Yu Zhao , Zedong Yang , Chaolin Wang , Jing Bi , Yongfa Zhang , Qiang Feng , Sheng Ren
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引用次数: 0
Abstract
The incidents where the stability of surrounding rock is affected due to the imperfection of insulation layers in tunnels in cold regions occur frequently. The majority of the reasons might be that the distribution characteristics of the freezing radius of the surrounding rock were not accurately captured. Therefore, based on superposition principle and boundary separation methods, an analytical solution of the 3-D temperature field considering the influences of the axial heat transfer and temperature gradient for the tunnel surrounding rock was put forward in this paper. The correctness of the analytical solution was verified by the numerical results of finite element. Meanwhile, the following results were revealed. (1) The action of the axial heat transfer imposed by the annual average temperature cannot be ignored when calculating the freezing radius of the surrounding rock, especially in areas near tunnel entrance or exit. (2) The relationship of the freezing radius to z∗ is a nonlinear relation composed of multiple negative power exponential functions. (3) The results of variance analysis show that among all factors, the exposure time (t∗) has the greatest influence on the temperature at a depth of 7 m and a radius of 5 m for the tunnel surrounding rock. (4) The thermal conductivity coefficient (k), specific heat capacity (c), density (ρ) and annual average temperature (T2) all show a high degree of influence, in which the influence degrees of the two factors ρ and T2 on temperature are approximately the same. In addition, the temperature gradient (Gd) has a significant impact on the temperature of the surrounding rock and the maximum average growth rate of temperature in the surrounding rock is 54 times that when Gd is not considered. Research results are expected to provide opinions for the design of insulation layer for the tunnel surrounding rock.
期刊介绍:
The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review.
The fundamental subjects considered within the scope of the journal are:
* Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow
* Forced, natural or mixed convection in reactive or non-reactive media
* Single or multi–phase fluid flow with or without phase change
* Near–and far–field radiative heat transfer
* Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...)
* Multiscale modelling
The applied research topics include:
* Heat exchangers, heat pipes, cooling processes
* Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries)
* Nano–and micro–technology for energy, space, biosystems and devices
* Heat transport analysis in advanced systems
* Impact of energy–related processes on environment, and emerging energy systems
The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.