Title: STABILISING ROCK SURFACES WITH A GLASS REINFORCED POLYMER SKIN |
Authors: Nemcik Jan, Baafi Ernest and Porter Ian |
DOI: 10.13168/AGG.2013.0021 |
Journal: Acta Geodynamica et Geomaterialia, Vol. 10, No. 2 (170), Prague 2013 |
Full Text: PDF file (1.2 MB) |
Keywords: bolts and anchors, TSL support, laboratory testing |
Abstract: Mine roadways developed in highly stressed strata are subject to roof shear, which under severe conditions may manifest as
the well known symptom of guttering, particularly at the roadway edge leading into the major horizontal stress. This roof
shear can progressively reduce the effectiveness of bolt confinement of the strata within the lower roof horizon affecting
stability of the immediate roof. This paper presents the results of a study to investigate the effectiveness of polymers as skin
reinforcement in highly stressed coal mine roadways, as they may provide better roadway skin support than the currently used
steel mesh. A large concrete block intercepted with artificial joints and reinforced with steel bolts without skin support, was
loaded until significant slip occurred along the joints. Upon loading, a roof cavity resembling a gutter developed, as some of
the jointed concrete parted from the free surface. In addition to bolts, subsequent models with identical fracture planes were
supported with steel mesh or with glass reinforced polymer skin bonded to the free side. Loads and displacements were
compared for models with and without skin reinforcement. As expected the skin support helped resist gutter formation, to
various degrees, while increasing the residual strength of the concrete block. It was found that there was significantly less
bedding displacements in models with the polymer skin, when compared with both steel mesh and no skin reinforcement.
This suggests that there would be benefits to using a spray on polymeric skin as surface support in roofs subject to severe roof
shear. |