DESCRIPTION OF ROCK MASS CHARACTERISTICS Standardized geologic mapping and logging procedures should be used for describing rock mass characteristics. The types of information collected will depend on site access, extent of rock outcrops, and the criticality of the proposed structure to be constructed on or in the rock mass. A method proposed by the International … Read more
Core Recovery and RQD (Rock Quality Designation) The easiest way to characterize the amount of material recovered during rock coring is to calculate “core recovery” as the amount (i.e. length) of recovered material divided by the total length of the core run (presented as a percentage). Rock Quality Designation (RQD) is a modified core recovery … Read more
How to Select Soil & Rock Properties for Engineering Design? A rational approach for selecting soil & rock properties for engineering design can be summarized as a logical twelve-step procedure that covers the 3 primary stages i.e. Site Investigation and Field Testing, Laboratory Testing and Interpretation, and Engineering Design This step-by-step process is presented on … Read more
Depth of Soil Exploration The object of site exploration is to provide reliable, specific and detailed information about the soil and ground water condition of the site which may be required for a safe and economic design and execution of the engineering work. Dr. B.C. Punima Generally soil exploration should be advanced to a depth … Read more
Geo-technical Engineering Terms Absorbed water Water held mechanically (by surface tension) in a soil mass Activity Ratio of the plasticity index to the clay fraction Adhesion Shearing resistance between soil and another material under zero externally applied pressure Adsorbed water Water in a soil mass, held by physio-chemical forces, having physical properties are substantially different … Read more
Root Pile Construction Root piles are very small diameter piles (generally 60 mm to 135 mm). Length of the root piles generally vary within 4 m to 30 m. The concept of root pile was first introduced by an Italian engineer named F. Lizzi. His primary concern behind root pile development was to do underpinning … Read more
What is A Gabion? A gabion is a netted (wire mesh) box (Fig-1) filled with aggregate material – compatible with the size of the net mesh – serving as gravity units forming retaining structures. It provides a means to contain such aggregates of small and diverse sizes which cannot be used to construct gravity retaining … Read more
Measurement of Soil Compaction in the Field It is necessary in many instances to know the wet/dry densities of the soil in the field, especially before planning activities such as compaction. The same becomes particularly important in instances such as the construction of earth dams, embankments etc. to control the field compaction, that is, to … Read more
Moisture content – Dry Density Relationship At a given input of compaction energy there exists a relationship between moisture content or water content and dry density, which is of the form shown in Fig-1. On the dry side, the added water creates a coating of a thin film of water on the surface of the … Read more
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