• Magazine of korean Tunnelling and Underground Space Association
• /
• v.19 no.4
• /
• pp.11-16
• /
• 2017

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.40 no.1
• /
• pp.97-103
• /
• 2020

The newly improved multistep steel pipe grouting method was applied to an existing steel pipe-reinforced grouting method. It was applied in order to prevent a damage caused by ground failure from excessive grouting pressure in a tunnel construction. The tunnel goes under a highway and a ramp connected to a rest area on OO highway with 11.3~12.1 m depth cover and is a part of roadbed facility construction section ordered by OO public corporation. The improved grouting method provides pre-construction work condition assessment technique through new water injection limit test and grouting effect assessment technique by grouting type assessment. It also includes assessments on interval of joints, appropriate grouting pressure, and optimal operation time to be applied to current operations. Application of the grouting method allowed the smooth road management in shallow-depth grouting construction area located upper part of tunnel excavation. Moreover, the possibility of the application of the method not only to shallow-depth grouting construction but also to various steel pipe-reinforced grouting constructions was confirmed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.40 no.4
• /
• pp.409-415
• /
• 2020

Low-flow mortar injection method grouting technology was selected and the traffic area was preserved as much as possible in order to secure safety for road traffic when the outflow and subsidence of landfill occurred due to ground-water, and etc. In particular, the current existing method was newly improved since there are risks of damage such as hydraulic fracturing at the lower part of the road, spilling of soil particles on steep slopes, and bumps on the road due to excessive injection pressure during construction. This study was carried out at the site of reinforcement work on the road as a maintenance work for the danger zone for collapse of the steep slope of the 00 hill, which was ordered from the 00 city 00 province. The improved low-flow mortar type grouting method adopted a new automated grouting management system and especially, it composites the method for grouting conditions decision by high-pressure pre-grouting test and injection technology by AGS-controlled and studied about grouting effect analysis by using new technology. By applying the improved low-flow mortar type grouting method, it was possible to lay the groundwork for road maintenance work such as the prevention of subsidence of old roads, uneven subsidence of buildings and civil engineering structures, and of soil leakage of ground-water spills. Furthermore, the possibility of application on future grouting work not only for just construction that prevents subsidence of old roads but also for various buildings and civil engineering structures such as railroads, subways, bridges, underground structures, and boulder stone and limestone areas was confirmed.

• Journal of the Korean Society for Railway
• /
• v.18 no.6
• /
• pp.543-551
• /
• 2015

Quick-hardening track (QHT) is a construction method which is used to change from old ballast track to concrete track. Sufficient time for construction is important, as the construction should be done during operational breaks at night. Most of the time is spent on exchanging the ballast layer. If it is possible to apply the ballast non-exchange type of quick-hardening track, it would be more effective to reduce the construction time and costs. In this paper, pouring materials with high permeability are suggested and a construction method involving a layer separation pouring process considering the void condition is introduced in order to develop ballast non-exchange type of QHT. The separate pouring method can secure the required strength because optimized materials are poured into the upper layer and the lower layer for each void ratio condition. To ensure this process, a rheology analysis was conducted on the design of the pouring materials according to aggregate size, the aggregate distribution, the void ratio, the void size, the tortuosity and the permeability. A polymer series was used as the pouring material of the lower layer to secure the void filling capacity and for adhesion to the fine-grained layer. In addition, magnesium-phosphate ceramic (MPC) was used as the pouring material of the upper layer to secure the void-filling capacity and for adhesion of the coarse-grained layer. As a result of a mechanics test of the materials, satisfactory performance corresponding to existing quick-hardening track was noted.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.12 no.1
• /
• pp.75-85
• /
• 2010

The focus of this study is to evaluate the field applicability of the newly developed inorganic thixotropic-grout in various ways. In order to do this, the volume stability and the permeability of the inorganic thixotropic-grout have been measured and compared to the existing silica type grouts. In addition, the filling capability of the grout into the tail void has been evaluated through both an experiment with a miniature tail-void filling equipment and a test filling at the shield TBM construction site. The volume loss of the inorganic thixotropic-grout after a 14 day-curing under the atmosphere condition was appeared to be minimal. The excellent waterproofing ability of the inorganic thixotropic-grout was confirmed through a permeability test. The toxicity of the inorganic thixotropic-grout has been evaluated through a toxicity test of aquatic fishes (KS M 0111) and the pH value of the liquid eluviated from inorganic thixotropic-grout was measured as an average of 8.0 and a fatality rate of goldfish after 96 hours was 10% or so. The existence of harmful heavy metals in the liquid eluviated from the inorganic thixotropic-grout has been also examined through an atomic absorption spectroscopy (AAS) test. Any of harmful heavy metals were not detected and the detected level of $Cr^{6+}$ and Cd was far below the standard. Based on both an experiment with a miniature tail-void filling equipment and a test filling at the shield TBM construction site, the filling ability of inorganic thixotropic-grout into the tail void was proved to be excellent.

• Journal of the Society of Disaster Information
• /
• v.19 no.4
• /
• pp.747-756
• /
• 2023

Purpose: In this study, a grout material mixed using non-alkaline silica-based materials, which is an eco-friendly injection material to stabilize ground, is investigated to improve conventional problems. Method: The homogel specimens of Eco-Friendly Non-Alkaline Silica Sol (ENASS) and L.W. and S.G.R., representative silicate grouting are manufactured. Physicochemical and engineering properties of the specimens are evaluated in laboratory with uniaxial compression strength, hydraulic conductivity, shrinkage, chemical resistance, elution, fish poison, waste leaching. Result: Laboratory test results show that the ENASS was superior in all aspects compared to the existing injection matirial. The suitability of the grout material with ENASS is investigated with filed tests. Conclusion: The results of laboratory and field tests demonstrates that the grout material with ENASS is eco-friendly material that increases the strength, decreases the permeability, and discharges pollutants without leaching.

• Journal of Korean Society of Disaster and Security
• /
• v.15 no.3
• /
• pp.101-113
• /
• 2022

This study is planned with the aim of developing a systematic construction process based on the scientific and engineering theory of the water-sealing grouting construction applied to the tunnel excavation process during the construction of the downtown underground traffic network, so that the construction quality of the relatively backward domestic tunnel water-sealing grouting construction is improved and continuously maintained no matter who constructs it. The main contents of the improved tunnel water-sealing grouting can be largely examined in the classification of tunnel water-sealing grouting application and the definition of grouting materials, the correlation analysis of groundwater pressure conditions with groundwater inflow, the study of the characteristic factors of bedrock, and the element technologies and injection management techniques required for grouting construction. Looking at the trends in global research, research in the field of theoretical-based science and engineering grouting is actively progressing in Nordic countries (Sweden, Finland, Norway, etc.), Japan, Germany, and the United States. Therefore, in this study, the algorithm is established through theoretical analysis of the elements of tunnel water-sealing grouting construction techniques to provide an integrated solution including a construction process that can effectively construct tunnel water-sealing grouting construction.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.20 no.6
• /
• pp.989-1002
• /
• 2018

Grouting for the rock joint is to strengthen the rock strata by infiltrating cement grout materials into the rock joints. Grouting is one of a field of study which is difficult to develop deterministic and quantitative design approach because of multiphase behaviors of grout materials and 3 dimensional features of rock joints. Therefore, GIN (Grouting Intensity Number) can be a good index with appropriate monitoring of pressure and volume of grout. In this paper, we investigate the effects of joint roughness (JRC) and rheology of cement material during the infiltration of cement grout material into rock joint through CFD (computational fluid dynamics) analyses. With rough joint surface and increase of WC ratio, the frictional resistance during the grouting increases. The results have been summarized with polynomial correlations.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2010.10a
• /
• pp.37-41
• /
• 2010

스프링클러설비와 방화구획 구성요소는 화재시 매우 중요한 역할을 한다. 그러나 기존에 15층이하 아파트는 스프링클러설비가 없어 화재시 방화구획에 의존해야 되는데 방화구획 관련 설계, 시공, 감리가 미비하여 화재에 쉽게 노출되어 있다. 설비슬리브, 전선관, 덕트등이 방화구획으로 되어 있는 부분을 관통하는 경우 그틈을 시멘트모르타르나 기타 불연재료로 메우도록 규정하고 있으나 화재발생시 관통부를 메운 재료의 내화성능 부실, 균열, 탈락 등으로 화재안전성이 떨어진다. 현장에서의 설계, 시공, 감리등 대응하는 자세가 너무 허술하다. 설계에 방화댐퍼, 관통부 틈새의 내용이 반영 되지 않고 건축, 기계, 전기, 통신, 소방등 각 분야의 허가 도면에 도장이 날인되어 나타난다. 시공자는 잘못된 설계도면을 가지고 허가 도면이라며 도면되로 시공한다. 또한 실리콘, 우레탄폼등을 방화구획 관통부 틈새에 주입하며, 작업자도 비숙련자로서 개념도 없이 방화용실란트와 우레탄폼을 혼용해가며 작업을 한다.

• Journal of Bio-Environment Control
• /
• v.18 no.3
• /
• pp.185-191
• /
• 2009

The construction of experimental greenhouses, operating test, and analysis on variation of different environment factors were conducted to provide fundamental data for design of Korean style air-inflated double-layer plastic greenhouse. The development of technology of attaching plastic to the structure and fasteners to be able to keep airtight was required in order to maintain proper static pressure in air space of double layer coverings. The insulation effect of air inflated greenhouse was better than conventional type. The temperature of arch type roof was greater about $2^{\circ}C$ than peach type roof in air inflated greenhouse. It was recommended that the plastic should be attached at the edges without clearance length in order to ease installation and raise airtightness of double layer coverings. The transmittance of arch type roof was greater than peach type in air inflated one span greenhouse. The transmittance of air inflated greenhouse was greater than conventional type due to frame ratio and distance between double layers in three span greenhouse. The condensation occurred on conventional type greenhouse was more than air inflated type. It was required to examine for a long time in order to analyze it quantitatively.