Experiment and calculation of vertical bearing capacity of large diameter belled pile

Abstract

Purpose–This paper aims to analyze the vertical bearing behavior of large diameter belled pile by carrying out static load test. Various calculation methods are used to calculate and determine the ultimate bearing capacity of large diameter belled pile.

Design/methodology/approach–(1) According to the calculation method of allowable bearing capacity of single pile, the design ultimate bearing capacity of test pile and the load classification of loading and unloading are obtained. (2) Q-S and S-lgQ curves are plotted in the light of the test data. end bearing and side friction of the test pile are analyzed and the ultimate bearing capacity is obtained. (3) The Van der Veen’ method, reversed slope method and three kinds of grey models are utilized to calculate the ultimate bearing capacity of the test pile. Eventually, the most precise method is determined by comparison and assessment of these calculated results.

Findings–(1) The Q-S curve of the large diameter belled pile has an apparent steep drop point, and the ultimate bearing capacity determined according to it is 16000KN. (2) The calculation results of the five methods show that the error of the result calculated by reversed slope method is the largest (23.23%). In general, the results calculated by the three grey models are more precise. Among these grey models, the best calculation effect is new information model (GM₂(1,1)) with the error of only 0.60%.

Originality/value–Due to complex stress distribution, applicability of bearing capacity calculation theory and design method, large diameter belled cast-in-place pile is rarely applied in the field of bridge. Therefore, the study on the experiment and calculation of ultimate bearing capacity of large diameter belled pile has prominent theoretical and practical significance for its reasonable design and application in bridge engineering.