基于大比例静力模型试验的高强度桩复合地基加筋垫层分析

Analysis of reinforced cushions in high-strength concrete pile composite foundation based on large-scale static model tests

为研究高强度桩复合地基加筋垫层的作用机理与筋带拉力的计算方法,采用一套自制的桩土差异沉降控制装置,进行了4组不同桩帽尺寸的大比例静力模型试验。测试了各级荷载作用下的加筋垫层筋带拉力,分析了筋带拉力的大小及分布随荷载增加的变化规律。结果表明:随桩顶和桩间土沉降差增加,筋带拉力逐渐增大,筋带拉力最大值出现在桩顶位置;随着桩帽覆盖率增加,桩间土范围内筋带拉力缓慢减小,桩顶范围筋带拉力变化较大,先增大后减小。加筋垫层的破坏模式表现为桩帽边缘的筋带断裂。

To study the mechanism of reinforced cushions and the method for calculating bar tensions, four groups of large-scale static model tests are carried out by means of a self-designed equipment system to control the differential settlement between piles and soil. The bar tensions in the reinforced cushions under different loading levels are tested. The variation rules of magnitude and distribution of tensions with the increasing loadings are analyzed. The test results show that the bare tension gradually increases with the increase of settlement differences between pile top and soil between piles, and that the maximum one occurs at pile top. With the coverage expanding of the pile cap, the bar tension in the soil between slowly decreases, and that at the pile top sharply changes, following a rule of increasing at the beginning and decreasing at the end of the settlement process. The failure mode of reinforced cushions is represented by the fracture of bar strip along the pile cap.