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 Exploration
DYNAMIC PROBE TEST FOR SOIL
Dynamic probe test is done to determine the penetration resistance of soil. Apparatus required for dynamic probe test of soil are: (a) Dynamic Probe: The anvils shall be rigidly fixed to the guide rod; the lower anvil shall also be rigidly fixed to the extension rods. The mass of the lower anvil shall be 1.5(…)
SOIL TESTS REQUIRED FOR SHALLOW AND RAFT FOUNDATIONS
Soil tests required to determine safe bearing capacity of shallow foundations and raft foundations are discussed here. These tests are as per IS 6403 – 1981. Apart from ascertaining the highest level ever reached by the ground water table and tests for classification of soil as per IS1498 – 1970 based on grain size analysis(…)
PLANNING FOR SOIL INVESTIGATION
Soil investigation is carried out to estimate the engineering properties of soils, which depends on soil structure, i.e. nature of soil grains and their arrangement, volume of air and water (degree of saturation and porosity). Since these properties of soil varies from one location to another, the program of soil investigation need to be evolved(…)
UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)
Unified soil classification system is adopted by ASTM D-2487-98 and IS: 1498-1970 for classification and identification of soils for general engineering purpose. Soils are broadly classified into three divisions: Coarse grained soils: In these soils, 50% or more of the total material by weight is larger than 75micron IS sieve size. Fine grained soils: In(…)
FIELD IDENTIFICATION OF SOILS
Composition and Types of Soils Soil grains consists of inert rock materials (cobble, gravel, sand and silt) often combined with significant amounts of clay (say more than 5%). While inert silt grains may be angular or rounded (thus contributing to greater or less angle of internal friction), particles of clay are small platelets with negative(…)
STANDARD PENETRATION TEST (WITH VIDEO)
STANDARD PENETRATION TEST The standard penetration test is the most commonly used in-situ test, especially for cohesionless soils which can not be easily sampled. The test is extremely useful for determining the relative density and the angle of shearing resistance of cohesionless soils. It can also be used to determine the unconfined compressive strength of(…)
SOIL INVESTIGATION AND EXPLORATION
The purpose of site investigation is to get clear information about the soil and hydrological conditions at the site. Site reconnaissance It means the inspection of the site and study of topography to get a proper information about the soil and ground water condition. SOIL EXPLORATION The purpose of site exploration is to get detailed(…)