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[求助] 隧道工程中文摘要

摘要:高应力软岩条件下的小间距隧道因施工过程的扰动,隧道变形及结构受力极其复杂,易出现支护结构破坏现象。本文结合在建成兰铁路—杨家坪隧道小间距段,采用理论分析、现场测试和数值模拟手段,分析了高应力软岩小间距隧道的变形和结构受力特点,对支护破坏原因进行了总结。首先采用数值模拟方法对不同间距下后行隧道施工对先行隧道变形的影响进行分析,并与实测数据进行对比;其次设置监测断面对先行隧道初支结构应力受后行隧道影响进行测试;最后结合变形特点,对二衬破坏原因进行总结。结果表明:在高应力条件下后行隧道施工使先行隧道拱顶和远中岩柱侧边墙位移增大,近中岩柱侧边墙位移减小,这必然引起初支及二衬受到偏压作用;在偏压作用下,初支钢架在近中岩柱侧边墙位置压应力集中,发生弯曲破坏,同时后行隧道施工破坏了中岩柱中锚杆与围岩粘结力,使近中岩柱侧边墙锚杆失去作用;后行隧道施工使先行隧道二衬在仰拱和拱顶产生拉破坏,在边墙位置产生压破坏,当间距较小时,上述三种破坏同时发生,当间距增大后,主要发生仰拱的拉破坏。
关键词:隧道工程;高应力;软岩;小间距隧道;隧道变形;支护受力
Abstract:Due to the disturbance of the construction process, the deformation and structure of the small spacing tunnel in the condition of high stress and soft rock are extremely complicated, and the support structure is easy to be destroyed. Based on the theoretical analysis, field test and numerical simulation, the paper analyzes the characteristics of deformation and structural stress of small spacing tunnels in high stress soft rock at Yangjiaping tunnel of Chengdu-Lanzhou Railway, and summarizes the causes of support structure failure. First of all, numerical simulation method is used to analyze the influence of latter tunnel’s construction at different spacing on the deformation of the antecedent tunnel and compare with the measured data. Secondly, the monitoring section was set up to test the influence of latter tunnel’s construction on structure stress of antecedent tunnel. Lastly, combined with the deformation characteristics, the causes of the damage of secondary lining is summarized. The results show that, in the high stress condition, the displacement of the vault and the side wall away from middle rock wall are increased and the displacement of side wall near the middle rock wall is reduced after latter tunnel constructing, which will inevitably cause the primary lining and the secondary lining to be biased; Under the action of bias, the stress of steel frame in primary lining at the side wall near the middle rock wall is concentrated and then occurs bending failure, and the latter tunnel's construction destroys the bonding force between the rock bolt and the surrounding rock, the rock bolt in side wall near the middle rock wall failed; when the spacing is small,the latter tunnel’s construction makes antecedent tunnel’s secondary lining occur tensile failure in the inverted arch and vault, and pressure failure in the side wall, when the spacing increases, the main failure occurred in the inverted arch.
Key words:tunnel engineering;high stress;soft rock;small spacing tunnel;tunnel deformation;structural stress
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