应用干孔声波法测试隧洞围岩松弛圈

Application of Dry Hole Acoustic Wave Method on Measuring the Loosing Circle of Surrounding Rock of Tunnel

由于工程岩体受爆破、机械开挖、松动卸荷等诸多因素的影响,使得隧洞围岩内部的应力重新分布,在隧洞围岩表层出现应力释放区,该区如不及时进行处理或加固,很容易形成松动而破坏。因此,正确认识和测定隧洞围岩松弛变化特征,对工程开挖、灌浆补强以及隧洞洞室稳定程度评价具有重要意义。介绍了隧洞围岩松弛圈测试的声波法基本原理、方法技术及成果分析,应用干孔声波法测试取得声波纵波速度随孔深的变化曲线,通过分析隧洞围岩松弛圈、应力集中区和原岩的弹性波速特征,确定围岩松弛圈厚度范围,为隧洞稳定性评价及支护设计提供科学依据。

Due to the rock mass is affected by blasting,mechanical excavation,rock loosening and unloading,and many other factors,the stress in surrounding rock of tunnel will be redistributed,and a stress release zone on the surface of surrounding rock will be formed,which is easy to be loosened and destroyed if it is not treated or strengthened in time.Therefore,it is of great significance for excavation,grouting reinforcement and stability evaluation of tunnel to correctly recognize and test the loosening change characteristics of surrounding rock.This paper introduces the basic principle,technology and results analysis of acoustic wave method for testing the loosening circle of surrounding rock.The curve of acoustic P-wave velocity with depth of hole is obtained by using dryhole acoustic wave method.The thickness range of loosening circle of rock is determined by the loosening circle,stress concentration zone and elastic wave velocity characteristics of original rock,which provides scientific basis for stability evaluation and support design of tunnel.