Analysis of thermal characteristics and thermal accumulation effect of integrated rigid pile-raft subgrade applied in the permafrost region of Qinghai-Xizang Plateau
Article Text (Baidu Translation)
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摘要: 为验证刚性桩-筏板一体化路基（以下简称桩筏路基）在青藏高原多年冻土地区的适用性，明确桩筏路基自身的温度变化特征及其对多年冻土地基的热扰动效应，对青藏高原多年冻土区首个公路桩筏路基试验段建设过程和建成后第一年的温度场进行了数据观测，并与临近的片块石路基和天然地基的温度场数据进行了对比分析。研究结果表明：对于季节冻融深度，桩筏路基上游无水孔、中游少水孔和下游多水孔分别为6.8、10.3、8.5 m，片块石路基为6.7 m，天然大地为2.9 m，其中桩筏路基中游孔在深度3.80~8.25 m范围内形成不冻夹层；桩筏路基的温度月均值-深度曲线簇呈现明显的右偏分布，表现为正温时间更长、深度更深，片块石路基次之，天然大地基本在0 ℃两侧对称分布；桩筏路基的导热能力、储热能力、导冷能力均高于半刚性基层沥青路面+片块石路基，桩筏路基呈现显著的聚热效应，片块石路基次之，天然大地冷热基本均衡，桩筏路基中游孔由于桩筏连续结构体形成的尺度效应使其聚热效应远高于其他孔位；一周期年内筏板底面热量流入累积值为139.2 MJ·m-2，年累计热量数值在浅层地基的剧烈波动现象与季节冻融层的含水量波动和冻融相变叠加作用相关，在深层地基的波动现象与地下水渗流传热相关。建议在筏板与路基填料之间增设隔热材料以减弱热量流入，保护下伏多年冻土。研究结果可为青藏高原多年冻土区桩筏路基的结构优化和工程应用提供参考价值。Abstract: To verify the applicability of the integrated rigid pile-raft subgrade (PRS) in permafrost regions of the Qinghai-Xizang Plateau and to clarify its thermal characteristics and thermal disturbance effects on the permafrost foundation, temperature field data during the construction and the first year after completion of the first highway PRS test section in the permafrost region were monitored, and comparative analyses were conducted with adjacent block-stone subgrade (BSS) and natural ground (NG). Research results show that the seasonal freeze-thaw depths of the upstream borehole without water, the midstream borehole with less-water, and the downstream borehole with more water in the PRS are 6.8, 10.3, and 8.5 m, respectively. The seasonal freeze depths of the BSS is 6.7 m, and that of the NG is 2.9 m. A non-freezing interlayer is formed in the midstream borehole of the PRS within the depth range of 3.80–8.25 m. The monthly average temperature-depth curve clusters of the PRS present an obvious right-skewed distribution, which is manifested by a longer duration and greater depth of positive temperatures. The BSS shows a similar but weaker trend, while the temperature distribution of the NG is approximately symmetrical around 0 ℃. The heat conduction capacity, heat storage capacity, and cold conduction capacity of the PRS are higher than those of the semi-rigid base asphalt pavement combined with BSS. A significant thermal accumulation effect is exhibited by the PRS, followed by the BSS, while the natural ground shows an approximately balanced thermal state. The thermal accumulation effect of the midstream borehole of the PRS is significantly higher than that of other boreholes due to the scale effect formed by the continuous pile-raft structure. Within one annual cycle, the cumulative heat inflow at the bottom surface of the raft reaches 139.2 MJ·m-2. Strong fluctuations of the annual cumulative heat in shallow foundation layers are related to the combined effects of water content variation and freezetthaw phase change in the seasonal freeze-thaw layer, while fluctuations in deep foundation layers are related to heat transfer driven by groundwater flow. It is suggested that thermal insulation materials be installed between the raft and the subgrade fill to mitigate heat inflow and protect the underlying permafrost. The analysis results provide a reference for structural optimization and engineering applications of the integrated rigid PRS in the permafrost region of the Qinghai-Xizang Plateau.
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图 1 试验段所处地理位置与水流情况
Figure 1. Geographical location of test section and development conditions of surface water and groundwater.
图 4 桩筏路基试验段温度场监测孔位及温度传感器深度布置
Figure 4. Layout of temperature monitoring field boreholes and thermal sensor depths in the pile-raft subgrade test section
图 5 监测孔温度场变化云图
Figure 5. Cloud maps of temperature field changing in the monitoring boreholes
图 6 监测孔温度月均值随深度变化曲线
Figure 6. Variation curves of monthly average temperature with depth in monitoring boreholes
图 7 监测孔冻结指数、融化指数、冻融指数随深度变化曲线
Figure 7. Variation curves of freezing index, thawing index, and freeze-thaw index with depth in monitoring boreholes
图 8 桩基混凝土水化硬化期温度变化情况
Figure 8. Temperature variations during the hydration and hardening period of the pile concrete
图 9 混凝土浇筑后30 d内筏板不同深度处温度变化情况
Figure 9. Temperature variations at different depths of the raft within 30 days after concrete casting
图 10 筏板和桩基不同深度范围累计热量变化曲线
Figure 10. Variation curves of cumulative heat at different depth ranges of raft and pile foundation
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[1] 程国栋, 赵林, 李韧, 等. 青藏高原多年冻土特征、变化及影响[J]. 科学通报, 2019, 64(27): 2783-2795.CHENG Guo-dong, ZHAO Lin, LI Ren, et al. Characteristic, changes and impacts of permafrost on Qinghai-Tibet Plateau[J]. Chinese Science Bulletin, 2019, 64(27): 2783-2795. [2] 徐晓明, 吴青柏. 三江源多年冻土活动层厚度变化特征研究[J]. 冰川冻土, 2024, 46(5): 1579-1593.XU Xiao-ming, WU Qing-bai. Research on the variation characteristics of active layer thickness of permafrost in the Three River Source Region[J]. Journal of Glaciology and Geocryology, 2024, 46(5): 1579-1593. [3] PENG H, MA W, MU Y H, et al. Degradation characteristics of permafrost under the effect of climate warming and engineering disturbance along the Qinghai-Tibet Highway[J]. Natural Hazards, 2015, 75(3): 2589-2605. doi: 10.1007/s11069-014-1444-5 [4] 汪双杰, 刘戈, 叶莉, 等. 多年冻土区宽幅路基热效应防治对策研究[J]. 中国公路学报, 2015, 28(12): 26-32.WANG Shuang-jie, LIU Ge, YE Li, et al. Research on control countermeasures of thermal effect of wide embankment in permafrost regions[J]. China Journal of Highway and Transport, 2015, 28(12): 26-32. [5] 权磊, 田波, 牛开民, 等. 青藏高原高等级道路路基路面温度变化特征[J]. 交通运输工程学报, 2017, 17(2): 21-30. https://transport.chd.edu.cn/article/id/201702003QUAN Lei, TIAN Bo, NIU Kai-min, et al. Temperature variation properties of pavements and subgrades for high-grade roads on Qinghai-Tibet Plateau[J]. Journal of Traffic and Transportation Engineering, 2017, 17(2): 21-30. https://transport.chd.edu.cn/article/id/201702003 [6] 汪双杰, 陈建兵, 金龙, 等. 冻土路基热收支状态的尺度效应[J]. 中国公路学报, 2015, 28(12): 9-16.WANG Shuang-jie, CHEN Jian-bing, JIN Long, et al. Scale effect of thermal budget of permafrost embankment[J]. China Journal of Highway and Transport, 2015, 28(12): 9-16. [7] 汪双杰. 多年冻土区公路路基尺度效应理论与方法[M]. 北京: 科学出版社, 2020.WANG Shuang-jie. Scale effect theory and method of road embankment in permafrost regions[M]. Beijing: Science Press, 2020. [8] 钟歆玥, 康世昌, 郭万钦, 等. 最近十多年来冰冻圈加速萎缩: IPCC第六次评估报告之冰冻圈变化解读[J]. 冰川冻土, 2022, 44(3): 946-953.ZHONG Xin-yue, KANG Shi-chang, GUO Wan-qin, et al. The rapidly shrinking cryopshere in the past decade: An interpretation of cryospheric changes from IPCC WGI Sixth Assessment Report[J]. Journal of Glaciology and Geocryology, 2022, 44(3): 946-953. [9] 余帆, 齐吉琳, 姚晓亮. 多年冻土区路基分层变形现场观测研究[J]. 冰川冻土, 2011, 33(4): 813-818.YU Fan, QI Ji-lin, YAO Xiao-liang. Monitoring settlement at different depths within an embankment in permafrost region[J]. Journal of Glaciology and Geocryology, 2011, 33(4): 813-818. [10] 马清祥, 房建宏. 基于附加应力分析的多年冻土路基变形机制分析[J]. 公路, 2021, 66(3): 34-41.MA Qing-xiang, FANG Jian-hong. Influence of additional stress on the deformation mechanisms of embankment settlement[J]. Highway, 2021, 66(3): 34-41. [11] 王庆波. 多年冻土区公路CFG桩-筏复合地基承载力研究[D]. 哈尔滨: 东北林业大学, 2014.WANG Qing-bo. Research for bearing capacity of CFG pile raft composite foundation of road on the permafrost[D]. Harbin: Northeast Forestry University, 2014. [12] 王冠夫. 退化多年冻土区公路加筋热融桩复合地基热力性能研究[D]. 哈尔滨: 哈尔滨工业大学, 2020.WANG Guan-fu. Performances of highway geosynthetic encased lime columns foundations in degraded permafrost regions[D]. Harbin: Harbin Institute of Technology, 2020. [13] 赵影. 基于桩-土作用机理的岛状冻土区混凝土管桩复合地基承载特性研究[D]. 西安: 长安大学, 2022.ZHAO Ying. Study on bearing characteristics of concrete pipe pile composite foundation in island permafrost area based on pile-soil interaction mechanism[D]. Xi'an: Chang'an University, 2022. [14] LI L L, DANG L P, WANG C B, et al. Effects of plateau environment on cement concrete properties: A review[J]. Journal of Road Engineering, 2025, 5(3): 467-479. doi: 10.1016/j.jreng.2024.08.001 [15] 王宏磊. 高温高含冰量冻土中粉喷桩复合地基热状况与承载特性研究[D]. 北京: 中国科学院大学, 2022.WANG Hong-lei. Research on thermal regime and bearing capacity of composite foundation by dry jet mixing pile in warm and ice rich permafrost[D]. Beijing: Chinese Academy of Sciences, 2022. [16] 闫穆涵. 岛状多年冻土区高铁桩网路基振动反应与荷载传递特性[D]. 哈尔滨: 哈尔滨工业大学, 2021.YAN Mu-han. Dynamic response and load transfer behavior of high-speed railway's geosynthetic-reinforced pile supported embankment in patchy permafrost[D]. Harbin: Harbin Institute of Technology, 2021. [17] 沈宇鹏, 李小和, 冯瑞玲, 等. 客运专线桩板结构复合地基的沉降特性[J]. 交通运输工程学报, 2009, 9(6): 32-35. doi: 10.19818/j.cnki.1671-1637.2009.06.007SHEN Yu-peng, LI Xiao-he, FENG Rui-ling, et al. Settlement properties of pile-plank composite foundation in passenger dedicated line[J]. Journal of Traffic and Transportation Engineering, 2009, 9(6): 32-35. doi: 10.19818/j.cnki.1671-1637.2009.06.007 [18] 陈想明. 桩板结构整治有砟轨道高速铁路路基沉降病害应用研究[D]. 兰州: 兰州交通大学, 2023.CHEN Xiang-ming. Study on the application of pile plate structure in treating subgrade settlement diseases of high speed railway with ballast track[D]. Lanzhou: Lanzhou Jiaotong University, 2023. [19] 王育恒, 肖宏, 乔少帅. 高速铁路桩筏结构的筏板合理设计研究[J]. 北京交通大学学报, 2021, 45(2): 19-27.WANG Yu-heng, XIAO Hong, QIAO Shao-shuai. Study on ideal raft design of pile-raft structure in high-speed railway[J]. Journal of Beijing Jiaotong University, 2021, 45(2): 19-27. [20] 杨晓华, 王东清, 张莎莎, 等. 盐湖区高速铁路长短桩复合地基变形特性[J]. 交通运输工程学报, 2024, 24(3): 181-192. doi: 10.19818/j.cnki.1671-1637.2024.03.012 YANG Xiao-hua, WANG Dong-qing, ZHANG Sha-sha, et al. Deformation characteristics of long-short pile composite foundation for high-speed railway in salt lake region[J]. Journal of Traffic and Transportation Engineering, 2024, 24(3): 181-192. doi: 10.19818/j.cnki.1671-1637.2024.03.012 [21] 朱旭伟, 田波, 权磊, 等. 高功率加热棒作用下高含冰量冻土的融化行为[J]. 交通运输工程学报, 2025, 25(4): 58-70. doi: 10.19818/j.cnki.1671-1637.2025.04.004 ZHU Xu-wei, TIAN Bo, QUAN Lei, et al. Thawing behavior of frozen soil with high ice content under the action of high-power heating rod[J]. Journal of Traffic and Transportation Engineering, 2025, 25(4): 58-70. doi: 10.19818/j.cnki.1671-1637.2025.04.004 [22] 权磊, 田波, 牛开民, 等. 高海拔多年冻土地区宽幅沥青路面-路基体系热效应实测分析[J]. 土木工程学报, 2019, 52(3): 111-119.QUAN Lei, TIAN Bo, NIU Kai-min, et al. Field observation and analysis on thermal effects of wide asphalt pavement-embankment structure in high-altitude permafrost region[J]. China Civil Engineering Journal, 2019, 52(3): 111-119. [23] PENG E X, HU X Y, SHENG Y, et al. Thermal effect of the accumulated water with different depths on permafrost subgrade in cold regions[J]. Advances in Climate Change Research, 2023, 14(2): 179-189. doi: 10.1016/j.accre.2022.08.003 [24] 张明礼, 周志雄, 周凤玺, 等. 降雨对多年冻土区公路路基内部水热影响试验[J]. 长安大学学报(自然科学版), 2024, 44(4): 38-47.ZHANG Ming-li, ZHOU Zhi-xiong, ZHOU Feng-xi, et al. Influence of rainfall on hydrothermal process within highway subgrade in permafrost regions[J]. Journal of Chang'an University (Natural Science Edition), 2024, 44(4): 38-47. -
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