Three-parameter model of a soil base and pile field taking into account irreversible structural deformations of the soil

Barvashov, V. A.; Fedorovskii, V. G.

doi:10.1007/bf02111773

Cited by 3 publications

(5 citation statements)

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“…For a field of piles of similar length, which are arranged in a regular grid, summing can be replaced by integration over the area, and the pile field represented in the form of a three-parametric contact model of a PSG consisting of a two-parametric Pasternak and Filonenko-Borodich model covered by a Winkler layer ( [16]); this substantially simplifies the analysis. This model is acceptable for a foundation with a high-profile raft of any planform.…”

Section: Analysis Of Load Distribution On Pile Foundation With Considmentioning

confidence: 99%

“…In [16[, this logarithmic function was, even prior to the appearance of "Guidelines [17]," approximated by a MacDonald function, which attenuates exponentially to infinity; this made it possible to account for the mutual effect of the piles at any distances, and represent the pile field as a PSG contact model [16], the parameters of which depend on the parameters of the pile and soil.…”

Section: Analysis Of Load Distribution On Pile Foundation With Considmentioning

confidence: 99%

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Experimental and theoretical research on analytical models of piled-raft foundations

Barvashov

Boldyrev

2009

Soil Mech Found Eng

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Inaccuracy and Suitability of Analytical Models (AM)"All models are inaccurate, but some of them are useful," or "... all models are inaccurate; the practical question is how inaccurate should they be in order to be useful" − these are oft-quoted statements of the familiar British mathematician George E. P. Box [2], V. Pareto's's principle "there are few significant factors, but trivial factors abound" ("principle 20/80") has pointed the way to more precise definition of AM: significant factors (20%) should be evaluated possibly more accurately, and the inaccurate ones (80%) with a much lower accuracy. To evaluate the importance of some factor, it must be determined just how sensitive the modeling system (in geotechnics, this is the "bed-foundation-structure") is to variations in this factor [3].These statements are critical to geotechnics, where building/structure settlements calculated in accordance with recommendations set forth in standard documents may be two-three times lower than actual values [4], and a deviation of 1.5 times is considered successful, and where conservative design solutions predominate; foundation failures are therefore extremely rare. Conservatism and wastefulness, however, are not always identified with enhanced reliability, and are not a replacement for scientificbased search for optimization of design solutions.In this connection, let us examine three AM of pile foundations, which are recommended in [1], from the standpoint of inaccuracy, usefulness, and importance of assumptions adopted, and the sensitivity of the "bed-foundation-structure" system. Methods for Analysis of Pile Foundations [1 and 5]The AM of a "conventional" foundation is inaccurate, but is widely used in design. The inaccuracy consists in the fact that there is no finite compressible stratum H under the tips of the piles, but Several methods for the design of pile foundations, including those recommended in Building Code 50-102-2003 [1], are analyzed,. Tests of a model of a pile foundation in a pan with freeze-frame photographs of the displacements of sand grains, and their digital processing by the method of particle imaging velocimetry (PIV) are described. A method of analyzing a rigid spatial pile foundation with "high-" and "low-profile" rafts of arbitrary planform, which makes it possible to obtain a uniform load distribution on the piles without use of finite-element software is proposed on the basis of experimental results. The method is implemented in the form of design software in the MathCad system. Examples of the analysis are presented.

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Section: Analysis Of Load Distribution On Pile Foundation With Considmentioning

confidence: 99%

Section: Analysis Of Load Distribution On Pile Foundation With Considmentioning

confidence: 99%

Experimental and theoretical research on analytical models of piled-raft foundations

Barvashov

Boldyrev

2009

Soil Mech Found Eng

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“…The introduction of a third parameter (CM SSS), which takes into account the depth of the cutthrough [12,13], reduces the contact problem of foundation/bed interaction to an integral Fredholm equation of the second kind, the solution of which does not possess singularity.…”

Section: Contact Models and Standards For Bfs Systemsmentioning

confidence: 99%

“…Use of CM with one, two, and three coefficients of subgrade regrade reaction [13,16] is always possible, is much more effective than the FEM, and requires considerably fewer calculations. Let us recall the words of L. D. Landau: "Mathematics is an art that is served without calculations, while physics is an art that is served without mathematics.…”

Section: Contact Models and Standards For Bfs Systemsmentioning

confidence: 99%

“…In our study, we employed a standard, which included a soil bed represented by a three-parameter CM CCC [13] (two-parameter Vlasov-Pasternak CM covered by a Winkler layer), for modeling of the BFS system. The existence of the upper Winkler layer in the CM CCC makes it possible to simulate the formation of cut-through [12] in the soil beneath the edges of the foundation.…”

Section: Contact Models and Standards For Bfs Systemsmentioning

confidence: 99%

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Sensitivity of the “bed-structure” system

Barvashov

2007

Soil Mech Found Eng

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Sensitivity, Adaptation, Risk ManagementThese concepts are widely used in describing the behavior of systems in various fields (power generation, telecommunication, medicine, ecology, etc.). The sensitivity of many systems is such that they can function where feedback, which includes monitoring, adaptation, and risk management, exists. In geotechnics, feedback is, in large part, monitoring, and only when necessary, adaptation, which is not previously specified in the plans, despite the risk associated with the indeterminacy of geologic-engineering data, the approximate nature of geotechnical calculations, and the conditionality of theoretical assumptions and hypotheses. Reliability of the BFS system is ensured only by safety factors introduced in the design stage.The observational method represents a more flexible approach to reliability assurance of an BFS system. The design is adapted in the construction process using data derived from on-going monitoring. This approach was first used by K. Terzaghi, and developed later on by Peck and Powderham [2].Unplanned situations also arise, however, during service. In Santos (Brazil) [3], therefore, tens of high-rise buildings had sustained significant settlements and tilts by the time their construction had been completed. The tilts could have been corrected had there been special devices specified by design [4] in these buildings.It is simpler to manage risks, if the sensitivity of the BFS system is assessed, i.e., its behavior as a function of variations in initial data. Monitoring data are insufficient for these assessments; it is possible, however, to compensate for this deficiency by numerical experiments using standards -simplified design schemes, which reflect existing behavioral characteristics of the BFS system. Standards permit use of highspeed computer programs, which are based on exact mathematical solutions free of the error-generated "noise" of numerical methods, and make it possible to obtain both expert, and also statistical assessments of the sensitivity of the BFS system (Monte Carlo method).As early as the 1980s, we had conducted a numerical analysis of the sensitivity of the BFS system [5,6,7]. This analysis is required in selecting design solutions, in developing regulatory documents, and for optimization of experiments, interpretation of monitoring data, calibration and verification of theoretical models, and development of practical intuition and adaptive measures.Mathematical modeling with the use of exact solutions [1] has made it possible to ascertain a number of qualitative characteristics features of the behavior of the "bed/foundationslab/structure" system (BFS) over the entire practical range of initial data.

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Surface settlements of a wedge-shape bed under a concentrated load

Fedorovskii¹,

Onopa²

1985

Soil Mech Found Eng

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Three-parameter model of a soil base and pile field taking into account irreversible structural deformations of the soil

Cited by 3 publications

References 1 publication

Experimental and theoretical research on analytical models of piled-raft foundations

Experimental and theoretical research on analytical models of piled-raft foundations

Sensitivity of the “bed-structure” system

Surface settlements of a wedge-shape bed under a concentrated load

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