본 연구에서는 사질토와 점성토의 인발저항의 관계를 파악하고, 나무말뚝의 직경 근입깊이, 직경과 근입깊이에 따른 근입비의 변화에 따라 인발저항력의 상관관계를 연구하고자한다. 그리하여 간척지 지반 특성인 점성토 지반 위 적당한 나무말뚝의 직경과 근입깊이, 근입비를 통하여 최적의 나무말뚝의 제원을 결정하고자 한다. SM과 ML로 이루어진 두 지반조건의 다짐률을 70 %로 동일하게 하여 말뚝의 인발저항력을 측정하였다. 직경과 근입깊이를 동일하게 하였을 때 ML 지반의 값이 더욱 크게 나오는 것을 보아 인발저항력은 점착력의 영향을 크게 받는다는 것을 알 수 있다. 또한 각 지반에 대해서 동일한 직경에 대한 근잎깊이 를 달리하여 말뚝의 인발저항을 측정하였을 때, 근입깊이가 깊을 수로 인발저항력의 크기가 비례하였다. 말뚝의 인발저항력은 주면면적이 클수록 증가하는 것으로 나타났다. 말뚝의 직경을 일정하고 근입깊이를 달리한 경우에는 근입깊이가 증가함에 따라 인발저항력은 증가하는 것으로 나타났다. 그러나, 직경이 일정하지 않은 경우 근입비 만을 고려하였을 때, 인발저항력과의 관계는 불규칙한 것으로 나타났다.

In this study, considering this construction process, the parametric study is performed and analyzed about factors affecting seismic analysis of cut-and-cover tunnel, such as analysis method(response displacement method, time history analysis method), surrounding soil(in-situ soil or refilled soils), refilled range(d). Consequently, it is hoped to provide the preliminary data for a better reasonable review on seismic design and seismic performance assessment of underground structures.

Experiments were conducted to find out the optimum level of slow release N fertilizers when total amounts of nitrogen required throughout the growing season in paddy were applied in the soil of seedling box. To evaluate the emergence rate and growth of rice seedlings, five levels of Meister (MS) 10, MS S10, and latex coated urea (LCU) which are equivalent to 0, 40, 60, 80, and 100kg N h a-l were mixed in soil of the seedling box. Emergence rate differed depending on the fertilizers and N levels; in MS 10 plots the emergence rate was 40.8% at 40kg N h a-l and no seedlings were emerged at the higher levels, in MS S10 plots higher than 80% at all the N levels, and decreased with the N levels from 70.0% at 40 kg N h a-l to 59.5% at 100kg N h a-l of LCU. Seedling started to wilt at 40 kg N h a-l of MS 10 and 80 and 100 kg N h a-l N of LCU on the 8th day after sowing, while seedling growth was normal at all the levels of MS S10. Field performance of rice was evaluated at the 0, 30, 60, 90, 120kg N h a-l of MS S10 applied in the soil of seedling box and N was not applied in paddy. Grain yield at 90 and 120kg N h a-l of MS S10 was similar to conventional urea split application (120 kg N h a-l ), but significantly higher compared to 30 and 60kg N h a-l of MS S10. Fertilizer N recovery decreased with N levels and the N recovery at 90 kg N h a-l of MS S10 and conventional urea split application were 62.2 % and 44.2%, respectively, with similar grain yield. The optimum level of MS S10 to be applied in seedling box seems to be about 90 kg N h a-l considering grain yield, price of fertilizer, labor applying fertilizer, and fertilizer N recovery.d fertilizer N recovery