• KIEAE Journal
• /
• v.8 no.1
• /
• pp.87-92
• /
• 2008

Sheathing work used for excavation in a crowded downtown is generally a temporary strut method using H-piles and sheathing wall includes lagging, CIP, SCW or slurry wall. A temporary strut serving the support for sheathing wall acts to resist the earth pressure, but it shall be removed when installing the underground structure members. A traditional temporary strut might cause the stress imbalance of the sheathing wall when it is demolished, resulting in time extension and the risk of collapse. A traditional temporary strut method thus needs to be improved for schedule and cost reduction, risk mitigation and for preparation for potential civic complaint. A permanent strut method doesn't require installing and demolishing the temporary structure that will lead to reducing the time and cost and the structural risk during the demolition process. And given the girder, the part of the underground structure, serves the role of strut, it can secure the wider interval compared to the traditional method, which enables to secure the wider space for the convenience of excavation as well as enhance the constructability and efficient site management. The thesis was intended to study the composite girder designed to use the strut as permanent structure so as to reduce the excavation and floor height.

• Journal of the Korean Geosynthetics Society
• /
• v.16 no.4
• /
• pp.191-210
• /
• 2017

The concern study, present the results of experimental study on the performance of deep excavation by using image processing technique particle image velocimetry (PIV). The purpose of present study is to check the application of PIV for the successive ground deformation during deep excavation. To meet the objectives of concern study, a series of reduce scale model test box experiments are performed by considering the wall stiffness, ground water table effect and ground relative density. The results are presented in form of contour and vector plots and further based on PIV analysis wall and ground displacement profile are drawn. The results of present study, indicate that, the PIV technique is useful to demonstrate the ground deformation zone during the successive ground excavation as the degree of accuracy in PIV analysis and measured results with LVDT are within 1%. Further the vector and contours plot effectively demonstrate the ground behavior under different conditions and the PIV analysis results fully support the measured results.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.9 no.2
• /
• pp.199-206
• /
• 2005

In many other countries framed structures with inadequate lateral strength and stiffness have been strengthened by providing reinforced concrete infilled wall. There is a general agreement among researchers those infilled walls have 3-5times greater lateral strength compared with bare frame. The main objective of this research is to investigate the behavior and strength of reinforced concrete frames infilled with concrete block and cast-in-place reinforced concrete panels used for strengthening the structure against seismic action. For this purpose three 1/3 scale, one-bay, one-story reinforced concrete infilled frames were tested under reversed cyclic loading simulating the seismic effect. The results indicate that infilled walls increase both strength and stiffness significantly under lateral loads. Especially Strength capacity and initial stiffness of CIP infilled wall increased 3.8 times and 6.6 times higher than lightly reinforced concrete frame.

• The Journal of Engineering Geology
• /
• v.22 no.1
• /
• pp.39-48
• /
• 2012

The behaviors of a diaphragm wall and a contiguous pile wall such as CIP(Case-in-place pile) and SCW(Soil-cement wall), applied to the top-down construction method, were analyzed using the SUNEX program, which is widely used to design earth retaining walls. Four types of earth pressures, as described by Rankine (1857), Terzaghi and Peck (1967), Tchbotarioff (1973), and Hong and Yun (1995a), were applied to the analysis program to predict the lateral displacement of walls. The results show that the displacements of an earth retaining walls vary with the applied earth pressure. The predicted lateral displacement based on Hong & Yun's (1995a) earth pressure is similar to the measured displacement. Therefore, the actual lateral displacement of an earth retaining wall, as applied to top-down construction method, can be accurately predicted by using an analysis program considering Hong and Yun's (1995a) earth pressure.

• Journal of the Korean Geotechnical Society
• /
• v.39 no.9
• /
• pp.13-24
• /
• 2023

To investigate the stability of temporary retaining walls during excavation, it is essential to develop reverse analysis technologies capable of precisely evaluating the properties of the ground and a learning model that can assess stability by analyzing real-time data. In this study, we targeted excavation sites where the C.I.P method was applied. We developed a Deep Neural Network (DNN) model capable of evaluating the stability of the retaining wall, and estimated the physical properties of the ground being excavated using a Differential Evolution Algorithm. We performed reverse analysis on a model composed of a two-layer ground for the applicability analysis of the Differential Evolution Algorithm. The results from this analysis allowed us to predict the properties of the ground, such as the elastic modulus, cohesion, and internal friction angle, with an accuracy of 97%. We analyzed 30,000 cases to construct the training data for the DNN model. We proposed stability evaluation grades for each assessment factor, including anchor axial force, uneven subsidence, wall displacement, and structural stability of the wall, and trained the data based on these factors. The application analysis of the trained DNN model showed that the model could predict the stability of the retaining wall with an average accuracy of over 94%, considering factors such as the axial force of the anchor, uneven subsidence, displacement of the wall, and structural stability of the wall.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.3
• /
• pp.254-258
• /
• 2000

Current leads of high $T_{c}$ superconductor were fabricated with Bi excess B $i_{2.2}$/S $r_{1.8}$/C $a_{1}$/C $u_{2}$/ $O_{x}$ composition by rapid cooling method. The dimensions of final samples were fixed 3 mm and 8 mm diameter with 50 mm length each To control uniform density the samples were preformed by CIP(Cold Isostatic Press) process and followed by partial or full melting process after raising up to 90$0^{\circ}C$ for 30min. Plate shaped microstructure was clearly observed adjacent to the Ag tube wall and the size of plate was about 100$\mu$m. However the severe destruction of growth orientation was shown in the inner growth part. critical temperature ( $T_{c}$) was about 53~71K after directional growth while Tc was decreased about 77~80 K before directional growth. After directional growth critical current( $I_{c}$) and critical current density( $J_{c}$) in the specimen of 8 mm diameter at 50 K were about 110 A and 280 A/c $m^2$ respectively.pectively.ely.

• Journal of the Korean Geosynthetics Society
• /
• v.22 no.3
• /
• pp.87-95
• /
• 2023

Recently, redevelopment of the original downtown area is underway, the necessity of construction in adjacent location is increasing. However, excavations in dense urban areas are prone to ground problems due to various causes, so it is necessary to use materials and methods that can minimize such problems. As a general earth retaining method, various methods such as diaphragm wall and CIP method are applied using cement. However, since a large amount of cement is used for the installation of earth retaining method, it is necessary to conduct research on the development of new cement substitute materials to significantly reduce greenhouse gas emissions. In this study, we utilized the hardening reaction of blast furnace slag powder, desulfurized gypsum and high calcium fly ash by alkali activation and applied it to the SCW method. As a result, it was analyzed that the compressive strength of solidified soil using development solidification material was 96.2 ~ 106.3% of OPC at 28 days of curing. In addition, the strength increment ratio was 2.06 for sandy soil and 2.41 for clayey soil, which was higher than 1.85 of OPC. It seems an advantageous in terms of long-term strength. In addition, from the environmental point of view, it was analyzed that there is no elution of heavy metals and that greenhouse gas emissions can be dramatically reduced. Therefore, if further studies are conducted, it can be applied to the SCW method.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.12
• /
• pp.1862-1867
• /
• 2006

A moderately halophilic, Gram-positive, spore-forming bacterium was isolated from the roots of Blutaparon portulacoides, a plant found in sandy soil parallel to the beach line in Restinga de Jurubatiba, Rio de Janeiro, Brazil. The strain, designated $M9^T$, was motile and strictly aerobic with rod-shaped cells. It grew in the absence of NaCl and up to 20% NaCl, and was able to hydrolyze casein and starch. Strain $M9^T$ had a cell-wall peptidoglycan based on L-Orn-D-Asp, the predominant menaquinone present was menaquinone-7 (MK-7), diaminopimelic acid was not found, and anteiso-$C_{15:0}$ and iso-$C_{15:0}$ were the major fatty acids. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain $M9^T$ belonged to the genus Halobacillus and exhibited 16S rRNA gene similarity levels of 97.8-99.4% with the type strains of the other nine Halobacillus species. The DNA-DNA relatedness of strain $M9^T$ with H. trueperi, the closest relative as regards 16S rRNA gene similarity, and H. locisalis was 21% and 18%, respectively. Therefore, on the basis of phenotypic, genotypic, and phylogenetic data, strain $M9^T$ (=ATCC BAA-$1217^T$, =CIP $108771^T$, =KCTC $3980^T$) should be placed in the genus Halobacillus as a member of a novel species, for which the name Halobacillus blutaparonensis sp. nov. is proposed.