From Engineering Geology, Second Edition
Geology is one of the most important factors in construction since construction takes place either at or below the ground surface. Hence, geology has an influence on most construction operations because it helps determine their nature, form and cost.
Open Excavation
Open excavation refers to the removal of material, within certain specified limits, for construction purposes. In order to accomplish this economically and without hazard, the character of the rocks and soils involved and their geological setting must be investigated. Indeed, the method of excavation and the rate of progress are influenced very much by the geology on site (Kentli and Topal, 2004). Furthermore, the stability of the sides of an excavation and the position of the water table in relation to the base level of an excavation are of importance, as are any possible effects of construction operations on the surrounding ground and/or buildings (Finno et al., 2005).
A Note on Slope Stability
The stability of slopes is a critical factor in open excavation. This is particularly the case in cuttings, as for instance, for roads, canals and railways, where slopes should be designed to resist disturbing forces over long periods. In other words, a stability analysis should determine under what conditions a proposed slope will remain stable. For a further note on slope stability, see Chapter 3.
Instability in a soil mass occurs when slip surfaces develop and movements are initiated within it. Undesirable properties in a soil, such as low shearing strength, development of fissures and high...
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Topics of Interest
Tunnels and Tunnelling Geology is the most important factor that determines the nature, form and cost of a tunnel. For example, the route, design and construction of a tunnel are largely dependent...
Highways The location of highways and other routeways is influenced in the first instance by topography. Embankments, cuttings, tunnels and bridges (viaducts) can be constructed to carry roads and...
4.2 Unsupported Excavations An unsupported cut with free slopes in soft cohesive soils are limited to very shallow depths (max. 3 m). Independent from the depth, however, unsupported excavations...
16. . : SLOPING AND BENCHING-1926 SUBPART P APP B (a) Scope and application. This appendix contains specifications for sloping and benching when used as methods of protecting employees working...
Retaining Methods For Excavation The simplest method of retaining the sides of an excavation in soil is to permit the soil to form a natural slope that will be stable even in the presence of water.
