Minimizing influence on existing buildings when tunneling in soft soil

VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY TRAN QUANG DUC MINIMIZING THE INFLUENCE ON EXISTING BUILDINGS WHEN TUNNELING IN SOFT SOIL VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY TRAN QUANG DUC MINIMIZING THE INFLUENCE ON EXISTING BUILDINGS WHEN TUNNELING IN SOFT SOIL MAJOR: MASTER OF INFRASTRUCTURE ENGINEER CODE: ………………… RESEARCH SUPERVISOR: Dr NGUYEN TIEN DUNG Dr VU MINH NGAN Hanoi, 2019 ACKNOWLEDGEMENT ABTRACT CONTENT ACKNOWLEDGEMENT ABTRACT CHAPTER I INTRODUCTION 1.1 Background 1.2 Outline research CHAPTER LITERATURE REVIEW 2.1 Empirical method 2.2 Analytical methods 2.3 Finite element method using software Plaxis 2D CHAPTER METHODOLOGY 3.1 General 3.2 Project case study 3.2.1 Main propert 3.2.2 Construction 3.3 Collection of soil condition data 3.3.1 Soil investiga 3.3.2 Groundwater 3.4 Collection of TBM’s operation data 3.5 Selection of analysis section 3.6 Ground settlement analysis by empirical method 3.7 Numerical analysis with Plaxis 2D 3.7.1 Mesh model 3.7.2Preparation input data 3.7.3Soil input parameters in Plaxi 3.7.4Properties of tunnel segment 3.7.5Water condition 3.7.6Contraction method 3.7.7Stress reduction method 3.8Collection of monitoring data CHAPTER RESULT AND DISCUSSION Ground surface settlement of the tunnel alignment 4.1.1Ground surface settlement of 4.1.2Ground surface settlement in t 4.2TBM’s operational parameters and its effect on settlement 4.3Analysis of ground surface settlement by Empirical method 4.3.1Trough width parameter (i) 4.3.2Volume loss (VL) 4.4Analysis of ground surface settlement by Plaxis 2D 4.4.1Contraction method 4.4.2Stress reduction method 4.5Comparisons of empirical method and numerical method CHAPTER 55 CONCLUSIONS AND RECOMMENDATIONS Conclusions 5.2Recommendations REFERENCES 47 FIGURE 52 APENDIX A: TUNNEL MACHINE AND LINNING SEGMENT 67 APENDIX B: GEOLOGY PROFILE 70 APPENDIX C: CROSS BUILDING STRUCTURE 73 CHAPTER I INTRODUCTION 1.1 Background In Vietnam, big cities such as Hanoi and Ho Chi Minh have reached approximately 10 million population, not including the sub-urban people residing and commuting due to the recent rapid urbanization This creates a dramatically pressure on the infrastructure system and the public transport system Construction of MRT with underground sections is the optimal and feasible solution to solve these problems of the cities Figure System map (planned) for Hanoi MRT system to vision 2050 (Hanoi Metropolitan Railway Management Board) Figure System map (planned) for Hochiminh city MRT system to vision after 2020 (HCMC urban railway management board) In bored tunel in urban areas, bored tunel with TBMs has recently been a popular and effective method in the world This technique has been developed and applied as a main method for underground MRT projects The two cities of Hanoi and Ho Chi Minh City are located at the center of the delta with geology condition a mostly consisted of soft soil Deformations including settlements and tilts should be well controlled when bored tunnel in order to protect the existing ground surface and minimize the impacts on existing structures By combining theoretical calculation, software analysis and comparison with monitoring data, results derived from this study can be applied for the bored tunnel design and construction in geo-conditions in Vietnam in order to obtain effective and safe bored tunnel projects 1.2 Outline research There are five chapters in this thesis Chapter is the introduction presenting the background of bored tunnel work and outline of the thesis Reviewing the theoretical to calculate the displacement of existing structures during and after the TBM drilling process is indicated in Chapter Chapter shows the displacement calculation carried out by finite element method to predict the degree of influence on existing works as well as the optimal efficiency Chapter describes a comparison between theoretical and numerical results with monitoring data in case study in Ho Chi Minh City Metroline project to verify methods of predicting settlement displacement Proposing solutions based on calculated and observed results has been derived in Chapter 10 Figure4.8 Figure4.8 61 Figure4.9 62 Figure4.9 Figure4.9 63 Figure4.9 Figure4.9 64 Figure4.9 Figure4.9 Figure4.9 65 Figure4.9 66 APENDIX A: TUNNEL MACHINE AND LINNING SEGMENT 67 68 69 APENDIX B: GEOLOGY PROFILE 70 71 72 APPENDIX C: CROSS BUILDING STRUCTURE Figure Building cross section along of tunnel alignment from CH 0+940;CH 0+ 966; CH 1+033; CH 1+860 73 Figure Building cross section along of tunnel alignment CH 1+161; CH 1+524;CH 1+235;CH 1+400 74 75 ...VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY TRAN QUANG DUC MINIMIZING THE INFLUENCE ON EXISTING BUILDINGS WHEN TUNNELING IN SOFT SOIL MAJOR: MASTER OF INFRASTRUCTURE ENGINEER CODE:... remaining section It is necessary for mitigation influence of settlement on existing building Should using jet-grouting, strictly monitoring and prepared planning adaption to prevent incident in surface... presented in Figure 3.3 below 17 Figure 3.3 Bored tunnel’s construction sequence 3.3 Collection of soil condition data 3.3.1 Soil investigation data At tender stage, the soil investigation reports consists