پديد آورنده :
كرمي، مهرداد
عنوان :
تأثير نوسانات فشار بر شكست هيدروليكي در تونل هاي تحت فشار با روباره كم Effects of pressure fluctuations on hydraulic jacking in pressurized tunnels with low overburden
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي عمران
صفحه شمار :
هفده، 79ص.: مصور
استاد راهنما :
عبدالرضا كبيري ساماني
استاد مشاور :
راحب باقرپور
توصيفگر ها :
فشارهاي گذرا , اندركنش سازه و سيال
استاد داور :
محمدرضا چمني، لهراسب فرامرزي
تاريخ ورود اطلاعات :
1395/02/01
چكيده انگليسي :
84 Effects of pressure fluctuations on hydraulic jacking in pressurized tunnels with low overburden Mehrdad karami Mehrdad karami@cv iut ac ir January 12 2016 Civil Engineering Department Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Abdorreza Kabiri Samani Email address akabiri@cc iut ac irAbstractOne of the most common problems in pressurized tunnels is the generation of cracks in the lining of thetunnel and the surrounding rocks as a result of high inner water flow pressures By increasing the size of thecracks exceeding the allowable value leakage would be happened from the lining towards the surroundingrock In tunnel engineering such phenomenon is a serious hazard so called as hydraulic jacking which couldbe resulted in structural failure There are several hydraulic structures such as water conveying tunnels penstocks pipelines and shafts which happened likely the hydraulic jacking phenomenon In some cases dueto the effects of an earthquake or fast operations valves and gates transient flow creates inside the abovementioned hydraulics structures thereby the water flow inside the tunnel imposes high fluctuating forces onthe rock surrounding the tunnel causing high displacements in the rock leading to rock fracture Therefore the effects of transient flow as well as the pressure fluctuations should be considered by design engineers In the present study a two dimensional pressurized water tunnel with a concrete lining was modeled usingthe finite element method by applying the ABAQUS software The lining was considered just as aroughening coverage to decrease roughness coefficient and to increase the flow discharge The mechanicalparameters of surrounding rock were assumed as weak as possible compared to the inner tunnel concretelining The water flow inside the tunnel was modeled using acoustic elements that are capable of simulatingthe hydrodynamic forces Accordingly the mechanism of developing the cracks in the surrounding rock asthe most probable place to prone this destructive phenomenon is studied applying both steady state andtransient pressure conditions considering fluid structure and rock interactions Steady state and transient flowanalysis were performed using the HAMMER software The hydraulic loadings resulted from the hydraulicanalysis by HAMMER software was transmitted to ABAQUS for structural analyses The stress analysis ofcracked elements of the surrounding rock was carried out based on Mohr Coulomb fracture criterion Theleast values of overburden rock to prevent the failure due to hydraulic jacking were evaluated by imposingthe water flow pressure in both steady and transient flow states Finally the effects of increasing the height ofthe overburden on hydraulic jacking phenomenon were investigated considering transient flow conditions Results indicated that because of coordinate of surrounding rocks elements extra overburden on tunnel isnot a safe Solution for the eradication of hydraulic jacking phenomenon in rock around tunnel Keywords Pressurized tunnel hydraulic jacking transient flow pressure Fluid structureinteraction overburden
استاد راهنما :
عبدالرضا كبيري ساماني
استاد مشاور :
راحب باقرپور
استاد داور :
محمدرضا چمني، لهراسب فرامرزي
