5.01A Recomended Use for Trench Boxes ADS, （5.01推荐使用槽盒广告,）.pdfVIP

TECHNICAL NOTE TN 5.01 Recommended Use for Trench Boxes March 2009 Introduction Trench boxes provide a safer work area to install pipe in deep trenches, restricted right-of-ways, or in soils that have insufficient stability. This technical bulletin provides guidelines on how to maximize the structural stability and alignment of the ADS pipe system while using a trench box. While these guidelines will work for most cohesive and noncohesive native soils, highly unusual soil conditions may require further investigation or different techniques. General Considerations OSHA regulations should be carefully followed for all aspects of pipe installation, including those that involve trench boxes. If information contained in this document conflicts in any way with OSHA or other safety regulations, those requirements must take precedence. Some installations may not require trench boxes if the trench sidewall can be sloped adequately. The design engineer should provide specific guidance on acceptable slopes, but in no case should the trench wall slope be greater than the angle of repose of the native soil. ® The length of the trench box should be suitable for the pipe length. Standard length for ADS N-12 IB is19.7 ft (6m) although it may be possible to supply shorter lengths for use in shorter trench boxes. Subtrench Installations The most effective way to maintain a sound system is to provide a ‘subtrench’ within which to place the pipe and backfill. The bottom of the trench box should be