EVALUATION OF MANY LOAD TESTS OF PASSIVE ROCK BOLTS IN THE CZECH REPUBLIC

Abstract

Within the research project "FR-TI4/329 Research and development - creating application system for the design and analysis of soil and rock anchors including the development of monitoring elements" was carried out extensive stage of field load tests of rock bolts. Tests were conducted at 14 locations with varied rock composition. Before the initial tests were designed and constructed loading stand. It was performed a total of 201 pieces of tensile tests for bolts lengths from 0.5 up to 2.5 m, a diameter of 22-32 mm. It was a fully threaded rods, self-drilling rods and fiberglass rods. Bolts were clamped into the cement and resin. The loading tests were always in material failure or shear stresses failure by interface cement/rock. At each location basic geotechnical survey was carried out in the form of core drilling length of 3.0 meters with the assessment of the rock mass in situ and laboratory testing of rock mechanics. Upon completion of testing protocols and rock mass properties analysis was performed focusing on the evaluation of shear friction at the interface of grouting/rock.