| Summary: | 碩士 === 淡江大學 === 土木工程研究所 === 83 === The mechanical properties of the rock material and the jointed
rock are anisotropic due to the pre-existing cracks and joints.
To well predict the behavior of the prototype by the model
behavior, the failure modes and failure mechanism between pro-
totype and model must be similar to the scale effect due to
local failure. The deformation of the jointed rock masses is
mainly controlled by the behavior of the slip and rotation of
the rock block materials. When the rotation deformation of rock
block, blocky material clearly show that moment transfer(couple
moment) is important mode of load transfer and depends on
defor- mation mechanism. The proportional value of the
characteristic length and the contact area of blocky rock is
used to evaluate the scale effect on the various types of
jointed rock masses in this research. Therefore, the degree of
scale effect on the rock mass of various classes is evaluating.
Some conclusions are drawn from this reasearch: (1) The
characteristic length of horizontal formation is more larger
than that of dip formation. (2) Based on the comparison of
joint spacing and its calculating characteristic length for
various class rock masses, it finds that the scale effect is
marked in the rock mass of class-IV. (3) The scale effect is
obvious in the smaller scale of tunnel and in the cases of
class-V rock mass with square blocks. The marked scale effect
is observed for the larger scale tunnel in the class of rock
mass with slender blocks. (4) The degree of scale effect by
rotation deformation is dependent of block shape, stack
pattern, dip angle and overburden of the rock masses.
|
|---|
