• Geophysics and Geophysical Exploration
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• v.14 no.1
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• pp.42-49
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• 2011

To locate anomalous features including seepage pathways through the Daeryong earth-fill dam, P and Rayleigh waves were recorded along a 250-m profile on the crest of the dam. Seismic energy was generated using a 5-kg sledgehammer and detected by 24 4.5-Hz vertical-axis geophones installed at 3-m intervals. P-wave and apparent S-wave velocities of the reservoir dam and underlying bedrock were then inverted from first-arrival traveltimes and dispersion curves of Rayleigh waves, respectively. Apparent dynamic Poisson's ratios as high as 0.46 were obtained at the base of the dam near its north-east end, where an outlet conduit occurs, and in the clay core body near the south-west end of the profile where the dam was repeatedly grouted to abate seepage before our survey. These anomalies of higher Poisson's ratios in the upper part of clay core were also associated with effusion of grout on the downstream slope of the dam during post-survey grouting to abate leakage. Combining P-wave traveltime tomography and inversion of Rayleigh wave velocities was very effective in detecting potential pathways for seepage and previous grouted zones in this earthen dam.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2004.11a
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• pp.65-65
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• 2004

• Geomechanics and Engineering
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• v.9 no.4
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• pp.483-498
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• 2015

This article describes a new in-situ load test called the Hydraulic Cylinder Test (HCT) and its application to determine the geotechnical properties of soil-rock mixtures. The main advantages of the test are its easy implementation, speed of execution and low-cost. This article provides a detailed description of the equipment and the test procedure, and examines a case study of its application to determine the geotechnical properties of an earth-filled dam for a tailings pond. The containment dams of the ponds are made from blocks of gypsum and marl, obtained from the excavation of the ponds, mixed in a matrix of sands and clays. The size of the rocks varies between 1 and 30 cm. The HCT is particularly useful for determining the geotechnical properties of this type of soil-rock mixture. Nine HCTs were carried out to determine its strength (c, ${\phi}$) and deformation (B, G) properties. The results obtained were validated using the Bim strength criterion, recently proposed, and some pressure meter tests carried out beforehand. The properties obtained are used to analyze the stability of the dam using computer simulations and a modification to its design is proposed.

• Geomechanics and Engineering
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• v.17 no.3
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• pp.271-278
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• 2019

In recent years, the crack accidents of earth and rockfill dams occur frequently. It is urgent to study the tensile strength and tensile failure mechanism of the gravelly soil in the core for the anti-crack design of the actual high earth core rockfill dam. Based on the self-developed uniaxial tensile test device, a series of uniaxial tensile test was carried out on gravelly soil with different gravel content. The compaction test shows a good linear relationship between the optimum water content and gravel content, and the relation curve of optimum water content versus maximum dry density can be fitting by two times polynomial. For the gravelly soil under its optimum water content and maximum dry density, as the gravel content increased from 0% to 50%, the tensile strength of specimens decreased from 122.6 kPa to 49.8 kPa linearly. The peak tensile strain and ultimate tensile strain all decrease with the increase of the gravel content. From the analysis of fracture energy, it is proved that the tensile capacity of gravelly soil decreases slightly with the increasing gravel content. In the case that the sample under the maximum dry density and the water content higher than the optimum water content, the comprehensive tensile capacity of the sample is the strongest. The relevant test results can provide support for the anti-crack design of the high earth core rockfill dam.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.461-474
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• 2023

The study area is located in Hyeonseo-myeon and Andeok-myeon of Cheongsong-gun, Korea around the Yeongcheon dam waterway tunnel, and in this paper, it is analyzed whether the groundwater level is recovered or not compared to groundwater level before waterway tunnel construction by measuring the groundwater level of 156 wells which were installed in areas near and away from the waterway tunnel. From September 2017 to August 2018, the groundwater level of the well was measured at least once a month, and as a result of groundwater level observation survey, the groundwater level of wells distributed in the directly affected zone by the waterway tunnel is relatively lower than that of the indirectly affected zone apart from the waterway tunnel. These results are estimated to be predominantly affected by the effect of waterway tunnel acting on geologic discontinuities rather than by terrain conditions, i.e. groundwater flows being leaked to the waterway tunnel through direct or indirect channels. Continuous monitoring and further investigation will be required to maintain groundwater facilities and preserve groundwater environments in the future.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.377-386
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• 2006

There is an inseparable relation between human race and engineering work. As world developed into highly industrialized society, a diversity of large structures is being built up correspondently to limited topographical circumstance. Though large structures are national establishments which provide us with convenience of life, there are some disastrous possibilities which were never predicted such as ground subsidence and degradation. It is very difficult to analyze the volume of total metamorphosis with the relative displacement measurement system which is now used and it is impossible to know whether there is structural metamorphosis within a permissible range of design or not. In this research with an object of 13-year-old earthen dam, through generating point-cloud which has 3D spatial coordinates(x, y, z) of this dam by means of 3D Laser Scanning, we can get real configuration data of slanting surface of this dam with this method of getting a number of 3D spatial coordinates(x, y, z). It gives 3D spatial model to us and we can get various information of this dam such as the distance of slanting surface of dam, dimensions and cubic volume. It can be made full use of as important source material of reinforcement and maintenance works to detect previously the bulging of the dam through this research.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.333-341
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• 2006

Since considerable time passed after completion of dam construction, Methods to judge the safety and/or to manage effectively have extreme limitation and restriction. Behavior analysis based on one point (site) by such as surface settlement gauge is typically performed in order to define deformation characteristic of dam. However, deformation characteristics of entire dam can not be analyzed by this method. This study adopted state-of-the-art terrestrial laser scanning technology, and developed the technology to analyze the entire deformation of dam. The analysis was compare with the outputs of surface settlement gauge to confirm the performance of 3D terrestrial laser scanning technology. As a result, through analyses of laser scanning data and the surface settlement gauge data, the studied dam shows behavior of deformation by own weight of dam. It is possible to confirm that the dam is entering the stage of stabilization presently.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.293-301
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• 2005

The CSG(Cemented Sand and Gravel) method is construction technique using as raw materials earth and gravel generated from a local construction site, mixing them with cement and rolling with vibration rollers. Recently, The use of this method for cofferdam and large dam is gradually increasing in Japan. The purpose of an CSG mix design is to develop project specific properties to meet the structure design requirements. But uniform mix design of CSG method has not yet been established. The experience of practitioners from the geotechnical and concrete disciplines has given rise to two genernal approaches to mix design for CSG. This paper reports the concept of how to set the mix design according to modified Proctor compaction test process and the test results on properties such as compaction, compressive strength and modulus of elasticity that obtained by unconfined compression test.

• Journal of Korean Society on Water Environment
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• v.36 no.3
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• pp.229-244
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• 2020

Hydrologic models, as a useful tool for understanding the hydrologic phenomena in the watershed, have become more complex with the increase of computer performance. The hydrologic model, with complex configurations and powerful performance, facilitates a broader understanding of the effects of climate and soil in hydrologic partitioning. However, the more complex the model is, the more effort and time is required to drive the model, and the more parameters it uses, the less accessible to the user and less applicable to the ungauged watershed. Rather, a parsimonious hydrologic model may be effective in hydrologic modeling of the ungauged watershed. Thus, a semi-distributed hydrologic partitioning model was developed with minimal composition and number of parameters to improve applicability. In this study, the validity and performance of the proposed model were confirmed by applying it to the Namgang Dam, Andong Dam, Hapcheon Dam, and Milyang Dam watersheds among the Nakdong River watersheds. From the results of the application, it was confirmed that despite the simple model structure, the hydrologic partitioning process of the watershed can be modeled relatively well through three vertical layers comprising the surface layer, the soil layer, and the aquifer. Additionally, discussions were conducted on antecedent soil moisture conditions widely applied to stormwater estimation using the soil moisture data simulated by the proposed model.

• Journal of the Mineralogical Society of Korea
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• v.32 no.4
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• pp.303-312
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• 2019

In this study, X-ray diffraction, ICP analysis, and leaching experiments were performed to analyze the heavy metals and dissolution characteristics of Andong dam sediments. As a result of X-ray diffraction analysis, Andong dam sediment consists of quartz, plagioclase, chlorite and illite. ICP analysis of sediment showed very high concentrations of As and Cd. Leaching experiments were performed in aerobic and anaerobic condition in a disturbed state. The results of leaching experiment showed that more heavy metals were leached in aerobic than anaerobic conditions. Heavy metal that increased in concentration with time in aerobic conditions were Mn, Zn and Cd, and those in anaerobic conditions were Mn, Fe and As. The leaching ratio of heavy metal concentration in sediment was Mn > Cd > Zn > Ni > Cu > As > Pb ≒ Fe ≒ Cr and Mn > As > Cu > Ni > Zn > Pb ≒ Cd ≒ Fe ≒ Cr in aerobic and anaerobic conditions, respectively.