Biopolymer-based soil treatment (BPST) for its application as an underground transmission pipeline backfill material
바이오폴리머 처리 흙 (BPST)의 지중송전관로 되메움재로서의 적용성 평가
- 주제(키워드) Biopolymer , Thermal conductivity , Stability/durability , Heat transfer
- 주제(DDC) 690
- 발행기관 아주대학교 일반대학원
- 지도교수 장일한
- 발행년도 2025
- 학위수여년월 2025. 2
- 학위명 석사
- 학과 및 전공 일반대학원 건설시스템공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000034368
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Many countries are accelerating urbanization to drive economic growth. Urbanization causes rapid population growth by concentrating large numbers of people in small cities. The demand for electricity is also increasing rapidly, and the construction of transmission pipelines is difficult due to the increasing number of structures and buildings on the ground due to urbanization. To solve these problems, underground transmission pipelines are required. However, if population growth continues, the number of transmission lines buried in a single transmission pipeline will increase. If a large amount of transmission cables is placed in a single pipeline, the temperature around the pipeline will be very high, which may reduce the transmission efficiency of the transmission cables or cause dielectric breakdown of the transmission cables. To solve the above problems, backfill material with great heat transfer is required. This study assessed the thermal conductivity, stability/durability, and water retention of the mixtures to be applied as backfill through laboratory thermal conductivity experiments, unconfined compression tests under first drying and repeated wetting-drying conditions, and SWCC measurements. In addition, the heat transfer when applied to the backfill material construction was analyzed using COMSOL Multiphysics. The experimental results of this paper show that biopolymers have a significant effect on improving the thermal conductivity, strength, and water retention of soil. When analyzing heat transfer, the immediate condition after construction and the condition after 10 days have passed were analyzed separately. The high-water retention backfill material maintained the water content above a certain level until 10 days and ensured favorable heat transfer.
more목차
CHAPTER I INTRODUCTION 1
1.1 Background 1
1.2 Scope-organization 3
CHAPTER II HEAT MECHANISMS AND GOVERNING FACTORS OF SOIL 4
2.1 Introduction 4
2.2 Heat transfer mechanisms 5
2.2.1. Influence of soil composition 5
2.2.2. Influence of water content 5
2.2.3. Influence of dry density 6
2.2.4. Influence of temperature 6
2.3 Correlation between thermal conductivity and electrical conductivity 7
2.4 Assessment methods 8
2.4.1. Steady-state method 8
2.4.2. Transient method 9
2.4.3. Outdoor measurement of thermal conductivity 11
2.5 Soil thermal conductivity amendment methods 12
2.6 Summary and conclusions 13
CHAPTER III ENGINEERED SOIL APPROACHES FOR SOIL THERMAL CONDUCTIVITY CONTROL 14
3.1 Introduction 14
3.2 Biopolymer-based soil treatment (BPST) 15
3.2.1. Electrical conductivity control 15
3.2.2. Biopolymer-based soil treatment (BPST) 16
3.2.3. Xanthan gum 21
3.3 Other materials 22
3.3.1. Sand 22
3.3.2. Graphite 23
3.3.3. Fly ash 24
3.3.4. Cement 25
3.4 Laboratory program 26
3.4.1. Test set-up 26
3.4.2. Needle probe 27
3.4.3. Test conditions 30
3.4.4. Sample Preparation 31
3.4.5. Results 31
3.5 Summary and conclusion 49
CHAPTER IV GEOTECHNICAL ENGINEERING BEHAVIORS OF ENGINEERED SOILS 50
4.1 Introduction 50
4.2 Soil stability assessment 51
4.2.1. Overview 51
4.2.2. Test set-up & method 51
4.2.3. Test condition 52
4.2.4. Sample preparation 53
4.2.5. Results and discussion 54
4.3 Soil durability assessment 56
4.3.1. Overview 56
4.3.2. Test program 56
4.3.3. Results and discussion 56
4.4 Soil-Water Characteristic Curve (SWCC) 59
4.4.1. Overview 59
4.4.2. Theory 59
4.4.3. Test set-up 61
4.4.4. Test method 62
4.4.5. Test condition 62
4.4.6. Results and discussion 63
4.5 Summary and conclusion 65
CHAPTER V NUMERICAL SIMULATION ON THE HEAT TRANSFER BEHAVIOR OF ENGINEERED SOILS 66
5.1 Introduction 66
5.2 Numerical modeling 67
5.2.1. COMSOL Multiphysics 67
5.2.2. Governing equations 67
5.2.3. COMSOL Multiphysics setting 70
5.3 Previous process for numerical analysis 72
5.3.1. Water content test 72
5.3.2. Water content prediction 74
5.4 Results 77
5.4.1. Immediate condition after construction 77
5.4.2. 10 days after construction 80
5.5 Summary and conclusion 83
CHAPTER VI CONCLUSIONS 84
6.1 Summary and conclusions 84
6.2 Recommendations for further studies 87
REFERENCES 88
