A Study on the Excavation Support Safety of Hand-dug Retaining Pile in Taichung

[ILOSH107-S305]

Abstract

  The pebble and gravel strata prevail in most areas of Taichung. Since diaphragm wall, sheet pile, and other earth retaining systems are unsuitable in such strata, hand-dug retaining pile, an unique retaining wall system, is often used in the pebble and gravel strata. As the hand-dug retaining pile requires workers to work in a narrow space that is 10-20 meters beneath the surface, accidents could happen if the sidewall protection or security measures are not implemented properly.

  The purpose of this study is to compile and analyze the engineering properties of the pebble and gravel strata in Taichung and to develop a sidewall protection method to evaluate its safety and stability. The outcome of this study is expected to improve the safety measures when constructing the hand-dug retaining pile. The research items include the collection and analysis of the past occupational accidents when constructing the hand-dug retaining pile, investigation of the current construction methods for the hand-dug retaining pile, and a discussion of the construction safety problems and the improvement measures. Based on the compiled subsurface information, specifically for the engineering properties of the pebble and gravel strata, a sidewall protection measure using concrete lining in the excavated opening will be developed and recommended. Finally, the construction procedure and safety guidelines for the hand-dug retaining pile will be proposed.

  The expected construction procedure and safety guidelines for the hand-dug retaining pile will provide workers with the basic knowledge for construction, which will in turn ensure their safety and reduce the occurrence of occupational accidents. Meanwhile, the guidelines will also allow the contractors to use this method with more confidence and higher effectiveness before better construction methods are developed.

Keywords: Hand-dug retaining pile, Pebble and gravel strata, Occupational accident, Construction safety