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针对常规楔形桩桩底进行注浆或夯扩施工形成的扩底楔形桩,具有单位材料利用率高、竖向桩侧摩阻力和桩端阻力较常规等截面桩高的技术优点。然而针对该新型桩竖向承载力提高幅度的定量试验研究相对较少。基于室内模型试验方法,开展两种桩周土(砂性土和黏性土)情况下扩底楔形桩竖向抗压承载力特性试验,测得桩顶荷载-沉降关系曲线,不同荷载等级下桩侧摩阻力、桩端阻力的分布规律及分担比;同时,开展等体积混凝土用量情况下的常规扩底桩的竖向抗压承载力特性试验作为对比分析。研究结果表明,试验条件下,砂性土中,等混凝土用量扩底楔形桩的极限承载力约为常规扩底桩的1.25倍;黏性土中扩底楔形桩和常规扩底桩的极限承载力比砂土中分别提高了11.1%和66.7%。
The wedge-shaped piles that are formed by grouting or ramming expansion of conventional wedge-shaped pile bottom have the technical advantages of high unit material utilization, vertical pile side frictional resistance and pile end resistance higher than the conventional sectioned piles. However, there are relatively few quantitative tests for improving the vertical bearing capacity of the new pile. Based on the indoor model test method, the vertical compression bearing capacity characteristics of wedged piles with two kinds of piles surrounding soil (sand soil and cohesive soil) were studied. The load-settlement curve of pile top was measured. Under different load levels Pile side friction resistance and pile tip resistance distribution law and share ratio. At the same time, carrying out the test of vertical compressive bearing capacity of conventional expanded-piles under the condition of equal volume of concrete used as contrast analysis. The results show that under the test conditions, the ultimate bearing capacity of wedge-shaped piles with equal amount of concrete in sand soil is about 1.25 times that of conventional expanded piles; and the ultimate bearing capacity of wedged piles and conventional expanded piles in clay The force increased by 11.1% and 66.7% respectively compared with sand.