[1]戴逸飞,杨 平,王 宁,等.交叠车站下穿段MJS加固温度场变化规律研究[J].郑州大学学报(工学版),2023,44(01):103-110.
 DAI Y F,YANG P,WANG N,et al.Study on temperature field variation law of MJS reinforcement for Underpass section of overlapping station[J].Journal of Zhengzhou University (Engineering Science),2023,44(01):103-110.
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交叠车站下穿段MJS加固温度场变化规律研究()
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《郑州大学学报(工学版)》[ISSN:1671-6833/CN:41-1339/T]

卷:
44
期数:
2023年01期
页码:
103-110
栏目:
出版日期:
2022-12-06

文章信息/Info

Title:
Study on temperature field variation law of MJS reinforcement for Underpass section of overlapping station
作者:
戴逸飞 杨 平 王 宁 娄 寅 冯俊青
Author(s):
DAI Y F YANG P WANG N et al.
文献标志码:
A
摘要:
在富水地层新建车站下穿既有车站时,需要采用MJS 与冻结法联合加固,而MJS 工法施工的水泥土会产 生大量水化热使加固体温度上升,将直接影响水平冻结效果。以南京地铁新建地铁7 号线站台层部分单层段需近 距离下穿上部既有车站为背景,采用数值模拟对MJS 加固体温度变化规律进行研究,并经实测验证了数值模拟的 正确性。结果表明: MJS 桩体施工完成后3~8 d 内达到最高温度,最高可达80. 07 ℃ ,且MJS 桩体布置越密集、加 固范围越大,在群桩加固体中心产生的温度越高、自然降温条件下前期降温速率越缓;MJS 桩体水化放热达最高温 度后,温度呈负指数幂函数形式下降,降温速度先快后慢;MJS 加固体对周围土体温度的影响范围随时间推移逐步 扩大,且加固范围越大,对周围土体温度的影响范围越大,影响范围可达加固体边界以外4. 5 m;距水泥土加固区越 近,土体温度越高。结合既有MJS 加固体水化放热规律及强度研究和数值模拟结果,考虑不同时刻水化热温度场 分布与温度值,今后类似工程MJS 加固完成后第60 天为建议的最佳开冻时机。
Abstract:
When a new station crosses the existing station in the water-rich strata, MJS and freezing method will be used to reinforce it. The cement soil constructed by MJS construction method will produce a lot of hydration heat, which can increase the temperature of added solids, and the horizontal freezing effect. This paper is based on the background that some single-layer sections of the platform layer of the newly-built Metro Line 7 of Nanjing Metro need to pass through the upper existing station at a short distance,the variation law of MJS reinforced soil temperature is studied by numerical simulation, and the correctness of numerical simulation is verified by actual measurement. The results show that the maximum temperature of MJS pile reaches 80. 07 ℃ within 3~8 days after completion of construction, and the more intensive MJS pile layout and the larger the reinforcement area, the higher the temperature generated in the solid center of pile group, and the slower the initial cooling rate under natural cooling condition. After the hydration heat release of MJS pile reaches the maximum temperature, the temperature decreases in the form of negative exponential power function, and the cooling rate is fast first and then slow. The influence range of MJS on the temperature of surrounding soil expands gradually with time, and the larger the reinforcement range is, the larger the influence range of surrounding soil temperature is, and the influence range can be up to 4. 5 m beyond the boundary of MJS reinforced soil. The closer it is to the cement-soil reinforcement area, the higher soil temperature is. Combined with the existing MJS hydration heat release law, strength research and numerical simulation results, considering the temperature field distribution and temperature value of hydration heat at different times, it is suggested that the best opening time should be the 60th day after the completion of MJS reinforcement in similar projects in the future.
更新日期/Last Update: 2022-12-07