ROCK ANCHORS-STATE OF THE ART. PART 3: STRESSING AND TESTING

In the first part of this paper the authors discuss special test anchors with reference to construction and testing conditions in Briain (Littlejohn 1970), Germany (din 4125:1972 and draft din 4125:1974), France (bureau securitas 1972) and Czechoslovakia (draft code 1974). The major advantages of test anchors are stated in relation to the information provided by adequate test procedures. The final part of the paper deals with the long-term behaviour of rock anchors in service, with particular reference to the load-retaining characteristics of anchors for periods in excess of 24 hours after final stressing. To illustrate the importance of the phenomena causing load loss, the authors, in discussing field observations, have assembled some of the better documented case histories. This is the third and final section of the paper on rock anchor stressing and testing. /TRRL/