초록 ▼

- 강관 외경 이상의 직경으로 천공하면서 강관을 끌고 전진하는 회수형 천공 비트의 개발 및 시험 적용을 통해 상용화함
- 회수형 천공 비트를 이용하고 강관을 구조부재로 이용하는 새로운 소구경 말뚝 공법인 강관 마이크로파일 공법을 개발함
- 강관 마이크로파일 요소 부재에 대한 실내실험을 통해 내하력을 검증함
- 강관 마이크로파일 공법의 시험시공을 통해 시공성을 확인하였고, 시험시공 현장에 대하여 표준품셈 기준으로 분석한 결과 공사비가 약 30.9% 절감되는 것으로 나타남
- 시험시공 현장에서 재하실험을 통해

- 강관 외경 이상의 직경으로 천공하면서 강관을 끌고 전진하는 회수형 천공 비트의 개발 및 시험 적용을 통해 상용화함
- 회수형 천공 비트를 이용하고 강관을 구조부재로 이용하는 새로운 소구경 말뚝 공법인 강관 마이크로파일 공법을 개발함
- 강관 마이크로파일 요소 부재에 대한 실내실험을 통해 내하력을 검증함
- 강관 마이크로파일 공법의 시험시공을 통해 시공성을 확인하였고, 시험시공 현장에 대하여 표준품셈 기준으로 분석한 결과 공사비가 약 30.9% 절감되는 것으로 나타남
- 시험시공 현장에서 재하실험을 통해 설계하중 이상의 내하력을 확인함
- 신설 말뚝에 기존 기초의 하중을 일부 분담시킬 수 있는 선재하 기술의 개념 도출하고 모형실험을 통해 선재하 기능을 확인함

(출처 : 요약서 3p)

Abstract ▼

□ Purpose & Contents
□ purpose of the research
- This project is concerned with the development of steel pipe micropile method, which reduces the total construction cost by 30%. It aims at the development of element technology and verification through test construction and loading exper imerit

□ Purpose & Contents
□ purpose of the research
- This project is concerned with the development of steel pipe micropile method, which reduces the total construction cost by 30%. It aims at the development of element technology and verification through test construction and loading exper imerit.
- In order to achieve the final goal, we commercialized the recoverable type boring bit technology while towing the steel pipe which is the element technology, developed the steel pipe micropile method which uses the steel pipe as the structural member, and carried out field test and load test Verified.
- Performance tests were carried out by performing laboratory tests on the main members that affect the function of the pile, such as the connection of the steel pipe micropiles, the connection between the pile and the foundation, and the adhesion between the pile and the grout.
- The concept of pre-loading technology, which is a element technology to improve the efficiency of pile, is applied to building remodeling work, and the pre-load capacity is confirmed through model test on single pile.
- Design method of steel pipe micropiles is established and applied to test construction to secure design ability of new technique.

□ Research content
○ Recovery-type boring bit Development
- Recoverable drilling bits are drilled bit technology that pulls the steel pipe forward while drilling to the outside diameter of the steel pipe, and can be recalled through the inner diameter of the steel pipe after completion of drilling.
- In this project, we made prototype of self-developed return type drilled bits and performed 7 test drilling in total, and confirmed that drilling and recoverable function works smoothly in the soil-weathered rock-soft rock-hard rock layer.
- The design of the drill bit is done directly by the researchers, and it is assembled after assembling parts such as chitting / machining / heat treatment by a professional manufacturer.
- We have secured prototypes and drawings that can be commercialized through 5 prototypes and several parts revisions in total, and have built-in various types of recoverable bit design technology.

○ Steel pipe micropile method development
- The design and application of the optimum element component are derived from the design of the joint between the steel pipe and the steel pipe constituting the steel pipe micropile, the end shoe, and the weld bead band for enhancing the adhesion force.
- Experiments were conducted on the ability of steel pipe to penetrate according to the presence or absence of a shoe combined with a recoverable type drilled bit.
- The connection of the steel pipe was examined by welding using a screw type connection,a ring type guide, and welding using a fixing jig, and considering the mass production cost and the workability, it was decided by welding using a fixing jig.
- We have examined the pressurized inject ion method and the gravity type inject ion method of cement milk and confirmed that it is possible to perform smooth injection by gravity type injection through test construction.

○ Laboratory tests for the confirmation member forces
- Experiments were carried out on the elements of the pile, such as the adhesion test between the steel pipe and the cement grout, the tensile test of the welded joint of the steel pipe, and the bearing capacity test of the connect ion between the foundation and steel pipe micropiles.
- Our research team prepared the test specimens and commissioned them to the national accredited test institutes in the Hybrid Structure Research Center (in Myongji University) to obtain the test reports.
- The concept of the pre-loading device which can partly share the load of the existing structure to the new pile was derived, and it was confirmed that the pre-loading function works through the same pile model test as the real one.

○ Field test construction and loading experiment
- A total of five vertical and horizontal drilling tests were carried out to verify the drilling and retrieval function of the recovered drilled bits, and it was confirmed that three of them were able to perform smooth work by installing steel pipe micropiles.
- In the field test construction, our research team prepares necessary for experiments such as experiment planning and supply and demand, and the equipment operation in the field utilizes equipment makers that have equipment such as pneumatic perforator.
- The field loading test was carried out by a recognized professional testing laboratory. The test load test was conducted to confirm that the load-carrying capacity over the design load was exerted for compressive force / tensile force / horizontal force.

○ Development of design technic,
- Based on domestic and foreign specification, design method was developed according to characteristics of steel pipe micropiles and used in test construction design.

□ ResuIts
- In this project, we developed a self-drilling drill bit that is drawn through the inner diameter of the steel pipe after drilling, and pu I led the steel pipe while drilling the steel pipe.
- Compared to existing technology, it has simple structure, eliminates malfunction and reduces manufacturing cost, and enables smooth drilling in hard rock layer.
- We have developed a steel pipe micropi le method that uses steel pipes as structural members by using reclaimed perforated bits and confirmed that the design load carrying capacity of the pile is demonstrated through test construction and loading tests.
- The total cost of the steel pipe micropi les developed on the basis of the test site is 22% lower than that of the conventional micropi les method.
- The concept of pre-loading technology that a I lows a new pile to share part of the load of existing building was derived, and load capacity was verified through laboratory model test.

□ Expected Contribution
- The recoverable bit is expected to contribute to technological advancement of various methods including ground and rock drilling in mining and construction.
- In particular, currently commercialized products will be sold in the tunnel reinforcement method, such as steel pipe reinforced multi step grouting method and underground water well drilling, in which the recovery function is not smooth and the ring type bit (one time use) is applied.
- The steel pipe micropile method is expected to perform construction in the domestic small diameter pile market because it has a great effect of reducing steel material cost and simple process, which is more economical than existing micropile.
- We plan to utilize the drilling equipment and greeting system applied to the existing construction method and to mass-produce the recovered drilling bits and materials proven in this project
- Since the steel pipe micropile method is developed for the first time in this project in Korea, the resuIt of this project can be a standard, and it can contribute to the reduction of construction cost and the development of the domestic construction industry through joint use of technology with a company wishing to use this technology has exist
- In the case of pre-loading technology, model tests were conducted for concept derivation and loading capacity confirmation, and it can be used as basic data for development of detailed structure and effective construction method for mass production in the future.

(출처 : SUMMARY 7p)

목차 Contents

• 표지 ... 1
• 제 출 문 ... 2
• 보고서 요약서 ... 3
• 국문 요약문 ... 4
• SUMMARY ... 7
• TABLE OF CONTENTS ... 10
• 목차 ... 12
• 제1장. 연구개발과제의 개요 ... 14
• 1. 연구개발 목적 ... 14
• 가. 회수형 천공 비트의 상용화 ... 14
• 나. 강관 마이크로파일 공법의 개발 ... 14
• 다. 선재하 기술의 개념 도출 및 타당성 검증 ... 14
• 2. 연구개발의 필요성 ... 14
• 가. 회수형 천공 비트 기술 개발 ... 14
• 나. 강관 마이크로파일 공법 개발 ... 15
• 다. 선재하 기술 개발 ... 15
• 3. 연구개발 범위 ... 16
• 가. 회수형 천공 비트 기술 개발 ... 16
• 나. 강관 마이크로파일 공법 개발 ... 16
• 다. 선재하 기술 개발 ... 16
• 제2장. 국내외 기술 개발 현황 ... 17
• 1. 회수형 천공 비트 기술 ... 17
• 2. 마이크로파일 공법 ... 19
• 3. 선재하 기술 ... 24
• 제3장. 연구 수행 내용 및 성과 ... 28
• 1. 회수형 천공 비트 개발 및 상용화 ... 28
• 가. 회수형 천공 비트의 시제품 제작 및 시험천공 ... 28
• 나. 회수형 천공 비트 상용 제품 설계 및 제작 ... 29
• 2. 강관 마이크로파일 공법 개발 ... 30
• 가. 요소별 대안 검토 및 실험 ... 30
• 나. 시험시공 과정 요약 ... 43
• 다. 재하실험 결과 및 분석 ... 45
• 3. 강관 마이크로파일 설계 기법 정립 ... 52
• 4. 강관 마이크로파일의 경제성 분석 ... 56
• 5. 선재하 장치 개발 ... 58
• 가. 선재하 장치 개념 도출 및 모형실험 ... 58
• 나. 개발 성과 및 향후 활용 방안 ... 61
• 제4장. 목표 달성도 및 관련 분야 기여도 ... 62
• 1. 목표 달성도 ... 62
• 2. 관련 분야 기여도 ... 63
• 가. 회수형 천공 비트 기술 ... 63
• 나. 강관 마이크로파일 공법 ... 64
• 다. 선재하 기술 ... 64
• 제5장. 연구개발성과의 활용계획 ... 65
• 1. 회수형 천공 비트의 판매 ... 65
• 2. 강관 마이크로파일 공사 수행 ... 65
• 3. 선재하 기술의 현장 적용 기술 개발 ... 65
• 제6장. 연구 과정에서 수집한 해외 과학기술 정보 ... 66
• 제7장. 연구개발성과의 보안등급 ... 67
• 제8장. 국가과학기술종합정보시스템에 등록한 연구시설·장비 현황 ... 68
• 제9장. 연구개발과제 수행에 따른 연구실 등의 안전 조치 이행 실적 ... 69
• 제10장. 연구개발과제의 대표적 연구 실적 ... 70
• 제11장. 기타 사항 ... 71
• 제12장. 참고 문헌 ... 72
• 끝페이지 ... 73