Compressive mechanical performance and constitutive model of shotcrete-surrounding rock composite
To investigate the compressive mechanical properties of shotcrete-surrounding rock composite,uni-axial compression tests were conducted on four different shotcrete-surrounding rock composite specimens using three-dimensional digital image correlation technology.The effects of fiber and rock type on the failure mode and compressive performance of the composites were explored.Based on Weibull statistical damage theory,a constitutive model of compressive stress-strain suitable for composites was constructed.The test results show that the failure modes of the composites with different surrounding rock bases are significantly different,but microcracks all develop first from the shotcrete.At failure,the surrounding rock part exhibits a single crack mode,while the shotcrete part shows a multi-crack expansion state.The peak strengths of the four composites are higher than the failure strength of single shotcrete,and the peak strengths of sandstone-based composites are higher than those of granite-based composites,with an average increase of 5.55％.Under the same sur-rounding rock conditions,the strengths of composites with fiber-reinforced shotcrete are slightly reduced,with an average decrease of 1.95％compared with composites with ordinary shotcrete.In addition,the model cal-culation results are in good agreement with the test data.
shotcretesurrounding rockthree-dimensional digital image correlation(3D-DIC)crack propa-gationconstitutive model
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