Common Properties: Soil

Description

Soil material properties commonly used in plate and brick property sets.

Properties

Soil (Bulk) Mass Density

Density of dry soil (i.e., excluding mass of any fluid present).

Units are Mass/Volume (e.g., kg/m³, lb/in³).

Drained Cohesion

Drained cohesion of soil. Shear strength of soil with zero normal pressure.

Units are Pressure (e.g., MPa, psi).

Friction Angle

Friction angle of soil. Relates changes in shear strength to normal pressure.

Units are Degrees.

Horizontal Stress Ratio (K0)

Initial horizontal stress as a ratio of vertical in-situ stress.

Dimensionless.

Void Ratio (e)

Ratio of volume of voids (i.e., water or air) to soil material.

Dimensionless.

Fluid Condition

Condition of fluid, which determines effects of external pressure on pore pressure.

• Drained

  Fluid in soil is free to flow. Changes in external pressure have no effect on pore pressure.

• Undrained

  Fluid in soil is assumed to be fully confined. Changes in external pressure will affect the pore pressure.

Fluid Level

Fluid level used for the analysis.

The direction of gravity specifies the coordinate that determines the fluid level.  For example, if gravity is in the global Y direction, the fluid level specifies a Y coordinate.

• Stage/Global Level

  Fluid level of this property is either taken from the level specified in Global: Stages or in SOLVERS Home: Fluid/Soil Parameters, depending on whether it is a staged or unstaged analysis.

• Property Level

  Fluid level of this property is specified in the Property set.

  Units are Length (e.g., mm, in)

Duncan-Chang Parameters

Properties specific to Duncan-Chang soil.

Modulus Parameters (K / Kur / n)

Parameters that, taken with the reference pressure, define the material modulus.

Dimensionless.

Poisson's Ratio (ν)

Poisson's ratio of the material. Used only when the bulk modulus, Kb, is not explicitly defined. .

Reference Pressure

A reference pressure that, taken with the modulus parameters, defines the material modulus.

Units are Pressure (e.g., MPa, psi).

Minimum Modulus

Material modulus after failure.

Units are Pressure (e.g., MPa, psi).

Bulk Modulus Parameters (Kb / m)

Bulk modulus and bulk modulus exponent.

Dimensionless.

Friction Angle (φ, Δφ)

Friction angle of soil and friction angle change parameter. Relates changes in shear strength to normal pressure.

Units are Degrees.

Failure Ratio

Failure ratio. Relates shear stress at failure to the asymptotic shear stress (at infinite strain).

Dimensionless.

Modified Cam-Clay Parameters

Properties specific to Modified Cam-Clay soil.

Critical State Line (M)

Slope of the critical state line.

Normal Consolidation Line (λ)

Slope of the normal consolidation line.

Also known as the virgin consolidation index.

Swelling Line (κ)

Slope of the swelling line.

Also known as the swelling index.

Poisson's Ratio (ν)

Poisson's ratio of the material, used only when the shear modulus is not explicitly defined.

Used to calculate constant ratio of shear modulus to bulk modulus using the unloading and reloading phases, when the material state is inside the yield surface.

Shear Modulus (a / b)

Parameters that determine the shear modulus at each integration point as G = a + b·P, where P is the mean stress at that point.

Void Ratio (er / pr)

Void ratios.

• er is the volume ratio of voids (i.e., water and/or air) to soil material.
• pr is the unit pressure ratio.

Both parameters are dimensionless.

Preconsolidation (PC0)

Initial consolidation pressure.

Units are Pressure (e.g., MPa, psi).

Overconsolidation (OCR)

Overconsolidation ratio.

See Also

• Materials: Soil