|
|
|
|
فشار خاک وارد بر مجاری جعبه ای مدفون در ترانشه به روش ترانشه ناقص تحت اثر فشار سربار
|
|
|
|
|
|
|
|
نویسنده
|
مرادی غلام ,حسن خانی ابراهیم ,حلبیان امیرمهدی
|
|
منبع
|
مهندسي عمران شريف - 1398 - دوره : 35-2 - شماره : 4/2 - صفحه:53 -65
|
|
چکیده
|
طراحی مجاری جعبه‌یی مدفون تحت فشار سربار، نیاز به ارزیابی دقیق مقدار تنش‌های وارد بر وجوه مختلف مجرا دارد. چنانچه مجرا تحت فشار سربار بزرگ قرار داشته باشد، ارائه‌ی راهکاری به منظور کاهش مقدار تنش وارد بر جعبه حائز اهمیت است. در مطالعه‌ی حاضر، با ترکیب دوروش متداول دفن مجاری زیرزمینی (دفن در ترانشه و دفن در ترانشه‌ی ناقص)، روشی معرفی شده است که بتوان مقدار تنش وارد بر وجوه مختلف را کنترل کرد و آن را کاهش داد. به این منظور، ابتدا صحت‌سنجی مدل‌سازی عددی انجام و سپس به مطالعه‌ی عددی اثر پارامترهای مختلف در مقدار ضریب اندرکنش برای وجوه مختلف مجرای جعبه‌یی تحت فشار سربار پرداختهشده است. تحلیل‌های عددی با استفاده از روش اجزاء محدود و به‌صورت دوبعدی صورت گرفته است. نتایج تحلیل‌ها نشان می‌دهند که توسعه‌ی قوس‌شدگی در خاکریز، عامل مهمی در کاهش مقدار تنش وارد بر سقف، دیواره و کف مجرای مدفون است.
|
|
کلیدواژه
|
مجرای جعبه‌یی، ترانشه، ترانشه‌ی ناقص، ضریب اندرکنش، قوس‌شدگی، اجزاء محدود
|
|
آدرس
|
دانشگاه تبریز, دانشکده ی مهندسی عمران, ایران, دانشگاه تبریز, دانشکده ی مهندسی عمران, ایران, دانشگاه صنعتی اصفهان, دانشکده ی مهندسی عمران, ایران
|
|
پست الکترونیکی
|
mahdi@cc.iut.ac.ir
|
|
|
|
|
|
|
|
|
|
|
|
|
|
INVESTIGATION OF APPLIED EARTH LOAD ON BURIED BOX CULVERTS IN TRENCHES USING INDUCED TRENCH METHOD UNDER EMBANKMENT PRESSURE
|
|
|
|
|
Authors
|
Moradi Gh. ,Hassankhani E. ,Halabian A.M.
|
|
Abstract
|
Underground box culverts have been applied to facilitate people's living standard in various ways including municipal sewer lines, water mains, gas and oil lines, electric and telecommunication conduits, and pedestrian and subway tunnels. Design and construction of these conduits demand determining exerted pressure due to the soil and embankment weight above. Several ways have been developed for buried culverts and calculating the soil earth to which the buried culvert is subjected to. Accordingly, the applied load is large and culverts are installed under high embankment; applied pressure becomes more significant. Therefore, the reduction and control of the earth load on culverts is of importance. To date, various methods and theories have been proposed to reduce the applied earth load on these underground structures. Among these, two methods are commonly used: Trench Installation (TI) and Induced Trench Installation (ITI). For the TI method, where the culvert is placed in a narrow trench, the deformable soil tends to settle down, while the adjacent trench walls hold the soil in place due to shearing stresses along the interfaces. This leads to the transfer of load from the fill to the trench walls developing soil arching, hence reducing the vertical pressure transfer to buried box culvert. Another method, ITI, is a construction technique employed to reduce the vertical pressure on buried structure, in which a layer of compressible material is placed directly on the buried culvert to induce positive arching thus reducing the applied vertical pressure on culvert crown. Meanwhile, researchers have addressed some deficiencies in each method. Trench Installation in comparison with Induced trench Installation transfers larger earth load to culvert roof. In addition, the development of positive arching directly above the culvert roof transfers more vertical stresses to adjacent soil columns, leading to larger horizontal stresses applied to buried culvert walls. In this study, by taking benefits of these two common methods, an installation method has been proposed in which the culvert is installed in a trench with a layer of deformable material placed above the box culvert roof, called Trenched Induced Trench Installation (TITI). Firstly, the pressure transferred to the culvert under the weight of soil and surface pressure has been validated using numerical analyses compared with analytical equations that predict the applied pressure. Then, twodimensional finite element analyses have been performed to explore the effect of various factors on the applied pressure on the roof, sidewalls, and bottom of buried box culvert in TITI method. Results show that soil arching reduces the earth pressure on roof and arching developed between box sidewalls and trench walls; the pressure applied on the culvert side walls can be controlled.
|
|
Keywords
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|