Quantifying hydraulic conductivity spatial variability for cement-based solidification/stabilization (S/S) remediation project: case study

This paper presents statistical analyses of hydraulic conductivity data collected from an existing cement-based solidification/stabilization (S/S) system. The goal is to characterize the spatial variability of hydraulic conductivity and to examine sampling recommendations for the quality control (QC) program of that system to achieve target decision error probabilities regarding the acceptance or rejection of the system with respect to hydraulic conductivity. Over 2000 QC hydraulic conductivity samples, taken over an area of 300 000 m2, are used as a basis for these analyses. The hydraulic conductivity spatial variability is described by a marginal lognormal distribution with correlation function parameterized by directional correlation lengths, which are estimated by best fitting an exponentially decaying correlation model to sample correlation functions. The spatial variability associated with hydraulic conductivity of the studied S/S system is then utilized to assess sampling requirements for the QC program of that system. Considering the “worst case” correlation length and the hydraulic conductivity mean and variance, hypothesis test error probabilities are used to provide recommendations for conservative sampling requirements. It is believed that the analysis of this large construction project represents a unique opportunity to review the current practice of S/S field sampling requirements.

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Spatial Variability of Contaminant Transport in a Fractured Till, Avedøre Denmark

Hydrology Research ◽

10.2166/nh.1999.0019 ◽

1999 ◽

Vol 30 (4-5) ◽

pp. 333-360 ◽

Cited By ~ 29

Author(s):

Larry McKay ◽

Johnny Fredericia ◽

Melissa Lenczewski ◽

Jørn Morthorst ◽

Knud Erik S. Klint

Keyword(s):

Hydraulic Conductivity ◽

Spatial Variability ◽

Field Experiment ◽

Contaminant Transport ◽

Tracer Test ◽

Conductivity Measurements ◽

Fine Grained ◽

Downward Migration ◽

Rapid Transport ◽

High Degree

A field experiment shows that rapid downward migration of solutes and microorganisms can occur in a fractured till. A solute tracer, chloride, and a bacteriophage tracer, PRD-1, were added to groundwater and allowed to infiltrate downwards over a 4 × 4 m area. Chloride was detected in horizontal filters at 2.0 m depth within 3-40 days of the start of the tracer test, and PRD-1 was detected in the same filters within 0.27 - 27 days. At 2.8 m depth chloride appeared in all the filters, but PRD-1 appeared in only about one-third of the filters. At 4.0 m depth chloride appeared in about one-third of the filters and trace amounts of PRD-1 were detected in only 2 of the 36 filters. Transport rates and peak tracer concentrations decreased with depth, but at each depth there was a high degree of variability. The transport data is generally consistent with expectations based on hydraulic conductivity measurements and on the observed density of fractures and biopores, both of which decrease with depth. Transport of chloride was apparently retarded by diffusion into the fine-grained matrix between fractures, but the rapid transport of PRD-1, with little dispersion, indicates that it was transported mainly through the fractures.

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EFFECT OF SPATIAL VARIABILITY IN HYDRAULIC CONDUCTIVITY ON WATER TABLE DRAWDOWN

Transactions of the ASAE ◽

10.13031/2013.21430 ◽

1997 ◽

Vol 40 (2) ◽

pp. 371-375

Author(s):

S. O. Prasher ◽

M. Singh ◽

A. K. Maheshwari ◽

R. S. Clemente

Keyword(s):

Hydraulic Conductivity ◽

Spatial Variability ◽

Water Table

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Experimental investigation to characterize simple versus multi scaling analysis of hydraulic conductivity at a mesoscale

Stochastic Environmental Research and Risk Assessment ◽

10.1007/s00477-021-02079-w ◽

2021 ◽

Author(s):

Guglielmo Federico Antonio Brunetti ◽

Samuele De Bartolo ◽

Carmine Fallico ◽

Ferdinando Frega ◽

Maria Fernanda Rivera Velásquez ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Spatial Variability ◽

Hydraulic Properties ◽

Scaling Laws ◽

Scaling Analysis ◽

Field Scale ◽

Porous Formation ◽

Proper Design ◽

First Time

AbstractThe spatial variability of the aquifers' hydraulic properties can be satisfactorily described by means of scaling laws. The latter enable one to relate the small (typically laboratory) scale to the larger (typically formation/regional) ones, therefore leading de facto to an upscaling procedure. In the present study, we are concerned with the spatial variability of the hydraulic conductivity K into a strongly heterogeneous porous formation. A strategy, allowing one to identify correctly the single/multiple scaling of K, is applied for the first time to a large caisson, where the medium was packed. In particular, we show how to identify the various scaling ranges with special emphasis on the determination of the related cut-off limits. Finally, we illustrate how the heterogeneity enhances with the increasing scale of observation, by identifying the proper law accounting for the transition from the laboratory to the field scale. Results of the present study are of paramount utility for the proper design of pumping tests in formations where the degree of spatial variability of the hydraulic conductivity does not allow regarding them as “weakly heterogeneous”, as well as for the study of dispersion mechanisms.

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Mean and variance optimization of non–linear systems and worst–case analysis

Computational Optimization and Applications ◽

10.1007/s10589-007-9136-7 ◽

2007 ◽

Vol 43 (2) ◽

pp. 235-259

Author(s):

P. Parpas ◽

B. Rustem ◽

V. Wieland ◽

S. Žaković

Keyword(s):

Linear Systems ◽

Case Analysis ◽

Worst Case Analysis ◽

Worst Case ◽

Non Linear ◽

Mean And Variance ◽

Non Linear Systems

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Investigation of Spatial Variability on Strut Diameters of Additively Manufactured Lattice Structures

Volume 2A: Advanced Manufacturing ◽

10.1115/imece2020-23752 ◽

2020 ◽

Author(s):

Recep M. Gorguluarslan ◽

O. Utku Gungor

Keyword(s):

Spatial Variability ◽

Random Field ◽

Extrusion Process ◽

Optical Microscope ◽

Measured Data ◽

Good Representation ◽

Lattice Structures ◽

Spatial Correlations ◽

Correlation Lengths ◽

Geometric Uncertainties

Abstract In this study, the influence of the spatial variability of geometric uncertainties on the strut members of the lattice structures fabricated by additive manufacturing is investigated. Individual struts are fabricated with various printing angles and diameters using a material extrusion process and PLA material. The diameter values of the fabricated samples are measured along the printing and radial directions at each layer under an optical microscope. Spatial correlations are characterized based on the measurements using the experimental autocorrelation function. Candidate autocorrelation functions are fitted to the measured data to identify the best fitted one for each diameter parameter and the corresponding correlation lengths are evaluated for random field. The applicability of the Karhunen-Loeve expansion (KLE) is investigated to reduce the dimensionality of the random field discretization. The results show that the diameters of the strut members at each layer are spatially dependent and the KLE method was found to give a good representation of the random field.

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