Study on corrosion fatigue and damage of pre-stressed anchor affected to prevention and control of mine pressure bump

In order to study a safety reliability of a pre-stressed anchor with a corrosion fatigue and damage under complicated dynamic environment and chemical function, tensile failure tests were conducted in lab on the site samples and the selected pre-stressed anchors and the corrosion status of anchors were observed. The strength and tensile value of anchors with different corrosion degree were measured and were applied to establish a constitutive equation of incremental theory. In com bination with the corrosion damage model, sustained strain of transient stress anchor and the stress concentrated failure process of damage part under plastic conditio n were revealed. The study results showed that under dropwise corrosion status of anchors, the dynamic geological effect around anchor body would be serious. When the corrosion degree of pre-stressed anchor was over 8.21%, the brittle phenomenon of anchor would be obvious. At the moment, the extension of anchor body would b e minimal. At the middle and late period of mine roadway, the anchor corrosion would make tensile capacity reduced.The transient dynamic effect of deep mine circulati on would cause sliding zone around the anchor and the plastic tensile value of anchor would be increased. Under the stress status, the corrosion of anchor body would be more serious than single chemical corrosion degree. When the corrosion degree caused anchor body in a brittle status, the strength of anchor would be reduced over 15%，the tensile value would be reduced over 86.4% and the bump prevention effect of anchor with expansion and energy absorption function would be failure in the lat e support period.