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 is critical state model?

Critical state is the core of the classic Cam Clay model. The sub-loading concept implies adoption of an inner (sub-loading) yield surface, according to specific hardening rules for some internal strain-like state variables.

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 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 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 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 Hvorslev surface?

What is a pq diagram?

1. Actual PQ diagram. The actual PQ diagram is a thermal diagram where the main theoretical curves represent isotherms of maximum admissible temperatures of different active parts of the electric generator.

What is a pq plot?

How is void ratio calculated?

Divide the weight by the volume (1,000 ml) to find the density of the sand. For example, if the sand weighs 1,500 grams, the density is 1.5. Multiply the voidage by the volume of the dry sand to find the volume of the void. With 1,000 ml of dry sand and a voidage of 0.4, you have a void volume of 400 ml.

When do you use critical state soil mechanics?

CRITICAL STATE SOIL MECHANICS (CSSM) – Is a tool to estimate soil responses when complete characterisation of soil at site is limited (to predict soil’s response from changes in loading during and after construction) – In corporates volume changes in its failure criterion (Mohr coulomb only defines failure as the attainment of the maximum stress.

Why are critical state and elasto plastic soil mechanics criticized?

Critical state and elasto-plastic soil mechanics have been the subject of criticism ever since they were first introduced. The key factor driving the criticism is primarily the implicit assumption that soils are made of isotropic point particles.

How are soil constants related to deviatoric stress?

Thus, {\\displaystyle \\ \\lambda } are soil constants. The first equation determines the magnitude of the deviatoric stress {\\displaystyle \\ p’} . The second equation states that the specific volume {\\displaystyle \\ u } occupied by unit volume of flowing particles will decrease as the logarithm of the mean effective stress increases.

How is the yield surface of Cam clay soil described?

The Original Cam-Clay model is based on the assumption that the soil is isotropic, elasto-plastic, deforms as a continuum, and it is not affected by creep. The yield surface of the Cam clay model is described by the equation.