Study Bearing Capacity of Revolving Digging Cast-in-Place Bored Pile Through Load Transfer Method
|Keywords||Auger bored pile Load transfer method Three line model Pile settlement Vertical bearing capacity|
Auger bored pile in loess area is a unique pile, the use of rotary drilling process into the hole by hole wall rough, to some extent, improve the skin friction. This article from the eastern outskirts of Xi'an, a typical example of a static load of departure, in-depth analysis of single pile under vertical load the load transfer process variation and load - After settling characteristics, respectively, of the upper and lower layers of unsaturated loess soil layer corresponding saturated play pile lateral friction characteristics for further analysis, based on different layers exhibit different stress-strain relationship proposed settlement of the pile lateral friction and improved load transfer displacement model - with varying soil deformation pile lateral friction three fold model. In this model, the stiffness of the pile body side friction coefficient ks2i pile of soil in plastic phase (s1i-s2i) can be positive, negative or zero can the concept of linear elastic can fully plastic model, softening and hardening model models are unified. For Q ~ s curve generally showed slow variants, no obvious damage to the pile of feature points as well as those on the upper part of the settlement is extremely sensitive to the structure should be based on the allowable pile settlement control. The proposed settlement on top of the pile pile vertical bearing capacity calculation method of analysis, using the \Aitken iterative method to calculate the settlement were top of the pile in the elastic, elastic-plastic or plastic state, such as different levels of state corresponding to the top of the pile load values ??deduced settlement and bearing capacity of the pile between the series formula for representing comprehensive simulation pile - soil interaction mechanism, in order to achieve the settlement amount to the pile bearing capacity of the pile to control the idea. Finally, the improved load transfer model - three line model instance validation. In the southern suburbs of Xi'an loess area teaching building site of a static load test data analysis among the first end of the elastic line segments corresponding to the amount of deformation as the elastic deformation of pile threshold s1i, then relatively stable trend of plastic segments fitted to the points a horizontal line, the line between the measured qs ~ s plastic deformation of the intersection as the threshold s2i. Pile stiffness coefficient of friction with ks2i ks1i the magnitude of the value of the elastic and plastic segment segment slope. Two corresponding major soil qs-s relationship with the development trend of the curve presented in this paper pile friction improvements three line model agree well. The proposed settlement in accordance with the pile bearing capacity controlled southern suburbs of Xi'an iterative calculation method using examples validate a teaching laboratory building, the calculated value of the pile load is compared with the actual observations, the results are more consistent with the curve Q ~ s. And fast convergence. Description This method can be used to guide engineering practice, and has good practical value.