Subsidence Investigation and Monitoring
Subsidence is the process of ground movement beneath a property causing the foundations to shift, which can adversely affect walls and overall structural integrity. Issues can manifest in several forms, including wall cracking, sloping floors, and jammed windows.
The most common cause of subsidence is the shrinkable nature of cohesive soils, which contract when dry and expand when wet. This seasonal phenomenon can be exacerbated by factors such as tree roots, changes in drainage, and climate variations. Tree roots themselves may physically damage foundations, especially in older structures or areas with pavements and paving.
Not all subsidence is natural; human factors can also contribute. Subsidence is prevalent in and around former mining towns, where abandoned mines, such as old coal workings, can settle and cause ground sinkage. In the south, there are old deneholes, iron age workings, and the Kent coalfield contributing to such issues.
The most common cause of subsidence is the shrinkable nature of cohesive soils, which contract when dry and expand when wet. This seasonal phenomenon can be exacerbated by factors such as tree roots, changes in drainage, and climate variations. Tree roots themselves may physically damage foundations, especially in older structures or areas with pavements and paving.
Not all subsidence is natural; human factors can also contribute. Subsidence is prevalent in and around former mining towns, where abandoned mines, such as old coal workings, can settle and cause ground sinkage. In the south, there are old deneholes, iron age workings, and the Kent coalfield contributing to such issues.
Other causes may include inadequate foundations, particularly those on peat soils or other weak ground. Additional structural loads (e.g., loft conversions) can overstress existing footings or trigger collapsible ground reactions. Leaks from drainage or water mains can soften or wash away ground, leading to voids and collapse.
Aggressive ground conditions or poor construction materials can also lead to deterioration in older foundations.
Sinkholes may occur in chalk or limestone areas, where parts of the bedrock dissolve to form voids, caves, and caverns. Gulling occurs in bedrock on sloping terrain, where joints and fissures open up to form voids or become loosely infilled.
Tunnelling and other construction activities can also induce detectable ground movements.
Aggressive ground conditions or poor construction materials can also lead to deterioration in older foundations.
Sinkholes may occur in chalk or limestone areas, where parts of the bedrock dissolve to form voids, caves, and caverns. Gulling occurs in bedrock on sloping terrain, where joints and fissures open up to form voids or become loosely infilled.
Tunnelling and other construction activities can also induce detectable ground movements.
