Settlement of soil Settlement of soil By Sloboda Danijela, By Sloboda Danijela, Vlaovic Goran, Vlaovic Goran, Zavisic Bojan and Zavisic Bojan and Merkovic Ivan Merkovic Ivan Date of presentation 21.12.2007. Teachers: Dr. Petar Santrac Dr. Ruza Ostrogonac GFS Univerzitet u Novom Sadu WUS Austria
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Any structure built on soil is subject to settlement. Some settlement is inevitable and, depending on the
situation, some settlements are tolerable.
In designing a structure it is commonly assumed that the foundation will not move. Correspondingly, if cracksappear in the structure it is assumed that the foundation did move and that this is the sole cause of cracking.
As building loads are applied to the ground an "immediate" settlement occurs as a result of instantaneous
compression of the soil. Most immediate settlement may be accommodated within the structure as it is built,
and fortunately much of the differential movement occurs at this stage. Under certain conditions, however,
fine-grained soils will continue to compress under constant load for many years. This long-term compression
is called "consolidation" settlement and is caused by the squeezing out of water from the pores in the clay.
Differential settlement occurs for a number of reasons:
- Local variations in soil compressibility,- Variation in thickness of compressible soil,
- Differences in footing sizes and pressures,
- Variation in applied loads,
- Overlapping stresses,
- Differences in depth of embedment of footings.
-Soil Permeability
-Soil Drainage
-Load to be placed on the soil-History of loads placed upon the soil (normally or over-consolidated?)
-Water Table
Types of Settlement
There are three basic types of settlement: uniform settlement, tilt, and non-uniform settlement
The most common types of geotechnical testing used to evaluate the modulus of the
soil are penetration tests such as the Standard Penetration Test (SPT) or the Static
Cone Penetration Test (CPT).
The standard penetration test (SPT) is the most commonly used in situ test. However,cone penetration test (CPT) is becoming increasingly popular as an in situ test for site
investigation and geotechnical design.
There are number of testing but we are going just to name some of them:
-analytic and numeric methods
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Lines of equal vertical stress caused by surface loads
These procedures and associated theoretical considerations of soil action constitute the modern science of Soil
Mechanics. The proper application of the results of such scientific studies now enables the foundation engineer
to design a foundation for any given combination of loads on even the most unpromising soil, as also upon soilsthat have not caused problems when utilized in more pragmatic ways.
These procedures and associated theoretical considerations of soil action constitute the modern science of Soil
Mechanics. The proper application of the results of such scientific studies now enables the foundation engineer
to design a foundation for any given combination of loads on even the most unpromising soil, as also upon soilsthat have not caused problems when utilized in more pragmatic ways.