THE APPLICATION OF A NON-DESTRUCTIVE METHOD FOR EVALUATION OF DISCONTINUITY OF A CEMENT LAYER SURROUNDING A ROCK BOLT GROUTED IN ROADWAYS UNDERGROUND

摘要

One of the obstacles in making inrnsitu measurements, especially in severernenvironmental conditions, is lack of a relativelyrnlow cost apparatus used for acquiring andrnrecording data. These severe conditions arernfrequently met in coal mines where rock bolts arerninstalled to support roof sections. Because of thisrnthe aim of the work undertaken by the author atrnthe first stage was inventing and constructing ofrna portable measurement system. As arnprogramming tool the LabVIEW program wasrnused and as hardware a DAQ card (datarnacquisition card) installed on a laptop platformrnand worked out conditioning signal unit werernintroduced to the measurement chain. After thatrnstage a process of calibrating was realized andrncomparison of results with those obtained on arnlaboratory stand was made. Having thernapparatus validated the data base of differentrncases of discontinuity of a cement layer, whenrnrock bolts are grouted into a rock, wererncalculated. Finally measurements in real workingrnconditions were performed and condition ofrngrouted rock bolts was check out.