Deep stabilisation is an effective method used in various applications in soft soil, primarily to reduce subsidence and improve soil stability. This method is economic and reliable and it is often used to reinforce soil on road and railway embankments, slopes, pits and pipeline installations.
The durability of the columns increases over time after installation, which further improves the interaction between the pillars and the surrounding soil. Lime stabilisation is also an environment-friendly method, because the introduction of lime raises what is often a low pH value of the soil.
By far the most common stabilisation agent is a mixture of 50% lime and 50% cement. The amount used is usually 80-100 kg per cubic metre of stabilised soil.
Burnt lime is produced by calcination of limestone in a lime kiln at temperatures above 1,000¡ C. Calcium carbonate (CaCO3) is converted into calcium oxide (CaO) and carbon dioxide (CO2). Active calcium oxide is highly reactive. In finely ground burnt lime a high level (80-90%) of calcium oxide guarantees good stabilisation reaction in the soil, favourable water reduction in the soil and a temperature increase upon slaking.
Other factors that can have a significant impact are the BET surface and the silicate content. The particle size is 0-0.2 mm, which enables good flow properties.
Stabilisation conept: The basic principle is that the soil properties are changed by mixing in a stabilisation agent.
Stabilisation technique: is based on the heat development that occurs when burnt lime is slaked when it comes into contact with the soil, and on the quick increase in durability that cement provides.
Mixingtool: A rotating mixing tool is used to mix clay with a binding agent to form a secure and durable column in the soil. The columns are installed in different patterns, either singularly or joined together in overlap.