Abstract:

Strongly weathered tuff geological condition was encountered under the construction of large crossing towers in the Yuhuan Substation–Yueqing Substation 500 kV double-circuit power transmission line project. Static pullout tests were conducted for nine single anchor foundations and six group anchors foundations. The variation of internal force and strain of anchors were tested and analyzed. Meanwhile, the failure modes and bearing characteristics of the rock anchor foundations were obtained. The experimental results show that the internal force of single anchor increases with the increase of load. The internal force decreases with the increase of buried depth, and reduces to zero beyond certain berried depth. The ultimate pullout capacity of group anchor foundation is not the simple sum of that of single anchor foundation, in which the group anchor effect exists. This study also provides a reference and basis for practical engineering application.

Key words: rock anchor foundation, ultimate uplift capacity, effective anchorage length, coefficient of group anchor effect