南通大学学报（自然科学版）

针对岩石中裂隙广泛存在且其几何特征会影响岩石力学特性的问题，有别于以往隧洞与裂隙相互作用研究多聚焦于直裂隙，本文探究曲形裂隙与隧洞的相互作用机制。运用离散单元法，采用PFC2D软件建立含曲形裂隙的隧洞模型，通过设置无曲形裂隙（方案A）及不同方位角曲形裂隙（方案B1～B5,β分别为0°、60°、90°、135°、180°）共6种计算方案，模拟加载过程，分析裂纹扩展、应力-应变曲线等。结果表明：曲形裂隙位置显著影响隧洞破坏模式、应力-应变曲线特征及峰值强度。无裂隙时破坏模式对称，有裂隙时随方位变化裂纹扩展复杂；无裂隙模型弹性刚度高、破坏突然，含裂隙模型弹性刚度低且塑性阶段曲线变化与裂隙方位相关；峰值强度无裂隙时最高，含裂隙方案中β=90°时相对较高、 β=60°时最低。无裂隙时隧洞裂纹扩展受自身形状和荷载控制，呈对称渐进式；含裂隙时，不同方位角下裂纹扩展方向和形态各异，β=0°时仅在隧洞周围产生裂纹扩展，β=90°时曲形裂隙与隧洞产生搭接裂纹；应力-应变曲线各阶段特征因裂隙存在和方位不同而变化。该研究成果有助于深入理解隧洞-曲形裂隙相互作用，可为隧洞工程设计、施工及安全运行提供参考，也为后续研究奠定了基础。

In view of the widespread existence of cracks in rocks and their geometric characteristics affecting rock mechanical properties, and the previous studies on the interaction between tunnels and cracks mostly focused on straight cracks, this study aims to explore the interaction mechanism between curved cracks and tunnels, and provide references for tunnel engineering design, construction and safe operation. By using discrete element method and PFC2D software,a tunnel model with curved cracks was established. Six calculation schemes without curved cracks(scheme A) and curved cracks with different azimuthing angles(scheme B1-B5, β = 0°, 60°, 90°, 135°, 180°) were set up to simulate the loading process. Crack growth and stress-strain curves were analyzed. The location of the curved fracture significantly affects the failure mode, stress-strain curve characteristics and peak strength of the tunnel. When there is no crack, the failure mode is symmetrical, and when there is a crack, the crack propagation is complicated. The intact model has high elastic stiffness and sudden failure, while the model with cracks has low elastic stiffness and the curve change of plastic stage is related to the crack orientation. The peak strength is the highest when there is no crack, β =90° is relatively high in the scheme with crack, β = 60° is the lowest. When there is no crack, the crack growth of tunnel is controlled by its own shape and load, and is symmetrical and progressive. The crack propagation direction and shape are different under different azimuths. When β = 0°, crack propagation occurs merely around the tunnel;when β = 90°, curved fissures interconnect with the tunnel via coalesced cracks. The characteristics of each stage of the stress-strain curve vary with the existence and orientation of cracks. The results of this study are helpful to further understand the tunnel-curve fracture interaction, provide critical theoretical insights and practical references for the design, construction, and safety assessment of tunnel engineering structures.