Composite E' (Modulus of Soil Reaction)

摘要

The Modulus of Soil Reaction (E') represents the stiffness of the embedmentrnsoil placed on the sides of buried flexible pipe. E' is used to estimate the deflectionrnof the pipe due to dead and live loads over the pipe. E' varies with the type ofrnembedment soil and with the degree of compaction. The resulting support for thernpipe also depends on the width of the embedment soil and the stiffness of the insiturntrench walls. This resulting support can be represented by a composite E' thatrncombines the stiffness of the embedment soil and the trench wall soil. The compositernE' is the E' of the embedment soil modified by a Soil Support Combining Factor.rnThe Soil Support Combining Factors are given in a table that uses the ratio of therntrench width to the pipe diameter and the ratio of the E' values of the embedment andrnthe trench walls.rnThe history and development of the composite E' is discussed. A newrnproposed table of presumptive E' values of the insitu trench walls is presented.