白牛厂矿节理化岩体力学参数与采场安全跨度评价

Estimation of Mechanical Parameter of Joined Rock Mass and the Safe Span of Stope in Bainiuchang Mine

白牛厂矿岩体节理发育、质量差,直接影响采场的稳定性。为了较真实地获得矿区岩体的力学参数,并准确评价采场安全跨度,先对扩展后的Hoek-Brown准则进行了部分修正。然后引入岩体节理间距Js,对传统的GSI确定方法进行了改进,以使节理化岩体结构的描述定量化;再结合Hoek-Brown准则的经典公式,对各种岩体力学参数进行处理。最后,推导了地质强度指标GSI与RMR、Q之间的数学关系,利用Barton提出的工程跨度经验公式,对矿区6种主要岩体采场安全跨度进行了评价,得出了井下无支护采场安全跨度应不大于10m的结论。所用的方法为节理化岩体力学参数的估计提供了一种简单、易行的途径,对采场安全跨度的评价也与生产实际相符,适合在同类矿山中应用。

The developed joint and poor quality of rock mass are the direct factors affecting the stability of stope in Bainiuchang mine.In order to obtain the actual mechanical parameters of rock mass and accurately evaluate the safe span of stope,the extended Hoek-Brown criterion was partially modified in this paper.Then,the traditional determination method of GSI was improved by introducing parameter Js（joint spacing in rock mass）,so to provide a more quantitative description of the structure of jointed rock mass.The various mechanical parameters of rock mass were treated by adopting classical formula of Hoek Brown criterion.Finally,the mathematical relation of geological strength index GSI to RMR and Q was derived.The safe spans of stope in six kinds of rock mass were evaluated by using the empirical formula of engineering span proposed by Barton.It was concluded that the safe span of underground stope without support is not more than 10 m.The results show that the proposed method provides a simple but convenient way to evaluate the mechanical parameters of jointed rock mass,and the estimated safe span of stope is also accord with practice of production,so the proposed method can be applied to similar mines.