Plastic Pipe Design # 2006 Washington DC
The Reclamation table of E′ (Modulus of Soil Reaction) values for use in estimating the deflection of buried flexible pipe was first published in 1977. The E′ value represents the stiffness of the embedment soil placed on the sides of the pipe. The table gave E′ values that depended on soil classification and placement density. A new 2006 Reclamation Table of E′ values is presented as a revised and updated version of the 1977 table. The 2006 E′ table is based on vertical deflections, rather than horizontal deflections, and on new data. The new table has been slightly reorganized, soil classifications updated, and the crushed rock category clarified. A composite E′, based on both the embedment soil and trench wall material, can be used when very stiff or very weak trench walls are encountered. The Reclamation Equation was used to develop the E′ values. Accordingly, the E′ values should be used only with the Reclamation Equation to estimate the vertical deflection of flexible pipe.