• Membrane and Water Treatment
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• v.13 no.6
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• pp.303-312
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• 2022

The natural hydrology and geological conditions of Xintian County was investigated, the development law of regional karst fissures was studied, the groundwater was collected and tested through a large-scale collection of groundwater to obtain the change law of chemical characteristics and water quality characteristics of groundwater, and the water quality evaluation was carried out for the regional karst groundwater in this paper. The results show that, the whole area is dominated by carbonate rock distribution areas, and the distribution of water systems is relatively developed. The strata are distributed from the Lower Paleozoic Cambrian to the Cenozoic Quaternary, and contain multiple first-order folds. The regional karst dynamic action is strong, and many tunnels or caves of different scales were shown, which are conducive to the enrichment of groundwater. Karst groundwater is neutral and alkaline water, the water is clear and transparent with good taste, and meets the national drinking water hygiene standards. The content of toxic trace elements and fluoride in the water source is generally lower than the limit value specified by the national standard and the accumulated toxic heavy metals is never found. The overall water quality is of good quality and suitable for the development and utilization of various purposes.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.69-73
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• 2007

Inorganic geochemical and mineralogical analyses from the trench sediments of the Hwayang wetland were carried out to verify the wet/dry conditions during 6000 - 5000 yr BP and abnormal event of 6300 yr BP of Korean west coast. Lithostratigraphy, mineralogy and major element concentrations of the sediments of the trench indicate that during 6000 - 5000 yr BP, a wet/dry conditions might be repeated at an interval of 200 years. Carbonate minerals precipitated with the decrease of water depth in the lake or wetland after about 6000 yr BP. On the other hand, the sediments coarser in mean grain size and larger in standard deviation were corresponded with periods of 6300 yr BP and 6230 yr BP. Especially, such a feature of grain size distribution of 6300 yr BP appears in other wetlands situated in the west coast, e.g., Hwangsan wetland and Cheollipo coastal wetland. During the period, the coarse sediments seem to have been delivered by a high energy like storming.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.424-442
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• 2005

In this paper a design of a large shield Tunnel through weathered soil and weathered rock in 703 section of seoul subway line No.7 extension project is presented. The geological investigation results show that the projecet region consists mostly of weathered soil with some local weathered rock in the tunnel excavation level. A EPB shield TBM is selected as a optimal excavation machine for the large shield Tunnel considering the geological and site conditions. Also, the shield machine head and cutter for the large shield tunnel type are designed considering site geological conditions and average advance rate in similar projects.

• Steel and Composite Structures
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• v.48 no.5
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• pp.499-505
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• 2023

Geological hazards in landslide is one of the most extensive and destructive phenomena are among natural disasters. According to the topography high mountains, tectonic activity, high seismicity, diverse conditions Geology and climate, basically China to create a wide spectrum of landslides have natural conditions and these landslides are annual. They cause a lot of financial losses to the country. It is very difficult to predict the time of the landslide, hence the identification landslide sensitive areas and zoning of these areas based on the potential risk is very important. Therefore, it should be susceptible areas landslides should be identified in order to reduce damages caused by landslides find. the main purpose of landslide sensitivity analysis is identification high-risk areas and as a result, reducing damages caused by landslides It is the way of appropriate actions.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.884-889
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• 2005

A lot of landslides were occurred in Gangnung, Macheon and Geochang areas by Typhoons such as RUSA(2002) and MEAMI(2003). Soil properties of these areas are investigated regarding geological conditions in this study. The shallow plane failure were occurred in Gangnung and Geochang areas, whereas the deep circle failure were occurred in Macheon area. The matrix in Gangnung and Geochang areas was composed of Granite, and the matrix in Macheon area was composed of Gabbro. The disturbed and undisturbed soils were sampled in these areas. As the results of laboratory tests using sampled soils, the coefficient of permeability in Granite region is lower than that in Gabbro region. In the cases that the silt and clay contents are included less than 4% for the soils of Granite region and less than 7% for the soils of Gabbro region, the coefficients of permeability are rapidly increased for both soils. In addition, the simple equations for predicting the coefficients of permeability are proposed using the effective particle size and the silt and clay contents according to geological condition.

• Geomechanics and Engineering
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• v.38 no.1
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• pp.69-77
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• 2024

The development of shield-driven cross-river tunnels in China is witnessing a notable shift towards larger diameters, longer distances, and higher water pressures due to the more complex excavation environment. Complex geological formations, such as fault and karst cavities, pose significant construction risks. Real-time adjustment of shield tunneling parameters based on parameter prediction is the key to ensuring the safety and efficiency of shield tunneling. In this study, prediction models for the torque and thrust of the cutter plate of ultra-large diameter slurry shield TBMs is established based on integrated learning algorithms, by analyzing the real data of Heyan Road cross-river tunnel. The influence of geological complexities at the excavation face, substantial burial depth, and high water level on the slurry shield tunneling parameters are considered in the models. The results reveal that the predictive models established by applying Random Forest and AdaBoost algorithms exhibit strong agreement with actual data, which indicates that the good adaptability and predictive accuracy of these two models. The models proposed in this study can be applied in the real-time prediction and adaptive adjustment of the tunneling parameters for shield tunneling under complex geological conditions.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.35-45
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• 2010

The soil tests have been performed on the specimens obtained from about 1,150 sites including landslides and non-landslides areas in natural terrains for last 10 years. Based on the results of those tests, the average soil properties are estimated and the simple equations for estimating permeability are proposed according to geologic conditions. The average permeability in Granite and Mudstone sites is higher than other sites and the content of silt and clay in Mudstone and Gneiss sites is higher than other sites. The correlation analysis and the regression analysis were performed to estimate the coefficient of permeability according to geological conditions. As the result of the correlation analysis, the coefficient of permeability is selected as a dependent variable, and the silt and clay contents, the water contents and the dry unit weights are selected as independent variables. As the result of the regression analysis, the silt and clay contents and the void ratio were involved commonly in the linear regression equations according to geological conditions. To verify the proposed the linear regression equations, the measured result of the coefficient of permeability at other sites was compared with the result predicted with the proposed equations. As the result of comparison, there were a little bit different between them for some data. However the difference was relatively small. Therefore, the linear regression equations for estimating the coefficient of permeability according to geological conditions may be applied to Korean soils. However, these equations should be verified and corrected continuously to improve the accuracy.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.878-883
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• 2005

This paper describes the effect of acid rock drainage(ARD) produced from the cut slope on the slope structures. Acid rock drainage is originated from a rock quarry located in coal mine zone and mineralization belt of Chosen Supergroup and Ogcheon group, andesite with the pyrite, and acid sulfate soils of Tertiary in Korea. The cut slope, where acid rock drainage comes out, almost has been constructed by shotcrete and planting works. According to the field observation results, in most cases, the acid rock drainage has an adverse effect on slope structures. The shotcrete, anchors and rock bolts produced corrosive action, and bad germination and growth diseases of covering plants of the slope planting construction due to ARD.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.2
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• pp.135-141
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• 2002

This research has been conducted to investigate the influence of mined cavities on a tunnel to be constructed around a coal mine. The location and dimension of cavities were supposed by analysing synthetically geological structures and condition of coal beds as well as gangway map since there does not exist any map describing mined cavities. Detailed geological and geophygical survey have also been carried out for the purpose of understanding the geological structure and rock mass conditions. The two dimensional numerical analysis with FLAC has been performed on the geological sections reconstituted from the obtained information and the affects of mined cavities on the tunnel have been assessed.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.1-8
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• 2015

Deep geological disposal is the preferred storage method for high-level radioactive waste, because it ensures stable long-term storage with minimal potential for human disruption. Because of the risk of groundwater contamination, a buffer of steel and bentonite layers has been proposed to prevent the leaching of radionuclides into groundwater. Quartz is one of the most common minerals in earth's crust. To understand how deformation and dissolution phenomena affect waste disposal, here we study quartz samples at pressure, temperature, and pH conditions typical of deep geological disposal sites. We perform a dissolution experiment for single quartz crystals under different pressure and temperature conditions. Solution samples are collected and the dissolution rate is calculated by analyzing Si concentrations in a solution excited by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). After completing the dissolution experiment, deformation of the quartz sample surfaces is investigated with a confocal laser scanning microscope (CLSM). An empirical formula is introduced that describes the relationship between dissolution rate, pressure, and temperature. These results suggest that bentonite layers in engineering barrier systems may be vulnerable to thermal deformation, even when exposed to higher temperatures on relatively short timescales.