Ground Settlement in Soft Soil due to Earth Pressure Balance : Tunnel Boring Machine (EPB-TBM) Excavation

다국어 초록 (Multilingual Abstract)

SUMMARY
Title: Ground Settlement in Soft Soil due to Earth Pressure Balance - Tunnel Boring Machine (EPB-TBM) Excavation

This thesis presented the analysis of soft soil tunneling effect using Earth Pressure Balance-Tunnel Boring Machine (EPB-TBM) which used in the MRT Jakarta Project Phase 1. Since the MRT Jakarta tunneling is the first project in Indonesia which uses a TBM for tunneling excavation and the MRT Jakarta is a long phase project (phase 1 only 16km from the total 230km on 2030), it becomes important to pay more attention for this project especially for decreasing the impacts of tunnel excavation. One of the challenges of shield tunnel construction is the settlement effect caused by tunnel excavation. The soil surrounding tunnel experienced a deformation due to tunneling process which can be a disaster for an infrastructure above the tunnel line and also for the tunnel its self.
The finite element program namely PLAXIS 2D will be used for predicting the settlement by modeling the structure and then calculating by applying some stages to see the behavior of the structures especially ground subsidence. Various parameters such as geometry model, groundwater level, excavation methods, construction stages, and overburden depth will be simulated to see the impact on the structures. The settlement result from PLAXIS calculations will be compared to the popular empirical method formula. The final calculations by PLAXIS give different reactions when estimating the ground settlement compares to the empirical methods. Empirical methods show higher settlement value in the conditions shallow overburden compares to PLAXIS result. However, PLAXIS seems overestimate in the conditions of deeper overburden.

Abstract
Ground Settlement in Soft Soil due to Earth Pressure Balance - Tunnel Boring Machine (EPB-TBM) Excavation

Name : Yayah Soleha
Supervisor : Prof. Kook Hwan Cho, Ph.D., P.E.
Department : Railway Construction
School : Graduate School of Railway
University : Seoul National University of Science and Technology

The Rapid of Jakarta’s economic development and the accelerated process of urbanization has caused the exploitation of underground utilization become an important step to solving the urban population. Nowadays, People require more alternative transportation services. Thus, the requirement for tunnels will be a strong preference to be carried out.
Tunnel Boring Machine (TBM) has no doubt become a modern technology that is commonly used in underground construction. Therefore, the technology is now deployed by The Mass Rapid Transit (MRT) Jakarta to drive MRT line from Senayan to Bundaran HI. This 6km section is part of 16km MRT Jakarta Project phase 1 from Blok M – Bundaran HI. One of the challenges of bored tunnel construction is settlement caused by tunnel excavation. The soil surrounding tunnel experienced a deformation due to tunneling process that can become a disaster especially for an infrastructure above the tunnel line and also for the tunnel its self.
Accordingly, this thesis objective focuses on the prediction of settlement that occurs in the structures of the surrounding tunnel especially above the tunnel axis. The finite element program namely PLAXIS 2D will be used for modeling and calculating the structure behavior includes ground subsidence. Various parameters such as geometry model, groundwater level, excavation methods, construction stages, and overburden depth will be simulated to examine the impact on the structures. The result from PLAXIS calculations will be compared to the popular formula in the empirical method.
The final calculations by PLAXIS give different reactions when estimating the ground settlement is compared to the empirical methods. The empirical methods show higher settlement value in the conditions of shallow overburden compared to PLAXIS result. However, PLAXIS seems to overestimate in the conditions of deeper overburden.

Keywords: TBM, EPB, PLAXIS, Settlement, Empirical Method.

국문 초록 (Abstract)

초록
토압 균형으로 인한 연약지반에서의 지반 침하 – 터널 시추 장비 (EPB-TBM) 굴착

Yayah Soleha
Prof. Kook Hwan Cho, Ph.D., P.E.
철도건설공학과
철도전문대학원
서울과학기술대학교

자카르타의 급속한 경제 발전과 가속화된 도시화 과정으로 인하여 지하 공간의 활용은 도시 인구 문제를 해결하기 위한 중요한 방법이 되었다. 오늘날, 사람들은 더 많은 대체 교통 서비스를 필요로 하고 있다. 따라서 사람들의 요구를 만족하기 위하여 지하 공간을 활용한 터널의 개발이 매우 필요하다.
현대 기술의 경우, 지하 공간 개발시 주로 터널 시추 장비(TBM)를 활용하고 있다. 이러한 TBM장비는 현재 자카르타의 Senayan ~ Bundaran HI 구간의 MRT(Mass Rapid Transit) 개발에서도 활용되고 있다. Senayan ~ Bundaran HI 구간은 6km의 연장으로 총연장 16km의 Blok M ~ Bundaran HI 구간 자카르타 MRT 프로젝트의 1단계에 속한다. 터널 건설시의 주요 문제점은 터널 굴착에 의한 침하이다. 터널 굴착면 주변의 지반은 터널 굴착이 진행됨에 따라 변형이 발생되며, 발생된 변형에 의해 터널 상부의 구조물 및 터널 자체에 문제를 초래할 수 있다.
따라서 본 논문에서는 터널 주변 특히 터널 상부에서 발생하는 침하 예측에 대하여 분석하였다. 터널 굴착시 발생가능한 지반 침하 및 구조물의 변형에 대하여 유한요소 프로그램인 PLAXIS 2D를 활용한 수치해석적 검토를 진행하였다. 기하학적 모델, 지하수위 굴착공법, 시공단계 및 과부하 깊이와 같은 다양한 매개변수를 시뮬레이션하였으며, 이를 통해 구조물에 미치는 영향을 검토하였다. 또한, 수행된 수치해석과 기존 경험적 방법에서 주로 사용되는 공식에 대하여 비교분석을 수행하였다.
지반 침하 추정시 PLAXIS를 활용한 수치해석적 방법과 경험적 방법을 비교한 결과, 서로 다른 결과를 얻을 수 있었다. 경험적 방법은 수치해석 결과에 비해 더 낮은 과부하 상태에서 더 높은 침하값을 나타냈다. 반면에, 수치해석의 경우 높은 과부하 상태에서 과대 평가하는 경향이 있는 것으로 분석되었다.

Keywords: TBM, EPB, PLAXIS, 침하, 경험적 방법

목차 (Table of Contents)

• Table of contents
• Summary ⅰ
• Table of contents ⅲ
• List of tables ⅴ
• List of figures ⅵ
• I. Introduction 1
• 1.1 Introduction 1
• 1.2 Problem Definition 2
• 1.3 Objectives 4
• 1.4 Scope of the Thesis 5
• II. Literature reviews 6
• 2.1 Tunnel Boring Machine (TBM) 6
• 2.1.1 TBM Part 10
• 2.1.2 Tunneling Excavation Method Using EPB-TBM 11
• 2.2 Tunneling induce Settlement 13
• 2.3 Empirical Methods 19
• 2.4 Finite Element Method 25
• III. Ground Subsidence Problems in MRT Jakarta Project 30
• 3.1 MRT Jakarta Project 30
• 3.1.1 Tunnel Specifications 32
• 3.2 Soil Characteristic 34
• 3.2.1 Stratigraphic Soil 34
• 3.3 Excavation Method 35
• 3.4 Prediction Subgrade Subsidence 39
• IV Subgrade Subcidence Modeling 43
• 4.1 Setting the Data Input 43
• 4.2 Modeling in PLAXIS 47
• 4.3 PLAXIS Results Calculation 50
• V. Analysis and Discussion the Result 54
• 5.1 Finite Element Result Analysis 54
• 5.2 Comparison with the Empirical Method 64
• 5.3 Plotting into Gaussian Model 67
• Ⅵ. Conclusions and Recommendations 79
• 6.1 Conclusion 79
• 6.2 Recommendations 81
• References 82
• Appendix 86
• Abstract 154
• Acknowledgments 158