Luo Yi, Pei Chenhao, Qu Dengxing, Li Xinping, Ma Ruiqiu, Gong Hangli
Hubei Key Laboratory of Road-Bridge and Structure Engineering, Wuhan University of Technology, Wuhan, 430070, China.
Sanya Science and Education Innovation Park, Wuhan University of Technology, Sanya, 572000, China.
Sci Rep. 2022 Mar 16;12(1):4478. doi: 10.1038/s41598-022-08560-y.
To explore the distribution of cracks in anchored caverns under the blast load, cohesive elements with zero thickness were employed to simulate crack propagation through numerical analysis based on a similar model test. Furthermore, the crack propagation process in anchored caverns under top explosion was analyzed. The crack propagation modes and distributions in anchored caverns with different dip angles fractures in the vault were thoroughly discussed. With the propagation of the explosive stress waves, cracks successively occur at the arch foot, the floor of the anchored caverns, and the boundary of the anchored zone of the vault. Tensile cracks are preliminarily found in rocks that surround the caverns. In the scenario of a pre-fabricated fracture in the upper part of the vault, the number of cracks at the boundary of the anchored zone of the vault first decreases then increases with the increasing dip angle of the pre-fabricated fracture. When the dip angle of the pre-fabricated fracture is 45°, the fewest cracks occur at the boundary of the anchored zone. The wing cracks deflected to the vault are formed at the tip of the pre-fabricated fracture, around which are synchronous formed tensile and shear cracks. Under top explosion, the peak displacement and the peak particle velocity in surrounding rocks of anchored caverns both reach their maximum values at the vault, successively followed by the sidewall and the floor. In addition, with the different dip angles of the pre-fabricated fracture, asymmetry could be found between the peak displacement and the peak particle velocity. The vault displacement of anchored caverns is mainly attributed to tensile cracks at the boundary of the anchored zone, which are generated due to the tensile waves reflected from the free face of the vault. When a fracture occurs in the vault, the peak displacement of the vault gradually decreases while the residual displacement increases.
为探究爆破荷载作用下锚定洞室的裂缝分布情况，基于相似模型试验，采用零厚度的粘结单元通过数值分析模拟裂缝扩展。此外，分析了顶部爆炸作用下锚定洞室的裂缝扩展过程。深入讨论了拱顶具有不同倾角裂缝的锚定洞室中的裂缝扩展模式及分布情况。随着爆炸应力波的传播，裂缝依次出现在锚定洞室的拱脚、底板以及拱顶锚固区边界处。在洞室周边岩石中初步发现了拉伸裂缝。在拱顶上部存在预制裂缝的情况下，拱顶锚固区边界处的裂缝数量随预制裂缝倾角的增大先减少后增加。当预制裂缝倾角为45°时，锚固区边界处出现的裂缝最少。在预制裂缝尖端形成了向拱顶偏转的翼状裂缝，其周围同时形成拉伸裂缝和剪切裂缝。在顶部爆炸作用下，锚定洞室围岩中的峰值位移和峰值质点速度在拱顶处均达到最大值，其次是侧壁和底板。此外，随着预制裂缝倾角的不同，峰值位移和峰值质点速度之间会出现不对称情况。锚定洞室的拱顶位移主要归因于锚固区边界处的拉伸裂缝，这些裂缝是由拱顶自由面反射的拉伸波产生的。当拱顶出现裂缝时，拱顶的峰值位移逐渐减小而残余位移增加。
