2009/2010 Stage 2 Problem Statement - SME

2009-2010 SME/NSSGA Student Design Competition
2.3. Geologic Structure
Through hand measurements and remote sensing methods, your geotechnical consultant
collected structural orientation data in the quarry. There are a total of four prevalent joint sets in
the rock mass which have the orientations as presented in Table 1.
Table 1: Dip and dip direction of joint sets at Bev Quarry
Joint Set Dip (degrees) Dip Direction (degrees)
J1 60 359
J2 78 212
J3 14 132
J4 78 306
The average dip and dip directions reported in Table 1 are based on 453 structural measurements
and the stereonet used to establish the joint sets is shown in Figure 1. It is evident that the
average dip and dip directions (and also the number of joint sets) is based on the judgment of the
Engineering Geologist who completed the field mapping and interpreted the stereonets.
Figure 1: Stereonet from Bev Quarry Rock Mass
The intersections of Joint Sets J2, J3, and J4 create orthogonal blocks. Joint Set J3 is associated
with faulting in the region and therefore, in many cases, this joint set is sheared, filled with clay
gouge, and slightly altered. Joint Sets J1, J2 and J4 are generally ‘clean’ and smooth or slightly
rough and moderately weathered.
4