56 In situ rock stress
To interpret these results further, we would have to study the 3-D
states of stress at the measurement points and obtain more information
on other faults and excavations in the area.
4.3 Additional points
The ISRM has published Suggested Methods (Kim and Franklin, 1987*)
for the four methods of rock stress measurement mentioned in Q4.3. In
the overcoring method, an initial borehole is drilled, the gauge installed
and a larger-diameter drill used to ’overcore’ the gauge. A technique has
now been developed’ - the ’compact overcoring’ technique (44.10) -
in which drilling at only one borehole diameter is required.
Useful references which comprehensively describe the subject of in
situ stress from the engineering viewpoint are given below.
(Conference proceedings) - Stephansson 0. (ed.) (1986) Rock Stress
and Rock Stress Measurements, Centek, Stockholm, 694pp.
(Book) - Amadei B. and Stephansson 0. (1997) Ruck Stress and Its
Measurement. Chapman and Hall, London, 490pp.
(Conference proceedings) - Sugawara K. and Obara Y. (eds) (1997)
Rock Stress. Balkema, Rotterdam, 552pp.
An idea of the in situ stress state in the continental part of the
Earth’s crust can be obtained from The World Stress Map. In this
project, which was initiated in 1986, stress measurement data have
been systematically collected and mapped. The data are available from:
http://www-wsm.physik.uni-karlsnthe.de/pub/Re197/wsm97.html
- Kim K. and Franklin J. A. (1987) Suggested methods for rock stress determination. Int.
J Rock Mech. Min. Sci. Geomech. Abstr., 24,1,53-73.