Fault Of Regional Tectonic Stress Field Characteristics, And Its Analysis Of Tunnel Surrounding Rock Stability Impact

The geological structure of Huilong Shan tunnel and Bai Shan tunnel in highway from Qujiang to Nanxiong lying in the city of Shaoguan is complex, the major mutual crossover faults of F1, F2, F13, F3, F4, F5 and F6 crosscut tunnel body, resulting in rock crushing, rock-level low. The reason for the effect of geological structure, rock fissures, strong corrosion, the water conductivity of F1, F2 faults and connected with underground caverns, maks a greater impact on construction during the rainy season; The existence of fault's fracture zone, easily induces geological hazards such roof fall, landslides and "Babel" after the tunnel excavation; Tunnel folds is broken and turn and fold repeatedly, connecting with faults, sinkholes and collusive network karst, which is easy to form a groundwater concentration of tissue and cause a sudden water and sudden mud; At the same time, the tunnel intersperses in stratum soft and hard interacted, and is very likely to collapse, which will result in greater impact on the tunnel construction and future operations. Relying on the Huilong Shan and Baishan tunnels of Shao Gan highway, this paper presents a study as the following:1. According to tunnel site of geological and structural characteristics, analyzed the fault structural planes forming mechanical mechanism in tunnel site, used the method of stereographic projection graphic out the site faults of Huilong Shan and Bai Shan tunnel in the main stress field direction, and identified the the specific location relationship of the main stress field direction and the Huilongshan tunnel trend.2. To facilitate the tectonic stress field of faults in being imposed on the numerical simulation model, derived the matrix expressions of three dimensional geometric transformation and three dimensional coordinate transformation, determined the relationship between the fault main stress field and the tunnel excavation face in the same space Cartesian coordinate system.3. Based on the Monitoring site data of Huilongshan tunnel, put the tectonic stress field of fault into displacement back analysis, and Verified the accuracy and reliability by considering a positive Operator.4. According to the inverted fault tectonic stress characteristics, simulated the dynamic construction of excavation and support with FLAC3D numerical methods, and analyzed the stability of surrounding rock of the tunnel.