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The California Bearing Ratio (CBR) is a measure of the strength of the subgrade of a road or other paved area, and of the materials used in its construction. The ratio is measured using a standardized penetration test first developed by the California Division of Highways for highway engineering . [ 1 ]
Many other agencies have adopted the California pavement design method, and specify R-Value testing for subgrade soils and road aggregates. The test method states: The R-value of a material is determined when the material is in a state of saturation such that water will be exuded from the compacted test specimen when a 16.8 kN load (2.07 MPa ...
The subgrade provides support to the subbase level and acts as an integral load-bearing layer. Failure of the subgrade can cause depressions and rutting of the upper base and surface courses. These in turn can lead to water pooling in deformations and cause vehicle aquaplaning among other issues.
The second method is called the California bearing ratio and was developed in the late 1940s. It is an extrapolation of the original test results, which are not applicable to modern aircraft pavements or to modern aircraft landing gear. Some designs were made by a mixture of these two design theories.
The bearing capacity of soil is the maximum average contact pressure between the foundation and the soil which should not produce shear failure in the soil. Ultimate bearing capacity is the theoretical maximum pressure which can be supported without failure; allowable bearing capacity is the ultimate bearing capacity divided by a factor of ...
In this report the CBR-method (California Bearing Ratio) is primarily referred to. The so-called CBR-value represents the ratio of the percentage of the loads required to press a punch of certain dimensions first into a well compacted sample of soil and then into a standard sample of compacted gravels, to a depth of 0.1 inch.
Soil compaction is a vital part of the construction process. It is used for support of structural entities such as building foundations, roadways, walkways, and earth retaining structures to name a few.
The first modern theoretical models for soil consolidation were proposed in the 1920s by Terzaghi and Fillunger, according to two substantially different approaches. [1] The former was based on diffusion equations in eulerian notation, whereas the latter considered the local Newton’s law for both liquid and solid phases, in which main variables, such as partial pressure, porosity, local ...