• Advances in concrete construction
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• v.13 no.5
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• pp.395-410
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• 2022

This study collected the results of material tests and full-scale pumping tests using 127 types of concrete mixtures with compressive strength ranging from 24 to 200 MPa. The results of 242 material tests showed high correlations between the viscosity of the lubricating layer and concrete, between the slump and the yield stress of concrete, between the water-binder ratio and the viscosity of lubricating layer, and between the time required to reach 500 mm of slump flow and concrete viscosity. Based on these correlations, pumpability was predicted using 101 pumping test conditions, and their accuracy was compared to the actual test results. When the rheological properties of concrete and the lubricating layer were directly measured, the prediction result showed the highest accuracy. A high accuracy can be achieved when the measured viscosity of the lubricating layer, a key determinant of concrete pumpability, is reflected in the prediction of pumpability. When measuring rheological properties is difficult, the slump test can be used to quantitatively predict the pumpability despite the lower accuracy than those of other prediction methods.

• Journal of the Korean GEO-environmental Society
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• v.14 no.8
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• pp.11-21
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• 2013

In-situ test to find the change of $Fe^{2+}$ and $Mn^{2+}$ concentrations and ion contents in groundwater was conducted during two pumping tests at the riverbank filtration site, where is the riverine area of the Nakdong River in Changnyeong-Gun. Groundwater was sampled at one pumping well and 10 monitoring wells during a 5 steps drawdown pumping test with the rates from $500m^3/day$ to $900m^3/day$ and a constant pumping test with $800m^3/day$. The change in ion concentration of groundwater was more remarkable during a step drawdown pumping test than a constant pumping test. Especially, the decrease in $Fe^{2+}$ and $Mn^{2+}$ concentrations was distinct in a step drawdown pumping test and it happens predominantly along the direction that the radius of pumping influence was small due to a good aquifer connectivity to a pumping position. The precipitation and the oxidation of iron and manganese were caused by an air inflow and a disturbance in groundwater flow due to an abrupt change in pumping rate. The pumping rate and spatial distribution of an aquifer around a pumping well need to be considered as an important factor for the development of in-situ iron and manganese treatment technology.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.415-422
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• 1999

A series of crosshole tests was conducted to evaluate the mechanical characteristics of railway subgrade materials which has been experiencing mud-pumping. The shear wave velocity profiles of mud-pumped sites were compared with those of adjacent intact sites. The shear wave velocities of mud-pumped layers are less than 150 m/sec.

• Journal of the Korea Institute of Building Construction
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• v.13 no.4
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• pp.400-406
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• 2013

In high-rise buildings, high-strength concrete is widely used to reduce the section of structure members under axial load. Also, the price increase of materials is very important item in the high-rise buildings. Especially, concrete used high-pressure pump due to consecutive structural assembly. Unlike slump type of ordinary concrete, high strength concrete has different properties of concrete pumping due to viscosity. However, there have been no Korean studies on the pumping properties of high strength concrete. Therefore, this paper measures the friction factor of high strength concrete with changes in the pressure of concrete pumping. We analyzed the trends of the friction factor based on changes in the pressure of concrete pumping, and then calculated the quantity of concrete deposited for each specified concrete strength and location of placement. After comparing these results with the quantity of concrete deposited measured in field, we evaluated the pumping properties of high strength concrete. Through the tests and the review, we attempt to suggest some basic information for the In-Situ application of high strength concrete.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.32-37
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• 1998

In this paper, the role of intermediate cover soils with respect to the leachate and gas flow is investigated from various field investigations and the hydraulic conductivity of the disposed waste is obtained using pumping and slug tests. From the results of field investigations, it was found that the flow of leachate and gas is prevented by the buried cover soils. The hydraulic conductivities of field pumping test and slug tests are well matched and stayed in the range of hydraulic conductivities of well compacted wastes in the literature.

• Journal of Soil and Groundwater Environment
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• v.12 no.3
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• pp.36-43
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• 2007

In the case of single well pumping tests the storativities are generally overestimated. To compensate these errors, the effective wellbore radius should be introduced as a distance to an imaginary observation well in the time-drawdown analysis. Effective wellbore radius can be calculated through step drawdown tests or using skin factor equation. But both are of trial-and-error methods guessing real storativity values and, therefor, are difficult to apply to the field conditions. An equation was developed to estimate effective wellbore radius from storativity values obtained from pumping well data. For this study, a total of 136 time-drawdown data set were used to derive the equation. The effective wellbore radius were estimated first by changing them till the storativity values obtained from the pumping-well data match the ones based on the observation-well data. Then the equation was regressed from the relation between effective wellbore radius and the storativity values obtained from the pumping-well data. It is believed that the equation would be useful in estimating effective wellbore radius from the single well tests.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.99-109
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• 1999

In the case of domestic general waste landfills, cumulated leachate level is often formed in the landfill due to the waste of high moisture content and it becomes important to characterize the hydraulic properties of the disposed waste. Although many hydrologic studies have been peformed for leachate barriers and pheriperal subsurface environments, few studies have been done to investigate the hydraulic property of the disposed waste and cover soils and to analyse the leachate flow behavior within landfills. In this paper, the geotechnical properties of the waste and buried cover soils are identified through the field experiment including pumping and slug tests. The results of various tests show that the field density of the cover soils is somewhat higher than the maximum laboratory density of cover soils and the vertical flow of leachate and gas in the landfill is prevented by the buried cover soils. The hydraulic conductivities of field pumping test and slug tests are well matched and stayed in the range of hydraulic conductivities of well compacted wastes in the literature.

• The KSFM Journal of Fluid Machinery
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• v.4 no.4 s.13
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• pp.16-21
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• 2001

The field tests on the waterhammer were carried out for PalDang intake pumping station of the metropolitan water supply 5th stage project. The pumping station was equipped with the pump control valve as the main surge suppression device and the surge relief valve as auxiliary. However, the pump control valve had not been early controlled in the planned closing mode, and the slamming occurred to the valve which abruptly closed during the large reverse flow. Because the pressure wave caused by the pump failure was superposed on the slam surge, the upsurge increased so extremely that the shaft of the valve was damaged. It was desirable that the surge relief valve was installed in the pumping station or near the pump exit for the delay of response. After reforming the oil dashpot of the pump control valve, the sliming disappeared and the measured pressure was in fairly good agreement with the results of simulation. In case of three pumps for ${\phi}2,600$ pipeline being simultaneously tripped, the pressure head in the pumping station increased to 95.6 m, and the upsurge caused by the emergency stop of four pumps for ${\phi}2,800$ pipeline was 89.6m. We concluded that the pumping station acquired the safety and reliability for the pressure surge.

• Advances in concrete construction
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• v.16 no.5
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• pp.231-241
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• 2023

The purpose of this study was to evaluate the practical application of high-flowing concrete for a steel-concrete panel (SCP) module for a liquefied natural gas (LNG) storage tank. We evaluated the physical properties and filling performance of the developed concrete for the SCP module. First, slump tests were performed to evaluate the performance of the proposed standards for the filling tests. All the concrete mixes showed satisfactory performance. Based on the results of the previous study, the reliability of the required time measured using the T₅₀₀ test and the rheometer results measured before and after pumping was 0.94, indicating that segregation and blocking should not occur. L-box and U-box tests were conducted before and after pumping. All the recommended standards showed satisfactory performance. The SCP structural module for LNG storage tanks was fabricated to a full scale to evaluate its practical application at the final site. Satisfactory filling performance was confirmed for all the specimens.

• International Journal of Concrete Structures and Materials
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• v.8 no.4
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• pp.269-278
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• 2014

When concrete is being transported through a pipe, the lubrication layer is formed at the interface between concrete and the pipe wall and is the major factor facilitating concrete pumping. A possible mechanism that illustrates to the formation of the layer is the shear-induced particle migration and determining the rheological parameters is a paramount factor to simulate the concrete flow in pipe. In this study, numerical simulations considering various rheological models in the shear-induced particle migration were conducted and compared with 170 m full-scale pumping tests. It was found that the multimodal viscosity model representing concrete as a three-phase suspension consisting of cement paste, sand and gravel can accurately simulate the lubrication layer. Moreover, considering the particle shape effects of concrete constituents with increased intrinsic viscosity can more exactly predict the pipe flow of pumped concrete.