TO EVALUATE THE COEFFICIENCE OF UNIT RESISTANCE FOR CALCULATING AXIAL RESISTANCE OF PILE USING PDA RESULTS

Abstract

Assessment of pile axial load capacity is extremely important in terms of technical and economic terms when orienting the application of pile foundation solutions for construction projects on soft soil. The predictive calculation of pile axial load capacity based on analytical methods gives rather scattered results. Therefore, at present, this work often has to combine with expensive field experiments.

The PDA test is one of testings gives good values about unit resistance along pile. We can use these results of PDA tests to evaluate the difference value of unit resistance from logical equation. The coefficence R_inter is suggested, which is .

Through initial analysis results based on 04 sets of PDA experimental data in 02 works, the value of R_f lateral resistance coefficient has a rather wide amplitude: R_f = 0.2÷1.9. The average value is at R_{f m} = 1.0 and is quite similar to the use of α coefficient of the Japanese Institute of Architecture, proposed in Appendix G, TCVN 10304:2014. In general, the results of the R_f analysis are similar in terms of rules compared with Tomlison's suggested values ​​of the coefficient α per c_u in cohesive soils and that of the Paris School of Bridges and Roads (ENPC) in sand layers.