An Improved Technology of Implementation of Foundations in the Rammed Pits
Implementation of foundations in the rammed pits allows to provide the construction of buildings on soft loess and subsidence soils, as well as on clay and loam grounds. Principle of the proposed pit ramming under foundation consists in the fact that a weight of 2.5-15 tons drops from a height of 6-12 m in a same spot. As a result of soil compaction the hollow is formed, in which the reinforcing rebar skeleton is installed and concrete is poured. Foundation in rammed pit, which created in this way, can hold the bearing capacity of up to 10,000 kN. Machineries based on the tractor, the crane-excavator or the ramming machine are used for pit ramming under the foundation. The main strike element is the rammer that falls under its own weight along the guiding rail trunk or the guiding rail road. Using of such machineries and foundation implementation in rammed pit can significantly reduce the volume of excavation work, material consumption and the complexity of implementation. Pit ramming in the soil with water-saturated layer (aquifer) is associated with some technical difficulties. The softened soil collapses into the pit bottom. Water at the pit bottom contributes to the creation of vacuum, during the removal of rammer, which generates the effect of its suction. It makes the pit ramming without any special measures quite problematic. And at the same time it is necessary to prevent the entry of water into the pit cavity for foundation implementation in the soils with water-saturated layer. A way to successfully cross the water-saturated layer and to implement the foundations in rammed pits is proposed. The developed technology has been repeatedly tested in the constructions of industrial and livestock buildings.