STABLE CRACK PROPAGATION STUDIES IN MARBLE AND TRAVERTINE

7th International Scientific Conference - SGEM2007, www.sgem.org, SGEM2007 Conference Proceedings/ ISBN: 954-918181-2, June 11-15, 2007

ABSTRACT

The crack propagation researches carried out on rock and rock mass are
important in mining, petroleum and natural gas engineering studies. It
is assumed that crack propagation is an important design parameter in
underground and open-pit mining applications. It has positive effects in some
mining activities such as drilling, blasting, excavating, block caving but also
negative effects due to cracks formed around mine roadways, tunnels and in
landslides. In this research, the marble and travertine were selected as natural
model materials. They have different texture, porosity, strength and natural
water contents. Double cantilever beam specimens were prepared from blocks.
These model samples were tested by hydraulic press which has 3000 kN capacity
with 0.2 kN divided scale. The vertical and horizontal deformations formed on
samples during crack propagation were measured by dial-gauge which has an
accuracy of 0.01 mm. Stable crack propagation was observed by video camera.
The crack propagation on samples was analyzed using data-base obtained from
test results. As a result, the effect on the crack propagation of the texture, initial
crack length and also fracture toughness depend on load were discussed and
their interpretations were presented in this paper.

Keywords:
Fracture toughness, strength, double cantilever beam (DCB).