|
Consolidation is a process by which soils decrease in volume. It occurs when stress is applied to a soil that causes the soil particles to pack together more tightly, therefore reducing volume. When this occurs in a soil that is saturated with water, water will be squeezed out of the soil. The magnitude of consolidation can be predicted by many different methods. In the Classical Method, developed by Karl Terzaghi, soils are tested with an oedometer test to determine their compression index. This can be used to predict the amount of consolidation. Loess field in Germany Soil horizons are formed by combined biological, chemical and physical alterations. ...
Figure 1 Stress tensor A mature tree trunk may support a greater force than a fine steel wire but intuitively we feel that steel is stronger than wood. ...
Karl von Terzaghi (Prague, October 2, 1883 – Winchester, Massachusetts, October 25, 1963) was an Austrian civil engineer, called the father of soil mechanics. ...
Geotechnical engineers perform geotechnical investigations to obtain information on the physical properties of soil and rock underlying (and sometimes adjacent to) a site to design earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions. ...
When stress is removed from a consolidated soil, the soil will rebound, regaining some of the volume it had lost in the consolidation process. If the stress is reapplied, the soil will consolidate again along a recompression curve, defined by the recompression index. The soil which had its load removed is considered to be overconsolidated. This is the case for soils which have previously had glaciers on them. The highest stress that it has been subjected to is termed the preconsolidation stress. A soil which is currently experiencing its highest stress is said to be normally consolidated. Austrias longest glacier, the Pasterze, winds its 8 km (5 mile) route at the foot of Austrias highest mountain, the Grossglockner A glacier is a large, long-lasting river of ice that is formed on land and moves in response to gravity. ...
The process of consolidation is different from secondary compression, compaction, and other processes of volume reduction. This page is a candidate for speedy deletion. ...
Consolidation analysis
Classical Method This methods assumes consolidation occurs in only one-dimension. Laboratory data is used to construct a plot of strain or void ratio verses effective stress where the effective stress axis is on a logarithmic scale. The plot's slope is the compression index or recompession index. The equation for consolidation settlement of a normally consolidated soil can then be determined to be: This article is about the deformation of materials. ...
Effective stress (σ) is a value reflecting the strength of a soil. ...
A logarithmic scale is a scale of measurement that uses the logarithm of a physical quantity instead of the quantity itself. ...
where
- δc is the settlement due to consolidation.
- Cc is the compression index.
- e0 is the initial void ratio.
- H is the height of the soil.
- σzf is the final vertical stress.
- σz0 is the initial vertical stress.
Cc can be replaced by Cr (the recompession index) for use in overconsolidated soils where the final effective stress is less than the preconsolidation stress. When the final effective stress is greater than the preconsolidation stress, the two equations must be used in combination to model both the recompession portion and the virgin compression portion of the consolidation process.
Time dependency The time for consolidation to occur can be predicted. Sometimes consolidation can take years. This is especially true in saturated clays because their hydraulic conductivity is extremely low, and this causes the water to take an exceptionally long time to drain out of the soil. While drainage is occurring, the pore water pressure is greater than normal because it is carrying part of the applied stress (as opposed to the soil particles). written by AmerHydraulic conductivity, mathematically represented as , is a property of soil or rock, in the vadose zone or groundwater, that describes the ease with which water can move through pore spaces or fractures. ...
See also Soil mechanics is a discipline that applies the principles of engineering mechanics to soil to predict the mechanical behavior of soil. ...
In geology, diagenesis refers to all the chemical, physical, and biological changes undergone by a sediment after its initial deposition and during and after its lithification, exclusive of surface alteration (weathering). ...
References Coduto, Donald (2001), Foundation Design, Prentice-Hall, ISBN 0-13-589706-8 |
Feeds |
Contact