Security And Stability Of The Tunnel And Under The Overlying Goaf

In recent years, many foundation engineering such as roads, railways, water conservancy, hydropower projects and facilities had to pass through or established on the goaf. Because of the needs of construction projects, in some special sections of geological and topographical conditions, however, caving of the goaf roof would directly affect the safe and stable operation of relevant projects in the overlying strata. So it is necessary to research the security and stability of the goaf and the associated works inside the goaf overlying strata.This article studied about Fuyuan County Kuaize River diversion tunnel and the lead-zinc goaf under the diversion tunnel, using "three zones" theory to analyze the goaf caving scope and application of numerical simulation software ANSYS diversion the safety and stability of the tunnel and the goaf. The primary coverage is as follows:(1) Consulted related literatures and materials at home and abroad, learned about status quo and methods that researched safety stability of the goaf and related projects in the overlying rock or on the surface at home and abroad.(2) Through on-site research and data collection, analyzed relationship of the relative positions between the goaf and the diversion tunnel, as well as theirs engineering geological conditions.(3) Discusses the failure mechanism of goaf surrounding rocks, as well as the destruction and the caving mechanism of the overlying rocks, calculated and analyzed the impaction of the goaf caving zone with "three zones" theory, then, determined the affected area of the goaf caving. Obtained a high degree of the goaf caving is far above the diversion tunnel, some sections are in goaf caving zone framework. Once goaf instability, caving zone will develop to the position of diversion tunnel, and diversion tunnel will be destroyed.(4) Carry out simulation analysis on the safety and stability of the goaf and the diversion tunnel by use of ANSYS numerical simulation software. The existence of the goaf, whether stressful condition or displacement, diversion tunnel is in a state of unsafety, goaf must be dealt with.(5) Simulated after reinforcing and processing the goaf witth support column. Reinforcement of the existing of the goaf, local diversion tunnel is stable, local is instability, diversion tunnel is unsafe in the whole. Filling is needed to deal with in the whole.(6) Simulated after filling the goaf on the basis of reinforcement, stressful condition of the goaf and the diversion tunnel has been significantly improved, displacement is significantly smaller. That is, after filling, the goaf is stable, and the diversion tunnel can be entire safe and stable operation.