بررسی عددی اثر استفاده از خاک مسلح شده به‌وسیله ژئوفوم در کاهش اثرات ناشی از بارگذاری انفجار

نوع مقاله: پژوهشی

نویسندگان

1 گروه عمران، دانشکده فنی مهندسی، دانشگاه قم

2 گروه عمران، دانشکده فنی مهندسی، دانشگاه قم، قم، ایران

چکیده

سازه‌های امن زیرزمینی سازه‌هایی هستند که در عمق مشخصی از سطح زمین، عموماً به‌وسیله بتن مسلح ساخته ‌می‌شوند. در پژوهش حاضر با مدل‌سازی سه‌بعدی محیط خاک و لایه مسلح کننده ژئوفوم در نرم‌افزار اجزا محدود آباکوس به‌منظور بررسی کارایی ژئوفوم در کاهش حداکثر فشار ناشی از بار انفجاری، از متغیر درصد کاهش، در روند تحلیل‌ها استفاده‌شده است. نتایج نشان ‌داد که استفاده از لایه ژئوفوم، حداکثر فشار توسعه‌یافته در خاکریز سربار در اثر انفجار را به‌طور چشمگیری (تا 61 درصد) کاهش‌داده است. هم‌چنین با تغییر طول و عرض لایه ژئوفوم در محدوده 2 تا 8 متر، درصد کاهش 15.8 درصد افزایش‌یافته است. از سوی دیگر با افزایش ضخامت خاکریز سربار لایه ژئوفوم، درصد کاهش 9+ درصد تغییر‌یافته است که با در نظر گرفتن شرایط خاص هر پروژه ازجمله نمودار هزینه-فایده، می‌توان مقدار بهینه‌ای برای هر یک از متغیر‌های بیان‌شده به‌دست آورد. در پایان این پژوهش، رابطه‌ای برای محاسبه درصد کاهش به‌دست‌آمده است که در طراحی خاکریزهای دفاعی هوشمند کارایی دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical investigation of the effect of reinforcement soil by Geofoam on reducing the effects of explosion loading

نویسندگان [English]

  • mahdi khodaparast 1
  • Reza Mohammadmomeni 2
1 Department of Civil Engineering, University of Qom, Qom, Iran
2 Department of Civil Engineering, University of Qom, Qom, Iran
چکیده [English]

In recent decades, due to increased military and terrorist attacks in the world, attention has been paid to the construction of underground security structures. Since most of the vital, sensitive and important structures of the country, like other structures, are based on soil or in soil, the study of the effect of the explosion on the performance of these structures is essential for their safe design. Secure underground structures are structures that are constructed at a certain depth of the ground, generally made by reinforced concrete, then the embankment is applied as overhead cover. Overhead embankment plays an important role in removing the tensions caused by the explosion. Consideration of this aspect of the design of underground structures requires the expertise and knowledge of geotechnical engineering that combines civil engineering with passive defense, a step forward in the design of secure structures underground. In the present study, modeling of the soil mass and the geofoam layer in ABAQUS finite element software examined the efficiency of geofoam as an obstacle to the explosive separator. For modeling soil behavior, modified Dracke-Prager model with a cap and for modeling the behavior of geofoam, stress strain graphs under a high strain rate have been used, also, in order to analyze the effect of using geofoam in reducing the pressure caused by explosive charge, a reduction percentage was used to compare the results. Investigations have shown that the use of geofoam layer in underground structures overhead, the maximum pressure due to explosion significantly reduced (up to 61%). The change in the specific mass of the geofoam layer from 110 to 80 Kg per cubic meter, the reduction percentage has changed +10%. By changing the thickness of the geofoam layer in the range of 0.25 m to 1 m, the percentage of reduction +14.7% has improved and by changing the length of the geofoam layer in the range of 2 to 8 m, the reduction percentage has changed +15.8%. By increasing the thickness of the overhead embankment above the geofoam layer, the reduction percentage has changed +9%. With considering the specific circumstances of each project, including the cost-benefit graph, can be obtained an optimal and appropriate amount for each of the variables declared. At the end of this research, a relationship has been found to calculate the reduction coefficient that will be effective in designing intelligent defense embankments.

کلیدواژه‌ها [English]

  • Intelligent defense embankment
  • Geofoam
  • Underground security structure
  • Explosive loading
  • Reduction percentage