Volume 31, Issue 4 (July 2008)
A Polyaxial System for Testing of Jointed Rock Mass Models
A polyaxial loading system was designed and developed at Indian Institute of Technology Delhi, India for laboratory testing of mechanical behavior of rock mass. The large-scale rock mass models of different joint geometry can be tested under polyaxial stress state simulating in situ stress conditions using this true-triaxial system. The system consists of a 1000 kN capacity vertical frame, a biaxial frame of 300 kN capacity fitted with two pairs of hydraulic jacks and platens, constant confining pressure unit for applying, monitoring, and maintaining horizontal stresses (σ2 and σ3) on specimen faces, eight-channel data acquisition system, and a personal computer to record all load and deformation data. Its working was verified by conducting true-triaxial testing on several models specimens of sand-lime blocks having three sets of orthogonal joints.