To investigate the effects of nearby blasting on a horseshoe tunnel and to analyze dynamic response and crack growth with different loading directions, five laboratory experiments were performed using granite specimens of a rectangle plate containing a blast hole and horseshoe tunnel structure. HS photography and digital image correlation (DIC) methods were used to visualize the highly transient process of crack propagation in the surrounding rocks when the sidewall, spandrel, vault, corner, and bottom floor were selected as the front blasting faces. According to the experimental results, the shock wave attenuated to stress wave when the wave arrived at the front blasting face of the tunnel, and the radial fracturing played a significant role around the tunnel. The radial cracks originated from the borehole and merged with the cracks which from the tunnel. The central damage area between the borehole and the tunnel were similar for different loading directions. The initial stress wave became weak when it arrived at the tunnel back blasting face, the combined action of the reflected and diffracted stress waves played an important role in the crack growth. The side cracks were more easily generated in the orthogonal corner, and their growth was strongly influenced by the loading direction. Therefore, the reinforcement of the existing tunnel was valuable along the connection direction and corners.

为了研究附近爆破对马蹄形隧道的影响，并分析不同加载方向下的动力响应和裂纹扩展，使用包含爆破孔和马蹄形隧道结构的矩形板的花岗岩样本进行了五个实验室实验。HS摄影和数字图像相关（DIC）方法被用于可视化裂纹扩展的高瞬态过程在周围岩石时的侧壁上，拱肩，拱顶，拐角，和底板被选择为最前面爆破面。根据实验结果，当冲击波到达隧道的前爆破面时，冲击波衰减为应力波，径向裂隙在隧道周围起着重要作用。径向裂缝起源于钻孔，并与隧道裂缝合并。对于不同的加载方向，钻孔和隧道之间的中心破坏区域相似。初始应力波到达隧道后部爆破面时变得微弱，反射和衍射应力波的共同作用在裂纹扩展中起着重要作用。侧面裂纹更容易在正交角产生，并且裂纹的生长受到载荷方向的强烈影响。因此，现有隧道的加固沿连接方向和拐角是有价值的。反射和衍射应力波的共同作用在裂纹扩展中起着重要作用。侧面裂纹更容易在正交角产生，并且裂纹的生长受到载荷方向的强烈影响。因此，现有隧道的加固沿连接方向和拐角是有价值的。反射和衍射应力波的共同作用在裂纹扩展中起着重要作用。侧面裂纹更容易在正交角产生，并且裂纹的生长受到载荷方向的强烈影响。因此，现有隧道的加固沿连接方向和拐角是有价值的。