The dynamic effect of the turbogenerator is determined by a four-time weight of the turbogenerator itself and can reach up to 40-50% of its own weight of the entire installation along with the foundation. Given the features of the dynamic effects on the soil of the foundations for cars, which consists in repeated periodically repeating continuous loading and unloading of the soil, it is necessary to prescribe the permissible stresses of the value that would guarantee a constant state of the soil within the proportionality between the loads and precipitation.
You can find such a voltage either on the basis of a large production experience that has developed thanks to observation of the already built foundations, or on the basis of experiments with a trial testing of soil at the level of foundation sole (it is desirable to apply a large area of the loaded column). When experiencing the soil, you should not only strive to establish the limit of proportionality and the dependence between sediments and stress with an increase in the load, but also during the test at least twice to unload the column to determine the elastic recoil of the soil. The first unloading should be started with a voltage of 0.5 kg \ cm2, the second – with 1.0 kg \ cm2, since in rare cases the dynamic effect in stresses exceeds 0.5-1.0 kg \ cm ~. Read more about soil tests said in other departments of the reference book.
Having prescribed this or that permissible voltage to the soil, it is advisable to establish the coefficient of safety that guarantees us the stability of the structure. To do this, it is recommended to make calculations that theoretically find the permitted voltage on the soil depending on the depth of the foundation and on the physical characteristics of the soil.
For this purpose, the formula of prof. N. M. Gersevanova, placed in the collection of XV MIIT for 1930.
