Research on the testing method for grouting plumpness of prefabricated structural sleeve based on piezoelectric principle
In order to solve the technical challenges of high cost and difficulty in real-time detection of the sleeve grouting fullness in prefabricated structures,the detection method and device based on the piezoelectric testing principle were developed,and relevant material tests,model tests,and engineering applications were carried out.First,the influence of grouting material type and setting time on the piezoelectric test results was investigated by electrical properties test of grouting materials.Then,the effectiveness of the piezoelectric method for testing grout leakage defects was analyzed through the grouting-leakage cycle test of transparent sleeves.Furthermore,through prefabricated model tests,the threshold of the piezoelectric method for judging the grouting plumpness was determined.Finally,relying on the prefabricated bridge project of the connecting line between Dongxiao South Road and Guangzhou South Railway Station,the effectiveness and practicality of the piezoelectric method for testing grouting plumpness were verified.The research results show that the resonant voltage measured by the piezoelectric sensor is significantly reduced after being buried in the grouting material,and the voltage value generally remains stable within 60 minutes.Afterwards,as the setting time increases,the voltage value increases and gradually approaches the initial voltage value before the test.In the grouting-leaking cycle test,whether the sensor is laid horizontally or vertically,the resonant voltage shows obvious changes,indicating that the piezoelectric method is less affected by the sensor laying mode.For the case of full grouting in the sleeve,the ratio of the measured voltage to the initial voltage before grouting is less than 0.4,which can be used as the threshold for judging the grouting plumpness.The engineering application results indicate that the piezoelectric method is convenient for field operation,can guide on-site grouting for defective sleeves,and meet the quality control requirements during the grouting process of prefabricated structural sleeves.The research results provide a new approach and practical reference for solving the quality detection problem of sleeve grouting.
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