Determination of normative values of mechanical indicators of bonded soils based on dynamic probing data

Abstract

In the work on the basis of analytical analysis of tabular data, both current and previous domestic regulatory documents on civil engineering, for mechanical indicators of bonded soils of natural occurrence graphic and analytical (formula) interpretation of these values in relation to the values of the dynamic probing index of Pd, MPa, and yield index IL, units, for the degree of water saturation of these soils Sr ≥ 0.8 units is given. Correlation with the value of dynamic probing of Pd, MPa allows not only to differentiate engineering and geological (geotechnical) cross-sections, more or less detailed, but also to estimate the load-bearing capacity of selected layers of bonded soils accurately enough. The theoretical analysis has shown that the values of mechanical indicators of natural bonded soils adopted in the current regulatory documents, even taking into account their structural strength, can not be directly used as a prototype to assess similar indicators of compacted technogenic soils of artificial structures in the form of embankments of hydraulic dams, road embankments or airfields. This is due to the fact that in the vast majority of cases in civil construction assessed the properties of soils in the plastic state, which tend to have a lower density of dry soil than at the border of rolling, and a mandatory condition for the use of such soils in artificial soil structures is their compliance with the requirements of the so-called standard compaction, that is, the density of dry soil there should be more than the density of dry soil at the border of rolling. These soils are in a solid state (their concentration is ≥ 85 %) and indeed (through direct contact between the soil parts) work as an elastic body and can be characterized by a modulus of elasticity with a corresponding small elastic deflection lmax and a sufficiently large design critical resistance value of R0 ≥ 0.6 MPa, which must be determined at each laboratory test of the samples before they fracture or disproportional movement of the stamp.