What is shear test machine?
The shear test apparatus (art. no. 08.68) measures the shear stress of an undisturbed soil sample. During the measurement soil water matrix, compression stress and vertical displacement are simultaneously measured.
What are the various apparatus used in direct shear test?
apparatus required Loading Frame, Weights, Proving Ring, Micrometer Dial Gauge, Sample Trimmer or Core Cutter, Stop Watch, Balance, Spatula, Straight Edge, Shear box grid plates, porous stones, base plates, loading pad and water jacket shall conform to IS : 11229-1985.
What is direct shear apparatus?
Direct Shear Testing Equipment The direct shear test measures the force and horizontal displacement of a representative soil specimen that is sheared along a controlled horizontal plane at a constant rate of deformation.
Why is direct shear test done?
Direct shear test is simple and faster to operate. As thinner specimens are used in shear box, they facilitate drainage of pore water from a saturated sample in less time. This test is also useful to study friction between two materials one material in lower half of box and another material in the upper half of box.
What is CBR apparatus?
Digital CBR Test Apparatus It defines the relative bearing ratio and expansion characteristics under known surcharge weight of base, sub-base, and sub-grade soils for the design of pavements, roads, and runways. The CBR test is used widely in the control of sub-grades and selection of materials.
How many types of direct shear tests are there?
This test can be performed in three different drainage conditions namely unconsolidated-undrained, consolidated-undrained and consolidated-drained conditions. In general, cohesionless soils are tested for direct shear in consolidated drained condition.
What is the principle of direct shear test?
The Direct Shear Test is used for determination of the consolidated drained (or undrained) shear strength of soils. The test is performed by deforming a specimen at a controlled rate on or near a single shear plane.
What is the purpose of a direct shear test?
The purpose of a direct shear test is to determine the shear strength of a soil; this is done by forcing the soil to shear along an induced horizontal plane of weakness at a constant rate.
What does direct shear measure?
The Direct Shear Test is an experimental procedure conducted in geotechnical engineering practice and research that aims to determine the shear strength of soil materials. Shear strength is defined as the maximum resistance that a material can withstand when subjected to shearing.
What is the meaning of 100% CBR?
The California Bearing Ratio (CBR) test is a simple strength test that compares the bearing capacity of a material with that of a well-graded crushed stone (thus, a high quality crushed stone material should have a CBR @ 100%).
How CBR is calculated?
CBR is the ratio expressed in percentage of force per unit area required to penetrate a soil mass with a standard circular plunger of 50 mm diameter at the rate of 1.25 mm/min to that required for corresponding penetration in a standard material. The ratio is usually determined for penetration of 2.5 and 5 mm .
How is shear strength calculated?
Shear strength can be measured by a torsion test where it is equal to their torsional strength. When values measured from physical samples are desired, a number of testing standards are available, covering different material categories and testing conditions.