oa Civil Engineering = Siviele Ingenieurswese - Some problems in road design under tropical conditions
In the limited space available, the paper, discusses some unusual soil conditions which exist in East Africa and which require special consideration in road design. The effect of the very low in situ densities encountered and the effect of compaction on design are considered. Areas exist where there are craters filled with rock and soil in various stages of weathering. The modulus of subgrade reaction is given, and also the method of construction over them. The lack of high water table and the high voids ratio of the soils is mentioned. Road design is based on standard C.B.R. modified by the group index method. Stone quarrying presents considerable difficulty due to the heterogeneous mixture of soft and hard rock in the same quarry. The danger of using soft stone bases is stressed. Mechanical stabilization cannot be used due to lack of sands and gravels. Other methods of soil stabilization for subbases are discussed, but economy prevents their general use.
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