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<p>This study employed a split Hopkinson bar (SHPB) system to conduct dynamic impact tests on granite, and then simulated its dynamic failure process. SHPB numerical models were established for prefabricated single and double crack granite with crack lengths of 8&#xa0;mm, 12&#xa0;mm, and 16&#xa0;mm to investigate the effects of crack length and number on their dynamic mechanical behavior and failure process. The results show that the presence of prefabricated cracks significantly reduces the dynamic peak stress of the rock. For example, when the pre-crack lengths are 8&#xa0;mm, 12&#xa0;mm, and 16&#xa0;mm, the peak stress of the rock is reduced by 4.19%, 5.22%, and 6.26% compared to intact rock, respectively. Furthermore, the dynamic peak stress of prefabricated double crack rock is lower than that of prefabricated single crack rock. Under dynamic impact, the failure process of both prefabricated single and double crack specimens involves initiation of cracks at the prefabricated crack tips, continued initiation and propagation of cracks, and a subsequent stage of gradual crack development. With increasing prefabricated crack length, the internal crack propagation process of the rock accelerates. Under the same prefabricated crack length, the crack propagation process of specimens with prefabricated double crack initiated earlier compared to specimens with prefabricated single crack. This study can provide theoretical guidance for assessing the stability of defective rock masses under dynamic impact loading.</p>

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Dynamic Response and Failure Behaviour of Tunnel Surrounding Rock with Prefabricated Cracks Under Impact Loading

  • 期刊论文

  • 发表日期：

    2025年12月19日

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  • Chang Yadong

摘要

This study employed a split Hopkinson bar (SHPB) system to conduct dynamic impact tests on granite, and then simulated its dynamic failure process. SHPB numerical models were established for prefabricated single and double crack granite with crack lengths of 8 mm, 12 mm, and 16 mm to investigate the effects of crack length and number on their dynamic mechanical behavior and failure process. The results show that the presence of prefabricated cracks significantly reduces the dynamic peak stress of the rock. For example, when the pre-crack lengths are 8 mm, 12 mm, and 16 mm, the peak stress of the rock is reduced by 4.19%, 5.22%, and 6.26% compared to intact rock, respectively. Furthermore, the dynamic peak stress of prefabricated double crack rock is lower than that of prefabricated single crack rock. Under dynamic impact, the failure process of both prefabricated single and double crack specimens involves initiation of cracks at the prefabricated crack tips, continued initiation and propagation of cracks, and a subsequent stage of gradual crack development. With increasing prefabricated crack length, the internal crack propagation process of the rock accelerates. Under the same prefabricated crack length, the crack propagation process of specimens with prefabricated double crack initiated earlier compared to specimens with prefabricated single crack. This study can provide theoretical guidance for assessing the stability of defective rock masses under dynamic impact loading.