فاكتور تمركز تنش ديناميكي اصلاح شده براي تونل هاي دو قلو داراي تفرق از طريق روش نوين FEM-Scattering Method

Upgraded Dynamic Stress Concentration Factor for Twin Tunnels Dispersed by New Method FEM-Scattering Method

خرابي­ هاي متعدد تونل­ هاي جديد ساخته‌شده، تحت بارگذاري زلزله، موجب تحقيقات ­وسيع ­تري در زمينه ارزيابي اثر زلزله بر روي تونل­ ها گرديده است. در اين تحقيق با استفاده از تابع هنكل نوع اول و سه شتاب‌نگاشت مقياس‌شده مربوط به زلزله حوزه نزديك (نورتريج، طبس و كوبه) و با استفاده از برنامه گسترش‌يافته FESCAM اين تحقيق كه در محيط متلب طراحي شده است، تفرق در سازه تاريخي سي‌ و سه‌ پل بررسي شده است. تابع هنكل نوع اول با استفاده از شتاب ­نگاشت­ هاي ذكرشده مقدار تفرق، ميزان كرنش و تنش در اطراف تونل‌هاي دوقلو به‌عنوان يك پارامتر اضافه شونده به تحليل المان محدودي حاضر اضافه شده است. نتايج تحقيق نشان مي‌دهد كه ميانگين جا­به­جايي افقي سي‌وسه‌پل در مقايسه با عدم در نظر گرفتن اثر تفرق 28/8% افزايش داشته و ميزان جابه‌جايي قائم سي‌وسه‌پل در مقايسه با عدم در نظر گرفتن اثر تفرق 30/11% افزايش يافته است. نتايج آزمون من- ويتني آماري كه با برنامه SPSS انجام‌شده نشان مي­دهد كه اختلاف آماري معني­داري مابين عملكرد لرزه‌اي سي‌وسه‌پل با اثر تفرق تونل‌ها و بدون اثر تفرق تونل‌ها وجود ندارد.

Summary Several newly constructed tunnels, which have been damaged by earthquake loading, have led to extensive research on the evaluation of earthquake effects on tunnels. Underground structures are increasingly being built and exploited in the context of urban expansion and development. Tunnels are one of the most important underground structures. Failure of several tunnels under earthquake loading, and especially damage to these tunnels, have been the reasons to investigate the effects of earthquake on the tunnels. Introduction Various activities, especially during earthquake, on the adjacent structures are of particular importance. This importance will be more in the vicinity of the historical building, due to their vast material and spiritual values. In this research, using the Henkel type I and three scale accelerometers related to the earthquakes in Northridge, Tabas and Kobe, and employing the expanded FESCAM program in MATLAB environment, the historical structures of thirty-three buildings have been studied. Methodology and Approaches In this research, nonlinear time histories analysis has been used to generalize Henkel's relationship and to calculate the exact difference. The input waves have been investigated by the researchers for use in the Henkel harmonic waves function. The Henkel function of the first type using the mentioned accelerations is used considering the amount of dissociation, the degree of strain and stress around the twin tunnels as an additive parameter to the limited element analysis of the present study. Results and Conclusions In this paper, the operation of differentiation is expanded with the use of mathematical relations. A case study of twin tunnels is Si-o-se-pol twin tunnels. The results of this study show that the mean displacement of horizontal thirty three bridges there in comparison with the failure to consider the effect of fractionation is increased by 28.8% and the displacement rate of the thirty three bridges compared to the failure includes the difference of 11 / 30%. Moreover, the displacement of underground structures during an earthquake is less than that of the ground structures. The results of the Mann-Whitney test with the SPSS software program have shown that there is no significant difference between the seismic performance of the thirty three bridges with the effect of tunneling dispersion and without the effect of tunneling dissociation (P-value≥0.05).