Settlement Behaviour of Non-Linear Soil around Single Piles Subjected to Vertical Loads

Kuwabara, Fumio

doi:10.3208/sandf1972.31.39

Cited by 17 publications

(4 citation statements)

References 6 publications

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“…where f and g represent constant coefficients. Kuwabara [14] proposed a relationship for the analysis of axial-loaded piles in which a linear characteristic for the change of the G modulus was assumed as a function of log(g) in the range of 10 -2 % < g < 1%. On the other hand, Van Impe and De Clercq [15] applied the G modulus degradation function in a slightly modified form:…”

Section: Degradation Functions Of G Modulusmentioning

confidence: 99%

Interpretation of shear modulus degradation tests

Srokosz

Dyka

Bujko

2018

Studia Geotechnica Et Mechanica

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The problem is a continuation of the research conducted at the University of Warmia and Mazury in Olsztyn, Institute of Building Engineering. It concerns the development of methods for the interpretation of the shear modulus measurements based on the tests conducted on a torsional shear (TS) apparatus. The issue has significant importance in determining the deformation parameters, essential to perform numerical simulations of the interaction between a geotechnical structure and the subsoil. The purpose of this study was to conduct a comparative analysis of the various methods of interpretation of research results based on direct and reverse analysis, as well as automated classification of the first cycle of the relationship between the shear stress and the shear strain components obtained from the TS test. The methodology for verification of the presented interpretative methods consists in carrying out a series of laboratory tests on non-cohesive and cohesive samples of different granulation and state parameters. The course of the research includes the following steps: elaboration of the granulometric composition of several samples of soil, determination of soil index properties and execution of TS tests. Various methods of interpretation of obtained results were taken into account, in addition to conducting a comparative analysis. The study used a non-standard interpretation approach consisting of analysing one-fourth of the hysteresis loop of the first load–unload cycle of the tested samples. The obtained results confirmed the hypothesis that it is possible to estimate the degradation value of the shear modulus based on a part of the TS test results carried out under quasi-monotonic load conditions. The proposed methods of interpreting test results have confirmed their high usefulness, which is devoid of the uncertainty associated with standardised resonant column/TS testing.

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Section: Degradation Functions Of G Modulusmentioning

confidence: 99%

Interpretation of shear modulus degradation tests

Srokosz

Dyka

Bujko

2018

Studia Geotechnica Et Mechanica

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“…However, Figure 4 shows that for the piles TS1 and TS2 loaded to failure, the skin friction along pile depth approaches the limiting state, and decreases from a peak value with increasing load. In practice, a simple hyperbolic model is commonly used to simulate the relationship between unit skin friction and pile-soil relative displacement (Kuwabara 1991;Carrubba 1997;Kim et al 1999;Lee and Xiao 2001;Randolph 2003;Zhang et al 2010). In the hyperbolic model, a very large pile-soil relative displacement is required to fully mobilize the skin friction.…”

Section: Relative Displacement Between Pile and Soilsmentioning

confidence: 99%

Field and Theoretical Analysis on the Response of Destructive Pile Subjected to Tension Load

Zhang

2014

Marine Georesources & Geotechnology

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Most field tests are carried out using working piles for verification purposes in China, and loading tests are terminated before achieving true pile capacity. In this work, two full-scale destructive loading tests on tension piles instrumented with strain gauges were conducted to capture true pile capacity. The load-displacement response, load transfer, and threshold of the pile-soil relative displacement for fully mobilizing skin resistance in the uplift case were discussed. It was found that the shaft resistance degradation is observed to be along the pile depth with a reduction factor of 0.905 to 0.931, and the thresholds of pile-soil relative displacement for fully mobilizing skin resistance of the tension pile in different soils are found to be in the range 0.67% to 1.34% of the pile diameter. Based on the field test results, a simple softening model was proposed to describe the degradation behavior of skin friction along the pile-soil interface. Further study was conducted to assess the influence of the threshold of pile-soil relative displacement for fully mobilizing skin friction and the reduction factor on the skin friction. As to the analysis of the response of single pile subjected to tension load, a highly effective iterative computer program was developed using the proposed skin friction softening model. Comparisons of the load-settlement response for the well-instrumented tests were given to demonstrate the effectiveness and accuracy of the proposed simple method.

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“…Moreover, efforts to simplify equation 8so that equation 11could be solved analytically were not successful (Michaelides & Gazetas, 1995). By contrast, solutions have been presented for the static problem (Kraft et al, 1981;Kuwabara, 1991). To overcome this dif®culty, the soil was divided into four inhomogeneous{ ring zones and the`exact' radial variation of shear modulus (as given in equation (8)) was numerically curve-®tted with the following exponential expressions: Ã As this article was being ®nalized, a paper was published by Viggiani & Atkinson (1995) containing a wealth of experimental data, relating shear modulus at small strain levels to the mean effective stress, in the form G s A(ó 9 v ) n .…”

Section: Dynamic Soil Reaction (`Spring' and Dashpot' For A Pile Slice)mentioning

confidence: 99%

Approximate non-linear dynamic axial response of piles

et al. 1998

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The axial dynamic response of a single pile in clay is examined within the framework of a Winkler-type approach. Experimental data for the variation of soil shear modulus and hysteretic damping with the amplitude of shear strain and the soil`plasticity' index are curve-®tted and utilized in simulating in a realistic way the non-linearity of the surrounding soil arising from the stresses induced by the pile. An equivalent radially-inhomogeneous but linearlyhysteretic continuum is established, and thè springs' and`dashpots' of the dynamic Winkler model are obtained at each depth by solving analytically the pertinent plane-strain (in z) and axisymmetric (in r) elastodynamic problem. Slippage at the pile±soil interface is also taken into consideration in a simple approximate way. Analytical results are presented to demonstrate the practical signi®cance of soil non-linearity, soil`plasticity' index and interface slippage in the dynamic stiffness and damping of the pile.

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Settlement Behaviour of Non-Linear Soil around Single Piles Subjected to Vertical Loads

Cited by 17 publications

References 6 publications

Interpretation of shear modulus degradation tests

Interpretation of shear modulus degradation tests

Field and Theoretical Analysis on the Response of Destructive Pile Subjected to Tension Load

Approximate non-linear dynamic axial response of piles

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