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Among the different ways of in-situ soil investigation, cone penetration test data are selected to evaluate the spatial variability

of geomaterials and the scale of fluctuations is chosen to evaluate the correlation structure of CPT data. In this regard six case

studies in sandy materials from Australia, U.S.A. and Iraq are selected. Various techniques for the calculation of the scale of

fluctuation of geotechnical parameters are suggested in literature e.g. VXP, SAI, AMF, BLM and VRF without any preference or

privilege for any specific procedure. In order to isolate the stochastic portion of cone tip resistance, deterministic trend was first

removed by regression analysis. This study suggests that quadratic trend removal is more suitable for selected CPT data

soundings. The closeness of the estimated scale of fluctuation using different approaches is assessed too. Mean value of the scale

of fluctuation by five established methods ranges between 0.44 to 1.52 meter for six different cases and the coefficient of

variation for the scale of fluctuation calculated by these methods varies between 12 to 27 % showing that available established

methods produce almost compatible and comparable results.

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Soil reinforced with fiber shows characteristics of a composite material, in which fiber inclusion has a significant effect on soil permeability. Concerning to the higher void ratio of carpet fibers, at first stages it may be expected that an increase in fiber content of the reinforced soil would result in an increase in permeability of the mixture. However, the present article demonstrates that fiber inclusion will decrease the permeability of sand-fiber composite.A series of constant head permeability tests have been carried out to show the effects and consequently, a new system of phase relationships was introduced to calculate the dry mass for the sand portion of the composite. Monte Carlo simulation technique adopted with finite element theory was employed to back calculate the hydraulic conductivity of individual porous fibers from the laboratory test results. It was observed that the permeability coefficient of the porous fibers are orders of magnitude less than the skeletal sand portion due to the fine sand particle entrapment and also the fiber volume change characteristics.

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In this technical note, a methodology is introduced for reliability calculation of consolidation settlement based on cone penetration test (CPT) data. The present study considers inherent soil variability which influences consolidation settlements results. To proceed reliability analysis, the measured data of a sample corrected cone tip resistance (􀝍􀯧) is detrended using a quadratic trend and the residuals are assumed to be lognormally distributed random field. Realizations of 􀝍􀯧 is generated by using spatial variability of residuals including standard deviation and the scale of fluctuation. The quadratic trend and the generated residuals are then combined to correlate shear and bulk modulus as input consolidation properties for coupled analysis and subsequently consolidation settlement was calculated by using finite difference method adopted in Monte Carlo simulations. The results of reliability analysis are presented describing the range of possible settlements by considering characteristics of uncertainties involved at the particular site. Number of realizations rendering settlements smaller than the allowable settlement must be such that guarantee proper performance or acceptable reliability index.