실험결과 번역(한국어 원본)4. 실험결과 및 분석
4.1 건조다짐시험
저회와 쇄석의 배합비에 따른 다짐시험은 대형직접전단시험 및 Clogging 시험시 시료를 다져다짐밀도를 결정하기 위해 실시하였으며 그 결과는 표 5 및 그림 6과 같다.
각 시료의 다짐정도를 파악하기 위하여 다짐횟수를 0, 25, 55, 75회 타격하였으며 각 시료의 배합비에 따라 그 무게를 나타내었다.
완전 건조된 시료의 다짐횟수에 따른 각 배합비별 밀도를 살펴보면 다짐횟수가 증가할수록 밀도가 증가하는 경향을 나타내는데, 쇄석:저회 80:20의 밀도가 가장 크게 나타났다. 이로 인해서 각 배합비별 다짐횟수는 약 55회가 가장 효율적인 다짐정도이므로 대형직접전단시험 및 Clogging 시험에서 다짐말뚝 형성시 층별 다짐횟수를 55회로 결정하였다.
4.2 대형직접전단시험
쇄석다짐말뚝에서 지지력에 가장 큰 영향을 미치는 요인은 내부마찰각이다(천병식 등, 2002). 대형직접시험을 통하여 도출된 쇄석:저회의 혼합비 100:0, 90:10, 85:15, 80:20, 75:25, 70:30에 대한 변위 및 수직응력(60kPa, 120kPa, 180kPa) – 전단응력의 그래프는 그림 7∼13과 같으며 저회의 혼합률에 따른 내부마찰각과 최대전단응력의 변화는 그림 14와 같다. 시험결과 쇄석과 저회 혼합비가 80:20일 때 내부마찰각이 가장 크게 나타났으며 저회의 혼합비가 20%를 넘어가면 내부마찰각이 감소하는 경향을 확인할 수 있었다. 따라서 쇄석:저회 혼합비 80:20의 전단강도가 가장 큼으로 쇄석과 저회 혼합다짐말뚝의 적정 혼합비로 결정하였다.
4.3 정수위 투수시험
저회 및 모래의 초기 투수특성 파악을 위하여 각각의 투수계수를 구한 다음 대형직접전단시험에서 확인된 쇄석과 저회의 적정 배합비(80:20)에 따른 투수계수와 쇄석과 모래 배합비(80:20)의 투수계수를 비교·검토하였다.
그 결과 표 6과 같이 모래와 저회의 투수계수가 이상 나타났으며 비슷한 특성을 보였다. 또한, 쇄석과 저회 및 모래 각각의 혼합된 말뚝의 투수계수 역시 이상으로 투수성이 뛰어남을 확인 할 수 있었다. 4.4 Clogging 시험 |
실험결과 번역(영어 번역본)4. Experimental results and analysis
4.1 Dry compaction test
The compaction test according to the mixing ratio between the bottom ash and the crushed stone was conducted to determine compaction density by compacting the samples during the large-scale direct shear test and the clogging test. The result is shown in Table 5 and Figure 6.
To determine the degree of compaction of each sample, compaction was done 0, 25, 55 and 75 times, and the weight was shown according to the mixing ratio of each sample.
With regard to the density for each mixing ration by compaction frequency of the completely dried sample, as the compaction frequency increased, the density tended to increase. The density was greatest when the ratio between crushed stone and bottom ash was 80:20. As a result, the most efficient compaction frequency for each mixing ratio was about 55 times. So the compaction frequency by layer was determined to be 55 times when the compaction file was formed during the large-scale direct shear test and the clogging test. 4.2 Large-scale direct shear test
The factor that has the greatest influence on the bearing capacity with regard to the gravel compaction pile is the angle of internal friction (Cheon Byeong-Sik et al., 2002). The graphs of the displacement and vertical stress (60kPa, 120kPa, 180kPa) – shear stress with regard to the crushed stone:bottom ash mixing ratios derived through the large direct test (100:0, 90:10, 85:15, 80:20, 75:25 and 70:30) are shown in Figures 7∼13, and the changes in the angle of internal friction and the maximum shear stress according to the mixing ratio of bottom ash are shown in Figure 14. The test result showed that, when the mixing ratio between crushed stone and bottom ash was 80:20, the angle of internal friction was the greatest, and it was confirmed that if the mixing ratio of the bottom ash exceeds 20%, the angle of internal friction tends to decrease. Accordingly, as the shear strength of the 90:20 crushed stone:bottom ash mixing ratio is the greatest, it was determined to be the appropriate mixing ratio for the compaction pile mixing the crushed stone and the bottom ash. 4.3 Constant head permeability test
To determine the initial permeability of the bottom ash and sand, each coefficient of permeability was obtained, and the coefficient of permeability according to the appropriate mixing ratio (80:20) between crushed stone and bottom ash, confirmed in the large-scale direct shear test, and the coefficient of permeability for the 80:20 mixing ration between crushed stone and sand were compared.
As shown in Table 6, the result showed that the coefficient of permeability between sand and bottom ash exceeded , and displayed similar characteristics. The coefficient of permeability for the pile mixing crushed stone, bottom ash and sand also exceeded . It was confirmed that transmissibility was excellent. 4.4 Clogging test |
