Geotechnical investigation of the river Nzoia lower course floodplain, Western Kenya

Abstract

This dissertation presents the results of geological and geotechnical investigations of the floodplain at the lower course of River Nzoia in western Kenya. The study was aimed at establishing the geotechnical characteristics of the soils and rocks in the study area and the information obtained used for both qualitative and quantitative evaluation of the type of ground treatment required for construction of Sigiri Bridge and other shallow foundation structures. The suitability of the ground for supporting shallow foundation structures has been established from the results of fieldwork and from laboratory studies. The sites have been classified into five categories according to Zaruba and Mendl (1976). The categories are; 1) Very suitable sites providing foundation soils that do not present any problem and a small width of footing is possible. 2) Suitable sites differing from those in the above category in that a problem does arise during excavation such that a wide footing is necessary. 3) Conditionally suitable sites, where the layout and the particulars of the structure must be adopted to the site conditionsA) Sites of low suitability, where foundations present so many difficulties that the construction costs increase steeply, and, 5) Unsuitable sites, where only exceptionally high costs can make a given construction work possible.