Dynamic Soil-Structure Interaction Analysis for Complex Soil Profiles using Unaligned Mesh Generation and Nonlinear Modeling Approach

박장호,추프랑솨,조정래 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.4

Even if numerous studies were dedicated to propose soil-structure interaction analysis methods, most of these methods introduce several assumptions to circumvent the difficulties encountered in modeling and reduce computational efforts. The complex spatial configuration of the soil-foundation interface or the distribution of the soil medium are often simplified using flat-layered soil profiles and, the nonlinearity of the soil medium is generally dealt through an equivalent linear model. However, real soil profiles are featured by complex shapes, inclusion of discontinuities and nonlinear characteristics of soil. Accordingly, this paper presents a soil-structure interaction analysis method considering the characteristics of the structure, soil-structure interface and complex nonlinear distribution of the soil that could not be accurately modeled in previous methods. The proposed method adopts unaligned mesh generation and nonlinear modeling approach to model complex soil profiles. The validity and applicability of the nonlinear soil-structure interaction analysis method are verified through a numerical example.

논과 밭 토양에서 토층간 미생물 군집의 차이

김찬용(Chan-Yong Kim),박기춘(Kee-Choon Park),이영근(Young-Keun Yi) 한국토양비료학회 2009 한국토양비료학회지 Vol.42 No.2

인지질 지방산을 분석하여 특정 미생물군의 수직적분포와 토층간 미생물 군집 패턴을 조사하였다. 경북농업기술원에 위치하고, 질소, 인산, 가리의 화학비료만 장기 연용한 논과 밭 포장에서 15 cm 깊이까지 토양을 채취하였다. 인지질 지표 지방산을 주요인 분석으로 분석하여 토양 미생물 군집을 분석한 결과 논과 밭 토양의 미생물 군집은 뚜렷하게 구분되었으며, 토층간 차이보다 논과 밭의 차이가 더 컸다. 논보다 밭은 토층이 깊어짐에 따라 미생물 군집이 급격하게 변하였는데, 미생물 군집 측면에서 밭보다 논의 표층이 더 두껍다고 볼 수 있다. cyclopropyl/monoenoic precursor 비율과 전체 포화지방산/전체 불포화 지방산 비율은 토심이 깊어짐에 따라 증가하였는데, 이는 토심이 깊어질수록 탄소원과 통기가 부족하기 때문에 일어나는 현상으로 보인다. 대체로 표토는 그램음성균, 곰팡이 등의 상대적 비율이 높고 토심이 깊어질수록 세균과 방선균의 상대적 비율이 높아졌다. We examined the vertical distribution of specific microbial groups and the patterns of microbial community structure within the soil profile using phospholipid fatty acid (PLFA). Samples were collected from the soil surface down to 15 cm in depth from paddy and upland fields located in Daegu, Korea. The two fields have been fertilized with only chemical fertilizers N, P, K for 33 years. Principal component analysis of the PLFA signatures indicated that the composition of the soil microbial communities changed significantly with the cultivation practices and soil depth, suggesting that cultivation practices of paddy and upland fields had more significant influence on soil microbial community than the soil depth did. The soil microbial communities changed more drastically with soil depth in upland field than in paddy field, with making thicker soil surface in paddy field in terms of soil microbial community. The ratios of cyclopropyl/monoenoic precursors and total saturated/total monounsaturated fatty acids increased with soil depth, suggesting that the deeper soil horizons are more carbon-limited and anaerobic than surface soil. The community analysis using PLFAs as biomarkers revealed that Gram-positive bacteria and actinomycetes tended to increase in proportional abundance with increasing soil depth, while the abundance of Gram-negative bacteria and fungi were highest at the soil surface and substantially lower in the subsurface.

Vertical distribution of bacterial community is associated with the degree of soil organic matter decomposition in the active layer of moist acidic tundra

김혜민,Min Jin Lee,정지영,Chung Yeon Hwang,Mincheol Kim,Hee-Myong Ro,Jongsik Chun,Yoo Kyung Lee 한국미생물학회 2016 The journal of microbiology Vol.54 No.11

The increasing temperature in Arctic tundra deepens the active layer, which is the upper layer of permafrost soil that experiences repeated thawing and freezing. The increasing of soil temperature and the deepening of active layer seem to affect soil microbial communities. Therefore, information on soil microbial communities at various soil depths is essential to understand their potential responses to climate change in the active layer soil. We investigated the community structure of soil bacteria in the active layer from moist acidic tundra in Council, Alaska. We also interpreted their relationship with some relevant soil physicochemical characteristics along soil depth with a fine scale (5 cm depth interval). The bacterial community structure was found to change along soil depth. The relative abundances of Acidobacteria, Gammaproteobacteria, Planctomycetes, and candidate phylum WPS-2 rapidly decreased with soil depth, while those of Bacteroidetes, Chloroflexi, Gemmatimonadetes, and candidate AD3 rapidly increased. A structural shift was also found in the soil bacterial communities around 20 cm depth, where two organic (upper Oi and lower Oa) horizons are subdivided. The quality and the decomposition degree of organic matter might have influenced the bacterial community structure. Besides the organic matter quality, the vertical distribution of bacterial communities was also found to be related to soil pH and total phosphorus content. This study showed the vertical change of bacterial community in the active layer with a fine scale resolution and the possible influence of the quality of soil organic matter on shaping bacterial community structure.

복잡한 지반 형상을 고려한 비선형 지반-구조물 상호작용 해석

박장호 ( Jang Ho Park ) 한국안전학회(구-한국산업안전학회) 2011 한국안전학회지 Vol.26 No.1

This paper presents a nonlinear soil-structure interaction analysis approach, which can consider precisely characteristics of structures, complicated soil profiles and nonlinear characteristics of soil. Although many methods have been developed to deal with the soil-structure interaction effects in past years, most of them are nearly unpractical since it is difficult to model complicated characteristics of structure and soil precisely. The presented approach overcomes the difficulties by adopting an unaligned mesh generation approach and multi-linear model. The applicability of the proposed approach is validated and the effects of complicated characteristics of structure and soil on soil- structure interaction are investigated through the numerical example by the proposed nonlinear soil-structure interaction analysis approach

Across-fault distributions of radon concentrations in soil gas for different tectonic environments

Xiaolong Sun,Pengtao Yang,Yang Xiang,Xueyun Si,Dongying Liu 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.2

The radon concentration in soil gas at the crustal surface is closely related to the development of local fractures. Therefore, the spatial variation in soil-gas radon concentrations across faults differs between fault zones located in different tectonic environments. This study investigates the Beiluntai thrust fault and the Haiyuan strike-slip fault in west China, which are assumed to be typical examples of the different types of faults. Radon concentrations in soil gas were measured at various locations around these faults, and the spatial variation in these concentrations was characterized along fault-perpendicular profiles. For normal fault, our results indicate that concentrations are usually highest at the fault, and decrease gradually away from the fault in either direction. For thrust, however, concentrations increase in the hanging wall approaching the fault, but decrease sharply at the fault. For strike-slip fault with extension across the fault, soil-gas radon concentrations are relatively high at the fault, and decrease gradually with distance from the fault. For strike-slip fault with contraction across the fault, soil-gas radon concentrations are relatively low at the fault, and increase gradually with distance from the fault.

Application of Multiple SASW Technique to Investigate Cavity Existence under Asphalt Pavement

Vu Thanh Ngo,Hojin Cho,Jinwook Lee,Sungjin Lee,Yujin Lim 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05

This paper describes an experimental investigation for investigating cavity under the urban asphalt pavement. The cavity may appear in construction process or generate due to spilling of water from broken or old sewage pipes. Multiple SASW is a non-destructive method that uses Rayleigh waves to determine shear velocity (Vs) profile with depth in the soil. The Vs profile can explain homogenous level of the soil. In this study, it was verified that cavities could be checked by investigating shear velocity profile with depth which is produced by multiple SASW technique. A cavity in the soil generates lower shear wave velocity than that of surrounding soil. In this study, a 2D shear velocity profiles obtained by ABAQUS FE analysis and from the multiple SASW tests performed in Yong-in model site are used for verification of cavity in the soil. It was successfully verified that multiple SASW technique be used for investigating cavity in the soil

Determining potential habitat of Kermani Calligonum and Lentil Bead Salmaki in Sistan region of south eastern Iran

Mohammad Reza Moradi,Iraj Amiri,Mohammad Zare,Hassan Fathizad 대한공간정보학회 2017 Spatial Information Research Vol.25 No.2

In this study, potential habitat of two species, Kermani Calligonum and Lentil Bead Salmaki in Sistan region was determined by using geographic information system and measurements of distance techniques. For intraregional study, five habitants were randomly selected and in every location, 10 soil profiles were dug to a depth of 45 cm and soil samples were taken. According to samples taken in each profile parameters such as EC, texture, pH and organic matter in soil other physical parameters at each site such as altitude, temperature, evaporation, results show that Lentil Bead Salmaki in comparison with Kermani Calligonum is able to grow in soils with high salinity, less organic matter and soils with light texture and also tends to thrive and grow in acid soils. Finally, by combining different layers of information for each species, it was found that from total study area of 653,345 ha, three regions including 45,896 ha (7.02%) were suitable for growing Kermani Calligonum. 29,446 ha (4.5%) of this area belongs to habitat of Kermani Calligonum. Approximately remaining 16,450 acres (2.25% of the total area), is potential habitat and the results also indicated that three areas consisting of 8223 ha (1.25%) is suitable for Lentil Bead Salmaki growth. 1962 ha (0.3%) of this area belongs to Lentil Bead Salmaki habitat and the remaining 7546 ha (0.95%) is the area of potential habitat. The accuracy of determining the habitat (finding location) of the mentioned species is estimated to be over 95%.

Distribution characteristics of fungal communities with depth in paddy fields of three soil types in China

Xu Li,Huanhuan Wang,Xiang Li,Xinyu Li,Huiwen Zhang 한국미생물학회 2020 The journal of microbiology Vol.58 No.4

Little is known about the distribution of fungal communities with soil depth on relatively large scales. In this study, typical paddy soils in three regions (Hailun, Changshu, and Yingtan) from north to south China were selected to investigate the vertical distribution (0-100 cm) of the fungal community by Illumina MiSeq sequencing, and to identify the main factors influencing the fungal community distribution. The results indicated that the structure of the soil fungal community changed significantly with region and soil depth. Soil fungal taxa such as Zygomycota, Glomeromycota, Saccharomycete, Kazachstania, Mortierella, Massariosphaeria, Hypholoma, and Zopfiella were enriched at depths of 0–20 cm, whereas Dothideomycetes, Microbotryomycetes, Tremellomycetes, Sporobolomyces, Cryptococcus, Rhodotorula, Fusarium, and Pyrenochaetopsis had high relative abundances at 80–100 cm. Variance partitioning analysis indicated that the geographic distance contributed more to the fungal community variation than environmental variables on a large scale. In addition, soil total carbon and nitrogen contents were the main environmental factors driving the vertical distribution of the fungal community in paddy soils.

복잡한 지층 형상을 고려한 지반-구조물 상호작용 해석

박장호 ( Jang Ho Park ) 한국안전학회 2006 한국안전학회지 Vol.21 No.3

구조물과 복잡한 지층 특성을 고려한 지반-구조물 시스템의 동적 해석

박장호 ( Jang Ho Park ) 한국안전학회 2007 한국안전학회지 Vol.22 No.5