Studies on Rock Mass Classification for Mining Design

所得结果详列如下1。实验和数值结果表明，含水裂隙岩体中的纵波速度不是Wyllie等人提出的时间平均速度2。2 .含水裂隙岩体纵波速度随裂隙数目的增加而减小，即使裂隙厚度总和不变。3 .从野外记录中探测到的纵波到达时间主要受其射线路径裂缝内多次反射波的叠加控制。根据地下开采现场实测结果，阐明了采矿方法与岩体分类的关系。纵波速度随含水量的变化可以用混合纵横比的孔隙模型来定量说明。利用裂纹模型讨论了岩体的可变形性，阐明了岩体的可变形性可以通过测量岩体的纵波速度、岩体的裂缝密度和岩体的力学特性来估计。

The results obtained are itemized below.1. It is clarified both experimentally and numerically that P wave velocities in rock mass with water-saturated cracks are not a time average velocity proposed by Wyllie et al.2. P wave velocities in rock mass with water-saturated cracks decrease with increase of the number of cracks even if the sum of the thickness of the cracks remains constant.3. The arrival time of P wave which can be detected from the field records is mainly controlled by the superposition of the waves having multiple reflections within the cracks in their ray-path.4. From the results of a field measurement performed at the under-ground mining the relation between mining method and rock mass clasification is clarified.5. The variation of P wave velocity with respect to water content can be quantitatively illustrated by the use of a pore model with mixed aspect ratios.6. Deformability of rock mass is discussed by using the crack model, and it is clarified that the deformability of rock mass can be estimated by measuring the P wave velocity of rock mass, the crack density in-situ, and the mechanical properties of the spacimen.