Sampling interval-size effects and differential sensitivities of different morphology parameters of rock joint

Abstract

The description accuracy of the rock-joint morphology is closely related to the sampling interval and the sampling window size. In this study, a diorite joint was taken as the research object. By selecting five morphology parameters (D, Z2, Rp, θ*max/(C+1)2D and M), according to the principle of the progressive coverage method, characteristics of the five morphology parameters were analyzed under the condition of five sampling intervals and five sampling window sizes. The results show that in general, the large sampling window is more conducive to obtaining stable values of the morphology parameter, while Rp, θ*max/(C+1)2D and M are more sensitive to the sampling spacing effect under the condition of small sampling interval; the differential sensitivities of the sampling interval effect and the sampling size effect of these morphology parameters were comprehensively compared, and the interaction between the sampling interval effect and the sampling size effect was discussed. The influence of the sampling window size on the sampling interval effect (and the influence of the sampling interval on the sampling size effect) can be ranked as: M > D > Rp > θ*max/(C+1)2D > Z2; the normalized standard deviations were calculated based on the normalized morphology parameters, and it is found that there is correlation between the joint roughness and the sensitivity of the morphology parameters to the sampling interval-size combined effect, which can be used to judge the applicable roughness conditions of different morphology parameters. The research results are not only conducive to improving the understanding of the high-precision quantitative description of rock-joint morphology, but also can provide references for future research on the relationship between rock-joint morphology and shear mechanical behavior of rock joint.