The base device should be approached especially carefully.. The strength and long service life of the entire structure largely depends on this. A wall without a base begins to collapse very quickly: cracks appear in it, it deforms or slips. For all walls without exception, it is necessary to create a cushion of crushed stone and sand, which ensures uniform transfer of the load to the ground and performs a drainage function.
The width of the trench dug under the pillow should be slightly larger than the width of the lower part of the wall, the depth should be about 30 cm. The side walls and the bottom should be lined with geotextiles. Then cover with a layer of crushed stone (20 cm) with a fraction of 20-40 cm and a layer (10 cm) of sand. For low walls, these measures will be sufficient. However, in the case of high (from 6 m) and heavy walls, a foundation will be required: a pile foundation — for sandy soils (especially quicksand sands), a strip or solid slab — for clay soils (primarily heavy clays).