• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.3 no.4
• /
• pp.60-73
• /
• 2000

The purpose of the study was to analyze the feasibility of the alluvial deposit deposited on upper terrace in Han River as a substitute for conventional plant soil. For this purpose, the soil characteristics were analyzed, and germination and growth rate of pansy and marigold for 75 days were investigated. Soil contamination level of all the samples, except mineral oil, was analysed under the legal contamination level, while some mineral oil was detected in almost samples at 2.0~32mg/kg. The measures of the soil texture (sandy loam or loam), organic matter (2.5~5.5%), available phosphate (22~98mg/kg), exchangeable cation of K (0.5~1.1cmol/kg), Ca (0.9~9.6cmol/kg), Mg (0.1~0.7cmol/kg), Na (0.7~3.1cmol/kg), CEC (3.1~24.3cmol/kg) were identified as not worse than those of conventional planting soil. But the pH (5.1~5.3) was detected slightly lower than the range (5.5~6.9) of average domestic field soil. The germination rate of pansy in alluvial deposit was lower than that of fertile field or paddy field soil, while the growth rate of pansy for 75 days in alluvial deposit was as good as that of the compared fertile soils. But the germination rate and growth rate of marigold in alluvial deposit were much poorer than those of marigold in compared fertile soils. Consequently, the feasibility of alluvial deposit as a substitute for planting soil was evaluated to be high.

• Korean Journal of Soil Science and Fertilizer
• /
• v.17 no.3
• /
• pp.224-231
• /
• 1984

Four kinds of soil conditioners, such as red earth, clayey tidal deposit, silty tidal deposit and tertiary deposit were evaluated for the rice growth and for the effectiveness of soil improvement in sandy paddy soil (Gangseo series) whose percolation and nutrient leaching are usually severe. Experiment was conducted at the farmer's field in Hackpo Ri, Bugog Myeon, Changyeong Gun, Gyeong Nam Province for two years (1980-1981) with using two rice varieties, Milyang 42 for 1980 and cheongcheongbyeo for 1981. For both experimental years, the grain yields were increased on the plots that were treated with soil conditioners compared with nontreated plot. The increase in grain yield was particularly high on the plots treated with clayey tidal deposit and teritary deposit. The dry weight of the plant and the uptake amount of inorganic ingredient tended to increase on the plots of clayey tidal deposit and tertiary deposit during whole rice growing season because of the residual effect of soil conditioners in the second experimental year. Cation exchange capacity, available silicate, exchangeable potassium and active iron was increased by the treatment with the soil conditoners. Especially cation exchange capacity was highest in the tertiary deposit treatment plot. Aggregation content and plastic index were increased for the all treatment plots with soil conditioner, however, hydraulic conductivity was conspicuously decreased by the tertiary deposit and clayey tidal deposit treatments.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.1332-1343
• /
• 2008

The purpose of this study was to investigate the feasibility of using sedimentation calcium carbonate production based on microorganism activities in the strength manifestation of various soil conditions including ground. For analysis and comparison of microbial cementation soil's strength, unconfined compression test was executed by each content of soil(S), water(W), microorganism(B), microorganism and deposit (BF), microorganism, admixture and deposit(BCF) at specimen. The result, the strength of SB(soil+microorganism) and SBF(soil+microorganism+deposit) increased about 8%, 15% than SW(soil+water). Also, initial strength increased. But the strength of SBC(soil+microorganism+admixture) and SBCF(soil+microorganism+deposit+admixture) increased about 71%, 115% than SW(soil+water). The results of the SEM analysis, leading to the formation of an adhesive substance layers at the surface and resulting in firm particle configuration. The XRD examination of the sediment resulting from the reaction between the microorganism and the deposit control agent confirmed the presence of a type of calcium carbonate ($CaCo_3$) vaterite, which affects soil strength formation, as well as sodium silicate, silicides and so forth. This indicates that microorganism plays an important role in the production of carbonate ($CaCo_3$), sodium silicate and silicides. It affects to revelation of ground strength.

• Journal of Korean Society of Forest Science
• /
• v.102 no.2
• /
• pp.161-169
• /
• 2013

This study was carried out to examine characteristics of physical and chemical current status and problems of Salix spp. communities based on growth characteristics by tree age and height of the tree species in around Namgang Dam reservoir area. Tree density in 4 survey areas was 5,284 trees/ha, but all areas need to control high tree density. Tree crown area in 4 survey areas was 9,786.4 $m^2/ha$ and crown area of Salix spp. was the most dominant among tree species in watershed of the Jinyang lake. Mean soil depth in 4 survey areas was 65.5 cm higher in the sedimental deposit soil (78 cm) than in forest soil (12.5 cm) near the watershed. Soil bulk density was also higher in the sedimental deposit soil than in forest soil because of poor porosity in the sandy sediment. Soil pH was higher in sedimental deposit soil (A, B horizon:pH 6.7) than in forest soil (A horizon:pH 5.3; B horizon:pH 5.2) because of originated from non-point source polution and detergent of domestic sewage. The results suggest that growth of Salix spp. could be poor because of low fertility with low cation exchange capacity in sedimental deposit soil.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.4
• /
• pp.167-177
• /
• 2002

A test method has been attempted to estimate the soil stiffness by measuring and analyzing dynamic signals of stress waves reflected at the bottom end of the SPT rod contacting a soil deposit. Before conducting a real size testing, a series of parametric studies were conducted in this paper to examine the applicability and the theoretical adequacy of the test method. As a result of these studies, it has been shown that the most significant influence factor affecting the amplitude ratio of the reflected wave to the incident wave at the rod-soil interface was the variation of soil stiffness. Also, the variation of the amplitude ratio was found to be closely related with the variation of impedance ratio of the soil deposit to the SPT rod. As a result, a potential of the test method could be proved to estimate the impedance and the elastic modulus of the soil deposit interfaced with the SPT rod using the test method.

• Geomechanics and Engineering
• /
• v.19 no.5
• /
• pp.463-472
• /
• 2019

The mode perturbation method (MPM) is suitable and efficient for solving the eigenvalue problem of a nonuniform soil deposit whose property varies with depth. However, results of the MPM do not always converge to the exact solution, when the variation of soil deposit property is discontinuous. This discontinuity is typical because soil is usually made up of sedimentary layers of different geologic materials. Based on the energy integral of the variational principle, a new mode perturbation method, the energy-based mode perturbation method (EMPM), is proposed to address the convergence of the perturbation solution on the natural frequencies and the corresponding mode shapes and is able to find solution whether the soil properties are continuous or not. First, the variational principle is used to transform the variable coefficient differential equation into an equivalent energy integral equation. Then, the natural mode shapes of the uniform shear beam with same height and boundary conditions are used as Ritz function. The EMPM transforms the energy integral equation into a set of nonlinear algebraic equations which significantly simplifies the eigenvalue solution of the soil layer with variable properties. Finally, the accuracy and convergence of this new method are illustrated with two case study examples. Numerical results show that the EMPM is more accurate and convergent than the MPM. As for the mode shapes of the uniform shear beam included in the EMPM, the additional 8 modes of vibration are sufficient in engineering applications.

• Geomechanics and Engineering
• /
• v.34 no.4
• /
• pp.397-408
• /
• 2023

Pipe pile walls are commonly used as retaining structures for excavation projects, particularly in densely populated coastal cities such as Hong Kong. Pipe pile walls are preferred in reclaimed land due to their cost-effectiveness and convenience for installation. However, the pre-bored piling techniques used to install pipe piles can cause significant ground disturbance, posing risks to nearby sensitive structures. This study reports a well-documented case history in a reclamation site, and it was found that pipe piling could induce ground settlement of up to 100 mm. Statutory design submissions in Hong Kong typically specify a ground settlement alarm level of 10 mm, which is significantly lower than the actual settlement observed in this study. In addition, lateral soil movement of approximately 70 mm was detected in the marine deposit. The lateral soil displacement in the marine deposit was found to be up to 3.4 and 3.1 times that of sand fill and CDG, respectively, mainly due to the relatively low stiffness of the marine deposit. Based on the monitoring data and site-investigation data, a 3D numerical analysis was established to back-analyze soil movements due to the installation of the pipe pile wall. The comparison between measured and computed results indicates that the equivalent ground loss ratio is 20%, 40%, and 20% for the fill, marine deposit and CDG, respectively. The maximum ground settlement increases with an increase in the ground loss ratio of the marine deposit, whereas the associated influence radius remains stationary at 1.2 times the pipe pile wall depth (H). The maximum ground settlement increases rapidly when the thickness of marine deposit is less than 0.32H, particularly for the ground loss ratio of larger than 40%. This study provides new insights into the pipe piling construction in reclamation sites.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.6 no.3
• /
• pp.1-10
• /
• 2003

RUSLE(revised universal soil loss equation) has been widely used for estimating soil loss. It is very difficult to validate the model estimation since the calculated soil loss should be compared with the survey data for quantification. The input variables for RUSLE model were estimated to grid cell for raster analysis in Bosung basin. Both reconnaissance(1:250,000) and detailed(1:25,000) soil maps were used to derive the input variables for soil erodibility factor. Soil loss calculated using RUSLE were compared to the unit sediment deposit surveyed by KICT(Korea Institute of Construction Technology, 1992) in Bosung basin for assessment. Unit sediment deposit from the cell size of 120m and 150m were the closest to the survey data in 1:250,000 and 1:25,000 map scale, respectively.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2007.09a
• /
• pp.351-362
• /
• 2007

Predicted behaviour of a soft clay deposit in design stage is sometimes different from in-situ settlement and pore pressure measured during and after construction. In this paper, characteristics of settlement and pore pressure occurred in soft soil deposits were investigated briefly in order to get a better understanding of time-dependent viscoplastic behaviour and prevent geotechnical problems resulted from long-term settlement, differential settlement, etc.

• Structural Engineering and Mechanics
• /
• v.45 no.3
• /
• pp.311-321
• /
• 2013

In this study, to have a better judgment on the structural performance, the effects of dynamic Soil-Structure Interaction (SSI) on seismic behaviour and lateral structural response of mid-rise moment resisting building frames are studied using Finite Difference Method. Three types of mid-rise structures, including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing soil classes $C_e$, $D_e$ and $E_e$, according to Australian Standard AS 1170.4. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural lateral displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that the dynamic soil-structure interaction plays a considerable role in seismic behaviour of mid-rise building frames including substantial increase in the lateral deflections and inter-storey drifts and changing the performance level of the structures from life safe to near collapse or total collapse. Thus, considering soil-structure interaction effects in the seismic design of mid-rise moment resisting building frames, particularly when resting on soft soil deposit, is essential.