On the bearing capacity of sandy foundation beds

Abstract

IntroductionThe problem of evaluating the bearing capacity of foundation beds is critical to practical design. It becomes increasingly important for industrial and civil construction involving large-scale transition to slab and slab-pile foundation designs, which attain planform dimensions of 50 100 m and more, and loads of up to 1 MPa.In this study, we examine certain results of analytical investigations of rigid foundations subjected to a centrally applied vertical load, which were conducted using the software package "GEO-MIGG" [1]. This program is one of the software versions developed by various authors (V. N. Lombardo, M. E. Groshev, V. V. Orekhov, V. N. Vorob'ev, M. I. Karabaev et al.) utilizing Yu. K. Zaretskii's model of the elasto-viscoplastic behavior of soil materials, which is outlined in detail in [2][3][4]. The proposed soil model and algorithms for its application in analyses have been repeatedly verified on actual entities over a period of more than 20 years. Large-scale construction and water-development projects were subjects of the verification. Design practice involving water-development projects requires [5] basic technical solutions to be supported by "scientific-research, including experimental studies, the results of which should be included as a component part of design documentation." In Section 5.3.1 of Construction Rule and Regulation 33-01-2003, moreover, it is indicated that substantiation of the stress-strain state of the "structure-bed" system should be made based on "utilization of modern, primarily, numerical methods of continuum mechanics with allowance for the actual properties of the materials and rocks of the beds."The scales of civil and industrial structures, and their effects on the foundations of these structures, as well as the influence exerted by new construction on surrounding development with respect to its liability and geotechnical problems approach those of hydraulic construction. Here, evaluation of the bearing capacity should be examined as a result of transition of the "structure/geological-medium system" to the limiting state, which can be characterized by the impossibility of continued service of any structures of this system with allowance for the character and sequence of the effects. The bearing capacity of the beds of structures will depend on three factors: the structure, bed, and effects.As applies to public and industrial structures, it is necessary to evaluate the influence exerted on the bearing capacity of the beds, above all, by the scale of the foundations. We have attempted to illustrate this problem, certainly not in its entirety, by analyzing results of a series of calculations and some experimental data made available to us.Results of analytical investigations using the software package "GEO-MIGG", which establish the scale effect of a structure on the bearing capacity and settlement of the foundation bed, are presented.