• Geomechanics and Engineering
• /
• v.17 no.6
• /
• pp.507-513
• /
• 2019

Reinforced soil and Expanded Polystyrenes (EPS) mixture (RSEM) is a geomaterial which has many merits, such as light weight, wide strength range, easy for construction, and economic feasibility. It has been widely applied to improve soft ground, solve bridge head jump, fill cavity in pipeline and widen highway. Reutilizing dredged sediment to produce RSEM as earthfill can not only consume a large amount of waste sediment but also significantly reduce the construction cost. Therefore, there is an urgent need understand the basic stress-strain characteristics of reinforced dredged sediment-EPS mixture (RDSEM). A series of cyclic triaxial tests were then carried out on the RDSEM and control clay. The effects of cement content, EPS beads content and confining pressure on the cyclic stress-strain behaviour of RDSEM were analyzed. It is found that the three stages of dynamic stress-strain relationship of ordinary soil, vibration compaction stage, vibration shear stage and vibration failure stage are also applicative for RDSEM. The cyclic stress-strain curves of RDSEM are lower than that of control clay in the vibration compaction stage because of its high moisture content. The slopes of backbone curves of RDSEMs in the vibration shear stage are larger than that of control clay, indicating that the existence of EPS beads provides plastic resistance. With the increase of cement content, the cyclic stress-strain relationship tends to be steeper. Increasing cement content and confining pressure could improve the cyclic strength and cyclic stiffness of RDSEM.

• Journal of Korea Water Resources Association
• /
• v.52 no.2
• /
• pp.133-139
• /
• 2019

In this study, the degree of scouring according to the bed material according to the flow rate and the relationship between the flow velocity and the bed scouring were investigated in order to examine the operability of the revetment and embankment. The materials used in the experiment were sand and loess as materials used in the embankment. We measured the scouring of the material according to the change of the flow velocity by using the indoor high flow velocity experiment device and verified the flow rate. In this way, The purpose of this study was to compare and analyze changes in material before and after scouring, and compare basal scouring evaluation by bed material with high flow velocity. In case of sand, the cohesive force is very weak, so more than 40% of the material is lost even at less than 1.0 m/s. In the case of loess, less than 6% of the bed material is lost at more than 2 m/s. The reason why the material was lost was that the cohesion was so strong that the material was dried after the compaction and cracked. As a result, the material was lost from the part where the dry crack occurred. In this study, the composition and loss of bed materials were evaluated.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1542-1549
• /
• 2009

The function of subgrade in the railway is to support track load on the subgrade as well as train load. Unlike the traditional railway, the uppermost subgrade layer in the Gyeongbu high speed railway was constructed as the reinforced road bed. The reinforced road bed comprises sub-ballast in the upper part and grade ballast in the lower part. The filling material such as soil and rocks in the subgrade can be settled by consolidation of original ground, compression due to self weight, plastic displacement due to train operation, and unequal settlement due to embankment material or improper compaction, therefore many efforts have been given for sufficient compaction and use of proper filling materials in the construction stage. The purpose of this study is to investigate the deformation state of subgrade in the Gyeongbu high speed railway. The investigation on the subgrade settlement was performed by choosing representative sections suspected to be settled based on the previous GPR test results and track maintenance history, measuring the settlement for some time period after installing settlement measuring instruments on and under the reinforced road bed. and analyzing the long-term subgrade settlement data from monitoring system which was installed at the construction stage of the high speed railway.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.40-48
• /
• 2010

Saemangeum reclaimed area is needed to construct much green zone to make high-quality multi-functional land such as tide embankment, lake dike, industrial complex, environmental spaces, etc. However, growth of plants is somewhat difficult because a salinity of Saemangeum soil is very high and a soil fertility, water content of soil are low. Therefore, it is essential to initial desalination of soil and continuous management for planting base. It is recommended that a group of grassland to raise the efficiency of covering should be made in the first stage and a forest by improvement of vegetation should be made in the mid and long term stage. It is recommended that the construction of vegetation base should be made with a regular thickness of soil of good quality in multi-functional area such as a shrub and wood. In case of construction of a windbreak forest, it is necessary to make a wood base of suitable depth using soil brought from another place or filling of soil. Also, it is necessary to keep a maintenance of woods in early stage. Saemangeum reclaimed land will be brand-named worldwide tourist attractions due to construction of much green zone having high quality multi-functional facilities.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1994.09a
• /
• pp.1-59
• /
• 1994

The design and construction of strutted and anchored sheet pile walls in soft clay are reviewed based on experience gained mainly in Singapore during the last 10years where mainly strutted sheet pile walls diaphragm walls, and contiguous bored piles are used. It is important to consider in the design the high lateral earth pressures acting on the sheet piles below the bottom of the excavation when the depth of the excavation is large compared with the shear strength of the clay. The strut loads and the maximum bending moment in the sheet piles can in that case be much higher than indicated by a conventional analysis. Different methods to increase the stability have been investigated. With jet grouting, embankment piles and excavation under water it is possible to reduce significantly the maximum bending moment, the strut loads, and the settlements outside the excavated area as well as the heave within the excavation.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.420-427
• /
• 2011

It is most important to support the track as well as to be directly connected to run safety. The performance design satisfied with the more safe and economic embankment study is required due to the high speed, design load and growth of traffic. Therefore, in this paper the relation between main design elements to adopt the method of the performance design were analysed. And the correlation among design indices developed and used in an advanced countries such as germany, japan were evaluated.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.472-477
• /
• 2006

This study aims at investigating the failure cases of the pre-cast block system in river environments which widely used nowadays and reviewing the effect and flow resistance for grass concrete structure through the physical experiments by hydraulic model test and developing application method in river slope or levee which has rigid flood resistance. Grass concrete structure has been independently tested under high velocity flow under the super critical condition, it survived the 8 m/sec maximum flow velocity. This results shows grass concrete system is also suited to use in aggressive river environments such as repairing a flood damaged embankment that had placed at risk the adjacent drainage channel with vegetation.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.48 no.6
• /
• pp.79-85
• /
• 2006

A simulation was done to analyze the seepage problems due to seawater intrusion through the embedded rock layers on heterogeneous layers of sea-dike. Numerical analysis with SAMTLE(developed by author) was done by taking various relative permeability $ratio(R_r/R_e)$. These results showed, when the sed-dike is newly designed, operated, and maintained considering the safety of sea-dike in seepage problems, these embankment materials are prudently chosen. The permeability of the soil materials, within the range of salinity management in freshwater, is comparatively high, however, the permeability of rock materials for bottom rock layer is low. Therefore, when the relative permeability $ratio(R_r/R_e)$ is bellow 10 it is safety in seepage problems of sea-dike.

• Advances in environmental research
• /
• v.4 no.3
• /
• pp.183-196
• /
• 2015

Migration of leachate generated through embankment of construction waste soil (CWS) in low-lying areas was studied through physical and chemical analysis. A leachate solution containing soluble cations from CWS was found to have a pH above 9.0. To determine the distribution coefficients in the alkali solution, column and migration tests were conducted in the laboratory. The physical and chemical properties of CWS satisfied environmental soil criteria; however, the pH was high. The effective diffusion coefficients for CWS ions fell within the range of $0.725-3.3{\times}10^{-6}cm^2/s$. Properties of pore water and the amount of undissolved gas in pore water influenced advection-diffusion behavior. Contaminants migrating from CWS exhibited time-dependent concentration profiles and an advective component of transport. Thus, the transport equations for CWS contaminant concentrations satisfied the differential equations in accordance with Fick's 2nd law. Therefore, the migration of the contaminant plume when the landfilling CWS reaches water table can be predicted based on pH using the effective diffusion coefficient determined in a laboratory test.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1244-1248
• /
• 2007

This study aims at investigating the in situ applying grass concrete system in river environments which widely used nowadays and reviewing the effect and flow resistance for grass concrete structure through the physical experiments by hydraulic model test and developing application method in river bed which has rigid flood resistance. Grass concrete structure has been independently tested under high velocity flow under the super critical condition, as well as sud critical flow measuring velocity and water surface elevation along the cross section. This results shows grass concrete system is also suited to use in aggressive river environments such as repairing a flood damaged embankment that had placed at risk the adjacent drainage channel with vegetation.