A Study of the bearing capacity of pre-bored PC pile based on SPT N values - a case of pile load tests in Ta Lin power station site

• Main Authors: Min-Chu Tsao, 曹敏莒
• Other Authors: Kuo-Hung Tseng
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/30604628308148016352

碩士 === 國立高雄第一科技大學 === 營建工程研究所 === 101 === This study used results of the pile load test obtained from construction sites in Talin Power Plant and China Steel Corporation to analyze the soil characteristics and to discuss the bearing capacity of pre-bored PC piles. It also refer to variant formulas for evaluating pile bearing capacity by N values of soil to derive applicable empirical formula by regression analysis. In compare to former empirical formulas and cases as well as cross-checking parameters, the results is applicable for reference on design, planning, construction characteristic, improvement mechanism, scope of application and specifying construction parameter of areas with similar environmental factor and soil condition. The results are also useful on design and construction of pre-bored PC piles in Taipower’s projects or other construction projects to save cost and expedite work. For the side resistance of ultimate load capacity of pre-bored PC piles, the results show that α value (i.e., f/N) varies with the depth of pile. By analyzing data collected from pile load tests, the formula of side resistance was derived on the basis of the relation between α and N as well as the correlative function of α and depth d. With identical method to derive tip capacity, then, the formula of ultimate load capacity (Qu) of pre-bored PC piles is concluded as follows, Qu＝10*N*Ab +Σα*NS*LS*Φ (sandy soils) +Σ NS*LS*Φ (clay) For verification, the data taken from related load test cases were substituted into derived formula and empirical formulas in Building Technical Regulations (2001), Japanese Seismic Design Specifications for Highway Bridges (1996) and CSC method (2008), and apply comparative analysis approach to investigate the differences on varied bearing capacity formulas evaluated by N values of soil. Then, the ultimate bearing capacity formula obtained in this study was verified.