黄土隧道围岩压力的一种极限平衡理论计算方法研究

摘要

The calculation method for surrounding rock pressure is a key problem in designing the supporting structure of tunnel engineering.Based on the failure mode of loess tunnel and the field measuring results of surrounding rock pressure,a new failure mode is proposed in this paper.Ac-cording to the limit equilibrium condition of the soil mass upward loess tunnel and the soil mass on both sides,the calculation method is derived.A comparison between the new method and five common methods is conducted by calculating the surrounding rock pressure of the same loess tun-nel,revealing that result by the new method is between the maximum value and the minimum value.And with the increase of the bedded depth,the peak depth of the loess tunnel is indicated, it shows the critical bedded depth of shallow and deep tunnel with the same strength characteris-tics.At the same time,the variation of surrounding rock pressure with the change of soil strength index is also studied,which is still between the maximum value and the minimum value of common surrounding rock pressure.%隧道围岩压力的计算方法研究是隧道工程支护结构设计中的关键问题。本文依据黄土隧道围岩的破坏模式调查和围岩压力的现场实测结果，提出了黄土隧道破坏模式，进而按照隧道上方土体与侧面楔形体的极限平衡条件，解析得到一种适用于黄土隧道的围岩压力计算方法，并将实际黄土隧道的围岩压力计算结果，与以往土质隧道的5种常用方法计算结果进行对比。研究结果表明：该方法的计算结果介于以往围岩压力计算结果的最大值与最小值之间，且随着埋深增大存在峰值，该峰值可用于判断深浅埋临界深度，并且随黄土强度指标变化，围岩压力计算结果仍处于前述变化范围内。