Borehole deviation limits and injection permeability

Monitoring drilling deviation is important for drilling of boreholes and measuring injection rock per- meability by Lugeon value for safe and efficient drilling and grouting. This paper is aiming at the study drilling deviation and relationship between drilling and injection permeability at the depth of 100 m in dam of Pushi Riv- er. The results show that at different depths the deviation of grouting borehole is within the allowable range ac- cording to specifications. LU value decreases with the depth increased in general , but at the depths between 40- 41 m the permeability is 1. 5 LU , and at 24 m the LU value is the largest ( 2 LU ) in this site by this study. The study thus concludes that even though the rocks are hard and their injection permeability decreases with depth increased , good drilling practices including carefully considering technical and geological specifications can get good drilling boreholes.