What is modulus of subgrade reaction of soil?

The modulus of subgrade reaction ks is a function of the contact pressure and allowable settlement on an unit area of soil. It is also known as Pressure per unit settlement. On the other hand, the safe bearing capacity is the maximum pressure which the soil can carry safely without risk of shear failure.

What is modulus of subgrade reaction k?

The modulus of subgrade reaction (k) is used as a primary input for rigid pavement design. It estimates the support of the layers below a rigid pavement surface course (the PCC slab). The k-value can be determined by field tests or by correlation with other tests.

What is a good modulus of subgrade reaction?

Typical values of modulus of subgrade reaction

Soil description Modulus of subgrade reaction (kN/m2/m)
Fine or slightly compacted soil 15000 – 30000
Well compacted sand 50000 – 100000
Very well compacted sand 100000 – 150000
Loam or clay (moist) 30000 – 60000

What is subgrade modulus?

The Subgrade Modulus, also known as the Modulus of Subgrade Reaction, is a stiffness parameter typically used in defining the support conditions of footings and mat foundations, such as that shown on Figure 1. The parameter is expressed in units of [Force]/[Length]3.

How do you calculate the k value of soil?

It is expressed as k=p/s. Here, k = modulus or coefficient of subgrade reaction; p = applied pressure and s = deformation of soil settlement. The coefficient of subgrade reaction is expressed in load intensity per unit of displacement.

What is K value test?

0.2 The ‘modulus of subgrade reaction test’, usually known as K-value test, is essentially a plate bearing test. This test is used for the design of pavement structures and raft foundations.

What is a typical subgrade modulus?

Typical values of subgrade modulus range between 100-400 pci for coarse grained soils and 25-150 pci for fine grained soils.

How do you measure soil modulus?

Soil elastic modulus can be estimated from laboratory or in-situ tests or based on correlation with other soil properties. In laboratory, it can be determined from triaxial test or indirectly from oedometer test.

What is soil modulus?

in Parameters. Soil Young’s modulus (E), commonly reffred to as soil elastic modulus, is an elastic soil parameter and a measure of soil stiffness. It is defined as the ratio of the stress along an axis over the strain along that axis in the range of elastic soil behaviour.

How do you calculate subgrade modulus?

What is modulus of subgrade reaction? Modulus of subgrade reaction is defined as the pressure per unit deformation of the subgrade at specific pressure or deformation. It is expressed as k=p/s. Here, k = modulus or coefficient of subgrade reaction; p = applied pressure and s = deformation of soil settlement.

What is PCI soil?

-lb units, pounds per cubic square inch, or psi per in. or, as commonly expressed, pounds per cubic inch (pci).