| Popis: |
The issues of changing the physicomechanical characteristics of the soil of the underlying compacted core layer are considered when piling unit is immersed in clay soils by a pile driving unit. The substantiation of the change in the specific cohesion of the clay soil C is given, taking into account the change in the electromolecular forces in the array of the underlying layer during the transfer of forces by the compacted core to the underlying (compacted core) of its layer. After each blow of the hammer on the pile head, a «failure» of the pile is formed, which is accepted by us as the main indicator, which takes into account the mass of the pile and mas-shock part of the hammer (their ratio), taking into account that the mas-shock part of the hammer should be not less than the pile weight. The question of using the same similar compression dependence when determining the change in the angle of internal friction φ = f («a», IL) of the soil of the underlying core layer is considered. For a predetermined «failure» «a» and a yield stress indicator IL, the specific values of specific adhesion C and internal friction angle φ of the underlying core layer are calculated. the results of calculations are summarized in Tables No. 1 for changing the specific clutch C and No. 2 for changing the angle of internal friction φ. For specific values of strength indicators C and φ of the soil of the underlying layer, it is necessary to interpolate the tabular data on the corresponding specific value of the failure value «a» and the turnover rate IL, which are determined in the process of piling the pile driving unit. According to the available values of the interpolated strength indicators of the soil of the underlying layer C, φ and the depth of the «sole» of the compacted core d, the calculated soil resistance R is calculated, underlying the compacted core of the layer using the solutions of prof. N. Puzyrevsky or the methodology presented in DBN B.2.1-10-2009 (formula E.1) by the same decision. Having the compacted core area (horizontal projection) A and the calculated resistance R of the soil of the underlying layer, the bearing capacity of the «pile» Fd or pile foundation is calculated by the formula F_d=R∙A а taking into account the coefficients of working conditions depending on the current operational situation. |
