탄성복원력을 이용한 마찰형 강관 록볼트 및 기존 록볼트에 대한 인발력 실험연구

손무락,김지현 사단법인 한국터널지하공간학회 2023 한국터널지하공간학회논문집 Vol.25 No.6

In this study, an experiment on pullout capacity was conducted of rock bolts using grouting materials such as cement mortar and resin, which are widely used, and a newly proposed steel pipe friction type rock bolt using elastic restoring force, and the results were compared and analyzed. The experimental results showed that the pullout capacity on the rock bolts with cement mortar under a dry condition (no ground water) was relatively larger than the rock bolts with resin and the steel pipe. Nevertheless, the friction type steel pipe rock bolt to use elastic restoring force is expected to be useful in the field particularly where groundwater exists and it affects the loss and curing of grouting materials such as cement mortar or resin. In addition, it was found to have the advantage of being easy and quick to install.

터널굴착으로 발생한 지반거동에 대한 수치해석적 분석

손무락,윤종철,Son, Moo-Rak,Yun, Jong-Cheol 한국터널지하공간학회 2009 한국터널지하공간학회논문집 Vol.11 No.3

본 논문에서는 터널굴착으로 발생한 지표면에서의 최대 침하 및 수평변위와 총 침하부피량을 추정하기 위하여 서로 상이한 지층에서 다양한 깊이 및 직경, 서로 다른 시공조건(지반손실량)을 가진 터널에 대해 수치해석을 수행하였다. 수치해석 결과로부터 얻어진 지표면에서의 최대 침하량은 터널 굴착부 천단에서의 최대 침하량과 지층별, 터널직경 및 깊이, 시공조건(지반손실량)별로 비교되었으며, 또한 지표면에서의 최대 침하량은 지표면에서의 최대 수평변위량과도 비교하였다. 뿐만 아니라, 터널굴착부에서 발생한 지반손실량($V_L$)과 지표면에서 형성된 총 침하부피량($V_s$)을 지층 및 터널깊이와 직경을 달리하여 상호 비교하였다. 수치해석을 통해 얻어진 결과는 그 적용성과 타당성을 검증하기 위하여 기존 현장계측자료와의 비교가 수행되었으며, 이를 통해 본 연구의 수치해석 결과가 향후 터널굴착으로 발생된 주변 지반의 거동을 파악하고 분석하는 실무자료로서 활용될 수 있다는 것을 파악하였다. Numerical analysis has been performed to estimate maximum settlement, maximum horizontal displacement and total settlement volume at the ground surface due to tunnel excavation varying ground condition, tunnel depth and diameter, and construction condition (volume loss at excavation face). The maximum surface settlement from the numerical analysis has been compared with the maximum settlement at tunnel crown considering ground condition, tunnel depth and diameter, and construction condition, and it has been also compared with the maximum horizontal displacement. In addition, the volume loss ($V_L$) at tunnel excavation face has been compared with the total surface settlement volume ($V_s$) with the variation of ground condition, tunnel depth, and tunnel diameter. The results from the numerical analysis have been compared with field measurements to confirm the applicability and validity of the results and by this comparison it is believed that the numerical results in this study can be utilized practically in analyzing the ground movements due to tunnel excavation.

Earth Pressure on a Retaining Structure in Layered and Jointed Rock Masses

손무락,Solomon Adedokun 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.4

This work looked into the earth pressure induced on retaining walls in different rock layer formations and joint conditions. Based on the simulation of a large-scale expermental test, extended numerical tests were carried out focusing on the effect of various rock layer formations on earth pressure characteristics. The earth pressures induced from single and multi-layered rocks were compared in terms of magnitude and distribution. The comparison showed that a rock layer formation affects the earth pressure on a retaining structure considerably depending on the composition of rock layer with regard to rock type and thickness. Additionally, the analysis results were compared with Peck’s soil earth pressure and it was turned out that a layered and jointed rock mass induces the earth pressure considerably different from those both in a single-layer rock mass and in soil ground. The findings form this work can help understand the characteristics of the earth pressure caused by excavation activities in layered and jointed rock masses.

터널 콘크리트 라이닝 및 공동구 신축이음 설치방안에 관한 연구

손무락,박양흠,박윤재,김재견,윤종철 한국지반공학회 2015 지반 : 한국지반공학회지 Vol.31 No.5

Effect of Torsion on the Structural Response to Ground Movements

손무락 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.10

Structures, which are subjected to tunneling or open cutting-induced ground movements, are frequently skewed with respect to the direction of tunnel advance or the excavation face. The structures may be subject to a torsion, which is a type of shear (angular) distortion, due to differential settlement or out-of-plane distortion in 3D conditions and can be damaged more severely than structures with only in-plane distortion. Therefore, the effect of torsion should also be carefully considered when investigating a stuctural response to ground movements. This study examines the effects of torsion on the structural response to ground movemnts based on field case studies and 3D numerical tests.

Comparison of Earth Pressure between Numerical and Analytical Methods for Jointed Rock Wedges

손무락,Solomon Adedokun 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.7

The magnitude of earth pressure of jointed rock wedges against a support system was investigated both analytically and numerically. Analytical method was based on the wedge analysis and numerical method was based on the discrete element method. To consider various rock wedge conditions, the controlled parameters included the rock type, number of joint, and joint shear condition. The results of analytical method were compared with the numerical test results. The comparison showed that the earth pressure of jointed rock wedges can be assessed larger by the analytical method than the numerical method and as the number of joints increases, the results of both methods becomes closer. In addition, the results indicated that the earth pressure of jointed rock wedges was strongly dependent on the rock type, number of joint, and joint shear condition. This study suggested that both the ground-structure interaction and rock and joint conditions are important for assessing the earth pressure of jointed rock wedges, and these factors should be considered when designing a support system economically and reasonably against jointed rock wedges.

터널 굴착하중 조건에서의 절리암반의 탄성계수 예측

손무락,이원기,황영철 한국지반공학회 2014 지반 : 한국지반공학회지 Vol.30 No.9

Strength Characteristics of Soil Cement Reinforced by Natural Hair Fiber

손무락,이재영 한국지반환경공학회 2018 한국지반환경공학회논문집 Vol.19 No.4

This study systematically examines the changes in the compressive and tensile strength of soil cement reinforced by natural hair fiber, which is regularly produced from human. Extensive experimental tests of various test specimens have been carried out in a laboratory. Several factors are considered, including the soil type, amount of cement, amount of fiber, fiber length, loading type, and curing age. The test results indicate that both the compressive and tensile strengths are significantly affected by the fiber, either increasing or decreasing depending on the conditions. The increase in tensile strength is significant in the sand-based soil cement due to the tensile resistance of the fiber which is interlocked with the surrounding soil or cement particles. The natural fiber provides a larger strain to failure due to its extensibility, which allows greater deformation. Based on the test results, natural hair fibers can be an effective and environmentally friendly way to improve soil ground subjected to tensile loading, such as an embankment slope, road subgrade, or landfill, thus reducing the cost for cement and waste treatment. The study results provide a useful information of better understanding the mechanical behavior of natural hair fiber in soil cement and the practical use of waste materials in civil engineering. The findings can be practically applied for improving earth structures under tensile loading.

헤어섬유로 보강된 점토흙의 강도특성 분석

손무락,송화선,이재용 한국지반공학회 2015 지반 : 한국지반공학회지 Vol.31 No.7

원형 수직구 굴착에 따른 발생 지반침하 분석

손무락,이강렬 사단법인 한국터널지하공간학회 2023 한국터널지하공간학회논문집 Vol.25 No.2

지반굴착은 필연적으로 인접지반의 지반변위를 유발시키며, 지반변위에 노출된 구조물 및 시설물들은 다양한 피해를 입을 수 있다. 따라서 굴착유발 인접구조물 및 시설물의 손상 및 피해를 최소화하기 위해서는 우선적으로 굴착으로 인해 발생하는 인접지반에서의 지반변위(침하 및 수평변위)를 예측하여야 한다. 흙막이 굴착 유발 지반변위 정보는 상대적으로 많이 존재하지만 원형 형태의 수직구 굴착에 대한 지반변위 정보는 충분치 않다. 본 연구에서는 수직구 굴착에 대한 사례분석 및 흙막이 굴착과의 비교를 통해서 수직구 굴착유발 인접지반 침하예측에 대한 정보를 제공하고자 한다. 본 연구를 통해서 수직구 굴착 시 침하관리 기준으로서 흙막이 굴착의 침하기준을 사용하는 것은 안전성 측면에서 보수적인 접근방법으로 판단되나 경제성 측면을 고려할 때 벽체의 과다설계를 초래할 수 있어 수직구 굴착에 대해 보다 합리적인 침하기준이 필요한 것으로 나타났다.