According to analysis of an accident of drilling tools which were buried in the bottom of a 107 meters deep pore, authors introduce measures adopted in this accident, direct reasons causing this accident, and three adopted fishing methods, which are air-vibrate hammer method, high-pressure water method, and the small drill head cleaning cinder method.

Large diameter bridge pile construction by vibration hammer——A new technique for large diameter bridge pile construction;

In order to offer theoretical support for the research on amplitude modulation mechanism of vibration exciter,the paper tries to find out,based on the study of dynamics performance of vibration hammer,the regular pattern affecting piling efficiency as a result of amplitude of vibration exciter.

Automatic vibration hammer is designed according to resonance theory.

This paper presents the selection of vibratory hammer types for construction of the pile foundations of Dashengguan Changjiang River Bridge in Nanjing and the problems and solutions to the problems encountered in application of Model APE400B tandem vibratory hammers to the construction of the Bridge.

For this purpose,large vibratory hammers with an excitation force of more than 2 300 kN had to be used to complete the installation of the piles.