Tilt Test (geotechnical Engineering) on:
[Wikipedia]
[Google]
[Amazon]
In geomechanics, a tilt test is a simple test to estimate the shear strength parameters of a discontinuity. Two pieces of rock containing a discontinuity are held in hand or mounted in test equipment with the discontinuity horizontal. The sample is slowly tilted until the top block moves. The angle with the horizontal at onset of movement is called the ''tilt-angle''.
The size of the specimen is limited to 10–20 cm for hand-held tests, while machine-operated tilt test equipment may handle up to meter-sized samples. In the field, the angle can be determined most easily with an
In geomechanics, a tilt test is a simple test to estimate the shear strength parameters of a discontinuity. Two pieces of rock containing a discontinuity are held in hand or mounted in test equipment with the discontinuity horizontal. The sample is slowly tilted until the top block moves. The angle with the horizontal at onset of movement is called the ''tilt-angle''.
The size of the specimen is limited to 10–20 cm for hand-held tests, while machine-operated tilt test equipment may handle up to meter-sized samples. In the field, the angle can be determined most easily with an inclinometer
An inclinometer or clinometer is an measuring instrument, instrument used for measuring angles of slope, elevation, or depression (geology), depression of an object with respect to gravity's direction. It is also known as a ''tilt indicator'', ' ...
as present in most geological or structural compasses.
Tilt-angle
The ''tilt-angle'' equals the material friction of the discontinuity wall plus the roughness i-angle (''tilt-angle'' = ''φwall material'' + ''i'') if no real cohesion is present (i.e. no cementing or gluing material between the two blocks), no infill material is present, theasperities
In materials science, asperity, defined as "unevenness of surface, roughness, ruggedness" (from the Latin ''asper''—"rough"), has implications (for example) in physics and seismology. Smooth surfaces, even those polished to a mirror finish, ar ...
do not break, and the walls of the discontinuity are completely fitting at the start of the test, while if the walls of the discontinuity are completely non-fitting, the ''tilt-angle'' equals the friction of the material of the discontinuity walls (''tilt-angle'' = ''φwall material''). If cementation or gluing material is present or asperities break, the ''tilt-angle'' represents a combination of the (apparent or real) cohesion and the friction along the discontinuity. If infill material is present, the ''tilt-angle'' is governed partially or completely by the infill, depending on the thickness of the infill and height of asperities.
See also
*Direct shear test A direct shear test is a laboratory or field test used by geotechnical engineers to measure the shear strength properties of soil or rock material, or of discontinuities in soil or rock masses.
The U.S. and U.K. standards defining how the test s ...
*Shear strength
In engineering, shear strength is the strength of a material or component against the type of yield or structural failure when the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a materia ...
*Triaxial shear test
A triaxial shear test is a common method to measure the mechanical properties of many deformable solids, especially soil (e.g., sand, clay) and rock, and other granular materials or powders. There are several variations on the test.
In a triaxial ...
References
Further reading
* * {{Cite book , last1 = Price , first1 = D.G. , editor1-last = De Freitas , editor1-first = M.H. , year = 2008 , title = Engineering Geology: Principles and Practice , publisher =Springer
Springer or springers may refer to:
Publishers
* Springer Science+Business Media, aka Springer International Publishing, a worldwide publishing group founded in 1842 in Germany formerly known as Springer-Verlag.
** Springer Nature, a multinationa ...
, page = 450
, isbn = 978-3-540-29249-4
Tests in geotechnical laboratories
Rocks
Tunnel construction