香炉山隧洞龙蟠-乔后断裂带西支蠕滑特性与位错模式

Creep Characteristics and Dislocation Mode of the West Branch of Longpan-Qiaohou Fault in Xianglushan Tunnel

为了全面认识活动断裂蠕滑运动的位错规律,以滇中引水工程香炉山隧洞的龙蟠-乔后西支断裂带(F10-1)为工程依托。综合地质条件、岩性参数和力学特征,建立F10-1的地质概化模型。研究整个服务周期内,断裂带的错动变形规律。考虑不同破碎带宽度和不同断层倾角的影响因素,分析其位错变形特征和位移梯度,并讨论隧洞的稳定性。结果表明:断裂带的位错模式较为相似,呈现“坡面”型。强度较大的错动盘呈现平动的位移模式,位移主要发生在软弱岩层的破碎区。随着服务年限增加、破碎带宽度增大和断层倾角减小,破碎带位移随之增加。由上影响带与破碎带交界面位移可知,隧洞的左肩窝位置存在较大变形(除30°和50°,其最大变形位于隧洞左侧);由位移梯度分布规律可知,位移梯度呈现先增加后减小的“单峰”分布特征,且峰值位于破碎区。峰值大小随着服务年限和断层倾角的增大而增大,随着破碎带宽度的增大而减小。研究成果可以为滇中引水工程隧洞的安全建设提供有力的支撑。

The aim of this research is to comprehensively understand the dislocation law of creep movement of active faults.The west branch of Longpan-Qiaohou fault zone(F10-1)in Xianglushan tunnel of the Central Yunnan Water Diversion Project is taken as research background.A generalized geological model is established to investigate the dislocation law of F10-1 in the whole service period according to geological condition,rock parameters and mechanical performances.The dislocation deformation characteristics and displacement gradients are analyzed,and the stability of the tunnel is discussed in consideration of width of fracture zone and dip angle of fault.Results reveal that the dislocation patterns of the fault zone are similar,showing a sloping type.Strong dislocation disk presents a translational displacement mode,with displacement mainly occuring in the fractured area of weak rock formation.The displacement of fracture zone increases with the increasing of the service life and the fracture zone width as well as the decreasing of fault’s dip angle.According to the displacement of interface between upper influence zone and fracture zone,a large deformation in the left shoulder socket of the tunnel(except for 30°and 50°)is found.The maximum deformation is located on the left side of the tunnel.The displacement gradient presents a single peak at the fracture zone;the peak of displacement gradient increases with the growth of service life and fault dip,while reduces with the expansion of fracture zone width.The research results offer strong support for the safety construction of Central Yunnan Water Diversion Project.