The Study on Mechanical Behavior of Highway Tunnel in Fault Fracture Zone
|Course||Bridge and Tunnel Engineering|
|Keywords||Highway tunnel Fault fracture zone Model test Numerical analysis Mechanicalbehavior|
In recent years, with the rapid development of economy and the continuous surge oftraffic demand in our country, road construction has entered a peak. More and more complexgeological bodies encountered in the process of tunnel construction, with the increasing oftunnel constructionquantity. When tunnel cross section of the layer fracture zone ofsurrounding rock, landslide, water burst and other geological disasters, which caused bySection of the layer fracture zone, always cause delays, loss of lives and property. Sometimes,it can even affect the normal operation of the tunnel. Therefore, mechanics behavior researchof tunnel in fault fracture zone has an extremely important significance. In this thesis, bytaking the project of Key technology research project of the southern mountainous areahighway tunnel construction safety guarantee long-term stability and structure technologyresearch of the Guangxi Zhuangzu Autonomous Region. With the object of Fault fracturezone rock surrounding tunnel, the stress and strain of fault zone and force of the supportingstructure are studied in the gravity stress field, where we set different occurrence fault and usedifferent excavation methods around the tunnel. In this research we use statistical analysis,model test and numerical simulation methods. The main researches of this research are asfollows:1. Through literature review and field survey, by statistics and analysis of a large amountof road, railway tunnel and hydraulic tunnel engineering examples of landslides caused byfault fracture zone, we summarize surrounding rock failure mechanism in the fault fracturezone.2. On the basis of statistical analysis, a set of model tests are carried out in laboratory.Taking geometric similarity ratio (CL=30) and similar bulk density than (Cr=1) as basicsimilarity ratio, so as to achieve complete similarity of various controlled physical andmechanical parameters in the elastic range and strictly simulate, we make the tunnel model.The stress and strain of fault zone and force of the supporting structure are studied in thegravity stress field, where we set different occurrence fault and use different excavationmethods around the tunnel. The change laws of surrounding rock stress, displacement andlining are summarized in different occurrence faul. 3. On the basis of model test, this paper makes a three-dimensional finite elementnumerical simulation, in addition to the model test. Then, compared with the results ofnumerical analysis and model test, we draw some conclusions of practical engineering value,The tunnel surrounding rock mechanics properties during the process of excavation isobtained. This conclusion has directive significance to the tunnel construction, and providesreference for design and safety construction of similar tunnel.