Картинка Буровые фундаменты

Drilling foundations

You can relatively quickly and easily make a drilling foundation. It will take you only some 20 minutes to drill a well 1.5 meters deep with a hand drill, as well as a minimum of building materials for its arrangement.

If the soil at the construction site has a normal bearing capacity (about 4 kgf / cm2), then it is enough for you to drill a well with a diameter of about 240 mm, insert an asbestos-cement pipe with a diameter of 200 mm into it, compact it from the outside with soil, so that the pipe is vertical , and then fill its inner cavity to 1/3 of the height with concrete mortar. After that, the asbestos-cement pipe is raised, and the concrete mixture in it, leaving the pipe, forms the base of a bored pile of a widened diameter. The pipe must be lifted to the required design height, the level of which is indicated by a stretched cord. Next, a concrete mixture is added to the pipe to a special mark, which is 10 – 15 cm below the installed top of the pipe, the mixture is compacted by baying, several reinforcement bars are stuck into it and the support is completely ready, you just need to wait until the concrete mortar has completely set.

The setting of the concrete solution and the set of its sufficient strength occur in about 3-5 days in warm weather in the summer. After that, beams of the lower strapping of the foundation frame or the lower crown of a wooden frame are installed on the columnar foundation. During installation, special care must be taken, since the concrete has not yet had time to fully gain design strength. For a reliable connection of the walls being erected with the foundation, its lower elements are fastened with steel anchors to the upper part of the pipes, so that they go into the pipes by at least 10-15 cm, after which the anchors are poured with concrete mortar.

A common mistake in arranging a drilling foundation is to refuse to use asbestos-cement pipes. The wells are simply filled with a concrete mixture with fine stone filler (brick scrap, crushed stone or small stones). This construction option is possible, but it is necessary to take into account one not very pleasant prospect. In this case, as a rule, due to the development of the drill, the column is obtained with a slight broadening in the upper part of the soil. The resulting broadening is very dangerous, since in winter, when the soil freezes, it will act on the broadened part of the column, pushing or destroying it. The consequences of this error can be avoided by using a smooth cylinder, which is installed on top of the well in diameter. The material for the cylinder can be any sheet material, for example, a sheet of roofing sheet. It can also leave a place for attaching anchors.