1. AASHTO. Permanent ground anchor specification. In situ soil improvement technique, AASHTO-AGC-ARTBA TF27 Rep., AASHTO, Washington, DC, 1990.
2. ABAQUS. Version 5.8, Hibbit, Karlson & Sorensen Inc., Pawtucket, RI, 1998.
3. Barley AD. The single bore multiple anchor system. In: Proc. Of the conf. on ground anchorages and anchored struct., Institution of Civil Engineers, London; 1997a.
4. Barley AD. Properties of anchor grout in a confined state. In: Proc. Of the conf. on ground anchorages and anchored struct., Institution of Civil Engineers, London; 1997b.
5. An isoparametric joint/interface element for finite element analysis;Beer;Int J Num Meth Eng,1985