Study On Prediction And Early-warning Of Geological Hazards During Tunnel Construction In Fault And Fracture Zone

Take the Qingdao Jiaozhouwan channel tunnel project as background, relying on the State "863 Project" syudy on tunnel that built on complicated geological conditions equipment and system of geologocal hazards early-warning .Aiming at the situation of frequent hazards happening during long and large tunnels construction under complicated geological conditions, and referring to massive literatures and theoretical analyses, based on analyzing the cause and the conformation characteristics of fault and fracture zone, dominant influencing factors of excavation in this zone are considered as well, the runnel geological prediction system for tunnel construction in fault and fracture zone is put forward by numerical simulation and theoretical analysis based on analyzing the cause and the conformation characteristics of fault and fracture zone, also, dominant influencing factors of excavation in this zone are considered . Some research achievements are shown as follows:1) On the basis of review to massive literatures, about the geological forecast methods for fault fracture zones, the characteristics and effect of present methods for predicting the geological conditions in advance are concluded. It makes us realize the present situation and development of application of tunnel geological prediction methods in fault and fracture zone.2) After studying the dominant influencing factors of tunnel excavation in fault and fracture zone, the numerical simulation is used to analyze the influence of individual factor to the stability of surrounding rock mass, moreover, the strain rule is obtained, which is analyzed in order to get the critical point of geological hazard and safe distance from tunnel heading face to fault and fracture zone (so-called predictable distance).3) By assessing present geological prediction methods, three key problems in geological prediction arise, e the geometrical imaging of target object, physical structure inverted imaging of target object, and structural detection of complicate geological mass. A general geological prediction method is brought fotward in order to solve the problems mentioned above following the four-combination principle.4) The closest relationship between prediction information and geological pre-warning is found out through research. Individually the level of prediction detail and reliability, and endangering level of fault and fracture zone to tunnel construction obtained by means of geological prediction results, combined with numerical simulation, are classified in order to calculate the predictable distance under different geological condition and make up the pre-arranged planning for tunnel geological hazard in fault and fracture zoneThe entire geological prediction system for tunnel construction in fault and fracture zone is built up, accompanied by some improvements for the geologocal hazards of present geological prediction and pre-warning methods in fault and fracture zone.