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The damage index is a crucial controlling parameter for rock mass strength and deformation in civil, geological and mining engineering projects. In this study, a new method was proposed for computing the damage index of a rock mass based on the field point load strength. This method provides a strength ratio whose numerator is the point load strength (PLS) of splitting along the pre-existing joint and whose denominator is the PLS of intact rock failure. To validate this method, the authors derived a relationship between the damage index and the integrality coefficient using an empirical relation. Moreover, numerous experimental tests were conducted, including P-wave testing and on-site point load testing. Finally, linear regression analysis was performed to analyse the correlation between the new damage index D R and the integrality coefficient K V . This study demonstrates that the presented new method is sensitive to both plasticity and damage in estimating the damage degree of rock masses in underground excavation and tunnel engineering.

Panel mining requires constructing lots of artificial pillars in underground metal mines. Along with the development of the mining process the stress-strain state of pillars changes constantly. Finite element numerical simulation with Midas/GTS software is used to analyze the stability of the pillar during the entire process of panel mining and consider randomness and fuzziness for material parameters of concrete and ore rock to get stress distribution in the pillar. In this paper, the performance function and equation of dynamic fuzzy reliability for a pillar in the whole mining process are established and are solved by a program developed with the MATLAB software. Applying the proposed theory and procedures to dynamic fuzzy reliability analysis and calculation of the pillar was set in panel mining under complex conditions in Zhao Tong Lead-Zinc mine. The results indicate that dynamic fuzzy reliability can better reflect the pillar stability during the entire process of panel mining and the proposed theory and procedures are effective in evaluating the dynamic fuzzy reliability.

Ecological safety problem from mining activities can not be ignored. Mining ecological security not only relates to ecological environment, also involves technology environment, political environment and cultural environment, etc. Through comprehensive analysis of situation and problems of mining ecological security, we can find Hengyang must go green mining road and must construct ecological mining from the environmental ecology, the political ecology and the cultural ecology, in order to realize mining sustainable development.