• The Journal of Engineering Geology
• /
• v.16 no.2 s.48
• /
• pp.125-134
• /
• 2006

In order to establish the in-situ application of the artificial storage and recovery (ASR) technology which is used the property of the aquifer storage of groundwater. We carried out to the in-situ experiments such as borehole TV logging, pumping test and artificial hydraulic fracturing in volcanic island, Ulleungdo. In-situ experiments were conducted to divide the before- and after-hydraulic fracturing. Pumping test was achieved to confirm the two fracture zones, GL-13m and GL-21m, which are determined by the borehole TV logging. From the results of the before- and after-pumping tests, the hydraulic connectivity was confirmed to locate at GL-13m in the residual deposit zone of pumice media as alluvium. However, in the bedrock tone at GL-21m the hydraulic connectivity could be considered to faulty. Consequently, in this study area the artificial recharge has a little unsatisfied to geo-structural condition and desired to more detail investigation works.

• Tunnel and Underground Space
• /
• v.18 no.2
• /
• pp.91-97
• /
• 2008

In this paper, in-situ technique for measuring hydraulic conductivity of Excavation Disturbed Zone (EDZ) in a direct way and its application to an Underground Research Laboratory (URL) site were introduced. It was understood that both the EDZ oriented test equipment as a hardware and analysis/evaluation technique as a software should be integrated for upgrading a quality of estimated EDZ hydraulic conductivity. The well-estimated EDZ hydraulic conductivity is expected to enhance a reliability of stability evaluation for caverns under groundwater table and design of a waterproof or drainage system as well as a grout system.

• Explosives and Blasting
• /
• v.19 no.4
• /
• pp.11-22
• /
• 2001

토목공사장에서 암파쇄 작업은 경제성과 안정성에 지대한 영향을 미치는 작업이다. 본 논문은 대전지역에서 수행된 암파쇄 공법 설계 및 시공사례로서, 현장암반의 특성을 고려한 적정발파공법을 선정하기 위하여 대상 지역의 지질현황을 조사·분석하고, 또한 민원이 첨예한 도로개설 공사장에서 시험발파를 실시하여 이를 토대로 암절취 공법을 선정하여 시공한 사례보고이다. 대전지역의 지질은 선캠브리아기의 변성암류와 변성퇴적암류 및 이를 관입한 심성암류와 중생대 화강암으로 이루어져 있는 복잡한 분포를 이루고 있다. 사례연구 대상 현장은 편상구조가 현저한 관입 편상화강암 및 화강암질 편마암으로 구성되어 있었으며, 시험발파 및 분석결과를 기초로하여 25.5m이내 지역은 HRS 등 무진동 파쇄공법의 적용을 제안하였고, 25.5∼36m 범위의 대부분 지역은 진동제어를 할 수 있는 제어발파공법을 권장하였고, 기타 진동 영향권에서 비교적 안전한 것으로 나타난 지역은 소발파공법을 적용하도록 제안하였다. 제안된 안에 따라 설계를 보완하고 시공한 결과 문제의 발생없이 성공적으로 시공이 완료되었다.

• The Journal of Engineering Geology
• /
• v.26 no.4
• /
• pp.497-503
• /
• 2016

The cement grouting by vibration method (CGVM), a new construction technology developed in Korea, aims to efficiently reinforce a target ground area by injecting vibrated grout into it. The present study applies the CGVM to test sites and verifies its effect. Standard penetration tests (SPTs), field permeability tests, and geophysical surveys were conducted in two study areas, and the results were compared between before and after CGVM application. The SPT conducted before and after the CGVM application showed that the N value was increased by 33.57% point to 60.90% point. The field permeability test showed that the permeability coefficient decreased. These results indicate that CGVM may increase imperviousness and improve reservoir system stability. In addition, a resistivity survey found no low-resistivity zone, unlike before the CGVM application, thereby indicating the excellent grouting effect of the CGVM.

• Tunnel and Underground Space
• /
• v.9 no.3
• /
• pp.204-213
• /
• 1999

NATM(New Austrian Tunnelling Method) uses a support system of shotcrete, rockbolt and steel support, which are installed after tunnel excavation. Recently, a lattice girder among these support system is used in tunnelling. A lattice girder is a new steel support developed in Europe for the replacement of an existing H-shaped steel set, which is reported to have some problems in installation. This is a triangular shape welded with steel rods and is a light-weight support system which enables fast and easy installation of porepolling. The major advantage of a lattice girder is the good bonding with shotcrete. In this study, to evaluate the applicability of a lattice girder in tunnelling in Korea, field tests were performed at a high speed railway tunnel with a large section. Also, features of lattice girder in field tests were compared with those of a H-shaped steel set respectively. Field tests proved that a lattice girder fully supported the initial earth pressure developed right after excavation and limited ground deformation effectively.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.1
• /
• pp.75-83
• /
• 2016

In case of underground construction affected by groundwater, CIP (Cast-In-Place Pile) method is generally used to resolve the geo-hydraulic problem. However, as this method has poor connectivity between piles, an auxiliary method for cut-off is needed in many cases. In this study, a new concept earth retaining wall method (H-CIP) with no auxiliary method, by using surfactant grout (Hi-FA) which improves antiwashout and infiltration ability, is introduced, and its field applicability is evaluated. CIP and H-CIP piles were installed with same ground conditions, and field and laboratory tests were conducted to verify the performance. As results, newly contrived H-CIP method shows higher field performance for cut-off and strength than conventional CIP method.

• Journal of the Korean Geosynthetics Society
• /
• v.13 no.2
• /
• pp.21-29
• /
• 2014

The use of filling material based on cement paste is inefficient at field construction because it needs a lot of the charging mass. In addition, it has environmental problem according to the large amount of cement use because its strength is also larger than criterion. The excavated soil with stabilizer can be used as the filling materials when the bored pile is constructed. Therefore, this paper describes field application of solidified soil for economical efficiency and environment-friendly. The static axial load tests and the load-transfer measurements were performed to examine the axial resistant behavior of the piles. As results, the flowability, segregation and bleeding, and bond strength of filling materials was a good performance than that of the existing cement paste. But the skin friction of pile by PDA was slightly decreased than that of the existing cement paste. However, as pile filling materials, and in terms of economics and environment, the applicability of filling material is considered very effective.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.8
• /
• pp.25-33
• /
• 2012

Although it is important to reflect the accurate information of the ground condition in the tunnel design, the analysis and design are conducted by limited information because it is very difficult to consider various geographies and geotechnical conditions. When the tunnel is under construction, examination of accurate safety and prediction of behavior are overcome the limits of predicting behavior by Artificial Neural Network in this study. First, construct the suitable structure after the data of field was made sure by the multi-layer back propagation, then apply with algorithm. Employ the result of measured data from database, and consider the influence factor of tunnel, like supporting pattern, RMR, Q, the types of rock, excavation length, excavation shape, excavation over, to carry out the reliable analysis through field applicability of Artificial Neural Network. After studying, using the ANN model to predict the shearing displacement, convergence displacement, underground displacement, Rock bolt output follow the excavation over of tunnel construction field, then determine the field applicability with ANN through field measured value and comparison analysis when tunnel is being constructed.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.18 no.5
• /
• pp.431-439
• /
• 2016

This paper dealt with contents of the quality evaluation method of lattice girder utilizing non-destructive method. Quality evaluation of ordinary lattice girder is performed through the tensile strength test of structural steel and visual inspection. The tensile strength test of structural steel is performed by collecting samples of lattice girder brought into the site, during which lattice girder must be damaged to obtain sample. In addition to such disadvantage, tensile strength tester is not available at the site in most cases, requiring an inconvenient service from test certification agency. In addition, it is substituted by mile sheet issued during the production of structural steel, which inevitably lacks reliability. Furthermore, visual inspection at the site entails a problem of lack of reliability, thereby requiring a method of easily and quickly evaluating the quality of lattice girder without damaging the material. Accordingly, this study comparatively analyzed the yield strength of tensile strength test and the yield strength of instrumented indentation test with same sample. The test results ensured over 95% precision level for the instrumented indentation test, based on which a quality evaluation method based on instrumented indentation test that allowed onsite direct quality evaluation is proposed.

• 전기의세계
• /
• v.44 no.4
• /
• pp.31-41
• /
• 1995

본 논문에서는 바다 한가운데를 매립하여 만든 인공섬 위에 부식영향에 취약한 지역에 나관상태로 매설되는 액화 천연가스 탱크기초 강관파일에 전기방식을 적용하는 사례를 통하여 전기방식관련 자료검토와 현장예비조사를 통한 적정한 전기방식설계 적용, 전기방식 전위측정 시험방법, 방식설비 주위시설물에 대한 간섭영향등을 논술하였다.