一种改进的岩体质量分级方法RMR_(Kv)

An Improved Rock Mass Rating Method RMR_(Kv)

RMR(Rock Mass Rating)是国际上广泛应用的岩体质量分级系统,它包含5项基本指标,即岩石单轴抗压强度(Rc)、岩石质量指标RQD、节理间距(D)、节理条件(Jcond)及地下水条件(GW)。其中岩石质量指标和节理间距均用来反映岩体的节理化程度,两者之间存在一定的相关关系,故在岩体分级系统中存在重复使用的问题,并且在实际应用中,岩石质量指标和节理间距的获取往往存在一定的困难,且具有一定的方向性和不确定性。采用岩体完整性指数代替原分级方案中的岩石质量指标及节理间距,建立了一种改进的RMR分级体系,从而省去了对这两项指标的野外测量和计算,提高了工作效率。该方法在玛尔挡工程中进行实例验证,与原RMR方法及国标BQ的分级对比结果表明:利用这一改进的分级方法获得的结果介于RMR与BQ之间,是一种切实可行的分级方案,可在更多的工程中应用。

RMR(rock mass rating)is a widely used rock mass quality classification system in the world.It contains five basic indexes,namely rock uniaxial compressive strength(Rc),rock quality designation RQD,joint spacing(D),joint condition(Jcond)and groundwater condition(GW).Among them,the rock quality designation and joint spacing are used to reflect the degree of rock mass jointing,and there is a correlation between them.Therefore,there are repeated use of rock quality designation and joint spacing in the rock mass classification system.Moreover,in practical application,the acquisition of rock quality designation and joint spacing is often difficult,and the designation and joint spacing are directional and uncertain.Based on this,this paper proposes to use the rock mass intactness index to replace the rock quality designation and joint spacing in the original classification scheme,and establish an improved RMR classification system,which eliminates the field measurement and calculation of the two indexes and improves the work efficiency.According to the engineering example of Maerdang project,the classification results of this method are compared with the original RMR method and the national standard BQ.It shows that the results obtained by this improved classification method are between RMR and BQ.It is a feasible classification scheme and can be applied in further projects.