The Rock Mechanics Laboratory of the Negev has been developed in order to meet the rising demand for advanced geological engineering input in current projects in Israel which have an impact on the environment, with particular emphasis on the Negev. The laboratory was established in April 1994.
The role of the Lab in the development of the Negev
The Negev is rapidly developing and its infrastructure is being improved continuously. Several sophisticated projects are planned and some are already under way. All projects involve the interaction of man with the environment, by the introduction of new loads to the rock mass. The successful execution of projects which involve surface and underground excavation depends therefore on the availability of a testing facility which can simulate the excavation induced loads on representative samples of the rock mass. Rock engineering projects which are currently under design or construction include:
Compressed Air Storage Plant
Underground storage of hazardous waste
Water and Sewage Tunnels
Open Pit Mining
Support Design for Ancient Underground Sites in Discontinuous Rock
Rock slope stability analysis and design
The Rock Mechanics Laboratory of the
Negev has been involved in the design and planing of such projects since its was
established in April 1994. Selected research projects in geological engineering
and rock mechanics can be viewed at the website of
Yossef H. Hatzor, director of the geological engineering program . In addition, basic research in rock
physics and in particular on electromagnetic radiation during rock fracture
processes is conducted at the lab since its establishment. The electromagnetic
radiation research group is directed by Prof. Dov Bahat
and details can be found in his home page.
Technical description of the Lab
Hydraulic, stiff, closed-loop servo controlled triaxail system. Load frame stiffness 5*109 N/m (TerraTek model FX-S-33090 ). Two control modes are possible for the axial piston: Load and Displacement. Axial force capacity: 1.4 MN. Confining pressure capacity: 70 MPa. Simultaneous electronic measurement of axial and radial strain using a two special four arm strain cantilever system sets with a maximum strain range of 7% . Precision: 0.25 - 0.5% linearity full scale on all strain/displacement transducers as well as load cells. Two load cells (LC) are currently in service: 1000 kN LC for strong rocks, and a 222 kN LC for weak rocks to allow for better resolution in low stress measurements. Using the close-loop system the following tests can be performed:
stiff, closed-loop servo controlled,
direct shear system. Load frame stiffness 7.0 MN/m (TerraTek
DS - 4250).Normal force capacity: 1000
kN, Shear force capacity: 300kN. Shear box
dimensions: 150mmX150mmX300mm. Normal load measured with a 1000kN LC with 0.5%
linearity full scale. Shear load measured with a 300
kN LC with 0.5% linearity full scale.
Vertical (normal) displacement measured with four 50mm range
LVDT's with 0.25% linearity full scale. Shear
displacement measured with two 50mm range
0.25% linearity full scale.
hydraulic, mini-load frame for
Point Load, and
Uniaxial tests according to ASTM and ISRM standards (SBEL model
Ultrasonic wave velocity for P and S wave determination on cores
according to ASTM and ISRM standards.
Sample preparation lab, fully equipped with a high precision drill
press, saw, and surface grinder. NX size solid cylinders are prepared
according to ASTM and ISRM standards regarding end roughness (smaller than
0.02mm) and perpendicularity (to within 0.005 radians).
Soils Classification Equipment
Hammer test device (ASTM, ISRM).
durability test device (ASTM, ISRM).
Helium porosimeter (CoreTest Inc., model PHI-220) for direct porosity measurements.