• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.10a
• /
• pp.581-590
• /
• 2005

The grouting method is widely used as the impermeable effect and ground reinforcement in construction. But, it has a problem that cement and grout material are not mixed well in the injection tip equipment and an opposite flow and interception state of the chemical grouting is happened. so, continuous work is difficult. McG method installed a special grouting and device, made possible go well mixing of grouting material and prevent flowing backward and block of nozzle also diversify powder rate of cement that is grouting material to select sutible material in layer conditions. YSS that lowered $Na_2O$ influencing durability and circumstance is developed by gel-forming reaction material. so eco-circumstance and durability is increased by minimizing dissolution of underground water. In this study, it is assumed that seepage state of the injection material using a special injection tip equipment and a unconfined compressive strenth by mixing a various injection material of various. And it is confirmed that strenth increase effect and permeable decrease of the improved body through the test execution and field execution.

• Journal of the Korean Society of Groundwater Environment
• /
• v.4 no.4
• /
• pp.191-198
• /
• 1997

The Seokdae municipal waste landfill was filled from 1987 to 1993. A disk tension infiltrometer was used to estimate the saturated hydraulic conductivity of the upper part of landfill cover. The estimated saturated hydraulic conductivity ranges from 2.2$\times$$10^{-4}$~8.1$\times$$10^{-3}$ cm/sec. Net infiltration through the Seokdae municipal waste landfill is estimated from precipitation data, hydraulic conductivity and reported landfill profiles by using an unsaturated flow model, HYDRUS. Total infiltration rate is estimated to be 939 ㎥/day. Leachate level rise and leachate seepage are computed by adopting a simple model.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.03a
• /
• pp.352-361
• /
• 2006

The grouting method is widely used in construction to reduce permeability and reinforce the ground. If the cement and grout material are not mixed well in the injection tip equipment, an opposite flow and Interception state of the chemical grouting can occur. McG method installs a special grouting device to allow better mixing of the grouting material and prevent backward flow. The block of nozzle also diversify powder rate of cement. YSS that lowers $Na_2O$ and thereby increases durability is developed by gel-forming reaction material. In this study, the seepage state and unconfined compressive strength of the injection material using the special injection tip equipment is tested. The results of laboratory and field tests clearly demonstrate that the strength increases and permeability decreases using the McG method.

• Structural Monitoring and Maintenance
• /
• v.6 no.2
• /
• pp.103-124
• /
• 2019

Present study concerns the safety evaluation of SefidRud dam's block No. 18 regarding probable crack propagation in the foundation gallery under a MCE record. Accordingly, a 3D finite element model of the block in companion with the reservoir and the foundation is modeled. All the associated thermal and structural parameters are derived via calibration with the records of thermometers and pendulums installed inside the dam body. The origination of the cracks and their whereabouts are determined by primary thermal and static analyses and through a linear dynamic analysis the potential failure zone and their extent and level are studied. The foundation gallery is the most probable zone among the other intensive tensile stress area to compromise the dam stability. Therefore, the nonlinear analysis of this risky region is inevitable. The results depict the permissible expansion of the cracks inside the gallery even under another future earthquake in MCE level. As a consequence, the general dam performance is assessed safe in spite of the seepage flow rate growth from the gallery fractures.

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.376-379
• /
• 2006

A numerous oil slicks of natural origin were revealed in the southwest (SW) part of Caspian Sea by the synthetic aperture radar (SAR) images acquired by Envisat satellite in 2003-2004. On the basis of computer processing, visual analysis of SAR images and comparisons with bathymetry, geophysical and seismic data in geographic information system (GIS), a link between these slicks and unloading of liquid hydrocarbons in the SW Caspian is established. Oil slicks are basically concentrated above domes of local geological formations of the sedimentary cover. In total more than 90 seeps and mud volcanoes having a repeating regime and representing an active type were identified; they are distributed across the SW Azerbaijan and West Iranian sectors. Periodical occurrence of slicks can reflect alternation of mud volcanism pulses forced by intensive seismicity with the quiet periods. Seepage rate of oil in the SW part of the Caspian Sea according to SAR images is estimated to be up to 16,000 metric tons per year. The importance of unloading of oils on hydrochemistry and ecological conditions of the Caspian Sea is demonstrated. Conclusion is done that the Envisat SAR to be an excellent tool for studying oil seeps through observation oil slicks floating on the sea surface.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.1
• /
• pp.71-80
• /
• 2011

In period of rapid economic development, as doing river conservation work by using harmful materials environmental pollution has adversely effected humans, animals and plants frequently. For recovery of environmental pollution it needs a lot of time and cost. Therefore, in this study, in order to take an environment-friendly method which is also economical and durable both results of the laboratory model test and field test were compared and analyzed. According to the results of the laboratory model test, those methods such as concrete paving, asphalt paving, bentonite mat, stabilized soil method and mixed soil method have small amount of seepage, but on the other hand compaction soil, grassland and permeable materials have considerable amount of seepage. The results of field test show a similar tendency with laboratory test and have been satisfied to assess standard of domestic water permeability below $1.0{\times}10^{-7}cm/sec$ and unconfined compressive strength is also than 1.0MPa so it has been satisfied about standard. In conclusion, as compaction rate increased, as unconfined compression strength increased and coefficient of permeability decreased.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.194-194
• /
• 2016

Gansu, located in the northwestern region, is a typical agricultural province of arid, semiarid in China. The shortage of water resources is the biggest obstacle of Gansu Province's development, and the dry farming water-saving is the eternal theme of Gansu agricultural sustainable development. In recent years, intensify reform in Gansu, has walked out a successful way in the agricultural water-saving. Using the integrated river basin governance as opportunity, the total water-using quantity was regarded as rigidity to retrain, distributed to counties (districts), irrigated areas, towns, associations, groups step by step. Agricultural water price was substantially increased, with the surface water price from about $0.1RMB/m^3$ to more than $0.2 RMB/m^3$, and the ground water from zero to more than $0.1RMB/m^3$. Simultaneously, the difference water prices and over-quota water progression price markup were carried out. The transaction of water rights was encouraged to impel the peasant to establish the consciousness of saving-water. The regulatory documents were formulated to standardize the scope, condition, mode, program etc. of agriculture water-rights transaction, to guarantees the transaction of water rights is carries out in order. The pattern of farming was optimized and adjusted, reducing the high water-consumption crop, increasing economic crops with high benefit and low water-consumption, developing industrialized agricultures such as green house. The relative engineering and measuring facility were comprehensively improved, with the anti-seepage of canal system and the enforcement of dynamo-electric well, developing high-efficient water-saving irrigation and overall metering facilities. The water fine-grained management has realized, and obvious water-saving effect has obtained: water-using rate in the irrigation area by river water has brought up to 0.57 from 0.52, and by well water up to 0.84 from 0.76. Although the water price has increased, the proportion that the water rate expenditure accounted for the cost lasts decline, and the farmers' income has gone up. The peasants express, the used water is few, and it is few to till land, but the income is many, and life is better.

• Journal of Korea Water Resources Association
• /
• v.48 no.3
• /
• pp.149-158
• /
• 2015

It is well known that emergency outlet works have to be provided for the safety of dams. However, concept of emergency outlet works did not applied for the design of the most dams in Korea. Korean design standard for low-level outlet works does not provide enough design criteria which could be used in design of emergency outlet works. In this research, as-built status and hydraulic design criteria of outlet works, such as drawdown rate or hydraulic pressure due to the impounded water depth, were examined. Another relationship between drawdown rate and the dam slope stability was also examined with SEEP model. It was found that 25% reduction of impounded water depth decreases the pressure forces about 50%. Therefore, outlet works should be designed to drawdown properly at the beginning of the emergency. Seepage analysis of dam bodies showed that most of Korean dams could safely stand for 1m/day drawdown rate. Higher drawdown rate could result high discharge so the drawdown rate must be related with the flood risk of downstream. Finally, multi-stage design was recommended that faster discharge for the initial 25% of water depth in 7-10 days than the rest of it in 1-2 months.

• Journal of the Korean GEO-environmental Society
• /
• v.10 no.7
• /
• pp.67-79
• /
• 2009

Although readjustment of monitoring system for existing fill dam maintenance is needed by the sustainable increasing of the abandonment rate of monitoring devices by malfunction through the life-cycle of dam, monitoring plans for long-term dam safety has relied on the experience and the opinion of minor expert group without systematic and quantitative analysis on the failure modes and the priority order of monitoring devices on maintenance. In this study the priority order of monitoring devices of existing 5 fill dams was evaluated quantitatively based on the preceding study (Andersen et al, 1999) and the result recommended the establishment of real-time monitoring system for seepage, pore pressure and crest settlement as the readjustment plan for existing fill dam monitoring system. This readjustment plan matches well with the recommendation of PWRI (1984), JCOLD (1986) and the results from Bagherzadeh-Khakkahali and Mirghasemi (2005).

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.83-83
• /
• 2023

댐의 침투수량은 준공이후 댐 안전성 확보를 나타내는 지표 중의 하나이며, 유지관리를 위해 침투수량 측정을 실시하여 관리를 하고 있다. 댐 타입별로 침투수량에 대한 허용치와 관리기준치는 다르지만, 기본적으로 댐에서 발생되는 침투수량은 측정범위를 넘지 않도록 관리를 하고 있다. 댐의 침투수량 측정은 댐 하류에 누수집수벽을 설치하고 댐에서 발생되는 침투수량을 집수한 후 삼각위어를 통하여 침투수량을 측정하고 있다. 이러한 침투수량 측정은 대부분의 댐에서 실시간으로 자동측정하고 있지만, 경우에 따라 미계측 구간이 발생되어 댐 유지관리 측면에서 미계측에 대한 원인분석이 필요한 실정이다. 일반적으로 침투수량의 미계측 원인은 계측기기, 삼각위어, 누수집수벽, 기초지반 등 다양한 원인이 있지만 명확한 원인을 찾기는 어려움이 많다. 특히, 댐 침투수량의 경우 지하수위, 댐 표면 우수, 침투수가 같이 측정되기 때문에 원인분석을 위해서는 다양한 검토가 필요하다. 본 연구의 표면차수벽형석괴댐은 누수집수벽을 통하여 침투수량을 측정하고 있으나, 일부 구간 미계측 부분이 발생하여 기초지반, 댐체 하류사면, 여수로와 댐체 접합부를 통한 누수를 원인으로 추정하였다. 이를 조사하기 위하여 전기비저항 탐사, 시추조사, 수압시험, 지하수위 측정 결과를 이용하여 누수발생 추정위치를 찾고, 침투수량이 미계측되는 원인을 분석하고자 하였다. 전기비저항 탐사는 여수로 접합부, 누수집수벽 상·하류 구간을 선정하여 측정한 결과 상·하류 저비저항대가 존재하는 구간을 추정할 수 있었다. 수압시험 결과 기초암반은 2.3 ~ 21.3 Lu(3.65×10^-5 ~ 3.65×10^-4 cm/sec)의 범위로 누수 가능성이 있는 높은 투수성을 갖는 부분을 확인할 수 있었다. 전기비저항 탐사, 수압시험, 지하수위 측정을 통해 누수집수벽 기초지반 누수발생 원인분석 결과 누수집수벽 기초암반을 통한 누수로 누수집수벽에 댐체를 통한 침투수량이 저류되지 못하는 현상이 발생하기 때문인 것으로 판단되었다. 침투수량계의 정상화를 위해서는 조사를 통해 확인된 누수집수벽 기초암반 누수구간의 그라우팅 보수보강이 필요함을 확인하였다.