• Geotechnical Engineering
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• v.14 no.3
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• pp.25-46
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• 1998

This paper shows that there are the results of a series of model tests on the behavior of single pipe pile which is subjected to lateral load in, Nak-dong River sand. The purpose of the present paper is to estimate the effect of Non-homogeneity. constraint condition of pile head, lateral load velocity, relative density, and embedded length of pile on the behavior of single pile. These effects can be quantified only by the results of model tests. Also, these are compared with the results of the numerical methods (p-y method, modified Vlasov method; new ${\gamma}$ parameter, Characteristic Load Method'CLM). In this study, a new ${\gamma}$ parameter equation based on the Vlasov method was developed to calculate the modulus of subgrade reaction (E. : nhz.) proportional to the depth. The p-y method of analysis is characterized by nonlinear behavior. and is an effective method of designing deep foundations subjected to lateral loads. The new method, which is called the characteristic load method (CLM). is simpler than p-y analysis. but its results closely approximates p-y analysis results. The method uses dimensional analysis to characterize the nonlinear behavior of laterally loaded piles with respect to be relationships among dimensionless variables. The modulus of subgrade reaction used in p-y analysis and modified Vlasov method obtained from back analysis using direct shear test (DST) results. The coefficients obtained from DST and the modified ones used for the prediction of lateral behavior of ultimate soil reaction range from 0.014 to 0.05. and from 0.2 to 0.4 respectively. It is shown that the predicted numerical results by the new method (CLM), p-y analysis, and modified Vlasov method (new parameter) agree well with measured results as the relative density increases. Also, the characteristic load method established applicability on the Q-Mnu. relationship below y/D=0.2.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.476-481
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• 2009

Bi-directional load test is one of O-cell tests. The O-cell test is a system which may be used for performing static load tests on cast in situ reinforced concrete bored piles. The technique was devised and developed by Osterberg of Northwestern University(USA) and has been in use around the world. The principle of the method is that an O-cell is installed in a cast in situ bored pile base. Once the pile concrete reaches its design strength the cell is connected to an hydraulic pump and pressured. Pressurization causes the cell to expand, developing an upward force on the section of pile above the cell loads, pile movements and strains within the pile then enable the capacity of the pile and its load settlement curves to be ascertained. The O-cell pile load test with variable end plate is operated on second steps - the first step is to confirming end bearing capacity with variable end plate and the second step is similar to the conventional O-cell test. In the study, To calculate ultimate capacity of bi-directional load test using model with the pile with variable end plate O-cell.

• Journal of the Korean GEO-environmental Society
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• v.15 no.7
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• pp.59-66
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• 2014

Nowadays, some studies are performed in order to introduce the Limit State Design method widely used in foreign work sites. LRFD (Load Resistance Factor Design) method is widely used in the fields in which the data accumulation is possible - such as deep foundations, and shallow foundations, etc. The limit state design in the retaining walls is insufficient in the country owing to difficulties applying load tests. The limit state design method for retaining wall structures are studied based upon the National Retaining wall Design Standard legislated in 2008 by Ministry of Land, Transport, and Maritime Affairs. In this paper several retaining walls were calculated according to LRFD design criteria analysis using the general program with limit state design method and the factor of safety for sliding and overturning. Comparing with their results, the Taylor's series simple reliability analysis was performed. In the analysis results of retaining wall section, safety factors calculated by LRFD were found to be lowered than those calculated in current WSD, and it is possibly judged to be economic design by changing wall dimensions. In the future, pre-assessment of the geotechnical data for ensuring the reliability and the studies including reinforced retaining walls with ground anchor are needed.