|
|
|
| Analysis of pile-soil heat transfer process based on field test in permafrost regions#br# |
| CHEN Kun1，2，YU Qihao1，GUO Lei1，LUO Xiaoxiao1，2，CHEN Ji3 |
| (1. State Key Laboratory of Frozen Soil Engineering，Northwest Institute of Eco-Environment and Resources，Chinese Academy of Sciences，Lanzhou，Gansu 730000，China；2. University of Chinese Academy of Sciences，Beijing 100049，China；3. Beiluhe Observation Station of Frozen Soil Environment and Engineering，Northwest Institute of Eco-environment and Resources，Chinese Academy of Sciences，Lanzhou，Gansu 730000，China) |
|
|
|
Abstract In order to study the temperature distribution and variation of piles and the pile-soil heat transfer process after concrete pouring in permafrost regions，a systematic study was carried out based on the observation results of in-situ test and theoretical analysis of cast-in-place piles in Beiluhe of Qinghai—Tibet Plateau. The results show that，with the completion of concrete pouring，the pile body presents an obvious stratification phenomenon in terms of heat transfer between the pile and the surrounding soil. The exothermic heat flow of the pile above the upper limit of permafrost is relatively weak，while the lower part is relatively strong. The direction of the heat flow vector is mainly horizontal and heat flow mainly concentrates near the upper limit of permafrost. In terms of temperature change，the upper and lower parts of the pile body show different temperature change processes. The upper part experiences a rapid heating and slow cooling process while the lower part shows a relatively stable cooling process，which results in a large temperature difference in the depth direction of the pile with a maximum temperature gradient of about 11℃/m. The heat mainly concentrates in the upper part of the pile，forming a high temperature core. Therefore，there may be a problem of insufficient strength due to low temperature at the pile bottom，and large temperature difference along the depth of the pile may lead to temperature cracks in the concrete. In order to raise the curing temperature of concrete and to reduce the generation of temperature cracks in concrete，it is suggested to control the molding temperature reasonably or to use low-temperature early-strength concrete.
|
|
|
|
|
|
[1] YU Q H，ZHANG Z Q，WANG，G S，et al. Analysis of tower foundation stability along the Qinghai–Tibet Power Transmission Line and impact of the route on the permafrost[J]. Cold Regions Science and Technology，2016，121：205–213.
[2] 俞祁浩，刘厚建，钱 进，等. 青藏直流联网工程±500 kV 输电线路的工程问题分析[J]. 工程地球物理学报，2009，6(6)：806–812.(YU Qihao，LIU Houjian，QIAN Jin，et al. Research on frozen engineering of problem analysis of Qinghai－Tibet 500 kV DC power transmission line[J]. Chinese Journal of Engineering Geophysics，2009，6(6)：806–812.(in Chinese))
[3] 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.(SHI Renjun，PAN Tingyu，LIU Meiru，et al. Research on concrete of cast-in-place pile for permafrost zone in Qinghai—Tibet plateau and its countermeasures[J]. Journal of Railway Engineering Society，2006，(3)：56–61.(In Chinese))
[4] 郭春香，吴亚平. 太阳辐射及气候变暖对冻土区单桩承载力的影响[J]. 岩石力学与工程学报，2014，33(增 1)：3 306–3 311.(GUO Chunxiang，WU Yaping. Effects of solar radiation and global warming on bearing of single pile in permafrost region[J]. Chinese Journal of Rock Mechanics and Engineering，2014，33(Supp.1)： 3 306–3 311.(in Chinese))
[5] 吴亚平，苏 强，郭春香，等. 冻土区桥梁群桩基础地基回冻过程的非线性分析[J]. 土木工程学报，2006，39(2)：78–84.(WU Yaping，SU Qiang，GUO Chunxiang，et al. Nonlinear analysis of ground refreezing process for pile group bridge foundation in permafrost[J]. China Civil Engineering Journal，2006，39(2)：78–84.(in Chinese))
[6] 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)：4 229–4 233.(WU Yaping，GUO Chunxiang，PAN Weidong，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)：4 229–4 233.(in Chinese))
[7] 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)：1 807–1 812.(WANG Xu，JIANG Daijun，LIU Deren 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)：1 807–1 812.(in Chinese))
[8] 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)：4 206–4 211.(WANG Xu，JIANG Daijun，ZHAO Xinyu，et al. An Experimental study on refreezing characteristics of large diameter bored pile in different permafrost areas of the Qinghai—Tibet Plateau[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23 (24)：4 206–4 211.(in Chinese))
[9] 商允虎，袁 堃，牛富俊，等. 多年冻土区桥梁工程钻孔灌注桩温度场研究[J]. 冰川冻土， 2016，38(4)：1 129–1 135.(SHANG Yunhu，YUAN Kun，NIU Fujun，et al. Study on ground temperature of cast-in-place pile of bridgein permafrost regions[J]. Journal of Glaciology and Geo-cryology，2016，38(4)：1 129–1 135.(in Chinese))
[10] 吴亚平，郭春香，赵世运，等. 青藏高原冻土区灌注桩入模温度对地温场的影响分析[J]. 铁道学报，2004，26(6)：81–85.(WU Yaping，GUO Chunxiang，ZHAO Shiyun，et al. Influence of casting temperature of single pile on temperature field of ground in permafrost of Qinghai—Tibet plateau[J]. Journal of the China Railway Society，2004，26(6)：81–85.(in Chinese))
[11] 贾艳敏，徐 达，郭红雨. 相变效应对灌注桩与冻土回冻过程影响的研究[J]. 工程力学， 2010，27(增1)：145–149.(JIA Yanmin，XU Da，GUO Hongyu. Study on phase transformation effect due to refrozen process of cast-in-place piles and frozen soil[J]. Engineering mechanics，2010，27(Supp.1)：145–149.(in Chinese))
[12] 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.(JIA Yanmin，TIAN Haiqi，GUO Hongyu. Refrozen process of cast-in-place piles considering the influence of molding temperature and hydration heat[J]. Engineering mechanics，2011，28(Supp.1)：44–47.(in Chinese))
[13] GUO L，YU Q H，LI X N，et al. Refreezing of cast-in-place piles under various engineering conditions[J]. Science in Cold and Arid Regions，2015，7(4)：376–383.
[14] 符 进，姜 宇，彭 惠，等. 多年冻土区大直径钻孔灌注桩早期回冻规律[J]. 交通运输工程学报，2016，16(4)：104–111.(FU Jin，JIANG Yu，PENG Hui. et al. Early refreezing law of large-diameter cast-in-place piles in permafrost regions[J]. Journal of Traffic and Transportation Engineering，2016，16(4)：104–111.(in Chinese))
[15] LIU Z Z，Sha A M，Hu L Q，et al. A laboratory study of Portland cement hydration under low temperatures[J]. Road Materials and Pavement Design，2017，18(S3)：1–11.
[16] 何江海，何景灏. 水泥水化热与混凝土绝热温升计算方法研究[J]. 科技信息，2010，21：465–466.(He Jianghai，He Jinghao. Study on the calculation method of the hydrate heat and adiabatic temperature rise of concrete. Science and Technology Information，2010，21：465–466.(in Chinese))
[17] 施惠生，黄小亚. 水泥混凝土水化热的研究与进展[J]. 水泥技术，2009，(6)：21–26.(Shi Huisheng，Huang Xiaoya. Study process on the hydration heat of Portland cement. Cement，2009，(6)：21–26. (in Chinese))
[18] GAO Q，WENG Z，MING F，et al. Applicability evaluation of cast-in-place bored pile in permafrost regions based on a temperature-tracking concrete hydration model[J]. Applied Thermal Engineering，2019，149：484–491.
[19] 杨世铭，陶文铨. 传热学[M]. 北京：高等教育出版社出版社，2006：4–5.(YANG Shiming，TAO Wenquan. Heat transfer[M]. Beijing：Higher Education Press，2006：4–5.(in Chinese))
[20] 徐斅祖，王家澄，张立新. 冻土物理学[M]. 北京：科学出版社，2010：82–90.(XU Xiaozu，WANG Jiacheng，ZHANG Lixin. Physics of frozen soils[M]. Beijing：Science Press，2010：82–90.(in Chinese)) |
|
|
|
2020, Vol. 39 
