시험방법 번역(한국어 원본)3.2 시험 방법
3.2.1 시험개요
쇄석과 저회의 혼합비 변화에 따른 특성을 알아보기 위하여 대형직접전단시험, Clogging 시험, 다짐시험과 투수시험을 실시하였으며, 다짐시험은 KS F 2312에 근거하여 실시하였고, 투수시험은 KS F 2322에 의거하여 실시하였다.
3.2.2 대형직접전단시험
대형직접전단시험에 관한 명확한 시험법이 정립되어 있지는 않으나 보통 직접전단시험을 기준으로 하여 시험되고 있다(신동훈, 2000; 이대수 등, 2005; 한국수자원공사, 1999).
본 연구에서는 연약지반에 시공되어지는 쇄석다짐말뚝에 발생하는 Clogging 현상을 억제하기 위해 쇄석다짐말뚝의 공극을 최소화 하면서 전단강도를 증대시키는 방안으로 쇄석다짐말뚝의 공극에 저회를 채워 상대밀도를 증가시키는 방법을 고안하였다. 따라서, 쇄석과 저회의 혼합비를 100:0, 90:10, 85:15, 80:20, 75:25, 70:30으로 변화시켜가며 대형직접전단시험을 실시하여 적정배합비를 산정하였다. 본 시험에서는 수직하중을 60, 120, 180kPa으로 변화시켜 가면서 쇄석:저회의 각 혼합비에 대하여 1mm/min의 전단속도로 시험을 수행하였다. 대형직접전시험 전경은 그림 4과 같다. 3.2.3 Clogging 시험
본 연구에서는 연약지반에 쇄석다짐말뚝 시공시 장기투수능 저하의 요인이 되는 Clogging 현상을 모사할 수 있는 모형토조를 제작하여 모형토조 내에 점토지반을 조성하고 각 배합비에 따른 혼합다짐말뚝을 시공하여 일정 측압을 가하여 시간경과에 따른 말뚝체의 투수능을 측정하고자 하였으며, Clogging시험기의 형태 및 구성은 그림 5와 같다.
Compressor로 일정 측압(300kPa)을 주면 모형토조 내 점토지반이 수압을 받아 압밀되고, 점토내 간극수가 투수계수가 큰 말뚝체를 통해서 배수되게 되는 구조이며, 일정측압 하에서 시간(약 8일)에 따른 △h(투수능 수두차)를 측정하여 투수능을 비교·분석하였다. |
시험방법 번역(영어 번역본)3.2 Testing method
3.2.1 Outline of the test
To understand the characteristics according to the changes in the mixing ratio between the crushed stone and the bottom ash, the large-scale direct shear test, the clogging test, the compaction test and the water permeability test were conducted,. The compaction test was performed in accordance with KS F 2312 and the water permeability test was conducted in accordance with KS F 2322.
3.2.2 large-scale direct shear test
There is no clear-cut test method defined for the large-scale direct shear test, but ordinarily it is conducted in accordance with the direct shear test (Shin Dong-Hoon, 2000; Lee Dae-Soo et al., 2005; Korea Water Resources Corporation, 1999).
This study proposed a method of increasing the shear strength while minimizing the air gaps of the gravel compaction pile to prevent the clogging occurring at the gravel compaction pile installed in soft ground. Accordingly, the large-scale direct shear test was conducted to find the appropriate mixing ratio while varying the mixing ratio between crushed stone and bottom ash was varied: 100:0, 90:10, 85:15, 80:20, 75:25 and 70:30. This test was conducted at the shear rate of 1mm/min for each mixing ratio between crushed stone:bottom ash while varying the vertical load: 60, 120 and 180kPa. The large-scale direct shear test is illustrated in Figure 4. 3.2.3 Clogging test
In this study a model tank was made to simulate the clogging which causes the deterioration of long-term permeability during the installation of gravel compaction piles in soft ground, and clay ground was made in the model tank, and mixed compaction piles were installed in accordance with each mixing ratio. A certain level of lateral pressure was applied, and the permeability of the pile was measured according to the passage of time. The shape and configuration of the clogging tester are shown in Figure 5.
If the compressor to apply a certain level of lateral pressure (300kPa), the clay ground inside the model tank receives water pressure and becomes consolidated. The interstitial water in the clay is discharged through piles with a large coefficient of permeability, and △h (permeability differential head) according to time (about 8 days) was measured under a certain level of pressure to compare permeability. |
