What is Creep in Soil Mechanics?

is the tendency of a solid material to move slowly or deform permanently under the influence of persistent mechanical stresses12. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength15 of the material. Creep is more severe in materials that are subjected to heat for long periods and generally increases as they near their melting point.

Creep is a time dependent material in which materials accumulate strengths (deformations) under the influence of constant effective stresses. Creep of soil can be often abserved in slopes where creep manifests as slow mass wasting, that is slow downhill movement of soil and rock mass. Creep considerations in soil mechanics are not limited to slopes. All infrastructure that introduces load in the subsoil is subject to creep, too. For economic and functional design the magnitude of creep is to be known. The creep project aims at developing new tools for creep in soft soils, frozen soils and hard soils.

When a soil consolidates (decreases in volume due to loss of water), it undergoes 3 stages. Immediate or elastic compression, which is the first stage and is due to distortion. Then there is primary consolidation where excess pore water pressures are dissipated as water flows out of the soil. This is the main consolidation phase for cohesive soils. The third stage is creep and is due to a rearrangement of the soil particles, after excess pore water pressures have dissipated.

It may be important depending on the soil characteristics, as while it progresses the soil is still settling. If this is significant (unusual) it may render a structure unusable.

Soil creep, also known as a soil floor landslides, and all these terms are called as a mass movement of soil due to the gravitational force and external loading.

In simple words, the slow movement of soil along the slope of land it is called soil creep. This occurs due to heavy saturation, which leads to regular expansion and contraction of particles, ultimately leading to soil creep.

Following are the features of creep of soil

1. It has shown a slow moment.
2. It is due to gravity load.
3. Generally, it occurs in less slope area that is low gradient slope.
4. Soil creep is a continuous process that requires long duration.

In soil mechanics, the meaning of creep is, It is the development of a time depended on shear or volumetric strain at constant effective stress.

The major reason to measure creep is that creep gives the long term deflection of ground soil and movement of slopes. Check the below photo for more detail on creep.

Creep; Creep is defined as the slow, often imperceptible downslope movement of soil is called Creep.

Importance; It happened because of material moves slowly creating an empty vacuum, which results in settlement of that soil leading to the imbalance of the buildings because of differential settlement. It is a slow process that takes several years to show it,s disadvantages.

Creep in soil is pretty much similar in concept to creep in general. Only the manifestation and consequences are different in different materials and can be very peculiar in soil.

Creep in soil is the time dependant development of shear strains and/or volumetric strains in a soil mass in the  state of a constant effective stress for a prolonged period of time.

It is also sometimes referred to as the gradual loss of cohesion over a prolonged period of time in soil.

Unlike concrete, where creep results in deflection and cracking, creep in soil  to may lead to long term settlement, movements of slopes, gradual loss of soil from slopes or shear failure.