Damage Evaluation for Rock Burst Proneness of Deep Hard Rock under Triaxial Cyclic Loading

Shuang You,Zijian Zhang,Chenghan Zhang,Hongguang Ji

doi:10.1155/2018/8193638

Abstract

High stress and strong excavation disturbance are the main causes of dynamic disasters, rock burst in deep hard rocks, and are more frequent and violent than those in shallow, which seriously restricts the deep mining. Given rock burst encountered in deep mining of Lingnan metal mines, the optimized triaxial cyclic loading and unloading tests are designed to characterize the performance of rock failure and to evaluate the rock burst proneness. The correlation between elastic energy index and damage evolution is built, and rock burst proneness in each status is analyzed; furthermore, the dissipation energy in the failure process of deep rocks is explicated. In this paper, the law that the elastic energy index via damage increases is drawn. In terms of the dynamic disaster conditions in the deep rock, the identification approach for the damage zone of the rock burst is established.

Highlights

In China, Li et al [12] studied the criterion of fault instability in the form of energy
Surrounding rocks are the equilibrium states that are formed after destruction through tectonic movements. e mechanical properties exhibited by the surrounding rock are the postpeak strength characteristics, it is a loading/unloading process on the surrounding rock during the excavation, and the surrounding rock exhibits di erent postpeak characteristics under di erent loading and unloading paths
Samples are selected from the Lingnan gold mine at the depth of about 1,000 m, and the diameter of the specimen is 50 mm with the height of 100 mm. e triaxial cyclic loading and unloading tests use the TAW-2000 servorock triaxial testing machine. e axial and hoop extensometers are used to measure the deformation of rocks

Summary

Experimental Progress

Surrounding rocks are the equilibrium states that are formed after destruction through tectonic movements. e mechanical properties exhibited by the surrounding rock are the postpeak strength characteristics, it is a loading/unloading process on the surrounding rock during the excavation, and the surrounding rock exhibits di erent postpeak characteristics under di erent loading and unloading paths. E triaxial cyclic loading and unloading tests use the TAW-2000 servorock triaxial testing machine. E axial and hoop extensometers are used to measure the deformation of rocks. In the process of the tests, the load-unload cycles are controlled by the strain. The initial axial deformation reaches to 100 μm; the axial load decreases to 0.1 MPa; and the axial loading increased by 100 μm again, and the axial unloaded to 0.1 MPa, the cyclic loading test stopped till a rock failure. Con ning pressures 1, 5, 10, 20, and 30 MPa were separately conducted in the triaxial compression loadunload cycle tests. E servopressure machine is controlled by the deformation with a loading rate of 0.01 mm/min and an unloading rate of 0.04 mm/min Con ning pressures 1, 5, 10, 20, and 30 MPa were separately conducted in the triaxial compression loadunload cycle tests. e servopressure machine is controlled by the deformation with a loading rate of 0.01 mm/min and an unloading rate of 0.04 mm/min

Damage Analysis Theories of Rock Burst Proneness

MPa 1 MPa