Settlement is the gradual sinking or downward movement of a structure due to the compression of the underlying soil or rock.

Clay is a fine-grained soil that is highly compressible and prone to settlement when subjected to load.

Settlement in sandy soils is primarily caused by the compaction of the soil particles under load.

Settlement in cohesive soils is primarily caused by the consolidation of the soil, which involves the expulsion of water from the soil pores.

Groundwater level does not directly affect the settlement of a structure, although it can influence the soil properties and behavior.

A settlement analysis is performed to estimate the amount of settlement a structure will undergo under various loading conditions.

Terzaghi's method is a widely used empirical method for estimating the settlement of structures on cohesive soils.

Immediate settlement occurs instantaneously and is caused by elastic deformation of the soil, while consolidation settlement occurs over time and is caused by plastic deformation. Immediate settlement is recoverable, while consolidation settlement is not.

Consolidation settlement is more significant for structures founded on clay soils because it can occur over a long period of time and can cause significant movement of the structure.

Differential settlement is the uneven settlement of a structure, which can cause structural damage.

Differential settlement can be caused by non-uniform soil conditions, uneven loading, and foundation defects.

Differential settlement can cause structural damage, cracking, and tilting of the structure.

Differential settlement can be minimized by using a deep foundation system, compacting the soil uniformly, and using a lightweight structure.

A settlement monitoring program is used to measure the amount of settlement a structure is experiencing, to identify the cause of settlement, and to determine if the settlement is within acceptable limits.

Common methods used for settlement monitoring include settlement plates, inclinometers, and piezometers.