45 d后桩侧温度逐渐恢复到0℃; 数值模拟结果显示在灌注完成60 d后桩身温度下降至0℃, 在灌注完成200 d后桩周土体回冻至天然状态; 入模温度每提高2℃, 桩侧峰值温度提高1℃左右, 而2倍桩径处峰值温度提高0.5℃左右。可见, 在大直径桩基条件下桩基混凝土中可以不添加或少添加早强剂, 也没有必要刻意降低拌合物入模温度; 桩基的施工时间最好安排在暖季, 为混凝土的养生提供较好的外部条件。Abstract: Based on the design and construction of pile foundation concrete in permafrost regions, the early refreezing law of large-diameter cast-in-place pile in permafrost regions was studied. Through pile filed test and numerical simulation model, the hydrate heat of concrete and the permafrost refreezing law around pile were analyzed. Analysis result shows that pile side temperature is above 1 ℃ within 25 d after finishing pouring, and gradually recovers to 0 ℃ in 45 d after finishing pouring. Numerical simulation result shows that the pile temperature decreases to 0 ℃in 60 d after finishing pouring. The soil mass around pile is refrozen to natural state in 200 d after finishing pouring. Every 2 ℃ increase of molding temperature results in 1 ℃ increase of peak temperature at pile side and 0.5 ℃ increase of peak temperature at two times of pile diameters away. For large-diameter pile foundation, the addition of hardening accelerator to pile foundation concrete can be avoided or decreased. It is not necessary to sedulously decrease the molding temperature of mixture. The best construction time of pile foundation is in warm seasons, which can provide a good external condition for concrete curing.
-
图 2 桩基地温监测剖面
Figure 2. Monitoring sections of ground temperatures for pile foundations
图 7 计算温度与监测温度的对比
Figure 7. Comparison of calculated temperature and monitored temperature
图 8 桩身温度与天然地温的对比
Figure 8. Comparison of pile temperature and natural ground temperature
图 10 不同入模温度下桩侧温度随时间的变化
Figure 10. Variation of temperature at pile side with time under different molding temperatures
图 11 灌注完成5 d后桩侧温度随深度的变化
Figure 11. Variation of temperature at pile side with depth in 5 d after finishing pouring
图 12 灌注完成30 d后桩侧温度随深度的变化
Figure 12. Variation of temperature at pile side with depth in 30 d after finishing pouring
-
[1] NIU Fu-jun, LI Guo-yu, ZHAO Shu-ping, et al. Current developments of research on permafrost engineering and cold region environment: a report of the 8th International Symposium on Permafrost Engineering[J]. Sciences in Cold and Arid Regions, 2010, 2(2): 93-103. [2] WANG Gen-xu, LI Yuan-shou, WU Qing-bai, et al. Impacts of permafrost changes on alpine ecosystem in Qinghai-Tibet Plateau[J]. Science in China Series D: Earth Sciences, 2006, 49(11): 1156-1169. doi: 10.1007/s11430-006-1156-0 [3] WU Qing-bai, SHI Bin, LIU Yong-zhi. Interaction study of permafrost and highway along Qinghai-Xizang Highway[J]. Science in China Series D: Earth Sciences, 2003, 46(2): 97-105. doi: 10.1360/03yd9009 [4] 符进. 国道214线多年冻土区高速公路特殊路基设计方法研究[D]. 西安: 长安大学, 2011.FU Jin. Study of design methods on special subgrade of expressway for permafrost regions in G214 highway[D]. Xi'an: Chang'an University, 2011. (in Chinese). [5] GUO Lei, YU Qi-hao, LI Xiao-ning, et al. Refreezing of cast-in-place piles under various engineering conditions[J]. Sciences in Cold and Arid Regions, 2015, 7(4): 376-383. [6] WU Ya-ping, GUO Jian, GUO Chun-xiang, et al. Exothermic process of cast-in-place pile foundation and its thermal agitation of the frozen ground under a long dry bridge on the Qinghai-Tibet Railway[J]. Journal of Zhejiang UniversityScience A: Applied Physics and Engineering, 2010, 11(2): 88-96. [7] WANG Shuang-jie, CHEN Jian-bing, QI Ji-lin. Study on the technology for highway construction and engineering practices in permafrost regions[J]. Sciences in Cold and Arid Regions, 2009, 1(5): 412-422. [8] FANG Jian-hong, XU An-hua. Permafrost in Qinghai Province: characterization and impact on transportation construction[J]. Sciences in Cold and Arid Regions, 2013, 5(5): 509-516. doi: 10.3724/SP.J.1226.2013.00509 [9] WANG Shuang-jie, CHEN Jian-bing, ZHANG Jin-zhao, et al. Development of highway constructing technology in the permafrost region on the Qinghai-Tibet Plateau[J]. Science in China Series E: Technological Sciences, 2009, 52(2): 497-506. doi: 10.1007/s11431-008-0355-7 [10] JIN Hui-jun, BREWER M C. Highway roadway stability influenced by warm permafrost and seasonal frost action: a case study from Glennallen, Alaska, USA[J]. Sciences in Cold and Arid Regions, 2008(1): 26-41. [11] 符进, 马君毅, 袁堃. 青藏公路高温高含冰量多年冻土地区以桥代路工程研究[J]. 路基工程, 2013(4): 62-65. doi: 10.3969/j.issn.1003-8825.2013.04.015FU Jin, MA Jun-yi, YUAN Kun. Study on replacing road with bridge in warm and ice-rich permafrost regions along Qinghai-Tibet Highway[J]. Subgrade Engineering, 2013(4): 62-65. (in Chinese). doi: 10.3969/j.issn.1003-8825.2013.04.015 [12] 符进, 谢前波, 李俊. 高原多年冻土区以桥代路设置的客观条件技术研究[J]. 公路, 2013(11): 142-146. https://www.cnki.com.cn/Article/CJFDTOTAL-GLGL201311033.htmFU Jin, XIE Qian-bo, LI Jun. Research on the objective conditions of replacing railway by bridge in plateau permafrost regions[J]. Highway, 2013(11): 142-146. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GLGL201311033.htm [13] 章金钊, 周彦军, 周纲. 青藏公路多年冻土地区桥梁桩基地基回冻时间的探讨[J]. 公路, 2010(1): 33-38. https://www.cnki.com.cn/Article/CJFDTOTAL-GLGL201001011.htmZHANG Jin-zhao, ZHOU Yan-jun, ZHOU Gang. Discussion on refreezing time of bridge pile foundation subgrade in permafrost regions of Qinghai-Tibet Highway[J]. Highway, 2010(1): 33-38. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GLGL201001011.htm [14] 孙常新, 王安明, 王旭, 等. 钻孔灌注桩在青藏铁路多年冻土地区的应用[J]. 铁道建筑, 2007(11): 65-67. doi: 10.3969/j.issn.1003-1995.2007.11.024SUN Chang-xin, WANG An-ming, WANG Xu, et al. Application of cast-in-place pile in permafrost regions of Qinghai-Tibet Railway[J]. Railway Engineering, 2007(11): 65-67. (in Chinese). doi: 10.3969/j.issn.1003-1995.2007.11.024 [15] 李小和, 杨永平, 魏庆朝. 多年冻土地区不同入模温度下桩基温度场数值分析[J]. 北京交通大学学报, 2005, 29(1): 9-13. doi: 10.3969/j.issn.1673-0291.2005.01.003LI Xiao-he, YANG Yong-ping, WEI Qing-chao. Numerical simulation of pile foundation conduction at different molding temperature in permafrost regions[J]. Journal of Beijing Jiaotong University, 2005, 29(1): 9-13. (in Chinese). doi: 10.3969/j.issn.1673-0291.2005.01.003 [16] 张守国. 多年冻土地区钻孔灌注桩早期承载能力增长规律研究[D]. 西安: 长安大学, 2013.ZHANG Shou-guo. Development of the bearing capacity of cast-in-place piles in permafrost regions during the early construction stage[D]. Xi'an: Chang'an University, 2013. (in Chinese). [17] 刘秀. 多年冻土地区钻孔灌注桩回冻过程承载力分析[D]. 哈尔滨: 东北林业大学, 2007.LIU Xiu. Analysis on bearing capacity of refreezing process of cast-in-place bored pile in permafrost region[D]. Harbin: Northeast Forestry University, 2007. (in Chinese). [18] 熊炜, 刘明贵, 张启衡, 等. 多年冻土区桩基温度场研究[J]. 岩土力学, 2009, 30(6): 1658-1664. doi: 10.3969/j.issn.1000-7598.2009.06.023XIONG Wei, LIU Ming-gui, ZHANG Qi-heng, et al. Temperature distribution along piles in permafrost regions[J]. Rock and Soil Mechanics, 2009, 30(6): 1658-1664. (in Chinese). doi: 10.3969/j.issn.1000-7598.2009.06.023 [19] 王旭, 蒋代军, 赵新宇, 等. 青藏高原多年冻土区不同地温分区下大直径钻孔灌注桩回冻规律试验研究[J]. 岩石力学与工程学报, 2004, 23(24): 4206-4211. doi: 10.3321/j.issn:1000-6915.2004.24.020WANG Xu, JIANG Dai-jun, ZHAO Xin-yu, et al. An experimental study on refreezing characteristics of largediameter bored pile in different permafrost areas of the Qinghai-Tibet Plateau[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(24): 4206-4211. (in Chinese). doi: 10.3321/j.issn:1000-6915.2004.24.020 [20] 王旭, 蒋代军, 刘德仁, 等. 低温多年冻土地基大直径钻孔灌注桩未回冻状态承载性质试验研究[J]. 岩石力学与工程学报, 2013, 32(9): 1807-1812. doi: 10.3969/j.issn.1000-6915.2013.09.011WANG Xu, JIANG Dai-jun, LIU De-ren, et al. Experimental study of bearing characteristics of large-diameter cast-in-place bored pile under non-refreezing condition in low-temperature permafrost ground[J]. Chinese Journal of Rock Mechanics and Engineering, 2013, 32(9): 1807-1812. (in Chinese). doi: 10.3969/j.issn.1000-6915.2013.09.011 [21] 王旭, 蒋代军, 赵新宇, 等. 青藏高原多年冻土区大直径钻孔桩回冻过程研究[J]. 铁道学报, 2005, 27(2): 102-107. doi: 10.3321/j.issn:1001-8360.2005.02.019WANG Xu, JIANG Dai-jun, ZHAO Xin-yu, et al. Study on refreezing processes of large diameter bored pile in permafrost area of the Qinghai-Tibet Plateau[J]. Journal of the China Railway Society, 2005, 27(2): 102-107. (in Chinese). doi: 10.3321/j.issn:1001-8360.2005.02.019 [22] 吴亚平, 郭春香, 潘卫东, 等. 冻土区桩基回冻过程对单桩承载力和桥梁施工的影响分析[J]. 岩石力学与工程学报, 2004, 23(24): 4229-4233. doi: 10.3321/j.issn:1000-6915.2004.24.023WU Ya-ping, GUO Chun-xiang, PAN Wei-dong, et al. Influences of refreezing process of ground on bearing capacity of single pile and bridge construction in permafrost[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(24): 4229-4233. (in Chinese). doi: 10.3321/j.issn:1000-6915.2004.24.023 [23] 马辉, 廖小平, 赖远明. 青藏铁路多年冻土区桩基础施工中的混凝土温度控制问题[J]. 冰川冻土, 2005, 27(2): 176-181. doi: 10.3969/j.issn.1000-0240.2005.02.004MA Hui, LIAO Xiao-ping, LAI Yuan-ming. Temperature control problem of concrete of pile foundation under construction in the permafrost regions of the Qinghai-Tibet Railway[J]. Journal of Glaciology and Geocrylogy, 2005, 27(2): 176-181. (in Chinese). doi: 10.3969/j.issn.1000-0240.2005.02.004 [24] 石人俊, 潘庭玉, 刘美茹, 等. 青藏高原多年冻土地段灌注桩混凝土的研究和对策[J]. 铁道工程学报, 2006(3): 56-61. doi: 10.3969/j.issn.1006-2106.2006.03.014SHI Ren-jun, PAN Ting-yu, LIU Mei-ru, et al. Research on concrete of cast-in-place pile for permafrost zone in QinghaiTibet Plateau and its countermeasures[J]. Journal of Railway Engineering Society, 2006(3): 56-61. (in Chinese). doi: 10.3969/j.issn.1006-2106.2006.03.014 [25] 唐丽云, 杨更社, 让艳艳, 等. 水化热对冻土地区桩基热影响分析[J]. 西安科技大学学报, 2011, 31(1): 28-32. doi: 10.3969/j.issn.1672-9315.2011.01.007TANG Li-yun, YANG Geng-she, RANG Yan-yan, et al. Effects of cement hydration heat on pile foundation in permafrost regions[J]. Journal of Xi'an University of Science and Technology, 2011, 31(1): 28-32. (in Chinese). doi: 10.3969/j.issn.1672-9315.2011.01.007 [26] 贾艳敏, 田海旗, 郭红雨. 水化热及入模温度对灌注桩回冻过程影响的研究[J]. 工程力学, 2011, 28(增1): 44-47. https://www.cnki.com.cn/Article/CJFDTOTAL-GCLX2011S1011.htmJIA Yan-min, TIAN Hai-qi, GUO Hong-yu. Refrozen process of cast-in-place piles considering the influence of molding temperature and hydration heat[J]. Engineering Mechanics, 2011, 28(S1): 44-47. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GCLX2011S1011.htm -
下载:
点击查看大图
图(12) / 表(1)
计量
- 文章访问数: 633
- HTML全文浏览量: 135
- PDF下载量: 530
- 被引次数: 0
