Abstract
The authors conducted an extensive open-cut survey on a grouted rock mass, which is a Triassic formation of sandstone inter-bedded shale. The salient results are:
1) From the traces of fractured obtained on both the horizontal and vertical sections of the excavation, three dimensional images for the distribution of original and grout injected fractures were obtained.
2) The directional distribution of the grout-injected fractures coincided with the one for all the fractures. Directional group sub-parallel to the geological bedding structures showed less tendency to be penetrated by grout than those of vertical or nearly vertical fractures.
3) The water/cement ratio of the grout dropped from 600% at mixing to about 80% after getting hardened inside the rock formation.
