Experimental Study of the Failure Mechanism of Rock Bridge

The effects of joint overlapping on shear behaviors of a rock bridge under high normal load were experimentally investigated. The model material used in preparing intact samples and jointed blocks was a mixture of plaster (37.5 %), cement (25 %) and water (37.5 %). Mixing, casting and curing of specimens were carefully controlled to obtain reproducible properties. Uniaxial and triaxial compressions besides the Brazilian tensile tests were performed by Machine Tool System (MTS) in a Rock Mechanics Laboratory at Graz University of Technology for determining the mechanical properties of intact model material. Seven samples with similar ligament lengths of 45 mm and different ligament angles of 0°, 25°, 50°, 75°, 90°, 115° and 140° were prepared (ligament length is the distance between the tips of two joints and the ligament angle is the counterclockwise angle between the ligament length and shear axis. By using direct shear testing, the failure process was visually observed and failure patterns were watched to be reasonable in accordance with logical results.

کلیدواژه ها:

Rock Bridge ، Joint Overlapping ، Shear and Tensile Cracks