Lugeon Test and Grouting Application Research Based on RQD of Grouting Sections

Rock quality designation (RQD) and permeability coefficient are important reference indexes for grouting application. Based on the readily available RQD, RQD is found to have no relationship with the depth of rock stratum, and a method for calculating the mean RQD (RQD(m)) of long stratum is proposed, which is applied to the calculation of RQD of grouting sections. Through Lugeon and grouting tests on the grouting sections, RQD(m) of the grouting sections is found to be directly related to the average permeability coefficient, permeability, and units of grouting per amount of rock mass. It is found that RQD(m) has a symmetrical relationship with permeability and grouting volume as well as a negative exponential correlation with unit grouting volume and average permeability coefficient. According to the curve of RQD varying with depth, the grouting amount at different depths can be obtained by using the fitting formula of unit grouting amount and RQD(m).