喷射混凝土对多年冻土区公路隧道围岩冻融圈的影响规律研究  

Research on the Influence of Sprayed Concrete on the Surrounding Rock Freeze-Thaw Circle of Highway Tunnels in Permafrost Regions

作　　者：沈世伟[1,2] 夏才初[1] 黎岩[3] 韩常领[4] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]吉林大学建设工程学院,长春130026 [3]广东省电力设计研究院,广州510663 [4]中交第一公路勘察设计研究院有限公司,西安710075

出　　处：《现代隧道技术》2015年第1期82-88,97,共8页Modern Tunnelling Technology

基　　金：国家科技支撑计划项目(2014BAG05B05);西部交通建设科技项目(20113184901070);国家自然科学基金项目(41472248)

摘　　要：在多年冻土区隧道施工过程中,围岩温度场和冻融圈的控制是保证隧道围岩稳定性和结构安全性的关键因素。文章建立了考虑水泥水化放热的隧道围岩二维非稳态温度场的传热模型,在此基础上分析了喷射混凝土前后围岩温度场的变化规律,以及喷混凝土的施作时机与厚度对围岩冻融圈的影响规律,并与现场实测结果进行了对比分析。研究结果表明,计算结果的整体趋势与现场实测值吻合,距离洞壁0.5 m以外的围岩温度,二者误差不超过0.5℃。在喷射混凝土之前,各深度的围岩温度呈现缓慢增长趋势。喷混凝土施工完成后,由于水泥水化热影响,距洞壁深度1.0 m以内的围岩温度呈现陡升—下降—趋于稳定的规律,且当喷混凝土施工每延迟1 d,或其厚度每增加5cm时,围岩冻融圈深度增加约10 cm。During tunnel construction in permafrost regions, control of the temperature field and freeze-thaw cir- cle of the surrounding rock is the key factor for ensuring the stability of the surrounding rock and the security of the structure. In this paper, a two-dimensional unsteady temperature field model for the heat transfer of surround- ing rock in light of the hydration heat of concrete is established. Based on this, the changing rules of the tempera- ture field of the surrounding rock before and after concrete spraying are analyzed, as well as the influence of con- struction time and thickness of the sprayed concrete on the freeze-thaw circle of the surrounding rock： A con- trastive analysis between calculated results and measured results is performed. Research results show that： the calculated data generally agrees with the measured data, with a temperature error of no more than 0.5~C for the rock at 0.5m away from the tunnel sidewall; before sprayed concrete construction, the temperatures of the sur- rounding rock at different depths are slow to grow; after sprayed concrete construction, the temperature of the sur- rounding rock within a depth of lm rises sharply at first, then declines, and later tends towards stabilization be- cause of the hydration heat of concrete; furthermore, when the sprayed concrete construction is delayed 1 day or its thickness increases every 5cm, the depth of the freeze-thaw circle increases about 10cm.

关 键 词：多年冻土区 公路隧道 喷射混凝土 围岩温度场 冻融圈 

分 类 号：U451[建筑科学—桥梁与隧道工程]