公路隧道围岩级别变化的瑞利波速度判据分析

Analysis of Rayleigh wave velocity criterion for the surrounding rock classification change of road tunnels

公路隧道开挖过程中围岩级别的准确判定和预报是合理选择支护参数和确定施工方法的重要依据.如何根据瑞利波频散曲线上的速度变化特征,超前预报围岩级别,经过大量的探测试验与规范法围岩级别的详细判定结果的比对,基于地质由已知到未知的工作原则,比照当前围岩状况,将围岩级别的变化划分为3种情况:同级别围岩、由高级别到低级别、由低级别到高级别,以瑞利波速度随深度变化率为判定指标,给出了围岩级别变化的瑞利波速度判据,说明使用该判据时的注意事项,并通过预报成果验证了判据的准确性.为隧道施工围岩级别预报提出了一种高效原位测试方法.

The accurate surrounding rock classification and forecast are the important basis for properly selecting support parameters and deciding on the work method in the process of road tunnel construction.In order to solve the problems of how to forecast the surrounding rock classification by the characteristics of Rayleigh wave velocity changes on the Raleigh wave frequency-disperse curve,the changes of surrounding rock were divided into three types,the same grade,the lower grade and the higher grade compared to the present surrounding rock condition.On the basis of the geological work principle,the Rayleigh wave velocity criterion for surrounding rock classification was given using the variety rate of the Rayleigh wave speed to depth as the surrounding rock classification. The regulations for using these criteria were also discussed.Then,the accuracy of the criterion was verified by the forecast results.An efficient in-situ test method for surrounding rock classification in tunnel construction was put forth.