• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.8-15
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• 2014

The increase of wet web solid content in wet pressing will save drying energy greatly. We applied wood flours as spacers to increase the old corrugated container (OCC) solid contents in wet pressing. The mixed furnish of OCC and wood flours of 3-5% (wt/wt) increased bulk and drainage rate, and by increasing wet pressing pressure, its solid content started to be higher than 100% OCC furnish at more than 50% solid content level. Addition of cationic starch and drainage aid to the mixed furnish increased solid content further up to around 2%. Cationic starch addition compensated or exceeded the loss of tensile and compressive strength caused by the addition of wood flour, but drainage aid did not. Cationic starch also improved the stretch of the OCC, which could mitigate cracking at folding in boxboard.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.147-157
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• 2002

In this paper, the testing cell and the related theory far the interpretation of constant rate of strain (CRS) consolidation test results in case of radial drainage were developed. The proposed method makes it possible to evaluate consolidation characteristics of clayey soil rapidly and accurately. To investigate the application of the developed testing device and theory, CRS consolidation tests and incremental loading(IL) tests in radial drainage condition with remolded and undisturbed samples were performed. Comparisons of consolidation parameters from consolidation curves including coefficient of consolidation values show the applicability and the reliability of the suggested method. The experimental data were compared with additional vertical drainage CRS tests and IL tests, and then were analyzed considering the effect of the drainage direction. In addition, the effect of excess pore water pressure generated during CRS consolidation test was investigated.

• Journal of Korea Water Resources Association
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• v.53 no.4
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• pp.303-312
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• 2020

An underground deep tunnel system is a facility in form of a reverse siphon for an under flood defense structure. In this study, the 'Shinwol rainwater storage and drainage system', which is under construction for the first time in South Korea, in order to confirm the effects of undular bore and pressurized air on the hydraulic stability of the facility in various flood scenarios a hydraulic model experiment was performed. As a result of this study, it was analyzed that the undular bore generated downstream pushed the pressurized air collected in the facility while moving upstream, and the pressure inside the pipe increased at this time. It was analyzed that the pressure during the passage of the undular bore was greater than the sum of the static pressure and dynamic pressure at the time and overflow occurred when the cross-sectional size of the pressurized air was more than 40% of the cross sectional area of the tunnel. It is determined that this is correlated with the volume of pressurized air collected in the facility, and it is determined that it is necessary to study the relationship between velocity of undular bore and the volume of pressurized air in the future.

• Journal of Yeungnam Medical Science
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• v.8 no.2
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• pp.35-44
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• 1991

Recently many authors have reported about the relationship of the volumes of hemorrhage in the brain parenchyme, hemorrhagic sites, optimal operation time, and the effects of mannitol and steroid on control of ICP to clinical manifestations. Many attempts to measue ICP in hydrocephalus, brain tumor, and head injury have been reported. But the measurements of intracranial pressure in spontaneous intracerebral hemorrhage are rare. Intracranial pressure was monitored prospectively in 30 patients who had stereotaxic surgery for spontaneous intracerebral hemorrhage. The results are as follows. 1. Intracranial pressure was increased in high $PaCO_2$. 2. There were no correlation in ICP, rebleeding and ADL at discharge(P > 0.05). 3. ICP was the most high level in 72 hours after operation. 4. There was 63.2% decrease in ICP after litigation with 6000 IU urokinase in the site of hemorrhage. 5. There was no correlation between the numbers of natural drainage and ADL at discharge(P > 0.05). 6. The higher the initial GCS, the higher the Postoperative GCS.

• Journal of the Korean Geotechnical Society
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• v.28 no.4
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• pp.101-113
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• 2012

The degradation of a tunnel drainage system leads to increases in pore water pressure around the tunnel and the lining stress, which results in affecting the tunnel stability. In the present study of the Namsan 3th tunnel, more than 30 year old tunnel, the effects of the drainage performance reduction due to drain hole clogging on the tunnel lining stability were investigated by examining pore water pressure distribution around the tunnel and the lining stresses through numerical analysis. Groundwater flow modeling on the Mt. Namsan region was done first and 3D seepage and coupled stress-pore water pressure finite element analysis were performed on the tunnel using the results of the groundwater flow modeling. The pore water pressure distribution and the tunnel lining stresses could be predicted using a drain hole outflow data measured in the tunnel site. This analysis method may be used to evaluate the current stability of old tunnels for which in most cases field investigations and related information are not readily available.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.45-51
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• 2012

The calcium hydroxide$(Ca(OH)_2)$ which is the cement hydrate flowed into the tunnel by groundwater is reacted with microorganism in the soil, carbon dioxide$(CO_2)$ and the vehicle's exhaust gas$(SO_3)$. So its by-products are precipitated at the drainage pipe and these cause the drainage clogging. By this phenomenon, Degradation of water flow at the drainage system of the tunnel occurred and also pore water pressure is increased. Hence the acceleration of seepage and degradation of lining is occurred. The purpose of this study is to evaluate the field applicability of the Quantum Stick and Magnetic treatment in prevention of scale deposits at the Namsan ${\bigcirc}{\bigcirc}$ tunnel and the Zone ${\bigcirc}{\bigcirc}{\bigcirc}$ of subway. These technologies were installed into drainpipes with their performance monitored through occasional site visits. SEM and XRD were also performed on scale collected from these drainpipes. As a result, in case which factor technology is applied, scale creation is remarkably decreased and especially Quantum Stick treatment performing better than Magnetic treatment. Therefore, additional application of Quantum Stick or Magnetic treatment to the existing drainage is expected to decrease the drainage clogging of the drainage.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.27-42
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• 2005

In this study, dynamic deformation characteristics of sands under dry, saturated drained and undrained conditions were investigated at small to intermediate strains using the modified Stokoe-type torsional shear tests. The equipment was modified to saturate the specimen and to maintain the B-value above 0.99 during the test. On two types of sands, Geumgang sand from Korea and Toyoura sand from Japan, tests were carried out at various drainage conditions, void ratios, and effective confining pressures. Based on the test results, dynamic deformation characteristics, shear modulus (G) and damping ratio (D), and/or pore-water pressure were measured with strain amplitude and number of loading cycles. Variations of G and D at small ($\gamma_c<{10}^{-3}\%$) to medium (${10}^{-3}\%<\gamma_c<{10}^{-1}\%$) strains were measured under various drainage conditions, and test results were intensively compared considering drainage conditions.

• Journal of the Korean Geosynthetics Society
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• v.5 no.4
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• pp.19-25
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• 2006

To examine the general features of a sand-clay composite triaxial test by making specimen varying ratios of diameters (dw) of sand columns that are installed on the soft ground as drains to diameters (de) of drain zone so called drainage space ratio (n=de/dw), densities of the granular columns, and strength of soft soils round around. I also conducted a test to research the reinforcement ability and effects of the ground when the granular columns are wrapped with supplementary materials such as geotextile. The results of the triaxial compression test showed that the shear strength increase is much big when the granular columns are wrapped with supplementary materials, while the shear strength increases as the diameter and density of the granular column increase in general. Also the drainage space ratio shows a distinct increase just below 3 and a similar shear behavior to sand is appeared. The pore water pressure coefficient decreases as the drainage space ratio decreases, however, when the drainage space ratio is less than 3~4, it declines significantly as shown in the results of shear behavior.

• Journal of the Society of Disaster Information
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• v.15 no.1
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• pp.84-97
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• 2019

Purpose: The consolidation settlement of soft ground is dependent on the distribution of pore water pressure which is also affected by hydraulic conductivities (boundary condition) of layers, thickness of clayey soil layer and surcharge. Results: However, the current consolidation analyses are mostly based on Terzaghi's consolidation theory that assumes the initial pore water pressure ratio with depth to be constant. In this study, numerical analysis are carried out to investigate the variation of pore water pressure dissipation with depth and thickness of clayey soil layer, time, surcharge as well as drainage conditions. Conclusion: Comparative study with Terzaghi's consolidation theory is also conducted. The result shows that Terzaghi's consolidation theory should be used with caution unless it is ideally corresponded to the isochrone.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.257-264
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• 2003

Tunnelling in water bearing soils influences the ground water regime. It has been indicated in the literature that the existence of ground water above a tunnel influences tunnel stability and the settlement profile. Only limited research, however, has been done on ground water movements around tunnels and their influence on tunnel performance. Time dependent soil behaviour can be caused by the changes of pore water pressure and/or the viscous properties of soil(creep) under the stress change resulting from the advance of the tunnel face. De Moor(1989) demonstrated that the time dependent deformations due to tunnelling are mainly the results of pore pressure dissipation and should be interpreted in terms of effective stress changes. Drainage into tunnels is governed by the permeability of the soil, the length of the drainage path and the hydraulic boundary conditions. The potential effect of lime dependent settlement in a shallow tunnel is likely to occur rapidly due to the short drainage path and possibly high coefficient of consolidation. Existing 2D modelling methods are not applicable to these tunnelling problems, as it is difficult to define empirical parameters. In this paper the time-based 2D modelling method is adopted to account for the three dimensional effect and time dependent behaviour during tunnel construction. The effect of coupling between the unloading procedure and consolidation during excavation is profoundly investigated with the method. It is pointed out that realistic modelling can be achieved by defining a proper permeability at the excavation boundary and prescribing appropriate time for excavation Some guidelines for the numerical modelling of drained and undrained excavation has been suggested using characteristic time factor. It is highlighted that certain range of the factor shows combined effect between the unloading procedure due to excavation and consolidation during construction.