夏梦然

摘 要：近年来市政隧道工程蓬勃发展，许多城市公路隧道受建筑、管线等因素的限制，并为节约用地、缩短工期等目的，大多被设计成小净距隧道。小净距隧道在施工过程中与分离式隧道最显著的区别是中隔岩柱受力状态复杂、稳定性难以控制。通过理论推导，对浅埋超小净距隧道土质中隔岩柱的失稳机理进行系统研究，基于小净距隧道中隔岩柱承载模型确定中隔岩柱上覆应力，结合土体极限应力公式对中隔岩柱在不同施工条件下的失稳破坏特征进行分析。结果表明，增大土体的黏聚力、内摩擦角及支护反力均能提高土体的极限应力，且增加支护反力效果更显著。

关键词：小净距隧道;土质中隔岩柱;围岩稳定性;隧道施工

Abstract： In recent years， municipal tunnel engineering has developed vigorously. However， many urban highway tunnels are restricted by factors such as construction and pipelines. In order to save land and shorten the construction period， most of tunnels are designed as neighborhood tunnels. The most significant difference between neighborhood tunnel and separated tunnel in the construction process is that the force state of the mid-adjacent rock is complicated and the stability of the rockis difficult to control.Through the theoretical derivation，the instability mechanism of the soil mid-adjacent rock in shallow neighborhood tunnel has been studied.The overburden pressure of mid-adjacent rock is determined based on the load-bearing model of the neighborhood tunnels mid-adjacent rock. Combined with the ultimate stress formula of the soil， the instability and failure characteristics of mid-adjacent rock under different construction conditions have been analyzed.The research results show that increasing the cohesive force， internal friction angle and support reaction force of the soil can all increase the ultimate stress of the soil， and the effect of increasing the support reaction force is more significant.

Keywords： neighborhood tunnel; soil mid-adjacentrock;surrounding rock stability;tunnel construction

随着隧道建设的快速发展，各种复杂地质条件不断出现，对隧道施工技术要求也不断提高。在隧道建设场地不受限时，往往选择分离式隧道，规范中对隧道最小净距提出了明确要求，从而能够使相邻两条线在施工过程中不影响彼此的应力、变形等。然而，在某些城市浅埋隧道的修建过程中，受场地限制、地质条件等诸多因素的影响，分离式隧道左右线净距很难满足《公路隧道设计规范》要求，从而常常采用小净距或连拱隧道方案[1]。但连拱隧道存在结构复杂、造价高、施工工序复杂、隧道的防排水效果不易控制等问题。小净距隧道有施工方法简单、造价相对低、工期较短、施工质量容易控制等优点，因此，小净距隧道更容易推广。……