Derin kazılarda çok sıra ankrajlı iksa sistemlerinin tasarımı ve bir bilgisayar programı ile desteklenmesi
Derin kazılarda çok sıra ankrajlı iksa sistemlerinin tasarımı ve bir bilgisayar programı ile desteklenmesi
Dosyalar
Tarih
1999
Yazarlar
Günsever, İnci
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Yayınevi
Fen Bilimleri Enstitüsü
Özet
Büyük kentlerde nüfus yoğunluğunun beraberinde gelen trafik, konut açığı gibi sorunlara çözüm getirmek bakımından yeraltı tesislerini arttırmak ve daha az yer kaplayan yüksek yapılar inşaa etmek yoluna gidilmiştir. Derin kazı gerektiren bu tip yapıların inşaası boyunca dar olan kazı sahaları içinde kazının düşey olarak teşkilini sağlamak, kazı sahasının çevresinde bulunan bina, yol ve mevcut tesislerde oluşabilecek hasar riskini en aza indirmek ve kabul edilebilir sınırlar ölçüsünde tutmak için göçme, kayma ve deformasyona engel olacak destekleme sistemleri yapılmaktadır. Kazı derinliklerinin önemli derecede büyük olduğu metro, yüksek bina temeli gibi yapılarda payanda, istinat duvarı gibi klasik destekleme sistemlerinin kullanılması yeter derecede güvenli olmamakta ve gerek ekonomik bakımdan gerekse inşaat alanını daraltması bakımından tercih edilmemektedir.. Bu durumlarda, zemin mekaniği ve temel mühendisliği bilgileri kullanılarak fonksiyonel, emniyetli ve ekonomik iksa perdeleri inşa edilmektedir. Derin kazı çukurlarının güvenli ve ekonomik olarak desteklenmesi için çok sıra destekli iksa sistemleri geliştirilmiştir. Derin kazı destekleme sistemlerinin rijitlikleri istinat yapılarına göre daha azdır. Ek olarak, destekleme sistemlerinde, bölgesel toprak basıncı yığılması sonucu destekleme sistemlerinin elemanlarında çok büyük yükler oluşmakta ve bunun sonucunda da sistemin toptan göçmesine neden olabilecek bir ardışık göçme mekanizması meydana gelebilmektedir. Yapılacak kazı nedeniyle oluşacak yatay hareketler kabaca, parabolik olarak nitelendirilebilecek basınç dağılımının oluşmasına yol açar. Çok sıra ankrajlı destekleme sistemlerinin boyutlandınlmasında gerçek toprak basıncı değerleri kullanılamadığından bir çok araştırmacı tarafından çalışmalar yapılmış ve zemin cinsine göre farklı toprak basıncı dağılımları elde edilmiştir. Bölüm 2' de çok sıra destekli iksa sistemlerinin tasarımında kullanılıcak toprak basıncı dağılımları incelenmiştir. Zemin ankrajlan, payanda veya istinat duvarlarının yetersiz kaldığı veya ekonomik olmadığı durumlarda, derin kazıların güvenle açılması ve inşaat sırasında emniyetli olarak durması için, yüksek şev duvarlarının desteklenmesinde kullanılan son derece yaygın destek elemanlarıdır. Bölüm 3 'de ankrajlann tasarım esasları ve hesap yöntemleri çeşitli ülke standartları gözetilerek incelenmiştir. Destekleme sisteminin elemanları, sisteme etkiyen toprak basıncına göre boyutlandınhr. Destekleme sistemine gelen toprak basıncı, önemli oranda sistemin deformasyonuna bağlıdır. Rankine ve Coulomb tarafından geliştirilen toprak basıncı teorileri dayanma duvarlarına, zemine ankastre perde duvarlara, tek sıra yatay destekli veya ankrajlı zemine sabit mesnetli veya ankraste perde duvarlara uygulanabilmekle beraber çok sıra yatay destekli veya ankrajlı destekleme xi sistemlerine uygulanamazlar. Bu, çok sıra destekli sistemin yapılış aşamalarının, deformasyon biçiminin ve sistemin göçme mekanizmasının diğerlerinden farklı olması ile açıklanabilir. Bölüm 4'de çok sıra ankrajlı iksa sistemlerinin tasarım esasları incelenmiş ve çeşitli destekleme sistemleri hakkında bilgiler verilmiştir. Bilgisayar programlama teknolojisi, bütün mühendislik alanlarında olduğu gibi geleceğin anahtar teknolojilerinden biridir. Bilgisayar programlarını üretmeden satın alıp kullanmak pratik gibi gözükse de, teknoloji üretimi sürecinden geçilmediği için, sistemi üretenler kadar verimli kullanma olasılığı yoktur. Ayrıca teknoloji üretiminde bulunmayanların yeni teknoloji geliştirme şansının daha az olduğu da açıktır.Bu nedenle geoteknik alanında teknoloji üretimine yönelik gerek bilgisayar yazılımı alanında, gerek yeni deney sistemlerinin geliştirilmesi alanında ve de gerekse yeni yapım yöntemlerinin geliştirilmesi alanındaki çalışmalar desteklenmelidir. Bu amaçla bu tez çalışması kapsamıda çok sıra ankrajlı iksa sistemleri ile ilgili bir bilgisayar programı Microsoft Vısual Basic Programlama dili ile geliştirilmiştir. MS Visual Basic çok amaçlı ve aynı zamanda kolaylıkla program geliştirilmesini sağlayan bir programlama ortamıdır. MS Visual Basic programlama diliyle geliştirilen programlannWindows işletim sistemi altında çalışması kullanıcıya veri girişi, analiz ve sonuçların kolay yorumlanabilmesi imkanım tanımaktadır. Geliştirilen program Bölüm 2, Bölüm 3 ve Bölüm 4'de verilen teori ve hesap yöntemlerine ve çeşitli ülkelerin konuyla ilgili standartlarına dayanarak geliştirilmiştir ve Bölüm 5'te geliştirilen program ayrıntılı olarak tanıtılmıştır. Geliştirilen program ile bir iksa sistemi projelendirilerek, elde edilen sonuçlar değerlendirilmiştir.
During the last few decades, deep excavations are becoming an important investigated object in the field of Geotechnical Engineering. The decrease in available construction areas and environmental effects such as neighbouring buildings, roads and other structures, have played an important role in the development and the necessity for the application of deep excavations, especially in great settling centers. It has been observed that the use of classical retaining structures like retaining walls are not safe enough and also not economical solutions to projects requiring deep excavations. A spectrum of these projects include underground subway tunnel constructions, high rise buildings, and the retaining of high slopes. Under geotechnic and foundation engineering considerations, the design of more functional, safer and more economical solutions like multiple anchored earth retaining structures are introduced. A lot of earth retainig systems have been developed to solve problems encountered during deep excavations. The problems maybe classified as displacement of the gorund during and after excavation, stability problems of the earth, high levels of underground water, uplift of the ground on the excavation surfaces, loads caused by environmental effects such as near structures and roads, existing undergorund sturctures and dynamic loads i.e. vibration problems. In this research multiple anchored earth retaining structures in deep excavations are examined in detail. In any such study many assumptions have to be made, the validity of which, in some cases, may be doubtful. Consequently these analyses can only be considered as guides for design which might assist engineering judgement. The mechanics of anchored earth retaining structure's behaviour can not be divorced from excavation behaviour since one attracts the other. The digging of an excavation causes a three dimensional change in the stress in the ground and as a result ground movements occur. When an anchorage system is used to support an excavation retaining wall, the design assumption made is to balance the lateral pressures on the wall by the horizontal components of the anchor loads. Thus lateral earth pressure change caused by excavation works is balanced whilst vertical stress change is not. As a consequence of this, the shear stresses induced in the ground increase with excavation deepening, causing the ground and the wall support system to deform in a complex manner dependent on the flexibilty and yield capabilities of the wall, the anchors and the ground respectively. Many variables such as construction sequence Xlll can not be dealt within a satisfactory manner analytically and consequently use has to be made of field trials and field observations to assess the significance of a particular construction sequence. The rigidity of earth retaining structures are less than the rigidity of classical retaining walls. Due to the horizontal movement of the earth during the excavation, it is expected to cause a parabolic load on the earth retaing structure. Classical approcahes like the Rankine and Coulomb theories are not valid in the design of multiple anchored earth retaining structures, hence certain amprical relations are developed and used in the design phase of the project. Many researches have provided these ampirical relations such as Terzaghi - Peck and Lehmann assumptions. A detailed study of these ampirical correlations are presented in Section 2 of the present work. Standarts of different countries are also presented in the same section, such as The Swedish Standarts for Anchorages SIA-191, and Swedish Building Code In recent years, new applications for ground achorage systems have to continued to appear regularly and today anchorages may be associated with earth retaining structures. There is a need for a detailed knowledge of the ground, which may demand a supplementary investigation and a proper design related to static and dynamic loads, location of anchorages, load transfer lengths and overall stability. Section 3 investigates the British Standart Code of Practice for Ground Anchorages BS-8081. The design considerations of multiple anchored earth retaining structures are presented in detail in Section 4 of the present work. A comparison of different types of earth retaining structures such as diaphram walls, reinforced concrete walls and pile walls is also available in the same section. Taking into consideration the rapid developments in computer technologies, the need for a computer program that is capable of analyzing multiple anchored earth retaining sturctures is evident. The idea of using presently available software, instead of producing such a software, may be thought of a common practice today. However, it is obvious that, without a contribution to technology, it is impossible to deal with rapidly growing countries and technologies. With these in mind the software was developed under Microsoft Visual Basic programing language for the analysis for multiple anchored earth retaining structures. The ease and ergonomicity of Windows operating system, makes it possible to input data, to process it and visualize the results easily and efficiently. The program is explained in detail, including the solution steps necessary, and the graphical user interface in Section 5. A sample case with the actual data from a recent project is analzed, and the results are presented in Appendix 1. The newly developed software package in the present work may be further developed to transfer data into CAD environments, for ease on project basis, and other solution modules that might be needed for possible future work can be added with ease.
During the last few decades, deep excavations are becoming an important investigated object in the field of Geotechnical Engineering. The decrease in available construction areas and environmental effects such as neighbouring buildings, roads and other structures, have played an important role in the development and the necessity for the application of deep excavations, especially in great settling centers. It has been observed that the use of classical retaining structures like retaining walls are not safe enough and also not economical solutions to projects requiring deep excavations. A spectrum of these projects include underground subway tunnel constructions, high rise buildings, and the retaining of high slopes. Under geotechnic and foundation engineering considerations, the design of more functional, safer and more economical solutions like multiple anchored earth retaining structures are introduced. A lot of earth retainig systems have been developed to solve problems encountered during deep excavations. The problems maybe classified as displacement of the gorund during and after excavation, stability problems of the earth, high levels of underground water, uplift of the ground on the excavation surfaces, loads caused by environmental effects such as near structures and roads, existing undergorund sturctures and dynamic loads i.e. vibration problems. In this research multiple anchored earth retaining structures in deep excavations are examined in detail. In any such study many assumptions have to be made, the validity of which, in some cases, may be doubtful. Consequently these analyses can only be considered as guides for design which might assist engineering judgement. The mechanics of anchored earth retaining structure's behaviour can not be divorced from excavation behaviour since one attracts the other. The digging of an excavation causes a three dimensional change in the stress in the ground and as a result ground movements occur. When an anchorage system is used to support an excavation retaining wall, the design assumption made is to balance the lateral pressures on the wall by the horizontal components of the anchor loads. Thus lateral earth pressure change caused by excavation works is balanced whilst vertical stress change is not. As a consequence of this, the shear stresses induced in the ground increase with excavation deepening, causing the ground and the wall support system to deform in a complex manner dependent on the flexibilty and yield capabilities of the wall, the anchors and the ground respectively. Many variables such as construction sequence Xlll can not be dealt within a satisfactory manner analytically and consequently use has to be made of field trials and field observations to assess the significance of a particular construction sequence. The rigidity of earth retaining structures are less than the rigidity of classical retaining walls. Due to the horizontal movement of the earth during the excavation, it is expected to cause a parabolic load on the earth retaing structure. Classical approcahes like the Rankine and Coulomb theories are not valid in the design of multiple anchored earth retaining structures, hence certain amprical relations are developed and used in the design phase of the project. Many researches have provided these ampirical relations such as Terzaghi - Peck and Lehmann assumptions. A detailed study of these ampirical correlations are presented in Section 2 of the present work. Standarts of different countries are also presented in the same section, such as The Swedish Standarts for Anchorages SIA-191, and Swedish Building Code In recent years, new applications for ground achorage systems have to continued to appear regularly and today anchorages may be associated with earth retaining structures. There is a need for a detailed knowledge of the ground, which may demand a supplementary investigation and a proper design related to static and dynamic loads, location of anchorages, load transfer lengths and overall stability. Section 3 investigates the British Standart Code of Practice for Ground Anchorages BS-8081. The design considerations of multiple anchored earth retaining structures are presented in detail in Section 4 of the present work. A comparison of different types of earth retaining structures such as diaphram walls, reinforced concrete walls and pile walls is also available in the same section. Taking into consideration the rapid developments in computer technologies, the need for a computer program that is capable of analyzing multiple anchored earth retaining sturctures is evident. The idea of using presently available software, instead of producing such a software, may be thought of a common practice today. However, it is obvious that, without a contribution to technology, it is impossible to deal with rapidly growing countries and technologies. With these in mind the software was developed under Microsoft Visual Basic programing language for the analysis for multiple anchored earth retaining structures. The ease and ergonomicity of Windows operating system, makes it possible to input data, to process it and visualize the results easily and efficiently. The program is explained in detail, including the solution steps necessary, and the graphical user interface in Section 5. A sample case with the actual data from a recent project is analzed, and the results are presented in Appendix 1. The newly developed software package in the present work may be further developed to transfer data into CAD environments, for ease on project basis, and other solution modules that might be needed for possible future work can be added with ease.
Açıklama
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1999
Anahtar kelimeler
Ankrajlar,
Bilgisayar destekli tasarım,
Derin kazı,
Tasarım,
İksa sistemleri,
Anchorages,
Computer aided design,
Deep excavation,
Design,
Shoring systems