Abstract: The integrity coefficient of rock mass is one of the important indice to evaluate the stability of engineering rock mass. Extensive research results show that the integrity coefficient Kv can comprehensively represent the integrity of rock mass. However, this parameter is difficult to obtain in frequent field tests. Therefore, a new integrity coefficient that can be easily obtained to represent the rock mass integrity is needed. Based on the literature review and a large number of engineering in situ data, this paper first studies the relationship between the volumetric joint count (Jv) and the integrity coefficient (Kv) of rock mass. A correction method of Jv representing Kv is then put forward considering the type of structural plane. The structural plane is divided into five categories according to the qualitative and quantitative properties of the structural plane. Moreover, the correction coefficient of structural plane, Jp, is determined based on the measured data. Comparing the Kv measured in the practical engineering, the Kv conversed from the international recommended standard value, the Kv conversed by the linear fitting, and the Kv conversed by the proposed correction method, it shows that the goodness-of-fit of the Kv conversed by the correction method and the measured Kv is the highest. The absolute residual reduce 58% and 32% compared to national recommended standard value and the linear fitting conversion, indicating that the conversion accuracy is higher. It is proved that the correction of the structural plane is feasible and exhibits promising application prospect in engineerings.

Key words: rock mass quality evaluation, rock integrity coefficient, volumetric joint count, classification of structural plane, correction of structural plane