高海拔多年冻土区砂石路面公路的路基温度场特征

包卫星; 刘亚伦; 毛雪松; 李伟; 秦川; 郭强; 陈锐

doi:10.19818/j.cnki.1671-1637.2023.04.004

高海拔多年冻土区砂石路面公路的路基温度场特征

doi: 10.19818/j.cnki.1671-1637.2023.04.004

包卫星^1,,
刘亚伦¹,
毛雪松¹,
李伟¹,
秦川¹,
郭强^{1, 2},
陈锐¹

1.
长安大学公路学院，陕西西安 710064
2.
新疆维吾尔自治区交通建设管理局，新疆乌鲁木齐 830000

基金项目:

国家自然科学基金项目 51878064

新疆维吾尔自治区重大科技专项项目 2020A03003-7

陕西省自然科学基础研究计划项目 2021JM-180

详细信息

作者简介:
包卫星(1979-), 男, 新疆乌鲁木齐人，长安大学教授，工学博士，从事特殊土路基工程研究

中图分类号: U416.168
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出版历程
- 收稿日期: 2023-03-15
- 网络出版日期: 2023-09-08
- 刊出日期: 2023-08-25

Characteristics of subgrade temperature field of gravel road in high altitude permafrost region

1.
School of Highway, Chang'an University, Xi'an 710064, Shaanxi, China
2.
Transportation Construction Administration of Xinjiang Uygur Autonomous Region, Urumchi 830000, Xinjiang, China

Funds:

National Natural Science Foundation of China 51878064

Major Science and Technology Projects of Xinjiang Uygur Autonomous Region 2020A03003-7

Natural Science Basic Research Project of Shaanxi Province 2021JM-180

More Information

Author Bio:
BAO Wei-xing(1979-), male, professor, PhD, baowx@chd.edu.cn

摘要

摘要: 为了研究修筑公路对高海拔多年冻土层热状态的影响，开展了新藏公路多年冻土区路段沿线病害调查，在海拔5 400 m地带修筑了冻土地温监测断面与气象监测站点；对气温、地温、辐射强度进行了监测，依据监测结果计算了冻土上限处的热流通量，分析了多年冻土层地温变化特征；基于热传导和热扩散理论，建立了天然地基及普通路基下部多年冻土地温-深度理论预测模型。研究结果表明：多年冻土区公路病害主要由于沥青路面大量吸热导致，热棒、隔热层等主动、被动保护的手段虽有一定效果，但不能改变多年冻土的快速退化；研究区域天然地基与路基中心一天内温差最高达19.66 ℃，左、右路肩一天内温差最高为4.94 ℃，天然地基下深层多年冻土温度稳定在-6.0 ℃左右，路基中心下部深层多年冻土温度稳定在-5.6 ℃左右，路基下部相较天然地基温度变化更为剧烈，且等温层温度更高；研究区域的辐射强度在一天的10:00~18:00显著增强，在一年的3~6月为辐射强度的顶峰期，浅层地温主要受辐射强度的年周期变化影响；天然地基、路基中心、阴坡路肩与阳坡路肩下部多年冻土层年热流通量依次为-4 001、-14 649、-4 487与58 303 kJ·m^-2，路基中心散热速率大于天然地基，阳坡路肩处大量吸热；天然地基的等温层出现在9.79 m深度处，而路基中心等温层出现在9.61 m深度处，路基中心等温层位置更浅，路基土的换填使路基下部浅层冻土温度变化更明显，短期内对下部多年冻土的散热有正向作用；在阴阳坡效应下，阳坡下部多年冻土温度升高，路基热稳定性降低，并产生不均匀沉降。
- 路基工程 /
- 多年冻土路基 /
- 地温预测模型 /
- 现场监测 /
- 热流通量 /
- 热扩散理论
Abstract: In order to study the effect of highway construction on the thermal state of permafrost layer in high altitude area, the investigation on the road diseases in the permafrost regions along the Xinjiang-Xizang Highway was conducted, a temperature monitored cross-section of the ground and meteorological monitoring sites were built in the area with an altitude of 5 400 m, and the air temperature, ground temperature and radiation intensity were monitored. According to the monitoring result, the heat flux at the upper limit of the frozen soil was calculated, and the changing characteristics of ground temperature in permafrost layer were analyzed. Based on the heat conduction theory and heat diffusion theory, a ground temperature-depth theoretical prediction model of the permafrost under natural subgrade and normal subgrade was proposed. Research results show that the road diseases in the permafrost region are mainly caused by the large amount of heat absorption of asphalt pavement. Although the active and passive protection measures such as hot rods and thermal insulation layers have some positive effects, they cannot change the rapid degradation of the permafrost. The largest temperature difference between the natural foundation and the subgrade center in the study area is up to 19.66 ℃ in a day, and the temperature difference between the left and right shoulders is up to 4.94 ℃ in a day. The temperature of the deep permafrost under the natural foundation maintains at about -6.0 ℃, and the temperature of the deep permafrost in the lower part of the subgrade center maintains at about -5.6 ℃. The temperature of the lower part of the subgrade is more drastic than that of the natural foundation, and the temperature of the subgrade of the isothermal layer is higher. The radiation intensity in the study area increases significantly at 10:00-18:00 in a day, the peak radiation intensity is between March and June in a year, and the shallow ground temperature is mainly affected by the annual cycle variation of radiation intensity. The annual heat fluxes of the permafrost layer in the lower part of the natural foundation, subgrade center, shady slope shoulder, and sunny slope shoulder are -4 001, -14 649, -4 487 and 58 303 kJ·m^-2, respectively. The heat dissipation rate of the subgrade center is greater than that of the natural foundation, and a large amount of heat is absorbed at the shoulder of the sunny slope road. The isotherm of the natural foundation appears at a depth of 9.79 m, while the isotherm of the subgrade center appears at a depth of 9.61 m, indicating the isotherm of the subgrade center is shallower. The compaction of the subgrade soil makes the temperature change of the shallow part of the permafrost more obvious, which has a positive effect on the heat dissipation of the lower permafrost in the short term. Under the sunny-shady slopes effect, the increase of the permafrost temperature in the lower part of the slope reduces the thermal stability of the subgrade and results in uneven settlement.
- subgrade engineering /
- permafrost subgrade /
- ground temperature prediction model /
- in-site monitoring /
- heat flux /
- heat diffusion theory

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图 1 研究区域地理位置

Figure 1. Geographic location of research region

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图 2 试验路基结构断面

Figure 2. Structure sections of test subgrades

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图 3 试验路段病害

Figure 3. Diseases of test road sections

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图 4 监测点布设

Figure 4. Monitoring points deployment

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图 5 监测断面

Figure 5. Monitoring section

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图 6 浅层地温变化曲线

Figure 6. Varing curves of shallow ground temperature

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图 7 天然地基孔、路基中心孔月均化温度-深度变化曲线

Figure 7. Monthly average temperature-depth varing curves of natural foundation pore and subgrade center pore

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图 8 护道孔月均化温度-深度变化曲线

Figure 8. Monthly average temperature-depth varing curves of berm pores

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图 9 路肩孔月均化温度-深度变化曲线

Figure 9. Monthly average temperature-depth varing curves of road shoulder pores

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图 10 天然地基孔各深度温度随时间变化曲线

Figure 10. Varing curves of different depths temperature of natural foundation pore with time

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图 11 各时刻的辐射强度在一年周期内的变化曲线

Figure 11. Radiation intensity variation curves at different moments over a one-year period

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图 12 一天中各时刻年均辐射强度

Figure 12. Average annual radiation intensities at all times in a day

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图 13 各孔位3.5~4.0 m深度热流通量

Figure 13. Heat fluxes of different pores at depths of 3.5-4.0 m

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图 14 天然地基孔与路基中心孔实测和拟合温度曲线

Figure 14. Measuring and fitting temperature curves of natural foundation pore and subgrade center pore

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图 15 天然地基孔与路基中心孔实测和预测温度曲线

Figure 15. Measured and predicted ground temperature curves of natural foundation pore and subgrade center pore

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图 16 各深度处长期实测与预测地温

Figure 16. Long-term measured and predicted ground temperatures at different depths

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图 17 多年冻土地温-深度预测等温线

Figure 17. Temperature-depth prediction isotherms of permafrost

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表 1 多年冻土参数

Table 1. Permafrost parameters

冻胀等级	标准冻深/m	最大冻深/m	含冰量/%	融沉系数
Ⅰ、Ⅱ	1.9~3.0	3.8	8~15	0.9~1.7

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表 2 路基下3.5~4.0 m深度土体的热收支

Table 2. Heat budgets of soil at depths of 3.5-4.0 m under subgrade

位置	天然地基	阴坡路肩	路基中心	阳坡路肩
土体年热收支/(kJ·m^-2)	-4 001	-4 487	-14 649	58 303

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