Piled Raft Foundation Between the geotechnical design parameters of bearing capacity and settlement, which are independent, if the design just satisfies bearing capacity, settlement will be over satisfied (i.e. settlement less than permissible), and vice versa, if the design satisfies settlement, bearing capacity will be over satisfied (i.e. factor of safety against bearing capacity failure … Read more
Dynamic Compaction of Soil The method can be used to improve all types of non-cohesive soils, mixed soil or those with limited amounts of cohesive material, as well as landfill sites such as waste dumps or spoil tips. There are also many instances of refuse and industrial waste dumps which have been successfully treated by … Read more
Leaning Tower of Pisa The Leaning Tower of Pisa in Italy is perhaps the most famous tower structure in the world, thanks to its lean (nearly 5.50 out of plumb – Fig-1) which makes it a great international tourist attraction. When the lean started becoming progressive and excessive, threatening its very survival, a geotechnical engineering … Read more
What is Drilling Mud? Drilling mud is thin slurry of clay in water. Special clay called bentonite, characterized by its ‘thixotropic (gelling) property’, is used for this purpose. How such a humble material has all but revolutionized the practice of modern geotechnical engineering is little known to professional geotechnical engineers themselves, not to speak of … Read more
In-situ Tests on Soil In situ testing is a division of field testing corresponding to the cases where the ground is tested in-place by instruments that are inserted in or penetrate the ground. In-situ tests are normally associated with tests for which a borehole either is unnecessary or is only an incidental part of the … Read more
Presentation of Geotechnical Investigation Report Upon completion of the geotechnical investigation and analysis, the information and findings must be compiled in a standard report format. The report serves as the permanent record of all geotechnical data known to be pertinent to the project and is referred to throughout the design, construction, and service life of … Read more
Determination of Organic Matter in Soil Purpose: This test is performed to determine the organic content of soils. The organic content is the ratio, expressed as a percentage, of the mass of organic matter in a given mass of soil to the mass of the dry soil solids. Standard Reference: ASTM D 2974 – Standard … Read more
Relative Density or Density Index Test of Sand Purpose: This lab is performed to determine the relative density of cohesionless, free-draining soils using a vibrating table. The relative density of a soil is the ratio, expressed as a percentage, of the difference between the maximum index void ratio and the field void ratio of a … Read more
Density Test of Soil Purpose: This lab is performed to determine the in-place density of undisturbed soil obtained by pushing or drilling a thin-walled cylinder. The bulk density is the ratio of mass of moist soil to the volume of the soil sample, and the dry density is the ratio of the mass of the … Read more
How to Classify Soil Visually on site? Purpose: Visually classify the soils. Standard Reference: ASTM D 2488 – Standard Practice for Description and Identification of Soils (Visual – Manual Procedure) Significance: The first step in any geotechnical engineering project is to identify and describe the subsoil condition. For example, as soon as a ground is … Read more