What is critical state concept of soil mechanics?

Abstract. The critical state (or critical void ratio) line is the locus of void ratio-effective stress conditions achieved after shearing a soil to large displacement and after all net void ratio changes and effective stress changes are complete.

What are critical state parameters?

The five critical state soil parameters are: λ, slope of the normal compression line (NCL) in the specific volume (υ)—natural logarithm of the mean effective stress ln (p′) plot; κ, slope of the swelling line in the υ − ln (p′) plot; Ν, value of specific volume when p′ = 1 kPa on the normal compression line; Μ, slope …

What is critical state model?

The “modified Cam-clay theory” is a classical plasticity model. It uses a strain-rate decomposition in which the rate of mechanical deformation of the soil is decomposed into an elastic and a plastic part, an elasticity theory, a yield surface, a flow rule, and a hardening rule.

What is Roscoe surface?

The surface of Roscoe (Hvorslev) is defined as the surface made of the last part of the set of trajectories ending to a given critical point and coming from all states of normally consolidated soils (from all states of over consolidated soils).

What is critical void ratio?

The critical void ratio is defined as the void ratio at which failure will occur at zero volume change. The concept was first established by Casagrande [1] and following that, a number of methods were suggested for determining this soil characteristic.

What is P and Q in soil mechanics?

The p-q diagram is a method of simplifying the analysis of triaxial and other stress data which are commonly used in soil mechanics. It can be used in a variety of applications and solve a range of problems.

What is critical state friction angle?

The angle of shearing resistance at critical state, or conventionally known as critical state friction angle (\phi_{cs}), is a fundamental soil property that plays an important role in a great variety of geotechnical applications, ranging from foundations and retaining structures to embankments and slopes.

What is the state of sand?

Sand reacts like a solid when you stand on it, and it is more than capable of supporting your weight. Now, if you were to put the same sand particles in an hourglass, these will start flowing through the hole like a liquid.

What is meant by critical state?

: a state attainable by every chemically stable pure substance in which the liquid and the vapor phases have the same density.

What is the void ratio of soil?

Void ratio of a soil sample is defined as the ratio of the space occupied by the voids i.e. volume of voids to the space occupied by solids i.e. volume of solids.

Can void ratio be more than 1?

The void ratio is thus a ratio which can be greater than 1. It can also be expressed as a fraction. Void ratio and porosity differ only in the denominator. Void ratio is the ratio of voids to solids, porosity is the ratio of voids to total volume.

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”.