Reasonable Design Method of Vertical Drain Depending on the Depth of Soft Ground

연약지반의 심도에 따른 연직 배수재의 합리적 설계 방안

In this study, to propose the reasonable evaluation method of degree of consolidation considering the depth of soft ground, the two soft ground areas were chosen and analyzed for the consolidation degree. One was a western coast area in which depth of soft ground was low, and the other was a southern coast area in which depth of soft ground was deep. At the area in which depth of soft ground was low, Barron's and Yoshikuni's methods showed that the evaluation of consolidation degree was large, and it is reasonable that $C_h=C_v$ be recommended to apply the Hansbo's and the Onoue's methods. At the area in which depth of soft ground was deep, it is reasonable that $C_h=C_v$ be recommended to apply the Barron's and the Yoshikuni's methods, and $C_h=(2{\sim}3)C_v$ to apply the Hansbo's and the Onoue's methods. According to the Hansbo's and Onoue's methods, degree of consolidation proved to be applicable with measured data when using the $k_s=(1/3)k_v$ at the area which depth of soft ground was low and using the $k_s=(1{\sim}1/2)k_v$ at the area which depth of soft ground was deep. According to the Hansbo's and Onoue's methods, degree of consolidation was proved to be applicable with measured data when using ds=(3~5)dm at the area which depth of soft ground was low and using ds=2dm at the area which depth of soft ground was deep.

연약지반의 심도를 고려한 합리적인 압밀도 산정 방법을 제시하기 위하여 연약층이 비교적 얕은 지역인 서해안 지역과 연약지반 깊이로 압밀도를 비교 분석한 결과를 요약하면 다음과 같다. 1. 연약지반 심도가 얄은 지역에서 Barron과 Yoshikuni방법은 압밀도를 크게 평가하는 것으로 나타났고, Hansbo와 Onoue방법을 적용할 경우 압밀계수는 $C_h=C_v$로 선정하는 것이 합리적으로 판단된다. 2. 연약지반 심도가 깊은 지역에서 Barron과 Yoshikuni방법을 적용할 경우 압밀계수는 $C_h=C_v$로 선정하며, Hansbo와 Onoue 방법에서는 $C_h=(2{\sim}3)C_v$로 선정하는 것이 합리적으로 판단된다. 3. Hansbo와 Onoue방법에 의한 교란지역 투수계수($k_s$)의 영향범위는 연약지반 심도가 얕은 지역에서는 $k_s=(1/3)k_v$를 적용하고, 심도가 깊은 지역에서는 $k_s=(1{\sim}1/2)k_v$를 적용하는 것이 실측치와 일치하는 것으로 나타났다. 4. Hansbo와 Onoue방법에서 드레인에 의한 교란 영역의 범위는 연약지반 심도가 얕은 경우는 ds=(3~5)dm 범위로 적용하고, 심도가 깊은 경우는 ds=2dm으로 적용하는 것이 실측치와 일치하는 것으로 나타났다.