摘要
基于一维应力波理论的低应变法广泛应用于新建桩基完整性检测。然而,针对铁塔桩基,由于铁塔上部结构的存在,会在界面上产生较为复杂的应力波,低应变法不能对输电铁塔基础结构的完整性进行判断。首先在传统低应变法的基础上提出双速度法,即在桩基侧面安装两个传感器,通过两个传感器测量的波形来判断桩基是否完整。最后,通过模型试验对比铁塔波形及有、无铁塔桩基的应力波的传播规律:当在桩顶施加动态荷载时,产生的下行波沿桩基向下传播,上行波沿铁塔向上传播,然后携带有桩基缺陷信号的应力波从桩底反射回来,另外携带有铁塔特征的应力波信号也从铁塔反射回来,它们有可能在传感器所在的地方合成,影响通过传感器得到的波形,进而影响桩基的判断。
The given paper has first of all made an introduction to the basic principle of the double velocity method. And,then,we have made a stressed introduction to the low strain method while emphasizing its chief advantage of non-destructive testing procedure of the pile foundations due to its low cost and convenience in operation based on the one-dimensional stress wave equation,by which the integrity of the wave pile can be judged by the phase change of the reflected stress waves. Nevertheless,the new pile foundation of the low strain method,or known as the double velocity method,can help to judge the wave pile integrity accurately,which is founded on the basis of the traditional low strain method but installed with 2 acceleration sensors on the side of its pile. It is due to its 2 accelerating sensors that can help the pile foundation integrated by the phase of the reflection wave equation. However,for the current transmission tower pile foundation,the traditional low strain method can no longer accurately identify and determine the integrity of the pile foundation. To solve the problem,we have built a model to simulate the transmission tower pile foundation under the different conditions to search for the rule of the waveform of the tower to the pile foundation according to the similarity ratio principle. The model test shows that,when the dynamic load at the top of the pile is applied to the model,the downward wave tends to propagate downwardly along the pile down,and,then,the upward waves with the pile defect tends to propagate along the tower up through reflection from the pile bottom,and then they would be reflected with the pile defect signals from the pile bottom in the form of the stress wave. Besides,the stress wave signals endowed with the characteristic features of the tower that can also be reflected from the tower,where they may be in the sensor synthesis,and,then,influence the waveform by the sensor,and,in turn,influence the evaluation of the pile foundation. The actual fact should be lying in that: The more complex the wave signals are reflected from the tower due to its complex waveform,the greater and stronger the influence of the waveform on the evaluation of the pile foundation defects.
作者
杨芒生
郭兆华
马键
黎凯旻
杨永
YANG Mang-sheng;GUO Zhao-hua;MA Jian;LI Kai-min;YANG Yong(Maoming Power Supply Bureau,Guangdong Power Grid Co.,Ltd.,Maoming 525000,Guangdong,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2020年第3期981-986,共6页
Journal of Safety and Environment
基金
广东电网有限责任公司科技项目(GDKJXM20162556)。
关键词
安全工程
岩土工程
模型试验
safety engineering
geotechnical engineering
model test
