• Journal of the Korean Geosynthetics Society
• /
• v.10 no.2
• /
• pp.91-100
• /
• 2011

This study presents the estimation for the possibility of liquefaction according to the liquefaction evaluation methods in Saemangeum reclamation area for tide embankment, Jeollabuk-do, Korea. Liquefaction estimation is performed by cyclic triaxial tests and seismic response analysis using earthquake records of the long- and short-term. This area appears to have greatly potential of liquefaction from the grain-size distribution curve of the dredged and reclaimed soil in the area. Because the liquefaction can occur in this area if the foundations or buried structures are built at a depth within 10m below ground surface, the meticulous care is required in the design of them in the future.

• Journal of the Korean Geosynthetics Society
• /
• v.8 no.1
• /
• pp.25-32
• /
• 2009

In reclaimed loose sandy layer with dredged soil, liquefaction by the small scale earthquake coud be occurred easily. A study has been carried out to investigate the Liquefaction characteristic on Saemangeum dredged sandy soil, and compared with other results from the literature investigation. A series of undrained cyclic triaxial compression tests were performed on dredged sandy soil of Seamangeum area. The tests were performed at the three different initial relative densities(namely 30%, 50%, 70%), different cyclic stress ratio and different consolidation stress condition. The results of this study showed that cyclic stresses (${\sigma}_d$) increased linearly with increase of consolidation ratio, but the stress ratios (${\sigma}_d/2{\sigma}^{\prime}{_c}$) were almost same. The stress ratios were increased almost linearly with increase of relative density. Compared with other sandy soil, Saemangeum dredged sandy soil showed relatively weak liquifaction characteristics.

• Journal of the Korean Geosynthetics Society
• /
• v.10 no.3
• /
• pp.19-24
• /
• 2011

In the preceding study, the possibility of liquefaction according to the liquefaction evaluation methods was predicted in Saemangeum reclamation area for tide embankment, Jeollabuk-do, Korea. The risk of liquefaction was also expected when foundations and underground structures were built at a depth within 10m below ground surface, and meticulous care was required in the design of them in the future. This study considered the effect of the embedded depth for foundation design regarding liquefaction based on the various earthquake data from literatures. On the basis of the results of this study, an alternative consideration in foundation design for liquefaction was proposed for the Saemangeum area.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.468-474
• /
• 2005

Recently 'Earthquake Resistance Design Regulations for Subway structures' has been established. It is the first time in our country. In this paper the regulations is reviewed and expalined briefly. Contents for the Performance Based Design Critetia and the estimation method for the design earthquake reponse spectrum in underground structures are reviewed. Earthquake resistance design for the evaluation of liquifaction, boundary spring coefficients for structural analysis modelling and soil response displacements are investigated and described also. Earthquake resitance design details shall be explained.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.5
• /
• pp.13-26
• /
• 2006

The purpose of this study is to examine the method of liquifaction potential occuring at the reclaimed land in Incheon district and to compare the result obtained by the method based on the earthquake of 6.5 magnitude. In addition, the effects of ground improvement and liquifaction potential were evaluated on the basis of SPT and CPT, which have been performed before and after the compaction pilot test. As a result, we realized that the bigger the energy of dynamic compaction test was, the better effect we got. After the dynamic compaction test, as the strength of ground increased, the safe factor also increased. It was evaluated that the method of dynamic compaction improved the seismic performance. Accordingly, the method of the quality control of reclaimed land based on dynamic compaction method was presented.

• Korean Journal of Microbiology
• /
• v.5 no.2
• /
• pp.43-54
• /
• 1967

The characteristics of enzymic sources and its effective uses concerned with brewing of Yack-Tack Joo which is traditional and popular liquors for all Korean have been studied. Results obtained are as follows; 1)Kock Ja (enrich of fungi and yeast produced in Korean brewery) is found to be weak in its liquifying(600U.) and saccharifying activity(1300U.), so that it is useful to conbine two factors effectively for better brewing. 2) The additional ratio of Kok Ja per materials is seems proper at line of 20 percent for better fermentation and the enzymic preparations inoculated of microorganisms in wheat bran is seems proper at 25 percent line. 3) Adding the enzymic preperation in which the strain Rhyzopus had been inoculated to the experimental mash at 5 percent per material, the rate of fermentation was revealed highest degree than those of else. 4) It is not proper to add a single Bun Kok in fermentation, as it produce much acid in mash during brewing. 5) However, the enzymic preparation composed of Asp usami and Rhyzopus sp. produced less acid in brewing. 6) The increasing of temparature in enzymic samples, temparatures of the mixtured Kuk(Kok Ja and enzymic preparation) are higher than those of single addition at the first stage in pre-fermentation, but there are no differences at the late stage of post-fermentation. 7) Amount of amino acids in the plot of enzymic prepation are found much more than those of single use at late stage of post-fermentation. In the plot of single use of Kock Ja, the amount was the most than else, the proteinase activity is strongest more than else. 8) In the brewing of Korean Tack-Yack-Joo, it is desirable less amount of acidity, more amount of amino acid, stronger liquifaction of starch and vigorous saccharification. Thren it was found that the application of two prepations(Kock Ja and Bun kok) is most effective to get moderate quality in Tack-Yack-Joo brewing.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.24 no.1
• /
• pp.16-23
• /
• 2020

Water pipes are important facilities and consist of pipes of various specifications and materials. The annual average number of earthquakes in Korea is steadily increasing. Therefore, in case of the water pipe, it is estimated necessary to prepare for earthquakes. Damages to the water pipe by the earthquake can cause problems such as water supply and fire suppression, and cause damage to life and property. In Korea, however, it is difficult to find examples of seismic performance evaluation of water pipes based on experimental study. Damage to the water pipes by the earthquake is caused by the displacement-controlled behavior of the ground which is the liquifaction and fault lines. Especially, The damage to the water pipes by the earthquake is concentrated on the joint of the pipe. In particular, piping less than 200mm in diameter was found to be dangerous. Thus, in this study, the seismic and settlement performance of iPVC buried water pipes with fixed joints with a clamp of 150mm was evaluated with a test approach.