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| The influence mechanism of smooth blasting forming of jointed rock mass tunnel |
| MA Chenyang, HU Yingguo*, LIU Meishan, XU Chenyu, HUANG Yuejun
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| Changjiang River Scientific Research Institute, Wuhan 430010, Hubei, China |
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Abstract In response to the serious problem of over- and under-excavation in the drilling and blasting excavation of jointed rock masses, the HJC(Holmquist-Johnson-Cook)model combined with compressive-shear and tensile-shear failure criteria was employed to analyze stress field distributions near profile blast holes and crack evolution paths under different joint characteristics. The results indicated that crack propagation was significantly affected by the dip angle, thickness, and strength of the joints.The most severe over- and under-excavation occurred when the angle between the joint and blast hole axis was 45°, forming a distinct “Z”-shaped profile. The weaker the joint strength was, the stronger the barrier effect on the explosion stress wave and the tensile failure effects would be. The same principle applies to the width of joints. Integrating the influence mechanism and practical effects of joint characteristics on contour formation, this research proposed a “blank hole induction” layout scheme for smooth blasting holes and optimized detonation sequencing measures. The research enriched the theory of directional fracture and contour forming in smooth blasting.
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Published: 19 September 2025
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