서울시와 같은 도심지의 경우 상수도관, 하수관, 가스관, 통신․전기선과 같은 인프라 시설물을 도로포장 하부에 매설하고 있다. 그 러나 도로 지하에 각종 시설물을 매설하거나 유지보수 등으로 인해 노면을 굴착할 경우, 포장체 구성에 불연속면을 생성하여 이에 대 한 복구가 적절하지 않았을 경우 지반침하, 포장 노면 균열, 평탄성 불량 등의 발생으로 도로 이용자의 승차감 저하 및 노면배수 불량 으로 인한 차량 주행의 안전성 저하, 보도의 경우 통행인의 불편 초래 및 안전사고를 유발할 수 있다. 그러나 현재 서울시의 도로굴착복구 공사는 도로 이용자의 편의를 위해 당일 굴착·당일 복구를 원칙으로 하고 있으며, 이를 위해 주 간 공사 및 장시간 교통통제를 지양하고 있어, 하루 중 야간 8시간 정도로 공사 시간이 부족하고 수많은 공사가 산발적으로 시행됨에 따라 관리 감독이 어려워 시공 품질관리가 미흡하며, 특히 지하 매설물 공사 이후 포장층 하부의 되메우기 공정은 다짐 작업이 제대 로 이루어지지 않는다. 일반적으로 서울시 도로굴착복구 공사는 공사 당일 임시포장을 시행하고, 일정 기간 경과 후 차로 단위로 항구 포장 복구를 시행하고 있으며, 이로 인한 도로 평탄성 불량으로 소음․진동 발생 및 포장 조기 파손의 원인으로 작용하고 있다. 특히 되메우기 공정의 경우, 현행 시방서에 따르면 신속한 되메움 복구 및 관로 주변의 조밀한 충진을 목적으로 관로 주변을 양질의 모래로 시공하는 것을 원칙으로 하고 있으나, 기존 되메움 재료인 모래는 결속력이 약해 인접 구간 공사 시 세굴로 인한 사고 발생 위험 요소를 내재하고 있으며, 누수에 의한 세굴 발생시 편토압 등으로 인해 주변 지반의 침하 등 2차 파손을 발생시킬 수 있다.
In the history of Chinese academics, Xu Shen’s Shuowen Jiezi (hereinafter referred to as Shuowen) is known as “the first of its kind in the world” because it has the dual characteristics of explaining the form, sound, and meaning of Chinese characters and the characteristics of theoretical works on philology, both of which are practical. It has not only become a treasure of codex for the compilation of character books and exegesis, but also laid down the basic patterns of traditional philology and biblio-linguistics, with far-reaching influence. Many scholars have researched Shuowen in the past dynasties, resulting in the formation of an independent thematic discipline called Shuowen, also known as Xuxue (許學). According to Ding Fubao (丁福保), Shuowen jiezi Gulin (hereinafter referred to as Gulin) attached to the Yingyong Zhushu Xingshi Lu (引用諸書姓氏錄) statistics, there were as many as 203 people in the Qing Dynasty who studied and wrote Shuowen. In fact, there are many scholars and their achievements that are not included in the statistics. After Gulin, especially in the last 30 years, a lot of new materials of scholars in the Qing Dynasty who studied the Shuowen have been excavated and published. Most of these new materials are dispersed in their original state in different large series, so they are rarely researched and utilized, and their documentary and scholarly value is in urgent need of formal recognition. Based on the preliminary results of the major project of the National Social Science Foundation (21&ZD299) chaired by Li Yunfu (李運富), this article discusses the excavation, collation, and research of new materials on Shuowen in the Qing Dynasty.
본 연구는 도로터널, 철도터널, 지하철, 전력구 등 각종 터널 시공을 위한 TBM(Tunnel Boring Machine) 기술의 시공성 향상을 위한 연속굴착형 TBM 장비와 나선형 세그먼트 통합 시공기술 개발 및 실증과 관련된 것으로 핵심모듈인 추진잭, 세그먼트 이렉터의 선제적인 유지관리를 통해 다운타임 을 최소화하고 굴진율을 안정적으로 확보하기 위한 연속굴착형 TBM 핵심모듈의 유지관리 및 장애대 응 기술에 대한 연구를 수행하였으며, 굴착환경과 연속굴착 운영특성을 고려한 시공 및 장비 운용 절 차를 정의하였다.
Deep disposal facility for High-Level radioactive Waste (HLW) uses a multi-barrier system to prevent the leakage of radionuclide. As a part of the engineered barrier, bentonite is primarily considered as the main buffering material. This is due to the adsorption and swelling properties of the bentonite, which are expected to effectively impede leakage of the radionuclide. In many cases, adsorption is generally regarded as occurring only within the buffer zone. However, several research has been conducted to explore the possibility of bentonite intrusion into the Excavation- Damaged Zone (EDZ) generated during excavation processes, because of the swelling properties of the bentonite. Generally, for host rock near the deep disposal facility such as granite, groundwater flows through the fracture network. Therefore, analysis of the characteristics of the fracture network is essential for predicting the behavior of radionuclide in groundwater. Accordingly, the bentonite intrusion into the fracture network is critical for safety assessment of the deep disposal facility. To analyze this, hydro-geochemical model was established utilizing COMSOL Multiphysics and PHREEQC, observing changes of the behavior of U (VI) along fracture network due to the swelling of bentonite. Modeling was conducted with progressively changing intrusion depth of the bentonite. According to the results, the behavior of U (VI) exhibited significant changes depending on the connectivity of the fractures. Based on the distribution characteristics of the fracture network, heterogeneous groundwater flow was observed. U (VI) was transported through the preferential pathway, which indicates high connectivity, due to the rapid groundwater flow. Notably, when changing the intrusion depth of bentonite, significant differences in behavior of U (VI) were observed in the 0-20 cm case. In contrast, as the intrusion depth increased, it was observed that differences became less evident. These results indicate that changes in the properties of fracture network in EDZ due to the swelling of bentonite significantly influence the behavior of U (VI).
In this paper, a dynamic centrifuge model test was conducted on a 24.8-meter-deep excavation consisting of a 20 m sand layer and 4.8 m bedrock, classified as S3 by Korean seismic design code KDS 17 10 00. A braced excavation wall supports the hole. From the results, the mechanism of seismically induced earth pressure was investigated, and their distribution and loading points were analyzed. During earthquake loadings, active seismic earth pressure decreases from the at-rest earth pressure since the backfill laterally expands at the movement of the wall toward the active direction. Yet, the passive seismic earth pressure increases from the at-rest earth pressure since the backfill pushes to the wall and laterally compresses at it, moving toward a passive direction and returning to the initial position. The seismic earth pressure distribution shows a half-diamond distribution in the dense sand and a uniform distribution in loose sand. The loading point of dynamic thrust corresponding with seismic earth pressure is at the center of the soil backfill. The dynamic thrust increased differently depending on the backfill's relative density and input motion type. Still, in general, the dynamic thrust increased rapidly when the maximum horizontal displacement of the wall exceeded 0.05 H%.
본 연구에서는 석문간척지 주변 농가들을 대상으로 간척지 논 범용화를 위한 암거공법 관련 세부 기술요인에 대한 농가 수요조사 및 분석을 통해 다음과 같은 결과들을 도출하였다. 첫째, 지하흡수공을 보다 필요하고 중요하게 인식할수록 해당 기술에 대한 수용의사가 증가하는 것으로 나타났다. 둘째, 지하배수를 보다 필요하고 중요하게 인식할수록 해당 기술에 대한 수용의사가 증가하는 것으로 나타났다. 셋째, 지하관수를 보다 필요하고 중요하게 인식할수록 해당 기술에 대한 수용의사가 증가하는 것으로 나타났다. 넷째, 심토파쇄를 보다 중요하게 인식할수록 해당 기술에 대한 수용의사가 증가하는 것으로 나타났다. 다섯째, 지하흡수공 기술에 대한 수용의사가 높은 농가들이 무굴착암거공법 수용확률이 높은 것으로 나타났다.
PURPOSES : In this study, to improve the quality and construction performance of backfill materials for road excavation and restoration, the basic properties of rapid-hardening materials and stone sludge are analyzed to propose an optimal mix design.
METHODS : To utilize rapid-hardening materials and stone sludge as controlled low-strength materials for pipeline construction in downtown areas, specimens were prepared for each compounding condition of fast-hardening materials. Flow, slump, and compressive strength tests were performed at various setting times. Subsequently, the physical and mechanical characteristics of the rapid-hardening backfill material for each mixing factor were analyzed.
RESULTS : When ultrafast hardening cement and stone sludge are used, a setting time exceeding 30 min is required for a water–binder (W/B) ratio of 200% or higher. Considering the economic feasibility of ultrafast hardening cement, a W/B of 300% is considered the most suitable when high-performance superplasticizer and retarders are mixed. A flow test was performed on the rapid-hardening backfill material and the results show that if the mixing time exceeds 10 min, then the fluidity decreases rapidly, which necessitates a higher amount of superplasticizer. When ultrafast hardening cement is used, the initial strength (based on 4 h) is 0.7 MPa or higher for all formulations at a W/B ratio of 300%, and the compressive strength decreases slightly as the amount of superplasticizer is increased by 0.1%.
CONCLUSIONS : Based on the fluidity and strength of the backfill material, which is composed of a rapid-hardening material and stone sludge, the most optimal performance is achieved when ultrafast-hardening cement with a W/B ratio of 300% is used in addition to a highperformance fluidizing agent 0.3% (wt./B) and retarder 0.2% (wt./B).
Excavation Damaged Zone (EDZ) is created by the excavation of deposition holes and disposal tunnels at high-level radioactive waste repository that causes macro- and micro-fracturing in the surrounding rock. Since EDZ can significantly increase the hydraulic transmissivity in the rock and act as a major pathway of leaked radionuclides, consideration of EDZ in terms of safety assessment is very important. Moreover, long-term stress changes such as stress redistribution due to excavation of nearby deposition holes and disposal tunnels, thermal stress due to temperature rise, effective stress change due to pore pressure change, and swelling pressure of bentonite buffer can increase EDZ size and change in thermal-hydraulic-mechanical properties, and consequently, it can affect the transport of radionuclides. Therefore, in order to analyze the effect of long-term evolution of EDZ on radionuclide transport, it is essential to conduct numerical analysis considering the coupled Thermal-Hydraulic- Mechanical (THM) behavior in EDZ. In order to simulate the behavior of EDZ, coupled THM model was developed using the Adaptive Process-based total system performance assessment framework for a geological disposal system (APro) proposed by the Korea Atomic Energy Research Institute (KAERI). The concept of damage was introduced to demonstrate the jointed rock as a continuous medium. Among several damage models, Mazars damage model was applied in this study. Mazars damage model is the most well-known model for concrete which has similar behavior with rock as brittle material, and the input data of the model can be easily obtained through laboratory testing. If damage occurs due to the influence of thermal-hydraulic-mechanical coupled behavior at the bedrock, the properties change according to the degree of damage, and as a result, the migration of the radionuclide is affected. Based on this conceptual model, radionuclide transport model in the near field considering the long-term evolution of EDZ was developed. To investigate the effect of EDZ in terms of process-based performance assessment, the modeling results with and without EDZ were compared. Finally, by simulating the coupled THM behavior of EDZ with damage model, the effect of long-term evolution of EDZ on radionuclide transport was investigated.
In recent years, the importance of the thermo-hydraulic-mechanical-chemical coupled processes is increasing in the performance assessment (PA) of the high-level radioactive waste repository. In the case of mechanical behavior, it is very important because it can affect fluid flow and radionuclide transport by changing the porosity and permeability of the medium. In particular, Excavation Damaged Zone (EDZ) should be considered essential in PA because the migration of radionuclide is affected by the enhanced hydraulic transmissivity and altered geomechanical behavior of EDZ. Furthermore, due to various thermo-hydraulic behaviors such as decay heat generated from radioactive waste, pore water pressure increase, and swelling pressure of bentonite buffer material, mechanical evolution is occurred which may change the size and physical properties of EDZ. Therefore, to solve this problem, analysis of coupled thermal-hydraulic-mechanical (THM) processes with the effect of long-term evolution of EDZ due to the mechanical behavior should be accompanied. In this study, numerical model for the long-term evolution due to mechanical behavior considering EDZ using the Adaptive Process-based total system performance analysis framework for a geological disposal system (APro) proposed by the Korea Atomic Energy Research Institute (KAERI). In the case of EDZ, the concept of Mazars’ damage evolution model was applied to simulate the behavior using the continuum model, and the change in hydraulic properties according to the degree of damage was considered. To investigate the importance of mechanical behavior in PA, the results were compared by performing numerical analysis according to the presence or absence of mechanical analysis. Finally, numerical analysis considering the mechanical evolution of EDZ was conducted using the model developed in this study to investigate the effect of EDZ.
개발사업 인허가 조건 하에 실시 하는 지표조사나 건설공사 과정에서 유물이 드러날 경우 발굴조사를 하여야 한다. 발굴조사 과정에서 발굴된 매장문화재들은 모두 국가에 귀속되며, 토지이용규제를 받게 됨으로써 사실상 재산권 행사가 불가능하게 된다. 소규모 발굴조사를 제외한 대부분의 발굴조사 현장에서는 발굴조사비용 일체를 개발사업 시행자가 부담하여야 하며, 공사 지연에 따른 사업비용 증가까지 감수하여야 한다. 정당한 보상 없이 재산권 제한 만을 강제하다 보니 건설공사현장에서는 매장문화재가 발견되면 문화재청이나 지자체에 신고하지 않고 매장문화재를 훼손하거나 유물을 은폐하는 불법적인 방법을 선택하는 경우가 적지 않다. 1962년 문화재보호법이 제정될 당시 우리나라의 문화재보호법에는 매장문화재 발굴에 따른 보상규정이 미비한 상태로 법률이 제정되었다. 이는 당시 열악했던 국가의 재정 상황, 입법부의 정쟁과 무관심, 재원마련의 어려움 등이 반영된 결과이다. 그동안 매장문화재 발굴과 관련한 재산권 제한과 이에 따른 손실보상 문제는 경제 논리나 시급한 사안에 밀려서 등한시 되어 왔지만, 우리나라의 경제 규모와 국가적 위상에 걸맞게 손실보상 규정을 보완하여야 한다. 본 연구에서는 매장 문화재 발굴 현황과 문제점을 제시하고 손실보상을 위한 개선방안을 제언함으로써 문화 재보호와 개발사업 간의 상생 관계를 찾기 위한 방안을 모색하고자 하였다. 이와 더불어 매장문화재 발굴과 그에 따른 정당한 보상과 개선의 요구를 담아 합리적인 정책적ㆍ법적 개선방안을 제시하였다.
도심지의 굴착공사는 도심지의 특성을 고려하여 굴착 관련 관계법규, 관련 제도나 기술 지침 파악과 문제점 및 위험 원인을 파악하고 설계자와 시공자, 하도급자, 제도의 관계 자별 위험 원인을 살펴보며, 법·제도적으로 실현 가능한 법규의 구성, 설계를 위한 지 반조사의 적정성, 시공이 가능한 설계가 되어야 할 것이다. 이러한 설계와 시방서를 토대로 시공자는 설계와 시방서를 준수하여 시공해야 하고 미시공이나 위험성을 무시한 설계변경 없이 안전한 시공을 해야 한다. 이를 잘 이행하는지 및 굴착공사 위험성의 발생 우려가 있는지를 허가권자 또는 건설사업관리기술자의 관리·감독을 철저히 하여 모든 분야별 맡은 바를 충실히 이행하여야 굴착공사의 위험관리가 수행되는 것이다. 따라서 도심지 굴착공사의 위험관리 원인 및 개선방안을 설계, 시공, 하도급, 법·제도의 분야별로 분류하여 분석하고 분야별 변인들을 작성하여 해당 건설 관련 전문가 5개 직업군의 실증적 분석을 통하여 개선방안을 개정안으로 제안하여 도심지 굴착공사의 위험 관리에 기여 하고자 한다.
PURPOSES : The purpose of this study is to measure and analyze the fugitive dust generated by each process through field tests to develop a technology to reduce fugitive dust generated during excavation-restoration work on road pavements.
METHODS : The testbed was constructed based on a typical excavation-restoration construction section and comprised five sections for reproducibility and repeated measurements. The excavation-restoration work was divided into pavement cutting, pavement crushing, pavement removal, excavation, and restoration processes and fugitive dust generated by each process was measured. Fugitive dust (TSP, PM10, PM2.5, and PM1) was measured using a GRIMM particle spectrometer, which applies the principle of a light scattering spectrometer and can be measured in real-time.
RESULTS : Analyses of the average mass concentration of PM10 generated by the excavation-restoration process are as follows: 1286.3 μg/m³ from pavement cutting, 246.8 μg/m³ from pavement crushing, 697.0 μg/m³ from pavement removal, 747.9 μg/m³ from excavation process, and 350.6 μg/m³ from the restoration process. In addition, the average particle size distribution of the excavationrestoration construction was in the order of PM10~PM2.5 (67 %), PM1 or less (24 %), and PM2.5~PM1 (9 %). The pavement cutting process is characterized by the emission of high concentrations of fugitive dust over a short time, compared to other processes. The pavement crushing process has the characteristic of steadily generating fugitive dust for a long period, although the emission concentration is small.
CONCLUSIONS : In this study, it was found that the concentration and characteristics of fugitive dust generated during road pavement excavation-restoration works vary by process and the reduction technology for each process should be developed accordingly.
본 연구의 대상은 도로 폭이 좁은 시가지에서 굴착공사 시 적용되는 장지간 주형의 연결부이다. 일반적으로 적용되고 있는 연결부에서 상부 플랜지의 단차와 피로균열 등의 문제로 연결부의 신뢰도가 저하된다. 연결부의 결함을 보완하고 안전성을 향상시킨 개선형 연결부를 개발하였다. 유한요소 기반의 상용프로그램(ABAQUS)를 이용하여 개선형 연결부의 거동을 평가하였다. 먼저, 개선형 연결부에 적용되는 고장력 볼트 연결 및 강재와 콘크리트의 합성거동을 구현하기 위한 수치해석 방법을 제안하였다. 비교논문의 실험결과와 수치해석 결과의 비교를 통하여 개선형 연결부를 해석하는데 있어 수치해석 방법의 적합성을 검증하였다. 본 연구에서 제 안하는 수치해석 방법을 적용하여 개선형 연결부와 일반형 연결부가 적용된 장지간 주형을 해석하였다. 장지간 주형의 탄소성 거동과 연결부의 응력분포를 수치 해석적으로 비교분석하였다. 개선형 연결부의 도입으로 25%의 압축응력이 감소되며 구조적 성능 개선 효과 및 안전성을 확인하였다.