摘要
在国道G109那曲至拉萨的季节性冻土路段设置监测断面,对季节性冻土区路基的地温、含水率和冻胀位移进行连续监测,依据实时监测数据,利用所建立的冻土路基水-热耦合模型,分析季节性冻土区公路路基水-热场的季节变化特征以及阴阳坡差异,并结合水-热场计算结果分析路基的冻胀性以及多种措施下防冻胀效果,并以路基监测期内含冰量的标准差表征路基损伤程度。研究结果表明:季节性冻土区公路路基的温度场与水分场具有明显季节变化特征,在路基路面以下8 m深度范围内,地温受外界环境变化影响较大;由于阴阳坡效应,温度场、水分场、冻胀量场与损伤场的横向分布不对称,相较于阳坡,阴坡冻胀量更大,严重损伤区域更多;路基冻胀量在2月份达到最大,2月底正常天气下路基阴坡肩和阳坡肩冻胀量分别为31.5 mm和26.0 mm左右,而极寒天气下,路基冻胀量明显增大;在保温板措施下,路基损伤区域明显减小,并集中于保温板外表面与路面之间;综合使用保温板、水泥稳定砂和碎石隔水层的措施下,路基阴阳坡肩冻胀峰值分别减少25.4%与30.7%,有效降低了路基冻害。
Monitoring sections were set up in the seasonally frozen soil section from Naqu to Lhasa of National Highway G109 to continuously monitor the ground temperature, moisture content and frost heaving displacement of subgrade in seasonally frozen soil areas. Based on the real-time monitoring data, the seasonal variation characteristics of water-heat field of highway subgrade in seasonally frozen soil areas and the difference of sunny-shady slopes were analyzed by using the established hydrothermal coupling model of frozen soil subgrade.Combined with the calculation results of the hydro-thermal coupling model, the frost heaving property and the anti-frost heave effect with various measures were analyzed, and the damage degree of subgrade was characterized by the standard deviation of the ice content in the monitoring period. The results show that temperature field and moisture field of highway subgrade in seasonally frozen soil areas have obvious seasonal variation characteristics.The ground temperature in the depth of 8 m below the road surface is greatly affected by the change of external environment. Due to the sunny-shady slopes effect, the transverse distribution of temperature field, moisture field,frost heaving amount field and damage field is not symmetrical. Compared with the sunny slope, the frost heaving amount of the shady slope is larger and the area of serious damage is more. The frost heaving amount of subgrade reaches its maximum in February. In normal weather at the end of February, the frost heaving amount of the shady slope shoulder and the sunny slope shoulder are 31.5 mm and 26.0 mm, respectively, while the frost heaving amount of the subgrade increases significantly in extremely cold weather. With the measure of insulation board,the damage area of subgrade decreases obviously, and is concentrated between the outer surface of insulation board and road surface. By adopting the measures combining insulation board, cement stabilized sand and gravel waterproof layer, the frost heaving peak of both shoulders of shady slope and sunny slope are reduced by 25.4%and 30.7% respectively, which effectively reduces freezing damage of subgrade.
作者
邓青松
曾超
何先志
陈风光
刘晓
DENG Qingsong;ZENG Chao;HE Xianzhi;CHEN Fengguang;LIU Xiao(Badong National observation and Research Station of Geo-hazards,China University of Geosciences,Wuhan 430074,China;China Communications Second Highway Survey and Design Institute Co.Ltd.,Wuhan 430056,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2022年第8期3113-3128,共16页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(42072314,41572279)
国家重点研发计划项目(2017YFC1501304)
中国博士后科学基金资助项目(2014T70758,2012M521500)
中交第二公路勘察设计研究院有限公司科技研发项目(KJFZ-2018-049)。
关键词
季节性冻土
公路路基
水热耦合模型
阴阳坡效应
路基损伤
防冻胀
seasonally frozen soil
highway subgrade
hydrothermal coupling model
sunny-shady slopes effect
damage degree of subgrade
anti-frost heave
