Prediction of Net Uplift Capacity of Single Pile with Variation of Ks Value

The paper pertains to the development of semi empirical approach to predict the net uplift capacity of single pile embedded in sand based on the fundamental concept of evaluating the unit shaft friction and then summing it up over the length of the pile. Two main factors that are important in using this approach namely the coefficient of lateral earth pressure coefficient (Ks) that may vary widely from Rankine passive to active earth pressure coefficients, Kp and Ka respectively and the pile –soil interface friction angle (δ). As such to the developed method the coefficient Ks is assumed to vary with depth from Kp to Ka, the variation being parabolic, linear or constant (average of Kp and Ka,). And for interpreting field tests, δ is considered to be 0.8. A comparative assessment of the net ultimate uplift capacity of pile so obtained from experimental and field data reported in literature and also from model tests conducted as a part of the present investigation show that the proposed method has an excellent potential in predicting the uplift capacity of piles embedded in sand. Keywords— model tests, piles, sand, uplift capacity

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