Rock Slope Stability

摘要

The use of down-hole televiewer methods can result in much improved confidence in rock mass conditions and structural data sets, which, in turn, can result in greater confidence in slope designs. Such systems can be used in all rock masses. Very heavily fractured rock masses can be lined with PVC to ensure borehole stability and orientation by ATV. The use of televiewer systems maximizes data from drill holes and represents a minimal cost in relation to a drilling programme - typically 10-20% of the total drilling cost, although it can be much less if using existing open holes or very deep boreholes. The advantages of using the system are: 1. Increased rock mass rating (only logging natural open structures) 2. More accurate fracture frequency/joint spacing calculation 3. Reduced variability in the orientation of major joint sets 4. Higher confidence in small-scale structures within the rock mass 5. Increased confidence in the orientation, locations and thickness/intensity of major structures 6. Provides fileable data that can be reassessed if necessary 7. Can be carried out on stable old boreholes and does not always require new drilling programmes.