Debris At The Junction Formation Tunneling Surrounding Rock And Support Structural Stability Analysis

The earth-rock interface stratum is one of the geological conditions encountered in tunnel construction, the most notable feature shows in the uneven strength of the surrounding rock. The careless in construction or improper support can cause some disasters, such as landslides and support cracking, which can result in schedule delays, economic losses and even loss of life. Therefore, the stability construction of surrounding rock and support structure is extremely important when tunneling in the earth-rock interface stratum.Based on the background of Miandu tunnel and Jiangmen tunnel, the stability of the surrounding rock and supporting structure are studied deeply using field test and ABAQUS in this thesis, and discuss on construction and supporting measures for tunneling in the earth-rock interface stratum. The main work of this thesis are the folio wings:1. The security risk of tunnel construction is Investigated by collecting the tunnel instance, when tunneling in the earth-rock interface stratum, and the risk factors is analysised.2. By collecting the formation information about earth-rock interface stratum encountered in Miandu tunnel and Jiangmen tunnel, the characteristics of surrounding rock and the uneven distribution of the strength are discussed. The date collected in single stratum and the earth-rock interface stratum is comparatively analysised to summarize the deformation and internal forces of supporting struction. Additionally, based on the test results, the stability of surrounding rock and primary Support is assessed during the construction period.3. The earth-rock interface stratums encountered in tunnel are classified from the transverse and route strike of tunnel, and to develop simulation programs, two-dimensional or three-dimensional tunnel simulation are made to simulate tunnel excavation using ABAQUS, Analysing the laws of the plastic failure,deformation and stress change and the in earth-rock interface stratums and deformation and internal forces of supporting struction. And, stability of the rock and supporting structure is evaluated on the condition of different parameters and stratum conditions.4. Based on the field testing and numerical simulation results, asymmetric support and advance pre-support measures are studied when tunneling in the earth-rock interface stratums. In addition, excavation method and blasting are disscussed to overcome the difficulties encountered in tunnel construction.