How to calculate the depth of the foundation
How to calculate the depth of the foundation
High groundwater, undergrowth and frost- the three worst enemies of the foundations. Uniting, they are able, if not to break, then at least shake the most solid foundation. There is only one way to prevent this - laying the foundation for such a depth, in which the effect of swelling of the soil in the winter time is harmless to the building.
You will need
- - calculator;
- - access to the Internet;
- - shovel or drill.
Instructions
1
Learn the value of the standard depth of freezingsoil for your area. It is taken from a schematic map of the depths of freezing for different regions, which is published on many construction sites. Using this parameter, you need to know that it corresponds to the maximum possible depth of freezing. Its actual values are, as a rule, much smaller.
2
Define the estimated (actual) depth soil freezing. To do this, use the formula Dr = k * Dn, where Dr is the desired value (the calculated depth of freezing); Dn is the normative depth of freezing; k is a coefficient that takes into account the influence of the heating regimes of buildings on the freezing of the soil adjacent to the foundation. The value of k is taken from SNiPa 2.02.01-83. If the building is heated, the value of k will be less than one, if not, k is assumed to be 1.1. It should be noted that if there is a possibility that the building will not be heated for at least one winter, k should be taken equal to 1.1.
3
Find out the type of soil in the zoneconstruction. Dig a few pits on the site and take soil samples. Even if you are not a specialist in soil science, it will not be very difficult to determine to which type the soil belongs. It can be rocky rocks, sands of various sizes, sands small and silty, clays and loam. In case of difficulty, consult a specialist.
4
The most important factor affecting the calculation of depth foundation, is the groundwater table. Dig a hole or drill a well depth 2.5 m, lower the pipe into it - plastic ormetal - and observe the position of the water surface at different times. In this case, you only need to know if the water is below the freezing point of the ground below or above 2 meters.
5
Proceeding from the data obtained in the previous steps, namely the calculated depth of freezing, groundwater level and soil type, according to Table 2 of SNiPa 2.02.01-83, determine depth laying foundation.
6
Generalized and somewhat simplified data fromtables can be presented in this form: • if the house is built on rocky rocks, the need for a foundation generally disappears; • if the distance from the groundwater surface to the ground is less than Dr + 2, the depth foundation should not be less than the calculated freezing depth (Dr) • If this distance is greater than Dr + 2, the groundwater level does not affect depth foundation and it can be taken at least 0.5 * Dr.
