This paper proposes representative constitutive relationship equations of dredging and reclamation soft soil in Korea. The marine soft soils were sampled at 23 dredged-reclaimed construction sites in the Busan, Gwangyang, and Incheon regions in Korea; then, laboratory tests were carried out. The consolidation property was classified as LL = 60% for Busan and Gwangyang marine soft soil and LL = 30% for Incheon marine soft soil by conducting basic physical property tests and consolidation tests. Busan soft soil showed a slightly higher consolidation settlement property than Gwangyang soft soil. Incheon soft soil showed the lowest consolidation settlement property among the three regions. In particular, 77 consolidation simulations were carried out at a high void ratio using the centrifugal experiment to realize high water content and in-field stress conditions. The constitutive relationship equations of each of the 23 specimens were analyzed with regard to the void ratio–effective stress and void ratio–permeability coefficient through the back analysis of finite consolidation theory from the experimental results. The constitutive relationship equation for Korean soft soil was determined to be a reasonable power function equation. The representative constitutive relationships for soft soils in the three regions were estimated using six equations, which were classified by physical and consolidation properties. The representative constitutive equations were compared to those in previous studies on high void ratio conditions of marine soft soil, and the results showed a similar range.

This study proposes two methods for the determination of optimum monitoring locations of pressure changes in a water distribution system. A sensitivity analysis method is used to calculate the pressure change in a junction due to the change in demand at other junctions. A pressure contribution analysis method is used to calculate the summation of pressure contribution of a junction due to the change in demand at another junction. These methods are applied to a small sample pipe network, pilot plant, and small distribution system for verification. Furthermore, unsteady analysis of the sample pipe network and an experiment in the pilot plant are conducted to verify the availability and accuracy of the proposed methods. To verify the methods, leakage at J-55 was artificially produced at the pilot plant. The pressure change was measured at five different combination groups of sensor locations. From the results, it was found that the top ranked group of sensor locations, J-116, J-140, J-22, and J-68, had the highest pressure contributions and sensitivity. The results of the newly developed methods for the determination of monitoring locations are in good agreement with the results of the unsteady analysis. Finally, the proposed methods are applied to a real distribution system of a small city as a test bed. It is found that the proposed methods for determining the monitoring locations of pressure changes in the water distribution system are useful and effective.

1. 서 론 헬리컬 파일(Helical pile)은 파일의 중심축에 나선형 원판 을 부착하여 말뚝의 중간에서 선단지지력의 효과를 발휘함 으로써 지지력 또는 인발저항력을 향상시킬 수 있는 공법이 다. 1836년 아일랜드 주택 기초보강을 위해 헬리컬 파일이

In this study, model experiments in laboratory were performed to analyze the behavior of debris flow that included the travel time and deposit area according to the change in topographic conditions and rainfall intensity. According to the experimental results, the travel time at failure initiation was shortened owing to the increased channel slope and rainfall intensity. Similarly, runout distance of the debris flow increased when the length of slope and thickness of the soil increased. Further, deposit area of the debris flow was increased as the channel slope, length of slope, and thickness of soil increased, and the analysis on deposit area was related to the increase in the amount of debris flow. According to the experimental result of the various topographical conditions, the deposit area was increased linearly as the travel time increased. Moreover, increase in the rainfall intensity resulted in decreased travel time and increased debris amount.