Knowledge based system on laboratory tests on the static and tensile performance of steel welded mesh support: IMCET 2019 / ANTALYA / TURKEY / April 16 – 19

Abstract

Previous studies have reported that the major function of mesh (welded or diamond) is to maintain the load bearing capacity of the rock mass along the excavation boundaries. Rock bolts are mostly used to control the overall stability of the excavation through arching, keying or reinforcement actions, while a mesh is installed to retain small to large pieces of loose rocks. Further studies have pointed out that the mesh support is more effective in building up hangingwall pressure to inhibit further slabbing at the vicinity of the bolt pattern. A detailed study on static performance tests on the welded mesh with the configuration of 5.6 mm diameter wires spaced at 100 mm centres and the mesh sheet of 1.5 m wide and 3.4 m long was done. The test was followed by the breaking strength/ tensile tests on the mesh strands to identify the maximum load that each mesh strand can withstand. For static tests, mesh samples were bolted onto the test frame in series with load cell and it was installed between the upper and lower platens of the 8 896 kN Mohr & Federhaff compression testing machine. The increase in load was applied gradually in perpendicular to the plane of the mesh through 500 mm long line loading interface across the wires. This loading was performed until the specimen failure took place. On the other hand, tensile tests of each strand of the mesh were performed through pulling the steel welded mesh strand until it breaks. Based on the three static tests results, it was noted that welded mesh can withstand several forces at a maximum force of 27 kN, 35.2 kN and 37 kN with the maximum displacement of 420 mm throughout the tests. On the other hand, tensile tests/ breaking strength results have shown that mesh strands can withstand maximum load ranging between 10.35 kN to 13.85 kN. It was then concluded that welded mesh has the ability to withstand the maximum load of 37 kN, with the displacement of 410 mm, while mesh strand was found to break at maximum of 13.85 kN.