What is undrained shear strength?
The undrained shear strength (su) is defined as the peak value of the horizontal shear stress. The undrained shear strength Csul is defined as the peak value of the horizontal shear stress.
What affects undrained shear strength?
The shear strength of soil depends on the effective stress, the drainage conditions, the density of the particles, the rate of strain, and the direction of the strain.
How do you determine the strength of a rock?
The tensile strength of rock is defined as the pulling force, required to rupture a rock sample, divided by the sample’s cross-sectional area. The tensile strength of rock is very small and is of the order of 0.1 times the compressive strength.
What is the importance of undrained shear strength?
The undrained cyclic shear strength has to be evaluated to calculate the capacity under cyclic loads. The undrained cyclic shear strength should be obtained for various stress paths. The remolded shear strength is an important parameter because it is used to calculate the penetration resistance of the skirt walls.
Is undrained shear strength the same as cohesion?
Based on analysis that undrained shear strength coincides with 50 percentile of distribution data meanwhile undrained compressive strength is around twice of cohesion for testing using unconfined pressure. This relationship is the most familiar equation.
What is the difference between drained and undrained soil?
As you all know in drained condition, the pore water can easily drain out from the soil matrix while in undrained condition the pore water is unable to drain out or the rate of loading is much quicker than the rate at which the pore water is able to drain out.
What is drained and undrained conditions?
What is shear strength of rock?
The shear strength of a discontinuity in a soil or rock mass may have a strong impact on the mechanical behavior of a soil or rock mass. Many slopes, natural and man-made, fail due to a low shear strength of discontinuities in the soil or rock mass in the slope.
What is tensile strength of a rock?
Tensile strength of rock material is usually defined as the maximum tensile stress which can be endured by such a material [1]. The tensile strength is often the critical mechanical parameter in the engineering practice involving rocks. Rocks shows lower tensile resistance than compressive and shear resistance.
Is undrained shear strength the same as undrained cohesion?
Does undrained shear strength vary with depth?
Undrained shear strength is not a fundamental soil parameter. It generally varies over depth as a function of insitu confining stress at a given depth. Note that larger confining stress reduces void ratio over the historical time. By the decrease of void ratio, undrained shear strength increases.
Is Clay drained or undrained?
Clay behavior depends on the rate of loading (or unloading). When “fast” stress changes take place then clay behavior is typically modeled as “Undrained” while slow stress changes or long term conditions are typically modeled as “Drained”. In the software, the default behavior of a clay type soil is set as “Undrained”.
How is shear strength related to effective stress?
• Shear strength is a function of effective stress. • Shear strength is defined by the Mohr- Coulomb strength equation in terms of effective stress. • In some cases the Mohr-Coulomb failure envelope [the line defined by the equation] passes through the origin.
What kind of shear strength does clay have?
Clay will have a constant short-term strength (Undrained Shear Strength, S u) May be lost through time (delayed failure) σ T S u 22
How does rock mass affect tensile strength of rock?
In general, rock mass strength depends on the strength of intact rock and the strength of rock discontinuities. In general, compared to intact rock, a rock mass has reduced tensile strength (almost zero), and reduced shear strength especi ally along discontinuity planes.
What are the strengths of low grade metamorphic rocks?
High porosity and some low grade metamorphic rocks show unconfined co mpressive strengths ranging between 10 and 50 MPa. Low porosity dolomite and quartzite can have unconfined compressive strengths up to 300 MPa. (6) uniaxial tensile strengths are usually 10 to 20 times lower than unconfined compressive strengths.