| 摘要 |
A stress measuring rock support device is provided, such as a cable bolt (20) or friction stabilizer (52), which has an internal longitudinal cavity, such as a groove (44) or a flat section (48) on the kingwire (42, 46) or a hollow core (40) in the kingwire (38) or the like. One or more rigid wires or filaments (68) extend in such cavity and their ends are anchored at predetermined anchor points (A, B, C) within the cavity. The other ends of the rigid wires or filaments (68) are spring-loaded and are provided with movable actuators (76) having electrical contacts (78) which are in contact with a linear potentiometer and measure the displacement of the actuators (76) resulting from the stretch of the cable (20). This is then correlated to measure the cable load or strain resulting from the stress applied to the rock support device. The spring-loaded arrangement as well as the linear potentiometer and the actuators with electrical contacts are enclosed within a suitable cover to form an instrumentation head assembly (28) for the rock support device. <IMAGE> |
