Overview

The following notation is used in this chapter:

2.1 Introduction

The purpose of this chapter is to discuss the different types of soil samples. Because the type of soil sample depends on the type of sampler and drilling operation, a brief introduction to subsurface exploration is provided in Sec. 2.2. The remaining sections then discuss the three types of soil samples that can be recovered from the subsurface exploration (Sec. 2.3), X-ray radiography (Sec. 2.4), soil structure (Sec. 2.5), and the standard practices for preserving and transporting soil samples (Sec. 2.6).

2.2 Subsurface Exploration

The general purpose of subsurface exploration is to determine the following (AASHTO 1996):

• Soil strata

  • Depth, thickness, and variability

  • Identification and classification

  • Relevant engineering properties, such as shear strength, compressibility, stiffness, permeability, expansion or collapse potential, and frost susceptibility

• Rock strata

  • Depth to rock

  • Identification and classification

  • Quality, such as soundness, hardness, jointing and presence of joint filling, resistance to weathering (if exposed), and soluble nature of rock

• Groundwater elevation

• Local conditions requiring special consideration.

There are different types of subsurface exploration, such as borings, test pits, or trenches. Table 2.1 (from Sowers and Royster 1978, based on the work by ASTM, Lambe 1951, Sanglerat 1972, and Sowers and Sowers 1970) summarizes the boring, core drilling, sampling, and other exploratory techniques that can be used by the geotechnical engineer.