Bearing capacity of cohesive soils The ultimate bearing capacity of saturated cohesive soils (clay and silt) with low permeability is most critical immediately after construction, before the excess porewater pressure has had time to dissipate i.e. undrained conditions. As time proceeds, consolidation occurs, the soil becomes stiffer and has more strength. Therefore design of foundations(…)
Soil Engineering
CAUSES OF FAILURE OF GROUND SLOPES
An exposed ground surface that stands at an angle with the horizontal is called slope. Slopes are required in the construction of highway and railway embankments, earth dams, levees and canals. These are constructed by sloping the lateral faces of the soil because slopes are generally less expensive than constructing walls. Slopes can be natural(…)
FACTOR OF SAFETY FOR BEARING CAPACITY OF SOILS
Bearing capacity of soils are reduced by a factor called factor of Safety to underestimate the bearing capacity of soils. This value of factor of safety depends on following factors: 1. Type of soil 2. Method of exploration 3. Level of Uncertainty in Soil Strength 4. Importance of structure and consequences of failure 5. Likelihood(…)
SOIL CLASSIFICATION FOR PURPOSE OF MEASUREMENT AND PAYMENT
Soil Classification for Purpose of Measurement and Payment All materials to be excavated is classified into one of the following classes and is paid for at the rate for that particular class of material. No distinction is made whether the material is dry, moist or wet. Any earthwork is classified under any of the following(…)
CONTACT PRESSURE AND DEFORMATION PATTERN
The shape of the deformation pattern varies depending on flexibility of the foundation and type of soil. Figure 1 illustrates the relative distribution of soil contact pressures and displacements on cohesion less and cohesive soil. Linear contact pressure distributions from uniformly applied pressure q are often assumed for settlement analysis, Figure 1-c and 1-d. An(…)
QUALITY CONTROL OF SOIL STABALIZED PAVEMENTS
Quality control is essential to ensure that the final product will be adequate for its intended use. It must also ensure that the contractor has performed in accordance with the plans and specification, as this is a basis for payment. This section identifies those control factors which are most important in soil stabilization construction with(…)
EFFECT OF WATER TABLE ON SAFE BEARING CAPACITY OF SOIL
The position of ground water has a significant effect on the bearing capacity of soil. Presence of water table at a depth less than the width of the foundation from the foundation bottom will reduce the bearing capacity of the soil. The bearing capacity equation incorporating the ground water table correction factors is given below.(…)
CALIFORNIA BEARING RATIO TEST
AIM: To determine the California Bearing Ratio value of the subgrade soil. APPARATUS: Loading machine-any compression machine can operate at constant rate of 1.25mm per minute can be used. Cylindrical moulds- moulds of 150mm diameter and 175mm height provided with a collar of about 50mm length and detachable perforated base. Compaction rammer, surcharge weight-annular weights(…)
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