高原多年冻土区隧道浅埋段热棒群防护工程效果评价  

Engineering effect evaluation of thermal probe group protection for the shallow section of permafrost tunnel in plateau permafrost area

作　　者：李奋 刘锟 蔡汉成 杨永鹏 程宏伟 

机构地区：[1]中铁西北科学研究院有限公司,甘肃兰州730000 [2]青海地方铁路建设投资有限公司,青海西宁810000

出　　处：《岩石力学与工程学报》2017年第A01期3416-3422,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：中铁二院科研项目(2015–俄高铁–06);交通运输部建设科技项目(2013 318 490 010)~~

摘　　要：以G214公路高原多年冻土区姜路岭隧道浅埋段热棒群防护工程为例,通过对隧道天然工况下和热棒群防护下的隧道围岩地温变化特征及冻融圈变化规律的研究,评价了利用热棒群对高原多年冻土区隧道浅埋段进行主动热防护的工程效果。研究表明:天然工况下隧道施工产生的冻融圈范围大于2.2 m;冻融圈回冻时间大于4 a;在热棒群防护下姜路岭隧道出口左洞洞侧人为冻土上限抬高0.5 m;隧道洞顶冻融圈的回冻时间为1 a,洞侧冻融圈回冻时间为2~3 a;地温总体上呈现出类似于正余弦曲线的变化形式,暖季地温较大,寒季地温相对较小,且随着时间推移,同期地温在逐渐降低;评价认为利用热棒群对多年冻土区隧道浅埋段进行主动热防护可以快速消除施工给隧道冻土围岩带来的热干扰,维持洞周冻土围岩的稳定,同时在洞周形成冻土防渗帷幕,阻隔冻结层上水向隧道结构方向的渗入,是一种有效保护隧道多年冻土环境的工程措施。Taking the protective engineering of thermal probe group in shallow buried section of Jiangluling tunnel in Road G214 in plateau permafrost regions as an example, based on the study of the characteristics of the ground temperature change and the change of the freezing thawing circle under both the natural condition of the tunnel and the protection of the thermal probe group, the engineering effect of using thermal probe group to initiate active thermal protection on shallow buried section of tunnel in plateau permafrost regions was evaluated. The research shows that, under natural conditions, the range of freeze-thawing circle caused by tunnel construction is larger than 2.2 meters, and the refreezing time is more than 4 years. Under the protection of the thermal probe group, in Jiangluling tunnel left exit hole, the artificial permafrost upper limit evaluates elevate 0.5 meter, and the refreezing time of freezing thawing circle in tunnel top area is 1 year, while its counterpart in surrounding area is 2 - 3 years. The ground temperature variation is overall similar to the sine and cosine curve. Specifically, the ground temperature is relatively high in warm season and low in cold season, and it decreases in the corresponding period every year with time going by. Elevation results show that, utilizing thermal probe group to initiate active thermal protection on shallow buried section of tunnel in permafrost regions is an effective engineering measure to protect the permafrost environment of the tunnel. It can quickly erase the thermal interference on the permafrost surrounding rock of the tunnel caused by construction and maintain the stability of the permafrost surrounding rock, simultaneously create frost proof curtain on the surrounding rock to reduce to tunnel structure, revent the water above frozen layer from infiltrating into the tunnel structure.

关 键 词：土力学 多年冻土 隧道浅埋段 热棒 地温特征 工程效果 

分 类 号：TU43[建筑科学—岩土工程]