Anchoring properties and CT analysis affected by the pyrolysis of the resin anchoring material at high temperature#br#
SU Xuegui1,2,DU Xianjie1,ZHANG Suo1,YANG Zongyi1,GUAN Jie1
(1. College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;2. State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221008,China)
Abstract:Resin anchor material has been widely used in underground engineering supporting. The pyrolysis characteristics of resin anchor material at high temperature directly affect its anchoring mechanical properties. The mechanical properties and variation characteristics of mesoscopic structures were analyzed using the pull-out tests and compression experiments and micro-CT scans undertaken at high temperatures. The high-temperature pull-out test results show that the anchoring force increases as the temperature increases from 20 ℃ to 250 ℃ and reaches the peak of 69.5 kN at 250 ℃ with an increase of 45.1% compared with the normal situation,which is due to the full solidification of the internal material. At the temperature of 250 ℃ to 350 ℃,the anchoring force is reduced to 47.2 kN,with a decrease of 29.2% compared with the peak value. At temperature of 350 ℃ to 400 ℃,the anchoring material in the simulated tube bursts and chars severely,with the average anchor force dropping to 15.2 kN. The anchoring force was completely lost from 500 ℃ to 600 ℃. In the high temperature compression experiments,the strength reaches the peak of 65.8 MPa at 200 ℃,with an increase of 31.3% compared with normal situation. At 350 ℃–400 ℃,the intensity reduces 95.2% compared with the normal value and at 600 ℃,the strength reduces 99.3%. CT analyses show that the average grey scale of the anchoring material reduces 22.6% at 350 ℃–500 ℃. The size of pore group increases 199.6%. Hence,the rapid pyrolysis and charring of resin anchoring material after 350℃ and the dramatic increase of internal pores are the fundamental causes of anchoring force attenuation.
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SU Xuegui1,2,DU Xianjie1,ZHANG Suo1,YANG Zongyi1,GUAN Jie1. Anchoring properties and CT analysis affected by the pyrolysis of the resin anchoring material at high temperature#br#. , 2016, 35(5): 964-970.
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