Study On Influence Of Squeezing Effect On The Bearing Characteristics Of Uplift Pile In Sandy Soil

With the acceleration of urbanization in our country in recent years, the development and utilization of underground space has been developing rapidly, with the requirement of anti-uplift of buildings increasing day by day, the anti-uplift problem of underground structure increasingly prominent, Currently the uplift pile foundation is the most widely used anti-floating type. After pile construction, squeezing effect is produced under the dual function of stress and compaction, the actual bearing capacity of single pile and its design value may have big discrepancy, it has been proved by more and more engineering practice. In pile foundation design, how to properly consider the effect of squeezing effect of pile group, in order to establish a design theory with advanced technology and reasonable economy, has become a major problem faced by the academia and engineering field.This paper studies the following aspects:(1) To study the influence of squeezing effect on the load-bearing characteristics of uplift pile in sandy region, In the Interior, Author respectively conducted the non-squeezing soil model test of single pile, the squeezing soil model test of double pile, and the squeezing soil model test of pile groups. Through the test data, Author analysis of the relationship between load and displacement of model pile, axial force of pile and side friction of pile distribution rule. Test research shows that the uplift load characteristics of uplift piles are connected with piles of pile length and pile spacing.(2) In the squeezing soil model test of double pile, on the basis of redefining the squeezing soil coefficient of response compaction strength, thus building a new formula to calculate the pull-out bearing capacity of single pile. Analysis the measured and calculated value, verifying the rationality of the new formula has.(3) In the squeezing soil model test of pile groups, on the basis of considering squeezing effect, re-established a formulae for calculating coefficients of pile groups efficiency, so as to set up a simplified ion model to calculate the ultimate pull-out bearing capacity of single pile of pile groups system. Using squeezing soil coefficient correction coefficient of pile groups efficiency can well reflect the squeezing effect, the bearing capacity of uplift group piles is close to the measured values.