微型钢管灌注桩的竖向承载性状研究

微型钢管灌注桩属于微型桩的一种,经常用于建筑物的基础加固工程。基于广州市白云区金沙洲某基础加固工程的微型钢管灌注桩静载试验成果,利用ABAQUS有限元软件建立钢管–核心混凝土–土–岩共同作用模型,探讨了基岩模量、嵌岩深径比、钢管壁厚等因素对微型钢管灌注桩承载力的影响。静载试验的数值模拟表明:对于上覆土层为软土的情况,微型钢管灌注桩虽是超长桩,但桩端阻力仍是承载力的主要部分;桩的承载力随基岩的弹性模量增加而增加,但并非线性关系,其增长趋势最终变缓;桩的竖向承载力随钢管壁厚增加而线性增加;嵌岩深径比对桩的竖向承载力基本没有影响。

Shaft bearing behaviors of micro cast-place piles with steel tubes

The micro cast-in-place pile with steel tubes is one of the micro-piles, which is often used in the foundation reinforcement of buildings. Based on the static load test results of micro cast-in-place piles with steel tubes in a foundation reinforcement project in Jinshazhou, Baiyun District, Guangzhou City, a model for the interaction between steel tubes, core concrete, soil and rock is established by using the ABAQUS finite element software. The influences of the modulus of foundation rock, the ratio of depth to diameter of rock socket and the thickness of steel tube on the bearing capacity of the micro cast-in-place piles with steel tubes are discussed. The numerical simulation of static load tests shows that the resistance of pile tip is still the main part of bearing capacity for super-long piles with overlying soft soil. The bearing capacity of piles increases with the increase of the elastic modulus of bedrock, but the nonlinear relationship leads to a slower growth trend. The vertical bearing capacity of piles increases linearly with the increase of the thickness of steel tube wall. It has little effect on the vertical bearing capacity of piles.