Abstract:

Double-row of piles is a new support structure of the deep foundation pit. But its design method is not simple and effective. By means of basic thought of the beam of Winkler foundation, and on the premise of neglecting the friction effect in vertical and space effect between pile and soil, this paper analyzes the mechanical mechanism of support structure of double-row of piles and builds plane bar finite element model based on the effect of pile-soil effect for double-row of piles firstly, and then study the distribution of soil pressure and elastic resistance coefficient around the key parameters of plane bar finite element model of double-row of piles. Considering the critical distance of traditional slip plane of soil behind pit increased by the tension of coupling beam, the distribution law of soil pressure by slip proportional coefficient is obtained. In view of the uncertainty of positive analytical value for elastic resistance coefficient, the value of elastic resistance parameter is proposed by using the optimization method of displacement back analysis. Finally, on the basis of solving steps of optimal criterion function for displacement in bar finite element and back analysis, the doublerowpile and doublerowpileparameter calculation program are compiled respectively; and corresponding engineering calculations are performed. The results show that the calculated displacements are consistent with monitoring displacements, internal forces accord with code requirements and elastic resistance coefficient is accurate comparatively.

Key words: double-row piles, mechanism, elastic resistance coefficient, displacement back-analysis