寒区隧道融化盘时空变化规律研究
发布时间：2018-11-03 07:57
【摘要】：随着国家西部发展战略的转移以及经济建设的需要，寒区公路隧道修建越来越多。但受多年冻土区的气候环境、地质条件、施工技术的影响，在建或已运行隧道出现了不同程度的冻害。其中主要原因在于寒区隧道的修建对原岩的热平衡状况产生了巨大的改变，洞内外温度环境造成了隧道融化盘在时空及隧道结构承载力的季节性变化，使隧道遭受季节性冻胀作用引起隧道病害。 本文利用数值模拟计算的方法重点研究了隧道在不同施工及运营阶段隧道融化盘的大小改变以及对隧道支护结构力学性态的作用。本次研究考虑了伴相变非稳态温度场、不同阶段洞内外温度分布特点、保温隔热层的铺设、不同围岩等级等因素，研究总结了隧道融化盘随时间的大小变化情况及寒区隧道支护结构的位移应力影响规律。 根据隧道实际施工中不同开挖阶段及洞内外温度分布的复杂性，本文采用有限元软件进行数值模拟研究主要分为两部分：一部分是将隧道施工开挖分为毛洞阶段、初支阶段、二衬及贯通运行阶段，考虑材料伴相变非稳态情况下施工暴露时间的长短以及洞内外温度分布的差异进行隧道融化盘大小变化规律的分析；另外一部分是考虑冻结岩体与未冻结岩体的物理材料参数在冷暖季节的改变，分别对比分析不同围岩等级以及不同融化盘范围深度影响下，，着重分析研究了隧道围岩衬砌支护结构的受力变形规律，并进行对比将作用程度进行了粗略量化。 通过对计算结果的对比分析得出：隧道融化盘季节变化受洞内外温度环境影响较大。隧道融化盘随洞内温度升高范围不断增大但增大速率逐渐降低；不同施工阶段对隧道融化盘影响不同，其中施工热源的作用较为明显；保温隔热材料的铺设能够有效避免隧道融化盘的季节性冻融变化。随着隧道融化盘深度的变大隧道支护结构的应力、位移及塑性应变增大，表明隧道融化盘对隧道结构稳定具有显著的作用，仰拱及拱脚位置比较容易先发生破坏。因此施工中隧道拱脚位置应采取一定强度加强措施。
[Abstract]:With the shift of western development strategy and the need of economic construction, more and more highway tunnels are built in cold area. However, due to the influence of climate environment, geological conditions and construction technology in frozen earth regions for many years, different degrees of freezing damage appear in the tunnels under construction or operation. The main reason is that the construction of tunnel in cold region has changed the thermal balance of the original rock greatly, and the temperature environment inside and outside the tunnel has caused the seasonal change of the tunnel melting disk in time and space and the bearing capacity of tunnel structure. The tunnel is damaged by seasonal frost heaving. In this paper, the numerical simulation method is used to study the change of the size of the tunnel melting plate in different construction and operation stages and its effect on the mechanical behavior of the tunnel support structure. This study takes into account the unsteady temperature field with phase change, the temperature distribution characteristics inside and outside the tunnel at different stages, the laying of thermal insulation layer, the different surrounding rock grade, and so on. The variation of the thawing disk with time and the influence of displacement stress on the tunnel support structure in cold region are summarized. According to the complexity of the different excavation stages and the temperature distribution inside and outside the tunnel in the actual construction of the tunnel, this paper uses the finite element software to carry on the numerical simulation research mainly into two parts: one part is to divide the tunnel construction and excavation into the Mao cave stage and the initial branch stage. In the second lining and through operation stage, considering the length of construction exposure time and the difference of temperature distribution inside and outside the tunnel under the condition of material with phase change unsteady state, the variation law of the size of the tunnel melting disk is analyzed. The other part is to consider the change of physical material parameters of frozen rock mass and unfrozen rock mass in the cold and warm seasons. The stress and deformation law of tunnel surrounding rock lining support structure is analyzed and compared, and the action degree is roughly quantified. Through the comparison and analysis of the calculated results, it is concluded that the seasonal variation of the tunnel melting disk is greatly affected by the temperature environment inside and outside the tunnel. With the increasing range of temperature in tunnel, the increasing rate of melting disk decreases gradually, and the influence of different construction stage on tunnel melting disk is different, among which the effect of construction heat source is more obvious. The laying of insulation material can effectively avoid seasonal freeze-thaw change of tunnel thawing disk. The stress, displacement and plastic strain of the tunnel support structure increase with the depth of the melting plate of the tunnel. It shows that the tunnel melting disk has a significant effect on the stability of the tunnel structure, and the inverted arch and arch foot position are easy to be destroyed first. Therefore, some strength strengthening measures should be taken in the position of arch foot of tunnel in construction.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U451
本文编号：2307180
[Abstract]:With the shift of western development strategy and the need of economic construction, more and more highway tunnels are built in cold area. However, due to the influence of climate environment, geological conditions and construction technology in frozen earth regions for many years, different degrees of freezing damage appear in the tunnels under construction or operation. The main reason is that the construction of tunnel in cold region has changed the thermal balance of the original rock greatly, and the temperature environment inside and outside the tunnel has caused the seasonal change of the tunnel melting disk in time and space and the bearing capacity of tunnel structure. The tunnel is damaged by seasonal frost heaving. In this paper, the numerical simulation method is used to study the change of the size of the tunnel melting plate in different construction and operation stages and its effect on the mechanical behavior of the tunnel support structure. This study takes into account the unsteady temperature field with phase change, the temperature distribution characteristics inside and outside the tunnel at different stages, the laying of thermal insulation layer, the different surrounding rock grade, and so on. The variation of the thawing disk with time and the influence of displacement stress on the tunnel support structure in cold region are summarized. According to the complexity of the different excavation stages and the temperature distribution inside and outside the tunnel in the actual construction of the tunnel, this paper uses the finite element software to carry on the numerical simulation research mainly into two parts: one part is to divide the tunnel construction and excavation into the Mao cave stage and the initial branch stage. In the second lining and through operation stage, considering the length of construction exposure time and the difference of temperature distribution inside and outside the tunnel under the condition of material with phase change unsteady state, the variation law of the size of the tunnel melting disk is analyzed. The other part is to consider the change of physical material parameters of frozen rock mass and unfrozen rock mass in the cold and warm seasons. The stress and deformation law of tunnel surrounding rock lining support structure is analyzed and compared, and the action degree is roughly quantified. Through the comparison and analysis of the calculated results, it is concluded that the seasonal variation of the tunnel melting disk is greatly affected by the temperature environment inside and outside the tunnel. With the increasing range of temperature in tunnel, the increasing rate of melting disk decreases gradually, and the influence of different construction stage on tunnel melting disk is different, among which the effect of construction heat source is more obvious. The laying of insulation material can effectively avoid seasonal freeze-thaw change of tunnel thawing disk. The stress, displacement and plastic strain of the tunnel support structure increase with the depth of the melting plate of the tunnel. It shows that the tunnel melting disk has a significant effect on the stability of the tunnel structure, and the inverted arch and arch foot position are easy to be destroyed first. Therefore, some strength strengthening measures should be taken in the position of arch foot of tunnel in construction.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U451
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