• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.87-96
• /
• 2010

PAP method is a combined measures which consist a anchored retaining wall method with permanent ground anchors and vertical precast concrete panels, step by step on the slope surface. And soil is back filled between slope and vertical precast panels. Therefore, this method is more effective than any other ground anchor reinforcing methods of slope stability, for example cross type concrete block ground anchor or buttress concrete block ground anchor method. Because of increasing effective anchor force and green tree planting.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2018.05a
• /
• pp.279-280
• /
• 2018

The waterproofing material can be roughly divided into a coating material and a sheet waterproofing material. In the case of coating waterproofing materials, sheet waterproofing materials, which are easy to use in terms of workability and quality control, have been recently used because of their incomplete use of coating thickness, long curing time and poor blending due to in situ blending. However, in the case of the sheet waterproofing material, since the sheet overlapping portion is inevitably generated, various defects (breakage due to the behavior) are frequently observed. Therefore, it is imperative to establish fundamental measures to minimize this.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.869-887
• /
• 2008

Coffer dam for tunnel type spillway in inflow section of Dae-am dam was originally planned as 2 lines sheet piles with Water Zet method. But, the result of pilot test was caused of some problems that vibration during installation of pile could pollute water and water leakage could the lower part. So, sheet piles was not satisfactory for faculty of coffer dam. Structural instability of sheet pile system need to reinforcement. Characteristic of Dae-am dam was small reservoir capacity but wide drainage area, of which it was judgment that security of leakage and stability was difficult during excavation of inlet part. So, we consider that water curtain method utilized with in site pouring concrete pile method was designed at weir part of spillway. We were known about basement rock that geological boring was carried out in weir part. After taking a deep consideration, PRD method was accepted as a new method. Concrete pile by PRD was installed to below country rock. CJM method was carried out with PRD. After making concrete wall using Top-down method, earth anchors were installed for supporting it. According to the result of numerical analysis, as water level rises, wall is stable.

• International Journal of Highway Engineering
• /
• v.11 no.2
• /
• pp.121-132
• /
• 2009

Thin bonded continuously reinforced concrete overlay(CRCO) was constructed on He existing jointed plain concrete pavement(HCP) surface at Seo-Hae-Ahn express highway in South Korea in order to evaluate its applicability and performance. Two sections of road were considered for this evaluation. In the first section, the concrete overlayer was placed and cut down to the existing layer to form transverse joints while CRCO was constructed on top of the existing layer in the second section. Early strength concrete(Type III) was utilized for both overlay sections. The depth of milling and the thickness of overlaid layer were 5 cm and 10 cm, respectively. Several vibrating wire gauges(VWG) were installed to evaluate the performance of CRCO with respect to curling, delamination, and crack propagation. As a result of the strength test, it was found that strength of the material reaches the design criteria within 1-3 days. Analysis with vibrating wire gauge(VWG) showed CRCO effectively restricts joint movement. High adhesive strength also was observed from the material regardless of length of aging. Meanwhile, transverse cracks were observed on the middle of the section where JPCP overlay was applied whereas arbitrarily cracks in transverse direction were observed on the section where CRCP was applied.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.19 no.6
• /
• pp.937-957
• /
• 2017

Urban roads are not only congested with vehicles and pedestrians, but also have many pipelines buried to provide convenience for inhabitants. In addition, urban inhabitants live comfortably in buildings adjacent to the road for residence, business, commerce, rest and so on. Therefore, despite the high cost of land, urban underground buildings with high land use efficiency are constantly being built. Recently, the construction of underground buildings has caused social problems such as the collapse of surrounding roads and adjacent buildings. Institutional improvement is being actively carried out to improve this. In this study, a new type of MSRC diaphragm wall was developed and a study on the construction method of underground building was carried out. It is intended to secure the underground excavation safety of underground buildings in urban areas and effectively prevent land subsidence complaints. Also, a reasonable design method of MSRC diaphragm walls using the ultimate strength design method is presented through the flexural performance Experiment.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.2 no.3
• /
• pp.30-35
• /
• 2011

This study investigates the optimum section properties of newly developed steel-concrete composite beam. For that purpose we developed computer program calculating section properties. The suggested new beam section highly contribute to save inter-story height and reduce construction duration and cost compared with conventional steel works such as H-beam and column + RC slab system. But the section shape have different section modulus with upper and lower fiber because of the unsymmetric cross section. Therefore the parametric study on thickness-ratio of top and bottom flange plate is needed. In this paper the change of neutral axis and section modulus for thickness-ratio of up and down flage plate is analysed and discussed.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.7
• /
• pp.197-206
• /
• 2004

The ground anchor support system may not be occasionally used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then could play important roles to reduce deformations mainly in the upper part of the nailed-soil excavation system as well as to improve local stability. In this study, a newly modified soil nailing technology named as the PSN (Pretension Soil Nailing), is developed to reduce both facing displacements and ground surface settlements in top-down excavation process as well as to increase the global stability. Up to now, the analytical procedure and design technique are proposed to evaluate maximum pretension force and stability of the PSN system. Also, proposed are techniques to determine the required thickness of a shotcrete facing and to estimate probability of a failure against the punching shear, Based on the proposed procedure and technique, effects of the radius of a influence circle and dilatancy angle on the thickness of a shotcrete facing, bonded length and safety factors are analyzed. In addition, effects of the reduction of deformations expected by pretension of the soil nails are examined in detail throughout an illustrative example and the $FLAC^{2D}$ program analysis. And a numerical approach is proposed PSN system using the shear strength reduction technique with the $FLAC^{2D}$ program.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.2
• /
• pp.87-96
• /
• 2004

Application of the soil nailing method is continuously extending in maintaining stable excavations and slopes. However, ground anchor support system occasionally may not be used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then could play important roles to reduce deformations mainly in an upper part of the nailed-soil excavation system as well as to improve local stability. In this study, a newly modified soil nailing technology named as the PSN (Pretension Soil Nailing) is developed to reduce both facing displacements and ground surface settlements in top-down excavation process as well as to increase the global stability. Up to now, the PSN system has been investigated mainly focusing on an establishment of the design procedure. In the present study, laboratory model tests are carried out to investigate the failure mechanism and behavior characteristics of the PSN system. Various results of model tests are also analyzed to provide a fundamental basis for the efficient design.

• Journal of the Korean Geotechnical Society
• /
• v.28 no.7
• /
• pp.5-16
• /
• 2012

Soil-nailing is the most popular method of reinforcing for slope stability. In general, two factors are considered as failure modes during the soil-nailing design stages: pullout failure mode and shear failure mode that will occur on the most probable failure plane. In many cases, however, shallow failure can also occur when the ground near the slope face is swept away by the horizontal stress release during the staged top-down excavation. In this paper, an optimized soil-nailing design methodology is proposed by considering the three failure modes mentioned above: pullout failure; shear failure; and shallow failure. The variables to be optimized include the bonded length and number of soil-nailings, and the confining pressure that should be applied at the slope face. The procedure to obtain the optimized design variables is as follows: at first, optimization of soil-nailings, i.e. bonded length and number, against pullout and shear failure modes; and then, optimization of confining pressure at each excavation stage that is needed to prevent shallow failure. Since the two processes are linked with each other, they are repeated until the optimized design variables can be obtained satisfying all the constrained design requirements in both of the two processes.