摘要
平行地震波法已被成功用于探测既有桩基的埋置深度,但该方法对桩基缺陷的探测效果尚不明确。设计并开展了大比例尺模型桩平行地震波测试试验,研究不同缺陷对应的应力波分布特征,并着重探讨桩-孔距和桩顶激振位置对应力波传递规律的影响。试验结果表明,测试钻孔紧邻受检桩时,平行地震波方法能有效识别桩身严重缺陷,桩-孔距增大将大大增加桩长和缺陷判别的难度。断桩和缩径可引起波速下降和初至时间延长,桩身轻微缺陷对应的应力波组异常特征不显著。当桩端持力层为坚硬基岩时,桩底沉渣可导致桩身初至波拟合直线斜率出现二次突变。对于桩身局部截面存在缺陷的情况,当缺陷靠近桩身应力波最短传递路径一侧时,初至波异常特征相对更加明显。
The parallel seismic method has been successfully used to detect the depth of the existing pile,but the effect of this method on detecting the pile defects is not clear.In this paper,a large-scale model pile experiment was designed and carried out to analyze the stress wave transmission corresponding to various defects,and the influence of test distance and excitation position on the stress wave transmission was further discussed.The results show that the parallel seismic method can effectively identify the serious defects when the test borehole is close to the test pile,and the increase of test distance will greatly increase the difficulty of detecting pile length and defect identification.The broken pile and the necking can cause the decrease of wave velocity and the prolongation of the first arrival time,and the abnormal characteristics of stress wave group corresponding to the slight defects are not significant.When the bearing stratum of the pile is hard bedrock,the sediment at the pile tip may lead to the second mutation of the slope for the fitting line of the first break wave.When the defect is close to the shortest transfer path of stress wave,the abnormal characteristics of first break wave are more obvious.
作者
杨军
孙晓立
卞德存
邵继喜
YANG Jun;SUN Xiao-li;BIAN De-cun;SHAO Ji-xi(Guangzhou Municipal Engineering Testing Co.,Ltd.,Guangzhou,Guangdong 510520,China;Guangdong Provincial Research Center for Testing and Monitoring Technology of Prefabricated Underground Structure,Guangzhou,Guangdong 510520,China;School of Civil Engineering&Transportation,South China University of Technology,Guangzhou,Guangdong 510641,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第3期874-881,共8页
Rock and Soil Mechanics
关键词
平行地震波
桩基础
缺陷
现场试验
parallel seismic method
pile foundation
defect
field experiment
