嵌岩桩承载变形特性的数值分析

Numerical analysis of bearing capacity and deformation about rock-socketed pile

嵌岩桩的单桩极限承载力高,现场试桩试验加载至极限状态代价和难度均较大,试验取得的数据较难全面反映嵌岩桩的承载变形特性。基于武汉绿地中心嵌岩桩试桩试验成果,采用ABAQUS有限元软件建立桩-土-岩共同作用模型,分析了基岩岩性、嵌岩深径比以及上覆土层厚度等对嵌岩桩承载变形特性的影响。数值计算表明,基于合理的本构模型、合理地参数取值,采用有限元方法对嵌岩桩试桩试验开展模拟分析,可以取得较为合理的拟合结果。基岩岩性、嵌岩深径比、上覆土层厚度对嵌岩桩的承载变形特性均有较大的影响。基岩岩性和嵌岩深度对上覆土层段侧摩阻力的发挥影响不大。嵌岩段的承载力是嵌岩桩总承载力的主要组成部分,但对穿越深厚上覆土层的嵌岩桩,上覆土层段桩侧摩阻力是嵌岩桩总承载力的重要组成部分,不应忽视。

The bearing capacity of rock-socketed pile is usually large, and it is difficult and expensive to obtained to the ultimate state on the field tests. The data obtained from the field tests are hard to reflect the bearing capacity and deformation of the rock-socketed pile. Based on the data of field tests at Wuhan Lvdi Center, ABAQUS finite element method is used to analyze the bearing capacity and deformation of the rock-socketed pile, which including the property of rock, depth-diameter ratio of the rock-socketed pile, and the upper soil covering. The numerical analysis shows that based on the reasonable constitute model, and the reasonable parameter value, the calculation results of FEM is consistent to the field measurements. The numerical analysis shows that, the above mentioned influencing factors are all important to the rock-socketed piles. The rock property and the depth-diameter ratio of socketed pile has little influence on the side friction of the upper soil covering. Bearing capacity of rock-socketed part is the main components of the bearing capacity of the whole pile; while to the pile with deep upper soil, the side friction of upper soil covering is a very important part of the bearing capacity of rock-socketed pile.