현장암반 평가에 관한 제안

Abstract

In rock mass classification, rock condition is expressed numerically by grading the rock properties that affects stability of tunnel, underground cave, dam, foundation excavating and rock slope. Rock mass classification is an important indicator that gives information that is necessary for economical and effective excavation and support design. Furthermore, it gives quantitative data and guide line for design and provides basic information for communication between engineering and geology. The purpose of this study is to find out rock mass classification method which is practically applicable in the field and to consider a correlation between the new method and the old method. Rock mass is an aggregate of separated blocks. To express the aggregate, the properties of both intact rock and rock mass should be considered. In this study, therefore, parameters for rock mass description are classified into rock strength and rock structure. Rock strength is evaluated by point load strength and joint condition and rock structure is evaluated by RQD and joint spacing. Indices for parameters evaluation are obtained from old method and by using those indices the strength and structure property of rock is described. Each obtained parameter is allocated 25 points. In rock mass classification, point graph of each parameter is used so that it is easy to understand the rough properties of rock mass. Probability between rock mass and classification point and grade is illustrated by using the graph. Moreover, a rock mass evaluated by RMR is classified by the method that is proposed in this study and the corelation with RMR is derived. As a result of that, is derived between RMRbasic and this study and is derived between revised RMR and this study. Coefficient of determination is R2=0.841 and R2=0.846 each.