Mechanical characteristics and practical application on stress shell of roadway surrounding rock

The mechanical characteristics of roadway surrounding rock stress shell and its effects on the stability of roadway surrounding rocks were investigated using the integrated research methods of numerical simulation,field meas- urement,and theoretical analysis. The results show that the stress shell composed of continuous concentrated stress ap- pears in the roadway surrounding rocks after the excavation of roadway. Roadway lies in the low stress zone under stress shell,and the strata behaviors of roadway are controlled by the surrounding rock stress shell and its spatial evolu- tion. The spatial distribution shape of roadway surrounding rock stress shell have a decisive influence on the stability of roadway surrounding rocks,and also there exists in two forms:stable and unstable. The stability control of roadway sur- rounding rock should be premised on guaranteeing the stability of roadway surrounding rock stress shell. Controlling the minimum deformation of roadway surrounding rocks through scientific roadway layout and effective supporting measures is a key to optimize the shape of surrounding rock stress shell and guarantee the stability of roadway surrounding rocks. Research and engineering practice all indicate that the direction of the maximum horizontal principal stress has an important influence on the evolution of roadway surrounding rock stress shell and the stability of surrounding rocks.When the roadway axial direction is parallel to the direction of the maximum horizontal principal stress,a stable stress shell easily exists in roadway surrounding rock,and the roadway is easy to be maintained. When the roadway axial di- rection is vertical to the direction of maximum horizontal principal stress,an unstable stress shell easily exists in road- way surrounding rock,and the roadway is difficult to be maintained.