In former times, people preferred to build only on suitable ground. Nowadays, in the course of dense construction activity and the scarce availability of building land, it can no longer be respected. This led to the fact that relevant ground improvement methods have been developed which are constantly advanced. The methods generally aim to increase the bearing capacity of the soil and to reduce or to speed up settlement.
According to the material used and the way it is placed in the soil, we differentiate between the following methods:
Deep Vibration Methods:
When vibrating naturally or artificially deposited coarse soil, the friction of the grains amongst each other is temporarily neutralized. Thus and additionally due to the influence of the gravity they are rearranged and the soil becomes denser. In comparison to the preliminary condition the porosity and thus the ability to compress is reduced and the shear strength is increased.
Vibro Flotation Densification
The reduced volume induces a settlement of the soil surface which accumulates funnel-shaped towards the compression point due to the increase in the soil density. This can be made up with material at hand or delivered to site. The material for the column is added through the depression cone being formed at the surface.
Vibro Displacement Densification
The coarse granular material is filled in a charging pipe at the tip of the vibrator, being equipped with a hopper. Depending on the filled in material we differentiate between the following additional products:
The product is chosen according to the soil conditions and the structural load the columns have to bear.
Coplan Soil Stabilisation Method (CSV) This is a highly flexible foundation technology, where a mixture of sand and a hydraulic binding agent are filled in the soil by an auger using the full displacement method.
Mortar Columns are produced by vibrating a lance into the soil. Then, the void is filled without pressure by the vibrator lance with mortar.
Soil Cement Columns Soil Cement Columns are produced using a contiguous auger to drill into the ground as the auger is reversed a cement slurry is mixed with the soil as the auger is removed from the ground to form the column.