Search results
Results from the WOW.Com Content Network
This phenomenon of soil behaviour can be included in the Hardening Soil model by means of a dilatancy cut-off. In order to specify this behaviour, the initial void ratio, e i n i t {\displaystyle e_{init}} , and the maximum void ratio, e m a x {\displaystyle e_{max}} , of the material must be entered as general parameters.
This loss of soil structure causes it to lose its strength (the ability to transfer shear stress), and it may be observed to flow like a liquid (hence 'liquefaction'). Although the effects of soil liquefaction have been long understood, engineers took more notice after the 1964 Alaska earthquake and 1964 Niigata earthquake.
The effects of soil liquefaction, seen after 2011 Canterbury earthquake In geology , soil liquefaction refers to the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, often in an earthquake. [ 6 ]
Soil temperature depends on the ratio of the energy absorbed to that lost. [68] Soil has a mean annual temperature from -10 to 26 °C according to biomes. [69] Soil temperature regulates seed germination, [70] breaking of seed dormancy, [71] [72] plant and root growth [73] and the availability of nutrients. [74]
Temperature variations are most extreme at the surface of the soil and these variations are transferred to sub surface layers but at reduced rates as depth increases. Additionally there is a time delay as to when maximum and minimum temperatures are achieved at increasing soil depth (sometimes referred to as thermal lag).
Finally, most models separate out the effects of hydrostatic stress and shear stress, with each assumed to cause only volume change and shear change respectively. In reality, soil structure, being analogous to a "house of cards," shows both shear deformations on the application of pure compression, and volume changes on the application of pure ...
Soil that has been consolidated to a large pressure and has been subsequently unloaded is considered to be overconsolidated. The maximum past vertical effective stress is termed the preconsolidation stress. A soil which is currently experiencing the maximum past vertical effective stress is said to be normally consolidated.
A second interaction effect, tied to mechanical properties of soil, is the sinking of foundations, worsened by a seismic event. This phenomenon is called soil liquefaction . Most of the civil engineering structures involve some type of structural element with direct contact with ground.