兰新高铁祁连山隧道围岩温度场及冻胀力研究

发布时间：2018-05-11 01:15

  本文选题：寒区隧道 + 冻胀力　； 参考：《西安科技大学》2017年硕士论文

【摘要】：寒区隧道工程是交通基础建设中的一项特殊工程,寒冷环境给隧道的设计和施工造成了新的困难,也带来了更多的挑战,对隧道建成后的运营和管理也提出了更高的要求。开展寒区隧道温度场及冻胀力研究对寒区隧道的建设具有重要的意义。本文以兰新高铁祁连山隧道为工程依托,对现场监测方案、实测监测温度和室内试验等关键数据进行分析,采取理论研究与有限元数值模拟计算相结合的方法进行系统研究。首先采集祁连山区的砂岩试样,通过热物性参数试验、单轴压缩试验、三轴压缩试验,对不同含水状态,不同温度砂岩试件比热容及导热系数进行分析,对不同温度砂岩单轴抗压强度、弹性模量、泊松比、不同围压时三轴抗压强度进行研究。发现祁连山地区砂岩导热系数均随着含水率的增大先增大后减小。砂岩的导热系数随着温度的降低增大。砂岩体积比热随着含水率的增加而减小,室温状态下砂岩体积比热值最小,随着温度的下降,体积比热容先增大后减小。负温情况下温度越低、围压越大砂岩的三轴抗压强度越大。随温度的降低,冻结岩石的塑性减弱、脆性增强。其次制定隧道温度监测方案,并对现场实测结果进行分析,得到祁连山隧道口外天然地面温度、隧道环境温度以及围岩温度的分布特征。总结出本隧道的环境温度与围岩温度场的分布规律。通过对监测数据的分析,可以为隧道的保温层设计提供依据。再次通过数值模拟软件FLAC~(3D)进行模拟,对隧道环境温度为-10℃、-20℃、-30℃、-40℃,贯通后隧道无保温层时围岩温度场的分布情况展开分析,总结出围岩温度场的分布规律,模拟计算得到的围岩温度沿径向分布规律与实际监测结果得到的规律基本吻合。模拟有保温层情况下最不利工况围岩温度场的分布,通过与无保温层相同环境温度的模拟结果进行对比,为保温层材料选取提供依据。最后利用FLAC~(3D)进行模拟,研究冻胀力在隧道衬砌不同位置的分布情况以及围岩等级、冻结深度、围岩含水率对冻胀力的影响,计算得到冻胀力沿隧道衬砌分布图。研究发现冻胀力沿衬砌轮廓的分布规律为:仰拱中心冻胀力最小,墙脚冻胀力最大。围岩级别、含水率、冻胀深度3个影响因素中,含水率对冻胀力的量级及分布影响最大,冻胀深度其次,围岩级别对冻胀力的影响本质为刚性影响。
[Abstract]:Tunnel engineering in cold area is a special project in traffic infrastructure construction. The cold environment brings new difficulties and challenges to the design and construction of the tunnel, and puts forward higher requirements for the operation and management of the tunnel after the completion of the tunnel. It is of great significance to study the temperature field and frost heave force of tunnel in cold region. Based on the Qilian Mountain Tunnel of Lanxin High-speed Railway, this paper analyzes the key data such as field monitoring scheme, measured monitoring temperature and indoor test, and adopts the method of combining theoretical research with finite element numerical simulation to carry out systematic research. Firstly, the sandstone samples from Qilian Mountains are collected, and the specific heat capacity and thermal conductivity of sandstone specimens with different water content and temperature are analyzed by means of thermal physical parameter test, uniaxial compression test and triaxial compression test. The uniaxial compressive strength, elastic modulus, Poisson's ratio and triaxial compressive strength of sandstone at different temperatures were studied. It is found that the thermal conductivity of sandstone in Qilian Mountains increases first and then decreases with the increase of water content. The thermal conductivity of sandstone increases with the decrease of temperature. The volume specific heat of sandstone decreases with the increase of water content, and the specific heat value of sandstone decreases at room temperature, and increases first and then decreases with the decrease of temperature. The lower the temperature is, the greater the confining pressure is, the greater the triaxial compressive strength of sandstone is. With the decrease of temperature, the plasticity of frozen rock weakens and the brittleness increases. Secondly, the tunnel temperature monitoring scheme is established, and the field measured results are analyzed, and the distribution characteristics of natural surface temperature, tunnel ambient temperature and surrounding rock temperature outside the tunnel entrance of Qilian Mountain are obtained. The distribution of ambient temperature and surrounding rock temperature field in this tunnel is summarized. Through the analysis of the monitoring data, it can provide the basis for the design of the insulation layer of the tunnel. The distribution of surrounding rock temperature field is analyzed when the tunnel environment temperature is -10 鈩，

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