impact-BNC²³⁶²¹³⁺¹ 例句 According to the engineering characteristics of the impact- echo technique and the grouted tendon duct, the test procedure for voids in post- tensioned grouted metal ducts is designed. 根据灌浆孔道施工的工程特点，研究设计了一套测试后张金属灌浆孔道内部空洞的工作方案。 cnki