铁路膨胀岩隧道支护结构稳定性与注浆范围分析

为分析膨胀岩对隧道工程造成的影响程度,综合分析膨胀岩的细观膨胀机理和宏观膨胀特性,确定膨胀发生的主客观因素,通过对膨胀岩试验结果的归纳,提出一种膨胀岩综合分级标准。针对膨胀岩的胀缩性质,推导湿度应力场和温度应力场的理论关系,以玉蒙铁路秀山隧道为工程背景,利用ANSYS软件分析不同膨胀级别、膨胀范围下膨胀力对支护结构的影响程度。结果表明,在弱膨胀工况下最大注浆加固范围为2m,中等膨胀工况下最大加固范围为6m,强膨胀工况下原断面不再适用。膨胀级别越高,支护结构变形越大,隧道拱顶位移随着膨胀力的释放由下沉逐步变为上升,仰拱产生底鼓,边墙收敛表现为在一定的加固范围下随膨胀系数增加而增加,在中、强膨胀级别下随着加固范围的增加表现为前期变形很快,而后期变小的现象,支护结构有被压扁的趋势。

Analysis of Supporting Structure Stability and Grouting Range in Swelling Rock Railway Tunnel

In order to analyze the effects of swelling rock in tunnel engineering,study the mesoscopic expansion mechanism and macro properties of swelling rock and determine the expansion of subjective and objective factors,a comprehensive expansion of rock classification standard is proposed based on swelling rock test results.With a view to swell rock properties,the relationship between humidity stress field and temperature stress field theory is deducted based on Xiushan tunnel engineering of Yumeng railway.ANSYS software is used to analyze the influence of expansion forces of different level and range on the supporting structure.The results show that under feeble expansion condition,the biggest grouting reinforcement range is 2 m;under medium level expansion condition,the biggest grouting reinforcement range is 6 m and under strong expansion condition,the original design of section is not applicable.The higher the level of expansion,the bigger the deformation of supporting structure.The displacement in the tunnel vault changes from sinking to rising gradually with the release of the expansion force,the inverted arch bottom heaving is generated and sidewall converging within certain range of the reinforcement increases with the increase of expansion coefficient.Deformation develops very quickly in the early stage with the increase of reinforcement range under medium and strong expansion level,and becomes slow in the late stage,and the supporting structure tends to get squashed.