Nedsettning

Nedsettning refers to the lowering of a surface or structure due to deformation or compaction of the underlying soil or rock, or due to removal of fluids such as groundwater. In geotechnical and civil engineering, the term covers both uniform settlement of an area and differential settlement where different parts settle at different rates.

Causes include consolidation of saturated soils under new loads, extraction of groundwater or hydrocarbons, drainage changes, mining or tunneling, and natural aging or creep of soils. Primary settlement occurs quickly as soils compress under load; secondary settlement (creep) continues over time under sustained loading.

Measurement and monitoring rely on settlement gauges, leveling and surveying, GPS, InSAR, and benchmark networks. Differential settlement can lead to cracking, distortion of foundations, and damage to utilities, roads, and buildings.

Prevention and mitigation involve proper foundation design such as deep foundations or pile groups, soil improvement (compaction, grouting, drainage), controlling groundwater (pumping, impermeable barriers), staged construction, and minimizing long-term changes in loading.

In practice, nedsettning is a critical consideration on sites with soft or compressible soils, reclaimed land, proximity to water, or prior excavations. A thorough understanding of soil behavior, project loading, and water management helps minimize the risk of excessive settlement.