The corrugated steel plate culvert structure was developed and actively developed in the United States in the 1930s and was introduced into the domestic scene in the 1970s. Currently, about 1,000 corrugated steel structures were being used for expressway concrete passage culverts and waterway culverts. Compared to concrete materials that require a basic curing time, corrugated steel plates could be assembled and backfilled, so that the construction speed is fast and the economics were excellent. However, as the number of public years has elapsed, problems in maintenance have been found. Therefore, there is a growing interest in the stability of corrugated steel plate structures. Therefore, in this study, the improvement for the efficient maintenance of the corrugated steel structure constructed on the expressway was examined.

The reinforced retaining wall was introduced in the late 1980s and has been actively used since the 1990s in Korea 's expressway construction. At the beginning of the introduction, proper stiffeners and backfill materials were used and compaction management was thoroughly carried out, which was recognized as an economical and excellent workability method. However, the current understanding of reinforced earth retaining walls about 30 years old is a negative image such as inadequate reinforcement materials, backfill materials, insufficient compaction, and insufficient drainage system. In this way, the reinforced earth retaining walls that have been constructed in the midst of the negative perception are about 1,000 at the expressway site, and about 1000 will be completed in a few years and about 2,000 will be used. Most of the problems of reinforced earth retaining wall were found during maintenance, and countermeasures are suggested by tracing back to what problems were observed in the design and construction of the observed phenomena. The retaining walls to be installed in future maintenance should be minimized in designing and constructing to prevent problems. It is estimated that such a problem can be solved by changing the recognition. Therefore, in this study, damage cases of reinforcement retaining wall which is frequently occurred in the expressway of Korea were analyzed to derive the preventive maintenance method of reinforced earth retaining walls. Then, the problems and countermeasures were analyzed for each type of damage.

Reinforced earth retaining walls are easier to construct and more economical than concrete retaining walls, and the applicability to the parts where the retaining wall structures are needed is gradually increasing. Since 1980, reinforced earth retaining walls have been used in various ground and environmental conditions, and various types of damage have been found in the maintenance stage due to various conditions of the applied site. Especially, when the ground is sloped, the damage is more serious than the case where it is not. Therefore, in this study, the long-term behavior of reinforced earth retaining wall constructed on the expressway according to the slope of the ground is analyzed.

In Korea, the structure is mostly located on the upper part of the high embankment considering the geographical conditions at the time of expressway construction. Embankment was managed stepwise compaction according to height, but creep settlement of embankment itself may negatively affect superstructure. Reinforced earth retaining walls, which were recognized as flexible structures, were no exception to such geographical conditions. Especially, in the case of reinforced earth retaining wall located on abutment wing wall, damage due to differential settlement supported by pile, damage due to differential settlement and uneven settlement of reinforced earth retaining wall itself was frequently occurred. Therefore, in this study, the damage of reinforced earth retaining wall structure located on the high toe part was analyzed based on case. These data will be used as basic data for future maintenance.

Reinforced earth retaining walls are applied to various fields such as clay part, cut part, adjacent part of structure (alternation, culvert) and reinforcement soil alternation in Korea. Therefore, they are applied more favorably than concrete retaining wall because of its excellent economy and construction. Analysis of reinforced earth retaining wall construction shows that the height is more than 10m higher than that of foreign countries, and when it is applied in multi - stage, it is more than 20m. The reinforced earth retaining wall was introduced in Korea in the 1980s, and the number of years of damage has been increasing due to the fact that the number of public years has been increased to 30 years since it was first applied to the present. Especially, in the case of multi-stage reinforced earth retaining walls having a height of 10 m or more, And the risk of the risk to reach the situation is found. Therefore, in this study, damage characteristics occurred in reinforced earth retaining wall constructed in multi - stage in expressway were analyzed.

As mentioned at the Davos World Economic Forum in 2016, there is now a worldwide wave of waves of the Fourth Industrial Revolution. The flow of government policy and R & D research is also focused on fostering industries based on the Fourth Industrial Revolution. Research in the field of geotechnical engineering can also be a research that lags behind trends if it is not merged with the technology related to the fourth industrial revolution in the future. Therefore, this study analyzed the applicability of the fourth industrial revolution technology in the field of expressway maintenance.

On the expressway, culvert structures serve as a channel or channel connecting villages and towns blocked by clay. The culvert structures are mainly constructed of reinforced concrete or corrugated steel sheets in various ground conditions. Most culverts are divided into aging and damage trends according to the number of public years. However, most of the damage to the culvert structures applied on the soft ground is likely to be caused by the subsidence of the ground. In addition, even if the settlement of the paper sheet is stabilized, if the road is constructed at the upper part, the culvert structure is also expanded at the time of the expansion work, and damage due to a behavior different from that before the expansion work may be found. Therefore, in this study, the behavior of the culvert structures according to the ground supporting force was analyzed. For this purpose, the causes of damage are derived through design review and field investigation.

Recently, maintenance science has been promoted and many advanced equipments have been developed such as GPR surveying, automatic gauging robot, bridge deck inspection robot. And the government - led policy on the fourth industrial revolution affects the R & D field of science and technology, and science for all fields remains a challenge. However, the equipment that has been developed so far is applied separately to each field, so that it is not possible to grasp the state of the entire structure. Therefore, in this study, the applicability of BIM and image information mapping technology in expressway maintenance was analyzed. To accomplish this, a basic analysis was conducted to identify the characteristics of the equipment developed for the current structure inspection and to build a platform to manage the collected data collectively.

Aromatase is an enzyme that converts testosterone to estrogen. This enzyme, present in the sperm as well as various tissue and cells, has been considered to be related to the fertility of human and mouse sperm. Therefore, we examined effect of aromatase inhibitor on viability and fertility of sperm, and quantity of aromatase in sperm groups with different density in pig. To analyze the effect of aromatase on sperm viability, we treated aromatase inhibitor to the sperm with different concentrations (0, 10, 20, 50, 100, 200, 500 μM) at different time (0.5, 1, 2, 4, 8 hours). After the treatment, the sperm viability was calculated by hypo-osmotic swelling test. We selected 0, 50, 100 μM concentration during 0.5 hour as inhibitor treatment condition before in vitro fertilization. Next, we examined fertility and quantified aromatase protein in sperms with different density. In the first experiment, viability of sperm was decreased following the increasement of inhibitor concentration. The aromatase inhibited sperm showed lower penetration rate and cleavage rate than those of non-treated sperm. Concentration of 50 μM inhibitor had no significant effect on the sperm viability, but it significantly reduced sperm fertility. Second, sperms with low density showed higher penetration rate, but no significant difference between sperms with high density. In conclusion, aromatase is responsible for viability and fertility of porcine sperm similar to mouse and human, however, density of sperm has no correlation with quantity of aromatase protein.