【摘要】 为更好地服务于钢管混凝土桩的低应变测试,文章建立钢管混凝土桩和混凝土桩三维有限元模型,对钢管混凝土桩和混凝土桩的低应变瞬态动测响应进行数值模拟,得到完整桩和缺陷桩的速度响应结果。通过对钢管混凝土桩和混凝土桩的速度时域响应和速度云图的对比,分析钢管混凝土桩桩顶速度时域响应特性和桩身应力波传播特性,同时得出一类典型缺陷钢管混凝土桩顶速度响应曲线的规律。研究结果表明:钢管混凝土桩顶入射波存在与混凝土桩类似的三维效应,当桩身长度较短时,桩顶面距桩心距离越远点的桩底反射波到达时间越早,波峰值越小;应力波在钢管混凝土桩中传播较混凝土桩快,当速度波传播到达一定深度后速度波波前呈拱形传播,对应的混凝土桩呈平面传播;变模量钢管混凝土缺陷桩的缺陷反射波规律和混凝土桩一致,混凝土桩的缺陷反射波较钢管混凝土桩更为显著。更多还原

【Abstract】 A three-dimensional finite element model was established to simulate the wave propagation in low strain dynamic testing of concrete filled steel piles and concrete piles in order to get a better effect of low strain integrity testing of concrete filled steel piles. The velocity responses in time domain on the top of intact piles and defective piles were obtained. By comparing the velocity responses and snapshots of concrete filled steel piles with concrete piles,the characteristics of the velocity responses of intact piles and the transient waves in pile body,as well as the regularity of the velocity responses curves of defective piles were analyzed. The results reveal that the three-dimensional effects of incident waves of concrete filled steel piled are similar to concrete piled,and the further the point away from the pile center,the earlier the arrival time of the peak of reflected wave. On the contrast,the peak values have opposite relationship. Stress waves transient faster in steel than that in concrete,which results in the wavefronts in concrete filled steel piles presenting an arch shape when it reaches a certain depth and a plane shape in concrete piles. The regularity of defective reflected waves of concrete filled steel piles is the same as concrete piles,while the defective reflected waves of concrete piles are more remarkable.更多还原