Stress arch bunch and its formation mechanism in blocky stratified rock masses

Stress arch is a common phenomenon occurring in continupous materials and has also been proved to have great influences on the self-stabilization of soils or rock masses after excavation. In this paper, based on UDEC simulation, stress redistribution after excavation is investigated for a kind of special discontinuous material, i.e. blocky stratified rock mass. A layered stress arch system is observed with each stress arch lying over another. This special phenomenon is defined herein as “stress arch bunch”. Effects of dip angle of bedding plane, lateral pressure and joint offset on this stress arch bunch are studied. Its formation mechanism is also discussed based on voussoir beam theory.