豆砾石充填体波速与应力实时同向相关性研究

豆砾石的充填灌浆质量关系到隧道衬砌和围岩是否共同受力,通过豆砾石充填体波速的变化来分析豆砾石充填体的工程质量是一种行之有效的工程措施。文章针对豆砾石充填体开展了单轴压缩试验,并在加载过程中进行波速与应力实时同向测试,获得了豆砾石充填体在加载过程中轴向声波波速与应力的演化规律。试验结果表明:豆粒石充填体横向应变在弹性变形阶段变化不明显,体应变在接近峰值应力时才出现拐点;在加载初期,波速快速上升,随着应力的继续增加,波速增幅变缓,后期基本保持不变,在峰后阶段波速基本维持在最大值直到试验结束,此阶段波速与应力的相关性不明显;根据轴向波速与应力的变化规律,得到了应力与波速的指数函数拟合公式,据此可以通过现场测试获得的波速预测现场豆砾石充填体的充填质量。

Study on Real Time Synchronized Correlation between Wave Velocity and Stress of Pea-gravel Backfills

The backfilling and grouting quality of pea-gravel concerns the issue if the tunnel lining and surrounding rocks will work jointly.And it is an effective engineering measure to analyze the engineering quality of pea-gravel backfills through the changes of wave velocity of the pea-gravel backfills.A uniaxial compression test on the back⁃fills of pea gravel is conducted,a real time synchronous test on wave velocity and stress is undertaken during loading test,and the evolution laws of acoustic wave velocity and stress in axial direction during loading on pea-gravel back⁃fills are obtained.The experimental results show that the change of lateral strain of pea-gravel backfills is not obvi⁃ous in elastic deformation stage and the volumetric strain does not reach the inflection point until it approaches the peak stress;at the initial stage of loading,the wave velocity rises rapidly and then increases slowly with the continuous increase of stress and remains basically unchanged at later stage,at the post-peak stage the wave velocity mainly re⁃mains at the maximum value until the end of the test,there is no obvious correlation between wave velocity and stress.Based on the relationship between stress and axial wave velocity,a fitting formula for exponential function of stress and wave velocity is obtained,so the quality of pea-gravel backfills can be predicted by the wave velocity ob⁃tained by field test.