1. Introduction
and Geology: The existing Jammu to Srinagar highway
connect Srinagar to Jammu and India which play a crucial role in the
field of land transportation. It is a very critical stretch having
steep and rugged terrain. Granitic gneiss rock at the above
said stretch belongs to Salkhala formation of Precambrian age.
Grey to dark grey granitic gneiss is well exposed along the
existing road with intercalation of quartzite and thinly layered mica
schist. Medium to coarse grained granitic gneiss is well
compacted, massive and partially weathered on surface with
normally dry to wet water condition. Rock slope at this location is having
an angle 60 to 80 degree, facing towards N 265-280 degree.
2. Rock Mass
Rating (RMR):Rock mass classification (RMR) system is introduced
by Bieniwaski in 1976 in details to classify the rock class based on
geo-mechnical characters in the field. This system is refined latter in 1989 to
estimate the strength of the rock mass. The following six
parameters are used to classify a rock mass based on values and rating (0
to 100):
a. Uniaxial compressive strength of rock material. b. Rock
Quality Designation (RQD). c. Spacing of discontinuities. d. Condition of
discontinuities. e. Groundwater conditions. f. Orientation of
discontinuities. The field data have been collected from sites which are
as follows:
Granitic gneiss consisting three sets of
joints including one sets of random joint. Most prominent foliation joint is
directed toward NE with moderate dip angle. 2nd set
of joint is directed opposite to foliation joint with moderate to high dip
angle. Third joint set directed perpendicular (SE and NWW) to foliation with
high dip angle. Sometime it is almost vertical. Joint planes are partiality
weathered, plane rough and open at surface. Persistence of joint sets is
moderate to high. Based of field data, granitic gneiss is classify as below at
this location.
