TABLE OF CONTENTS A number of investigations must be undertaken prior to the design and construction of an excavation. These include the drilling of soil borings and developing of Geotechnical Reports, the performing of Pre-Construction Surveys of adjacent properties and utilities, and the analyzing of the location of those utilities to verify potential interferences.
Prior to the design and installation of any underground improvement, an analysis of subgrade materials and conditions must be performed. This is usually done by drilling test borings and performing lab and field tests to characterize the subsurface conditions and ascertain various parameters of the soils. While borings are not always necessary, some form of subsurface investigation must be performed. The reliance on shallow test pits should only be undertaken when local knowledge of the area can supplement and confirm the findings of the test pits.
Soil borings are taken to develop an understanding of strength parameters of the soils and ground water conditions and document any incidence of contamination which may be evident. Borings can be undertaken in a number of ways to produce meaningful information. This chapter will not delve into the many and varied methods of drilling soil borings, but will concentrate on the useful data which should be available from those borings.
A geotechnical report which is helpful to both the designer and constructor of a shored excavation will include the following materials:
A listing of all soils encountered, described in accordance with a well recognized soil classification system such as...
