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Ground investigation
Published in Jonathan Knappett, R. F. Craig, Craig’s Soil Mechanics, 2019
Jonathan Knappett, R. F. Craig
An adequate ground investigation is an essential preliminary to the execution of a civil engineering project. Sufficient information must be obtained to enable a safe and economic design to be made and to avoid any difficulties during construction. The principal objects of the investigation are: (1) to determine the sequence, thicknesses and lateral extent of the soil strata and, where appropriate, the level of bedrock; (2) to obtain representative samples of the soils (and rock) for identification and classification, and, if necessary, for use in laboratory tests to determine relevant soil parameters; (3) to identify the groundwater conditions. The investigation may also include the performance of in-situ tests to assess appropriate soil characteristics. In-situ testing will be discussed in Chapter 7. Additional considerations arise if it is suspected that the ground may be contaminated. The results of a ground investigation should provide adequate information, for example, to enable the most suitable type of foundation for a proposed structure to be selected, and to indicate if particular problems are likely to arise during construction. BS5930 (2015) provides a broad overview of the ground investigation process and is the recommended code of practice (supported by various technical standards for specific procedures) within the UK.
Foundations, ground slabs, retaining walls, culverts and subways
Published in Charles E. Reynolds, James C. Steedman, Anthony J. Threlfall, Reynolds's Reinforced Concrete Designer's Handbook, 2007
Charles E. Reynolds, James C. Steedman, Anthony J. Threlfall
The nature of the ground can be determined by digging trial holes, by sinking bores or by driving piles. A trial hole can be taken down to only moderate depths, but the undisturbed soil can be examined, and the difficulties of excavation with the need or otherwise of timbering and groundwater pumping can be determined. Bores can be taken very much deeper than trial holes, and stratum samples at different depths obtained for laboratory testing. A test pile does not indicate the type of soil it has been driven through, but it is useful in showing the thickness of the top crust, and the depth below poorer soil at which a firm stratum is found. A sufficient number of any of these tests should be taken to enable the engineer to ascertain the nature of the ground under all parts of the foundations. Reference should be made to BS 5930: Code of practice for site investigations, and BS 1377: Methods of test for soils for civil engineering purposes.
Classification of soils
Published in John Atkinson, The Mechanics of Soils and Foundations, 2017
Soil description is essentially a catalogue of what the soil is and it is helpful to have a simple scheme to describe the essential features. There are several such schemes published in National Standards and to some extent these reflect the characteristics of the most common soils in the region; you should look up the relevant standard for the region you will work in. In the United Kingdom these are the British Standards for site investigations (BS 5930:1999) and for soil testing (BS 1377:1990) but slightly different schemes are used in other regions. A simple and universal scheme for soil description is as follows:
Cross-linking of biopolymers for stabilizing earthen construction materials
Published in Building Research & Information, 2022
Sravan Muguda, Paul Neil Hughes, Charles Edward Augarde, Céline Perlot, Agostino Walter Bruno, Domenico Gallipoli
In this study, the effectiveness of cross-linking of biopolymers for soil stabilization was evaluated on a soil mixture used for manufacturing earthen construction materials like rammed earth or compressed earth. An engineered soil mixture was used comprising 20% refined kaolin, 70% sand and 10% gravel by mass (denoted as Soil 2-7-1) (Chemical analysis of the kaolin by X-ray fluorescence showed SiO2 47% and Al2O3 38%) was chosen for this study, as it suits the recommendations from a number of sources for earthen construction materials (Houben & Guillaud, 1994; Olivier & Mesbah, 1987) and following much previous work in this area using this mixture. As the engineered soil mixture is classified as Clayey Sand (SC) as per UK standard BS 5930 (2015), the engineering behaviour of this soil mixture can be considered representative of natural soils with similar physical properties. The physical properties of the unamended engineered soil mixture, namely, the Atterberg limits and linear shrinkage were determined in accordance to BS 1377-2 (1990) and compaction properties (using the 2.5 kg Proctor test) in accordance with BS 1377-4 (1990). Table 1 presents the physical properties of unamended engineered soil mixture.