Geri Dön

Bir iksa sisteminin iki ve üç boyutlu sonlu elemanlaryöntemi ile çözülmesi ve saha ölçümleri ilekarşılaştırılması

Two and three dimentoned finite elements methodanalyses of a support system and comparison of resultswith on-site instrumentations

PDF İndir

  1. Tez No: 601188
  2. Yazar: DENİZ TÜRKMEN YILMAZ
  3. Danışmanlar: PROF. DR. MUSAFFA AYŞEN LAV
  4. Tez Türü: Yüksek Lisans
  5. Konular: İnşaat Mühendisliği, Civil Engineering
  6. Anahtar Kelimeler: Belirtilmemiş.
  7. Yıl: 2019
  8. Dil: Türkçe
  9. Üniversite: İstanbul Teknik Üniversitesi
  10. Enstitü: Fen Bilimleri Enstitüsü
  11. Ana Bilim Dalı: İnşaat Mühendisliği Ana Bilim Dalı
  12. Bilim Dalı: Zemin Mekaniği ve Geoteknik Mühendisliği Bilim Dalı
  13. Sayfa Sayısı: 104

Özet

Artan kentselleşmenin sonucu nüfusun ihitiyaçlarını karşılamak amacı ile konut, sanayi yapıları, iş merkezleri, spor merkezleri, altyapı projeleri gibi inşaat projelerinin artmasına yol açmaktadır. Yoğun nüfuslu kentlerde mevcut arsaların kullanımını en efektif şekilde değerlendirme mecburiyeti doğmuştur. Bu sebeple arazilerin görünmeyen kısımları da inşaat alanlarına dönüşmüştür. Bu alanlarda açılan kazı çukurlarını desteklemek amacı ile tasarlanan iksa sistemi yapılırken sisteme etkiyecek olan toprak ve su basıncının yanı sıra sürsarj basınçlarının hesaplanması gerekmektedir. İksa sistemine etkiyecek olan yükleri belirlemek için sağlıklı bir zemin etüdünün yapılması gerekmektedir. Yanlış yapılan zemin etüdleri neticesinde tasarlanan iksa sistemleri neticesinde çevre yapılarda ve yollarda yapısal hasar oluşabilmektedir. Oluşan hasarlar izin verilen sınırlar içeresinde kalmadığı takdirde can ve mal kaybına yol açmaktadır. Tasarımı yapılan iksa sisteminin hesaplanan yükleri izin verilen deplasmanlar sınırında tasarım ömrü süresince karşılaması gerekmektedir. Çalışmanın amacı, aletsel gözlemlerin derin kazılardaki önemi ve faydasının gösterilmesidir. Bu çalışma da tasarımı yapılmış olan derin kazı sisteminin analizler sonucu elde edilen deplasmanlarla sahada gerçekleşen deplasmanlarının karşılaştırılması anlatılmıştır. Tez kapsamında, İstanbul ili Avrupa Yakası kısmında yapılacak olan bir metro hatına ait istasyonunun kazı destek sistemi için öncelikle literatürdeki veriler ışığında sahada yapılan sondaj verilerine göre zemin parametreleri belirlenmiştir. Zemin profili, yeraltı suyu, sürsarj yükleri ve kesitler belirlendikten sonra PLAXIS 2D ve PLAXIS 3D yazılımı ile analizler gerçekleştirilmiştir. Tez çalışmasının birinci bölümünde iksa sistemlerinin öneminden bahsedilmiştir. İkinci bölümünde ise iksa sistemlerine etkiyen yanal toprak basınçları hakkında bilgi verilmiştir. Üçüncü bölümde yanal toprak basınçları ve çevresel yükleri sağlıklı bir şekilde taşımak amacıyla gerekli yatay-düşey destekler anlatılmıştır. Sonraki bölümde iksa sistemlerinin en önemli bir parçası olan geoteknik enstürümantasyonlar hakkında bilgi verilmiştir. Tezin beşinci bölümünde sonlu elemanlar yöntemi ve geoteknik analizlerde kullanılan Plaxis programı tanıtılmıştır. Tez kapsamında Plaxis 2D ve Plaxis 3D ile yapılan analizler sonucunda elde edilen deplasmanlar ile sahada gerekli enstürümantasyonlar ile ölçülen gerçek deplasmanlar karşılaştırılmıştır. Sonuç kısmında ise metro projesine ait istasyon için yapılan analizlerin sonuçları ile inklinometre ölçümlerinin karşılaştırılması değerlendirilmiştir. Belirlenen idealize zemin profili için farklı kazı uzunluğuna sahip kazı çukurunun çevre yapıların oturmasına etkisi incelenmiş ve tez çalışması tamamlanmıştır.

Özet (Çeviri)

Since the urbanization trend continues to grow throughout the world, so does the need of construction projects as the ever-growing human population demands and requires new houses, industrial facilities, social centers and infrastructures. This increase in demands made it a necessity in central cities for the land to be used as efficient as possible. As a result, the unseen parts of the land; the underground turned into construction sites. But making deep excavations in order to make use of underground areas require additional engineering designs. When designing a support system for an excavation site, surcharge loads must be taken into account in addition to earth and water pressure. To determine all loads that will effect the support system, a healthy soil investigation must be carried out first. Without the data from a healthy soil investigation, designing a support system might cause damage to nearby structures and roads. When exceeding the agreeable limits, these damages can lead to loss of lives or properties. The designed support system is expected to compensate the loads within agreeable displacement limits as far as the design life. As one of the problems solved in geotechnical engineering, deep excavations are a complex topic. This problem incorporates numerous factors which includes several vertical and horizontal members. The basic logic behind this design is to transfer the earth and water pressure as well as surcharge loads effecting the system through these vertical and horizontal members and eventually divert these loads into the soil. While designing the deep excavation support system, a lateral earth pressure distribution must be achieved behind the wall in order to determine final wall height and estimate support loads and bending moment of the wall. Unlike a standard excavation, when constructing the support system“top-down”; the deformation pattern would become much more complex and inconsistent with the theoretical Rankine and Coulomb earth pressure distribution. The aim of this study is to show the importance and benefit of instrumental observations in deep excavations. This study contains comparison of a designed deep excavation support systems displacements and actual displacements seen on site. Within the study, soil parameters for a deep excavation support system constructed as a part of subway construction in the European side of İstanbul were determined first. After determining the soil profile, ground water level, surcharge loads and sections; analyses were conducted using PLAXIS 2D and PLAXIS 3D software. The deep excavation system for the station structure will be approximately 21x99m. In the study area, surface elevations are fixed and the excavation height is 25.40m. The deep excavation system will be supported internally at 4 different levels. Reinforced concrete elements were preferred as internal support system in the first three levels, while steel pipe was preferred in the fourth level. In the first chapter of study, the reasons behind the increased use of deep excavations and this methods importance in geotechnical engineering were addressed. Following these details, study continues with earth pressures which is the main factor behind determining the dimensions of deep excavation support system elements. Prized scientists in Geotechnical Engineering such as Terzaghi, Peck and Tschebotarioff proposed various loadings based on the cohesion levels of the soil. The third section of the study focused on the vertical and horizontal support elements of the deep excavation support systems. Within the study; bored piles, diaphragm walls and sheet pile walls were showed as vertical support elements. The comparison and evaluation of these elements were touched on in details in respect of production method and difficulties in production. Furthermore; anchorages, soil nails and strut supports were showed as horizontal support elements. In it a fact that anchorages are used more often in comparison to soil nails as anchorages provide greater carrying capacity as a horizontal support element. Whereas the strut supports can also be preferred as they can be produced a lot faster and are usually required less in number. Following these details, in the fourth section study focuses on the monitoring of deep excavation support systems and surrounding structures. It is essential to monitor the behavior of support systems to ensure the structural safety of deep excavations and other structures surrounding the excavation site. It is very common to see engineering applications which show different behavior than their original designs. Because of this, geotechnical instrumentation holds great importance in all engineering applications. To this purpose, the respective section of the study shows crack gauges, deformation measurements, extansometers, piezometers, reflectors and inclinometers in detail. During deep excavations, high levels of stresses are faced. To compensate these stresses, diaphragm walls are often preferred as the safest system. The reason behind this is that diaphragm walls are much more rigid in comparison to pile systems and that they also allow displacements that will occur during the excavation to be monitored easily. The most common way to monitor these displacements is with inclinometers. The deep excavation this study is based on is carried out using diaphragm walls and struts. The displacements during excavation were monitored with inclinometers. The fifth chapter of the study refers to finite elements method and the PLAXIS software. In principal, finite elements method bears the logic of reaching to the whole through working on small pieces. In the last century, the fast development of computers made this method a frequently used supportive element in all engineering subjects. Today, finite elements method is used in many areas. One of the widely known software PLAXIS also uses finite elements method logic as its base in order to solve complex geotechnical problems. In the analyzes, soil units were modeled using 'Hardening Soil' model, while rock units were modeled using 'Mohr-Coulomb' structure model, structural elements were 'plate' and struts were modeled using 'node-to-node anchor' elements. The analyses conducted in two-dimensions and three-dimensions were then compared to on-site data. The results achieved after this comparison is as follows; The displacement behavior and values obtained in PLAXIS 2D and PLAXIS 3D analyses were found out to be similar and within close range. Boscardin and Cording have developed a method for determining damage to existing structures by angular rotation and horizontal unit deformations. According to this method, the displacement values obtained as a result of the analyzes were processed and the effect of displacements on the existing structures were examined and it was observed that the displacements in the structures remained in the negligible region in two-dimensional and three-dimensional analyzes. When the results obtained from finite elements method was compared to actual on-site data, it was seen that the results from finite elements method were higher in value. It is believed that the main reason behind this difference is the actual soil parameters are higher than the parameters taken from literature of which the analyses were based on or that the soil profile differs. In respect of displacement behavior, inclinometer results showed similarity to displacement results obtained through finite elements method. Internal forces of the diyaphram wall obtained through PLAXIS 2D and PLAXIS 3D analyses were found out to be similar and within close range. In the conclusion, the inclinometer measurements and the results of the analyzes for the station belonging to the subway project were evaluated and compared. For the idealized soil profile, the effect of excavation with different dimensions on the settlement of the surrounding structures was investigated and the thesis study was completed.

Benzer Tezler

  1. Tez No

    238283

    Analysis of corner effects on in-situ walls supporting deep excavations: Comparison of plane strain and three dimensional

    Derin kazı duvarlarındaki köşe etkilerinin analizleri: İki boyutlu ve üç boyutlu analizlerin karşılaştırılması

    GÜLİZ ÜNLÜ

    Yüksek Lisans

    İngilizce

    İngilizce

    2008

    İnşaat MühendisliğiOrta Doğu Teknik Üniversitesi

    İnşaat Mühendisliği Bölümü

    PROF. DR. ORHAN EROL

  2. Tez No

    578875

    İksa kaynaklı deplasmanların çevre yapılar üzerindeki etkisinin 2 ve 3 boyutlu analizlerle tahmini

    Predicting the effect of excavation induced settlements on the nearby structures by 2d and 3d analyses

    BURAK TÜRK

    Yüksek Lisans

    Türkçe

    Türkçe

    2019

    İnşaat Mühendisliğiİstanbul Üniversitesi-Cerrahpaşa

    İnşaat Mühendisliği Ana Bilim Dalı

    DOÇ. DR. MUSTAFA KUBİLAY KELEŞOĞLU

  3. Tez No

    356141

    Numerical analysis of prestressed anchored pile wall: Shoring system in front of historic building in Hilton Istanbul Bomonti hotel and conference center project

    Öngermeli ankrajlı kazıklı duvar nümerik analizi:Hilton İstanbul Bomonti hotel ve konferans merkezi projesi kapsamında yer alan tarihi bina önü iksa sistemi

    ECE AKTAN

    Yüksek Lisans

    İngilizce

    İngilizce

    2014

    İnşaat Mühendisliğiİstanbul Teknik Üniversitesi

    İnşaat Mühendisliği Bölümü

    PROF. DR. MUSAFFA AYŞEN LAV

  4. Tez No

    698035

    Zemin çivisi ile güçlendirilmiş şevlerin gerilme-deformasyon esaslı yöntemler ile değerlendirilmesi

    Evaluation of slope reinforced with soil nail by stress-strain based methods

    AKIN GÖKGÖZ

    Doktora

    Türkçe

    Türkçe

    2021

    İnşaat Mühendisliğiİstanbul Üniversitesi-Cerrahpaşa

    İnşaat Mühendisliği Ana Bilim Dalı

    DOÇ. DR. MUSTAFA KUBİLAY KELEŞOĞLU

  5. Tez No

    620881

    Derin kazılı iksa sisteminin sonlu elemanlar yöntemi ile analizi: İstanbul - Basf Teknopark örneği

    Analysis of the deep excaved shoring system by finite element method: Example of İstanbul - Basf Teknopark

    MERVE ÇOPAN

    Yüksek Lisans

    Türkçe

    Türkçe

    2020

    İnşaat MühendisliğiKaradeniz Teknik Üniversitesi

    İnşaat Mühendisliği Ana Bilim Dalı

    DOÇ. DR. SABRİYE BANU İKİZLER

Geri Dön