为减少动载荷作用下的隧道裂损，解决软硬复合地层中隧道力学响应复杂与裂纹扩展规律尚不明确的问题，利用含圆形孔洞的软硬岩组合隧道模型试样，进行霍普金森压杆（SHPB）冲击试验，结合基于数字图像相关技术的动态变形测试系统进行试验，获得不同软-硬岩界面角度（软-硬岩交界面与应力波入射方向夹角）下隧道周边应变演化进程，以及隧道围岩起裂、裂纹发展规律和破坏特征。研究结果表明： 1）随着软-硬岩界面角度的增加，试样动态抗压强度呈现出“先增加、后减小、再增大”的变化趋势，软-硬岩界面角度为60°时试样动态抗压强度最低。2）软-硬岩界面角度对隧道围岩破裂具有较大影响，不同角度下隧道围岩出现4种类型的裂纹，①沿软-硬岩界面扩展的裂纹； ②起源于隧道左侧帮、沿应力波传播方向扩展的裂纹； ③起源于隧道底板、沿应力波传播方向扩展的裂纹； ④与软-硬岩界面裂纹搭接、沿应力波传播方向扩展的裂纹。3）软-硬岩界面角度不同时，宏观裂纹受到不同的拉伸、剪切作用，最终导致隧道围岩破坏。不同角度下隧道围岩均产生沿软-硬岩界面扩展的裂纹，界面处需考虑加强支护。

To mitigate tunnel damage under dynamic loads, and address the challenges of complex mechanical responses and unclear crack propagation behavior of tunnel surrounding rock in mix ground, an impact test is conducted using a split Hopkinson pressure bar (SHPB) system. This test is conducted based on a soft and hard rock composite tunnel model with a circular cavity. The digital image correlation method is employed to observe the strain evolution around the tunnel, crack initiation, crack development, and failure modes of the tunnel surrounding rocks under different dip angles of the interface between the soft and hard rock layers. The dip angle refers to the angle between the interface and the incident direction of the incoming stress wave. The results reveal the following: (1) The dynamic compressive strength of the sample changes with the dip angle, showing a pattern of "increase, decrease, and then increase again". The lowest dynamic compressive strength occurs at a dip angle of 60°. (2) The dip angle at the interface between the soft and hard rock layers significantly affects the fracture behavior of the tunnel surrounding rocks. Four main types of cracks are identified at different dip angles: cracks extending along the interface between the soft and hard rock layers, cracks starting from the left side of the tunnel and spreading in the direction of the stress wave，cracks initiating from the tunnel floor and extending along the direction of the stress wave, and cracks overlapping with the fracture propagating along the interface. (3) Different dip angles expose the macroscopic cracks to different tensile and shear forces, leading to diverse failure modes. Cracking along the interface between the soft and hard rock layers occurs in the tunnel surrounding rock at various dip angles. This indicates that reinforcement support should be considered at the interface.