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Study on Real Time Synchronized Correlation between Wave Velocity and Stress of Pea-gravel Backfills
(1 State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071; 2 Department of Civil Engineering, Hefei University, Hefei 230601)
Abstract 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 backfills 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 backfills are obtained. The experimental results show that the change of lateral strain of pea-gravel backfills is not obvi0us 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 remains 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 obtained by field test.
Abstract：
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 backfills 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 backfills are obtained. The experimental results show that the change of lateral strain of pea-gravel backfills is not obvi0us 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 remains 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 obtained by field test.
HU Mingming1 GAO Yang1 CHEN Jiaqi2 SI Daxiong2 DUAN Yuanyu2
.Study on Real Time Synchronized Correlation between Wave Velocity and Stress of Pea-gravel Backfills[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(3): 135-140
2020, Vol. 57 