• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.101-113
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• 2007

A landslide was occurred due to soil cutting for construction to expand the Donghae express highway in Dong-hae-City, Korea. The total area of the landslide was about $9,550m^2$ with 100 m of width and 87m of height. The landslide was occurred due to the internal factor of the unstable geological structure including the clay layer and the external factor of continuous heavy rainfalls. As the result of field instrumentation during the landslide, the horizontal displacement of the slope ground increases with increasing the accumulated rainfall by continuous rainfall during the rainy season. Also, the depth of sliding failure was decided by the horizontal displacement distribution during landslide occurrence. It makes sure that the horizontal displacement starts from the depth of sliding failure and the depth of sliding failure matches well with the location of the clay layer. As the slope stability analysis using Bishop's Simplified Method at the landslide area, the safety factor of slope during the rainy season was 0.53. This safety factor of slope was enough to trigger the landslide at this area. The depth of sliding failure obtained by analytical method matches well with the depth of the clay layer.

• Research in Community and Public Health Nursing
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• v.4 no.2
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• pp.170-187
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• 1993

The natural growth rate of the Korean population has decreased from 3.0% in 1960 to 1.0% in 1990. This was done with family planning program which was introduced by the government in 1961. The family planning program focused on birth control rather than the characteristics of the individuals and motivations of contraception. People were simply forced to use the method. Whereas, Natural Contraceptive is a method of family planning based solely on the timing of intercourse with the naturally occurring' physiological manifestation of fertilization and in fertilization during the menstrual cycle. This is the combination of self fertility awareness with periodic abstinence. Natural family .planning(NFP) programs in Korea were first started in the Chun-Chen diocese of catholic church by Bishop Thomas Stewart in 1970 In 1975, the Bishops conference launched the Korea Happy Family Movement in the Catholic Hospital Association, to promote the natural family planning. An average of 70,000 people, including adolescents, college students, unmarried and married persons, arid the clergies were trained during a six-year period (1986-1991). 61.5%(24,542 people) of those who completed 3 cycles during 6 year period (1986-1991) became autonomous users and the range was from 48.1% to 78.2%. In 1986, 22.7% of NFP individuals who drooped out of the program because of the desire for conception (23.4%), the difficulty of the method used(25.8%), and the loss of interest(22.8%). During the six-year period the unplanned pregnancy rate at the NFP was 2.9%. The range of the pregnancy rate was at 1.2-9.8%. The rate was decreased as years passed. The major reason for the failure of contraceptive was error by the individuals(61.1%). The percentage of the success of conception was 18.1% of 2.979 for achieving pregnancy. The highest percentage was 58.2% (99 users) in Kwang-Joo diocese and next was 37.1% (10 users) in Chong Joo diocese.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.23-32
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• 2015

This paper addresses the effects of extreme rainfall on the stability of cut slopes in Yen Bai city, Northern Viet Nam. In this area, natural slopes are excavated to create places for infrastructures and buildings. Cut slopes are usually made without proper site investigations; the design is mostly based on experience. In recent years, many slope failures have occurred along these cuts especially in rainy seasons, resulting in properties damaged and loss of lives. To explain the reason that slope failure often happens during rainy seasons, this research analyzed the influence of extreme rainfalls, initial ground conditions, and soil permeability on the changes of pore water pressure within the typical slope, thereafter determining the impact of these changes on the slope stability factor of safety. The extreme rainfalls were selected based on all of the rainfalls triggering landslide events that have occurred over the period from 1960 to 2009. The factor of safety (FS) was calculated using Bishop's simplified method. The results show that when the maximum infiltration capacity of the slope top soil is less than the rainfall intensity, slope failures may occur 14 hours after the rain starts. And when this happens, the rainfall duration is the deciding factor that affects the slope FS values. In short, cut slopes in Yen Bai may be stable in normal conditions after the excavation, but under the influence of tropical rain storms, their stability is always questionable.