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Abstract The linear deforming joint was adopted to describe the deformation behaviour of the joint. Two measuring points were arranged in the line normal to the joint and were at two sides of the joint. The waveforms from the incident side and transmitted side were measured respectively. The spectrum of waveform at the measuring point of the incident side was calculated using the spectrum of waveform at transmitted side and the transmission and reflection coefficients of the normally stress wave propagating across the linear deforming joint. The method for measuring the joint stiffness was deduced assuming the spectrum of waveform of incident side equal to the calculated one. The rationality of the stiffness measurement was verified through the numerical simulation with FLAC3D. The joint stiffness and elastic modulus of rock were shown to affect the precision of the measurement. The greater the joint stiffness，the smaller the measuring error. The larger the rock elastic modulus，the bigger the test error. The peak frequency had little effect on the testing results. Experiments were carried out to a typical joint in a slope at Dexing Copper Mine. 9 tests were performed totally. The test results were all similar with the variance of normal stiffness of 0.72 and the variance of shear stiffness of 0.56.
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2015, Vol. 34 
