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| Experimental study on failure mechanism and bearing characteristic of double-pillar system |
| ZHOU Zilong，CHEN Lu，ZHAO Yuan，DONG Longjun，DU Xueming，CAI Xin |
| (School of Resources and Safety Engineering，Central South University，Changsha，Hunan 410083，China) |
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Abstract In order to understand the failure and bearing characteristics of pillars，the compressive tests on the single pillar and double-pillar specimens were conducted. The deformation，load and acoustic emission information of pillars were recorded and analyzed. It was found that when a single pillar was compressed，its bearing capacity decreased gradually with the propagation of micro-cracks. When it was not strong enough to bear the external load，the elastic energy stored in the test machine would release rapidly and caused the pillar to fail abruptly. In the compression process of the double-pillar specimen with two pillars having the same mechanical property，two pillars bore almost the same load and deformed simultaneously. In the compression process of the double-pillar specimen with two pillars having different mechanical properties，the pillar with the lower strength degraded earlier and lost the bearing capacity firstly. The load was then transferred to the other pillar. The system lost the bearing capacity when the macro-slip appeared in the pillar with the higher strength. For the multi-pillar systems，the strength of individual pillar，the inner stress state and the external load circumstance all have the influence on the final stability. In the underground mining practice，in order to prevent the massive pillar collapse effectively，it is wise and necessary to leave the barrier pillars among the normal pillars.
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2017, Vol. 36 
