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1
Houston, Sonia A. "Regulation of venular hydraulic conductivity by estradiol". MU has:, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060106.
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Hussen, Akif Ali. "Measurement of Unsaturated Hydraulic Conductivity in the Field". FIND on the Web, 1991.
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Hussen, Akif Ali 1957. "Measurement of Unsaturated Hydraulic Conductivity in the Field". Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/191170.
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Unsaturated hydraulic conductivity was measured using four different methods. Tension permeameters were used to measure unsaturated hydraulic conductivity in the field, using a single disc method, which depends on the measurements of sorptivity, steady state flow rate, initial and final water content (White and Perroux, 1987, 1989). Also, a double disc method was used which utilizes Wooding's (1968) equation for two different disc radii at the same tension for steady state flow rates. Undisturbed and disturbed soil cores were used to measure unsaturated hydraulic conductivity in the lab, using water retention curves with van Genuchten's equations. There were no significant differences in the mean of hydraulic conductivity between single and double disc methods in all the tensions used (0, 5, 10 and 15 cm). There were significant differences between the field methods and undisturbed soil cores in zero cm tension, and disturbed soil cores in 10 and 15 cm tension. The effect of land preparation on the unsaturated hydraulic conductivity was studied using the double disc method. Tilling has significant effects on the unsaturated hydraulic conductivity at all tensions used. The spatial variation of unsaturated hydraulic conductivity and steady state flow in different tensions using the double disc method was studied. We found exponential variogram models for unsaturated hydraulic conductivity at 5, 10 and 15 cm tensions and a random model for zero cm tension. Also, exponential models were best fitted for steady state flow corresponding to pores radii of 0.03 - 0.015 cm, 0.015 - 0.010 cm and steady state flow at 10 cm tension. A Michaelis-Menton model was used for steady state flow at 5 cm and 15 cm tension. Disc permeameters were also used to add 5 cm depth of water, bromide and dye solution at 0, 5, 10 and 15 cm tensions with three replicates. A comparison was made between field data and simulated model under the same boundary and initial conditions as in the field. Results showed that the water and bromide move deeper than the prediction of the simulated model in all tensions used. The differences were larger between simulated model and field data for both water and bromide concentrations in the lower tension and smaller in the higher tension as a result of elimination of some preferential flow paths. An equation was developed for cumulative infiltration valid for both small and large time. The parameters calculated using the developed equation closely matched the measured infiltration, and fit better than a three term series similar to the Philip equation for one-dimensional flow.
4
Harvey, Donald John 1951. "The effective hydraulic conductivity of unsaturated layered sands". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/192009.
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Accurate estimates of field-scale hydraulic conductivities of unsaturated heterogeneous soils are very difficult to obtain. In the present study, various approaches to determining effective conductivity values for heterogeneous sands are compared with laboratory measurements. The unsaturated hydraulic conductivity, K(Ψ), of two homogeneous sands and one layered sand composed of the two homogeneous sands was measured using the steady-state flux control method. A van Genuchten model and an exponential model were fitted to the data. Various means of the homogeneous sand fitted K(Ψ) curves were compared with the layered sand K(Ψ) data using a direct averaging approach. The observed suction head variance, effective hydraulic conductivity, and the anisotropy were compared with expressions developed from stochastic theory. The results qualitatively support the stochastic approach. The outcome of the direct averaging approach was inconclusive however. Additional laboratory and field experimentation is needed.
5
Lien, Bob Kuochuan 1959. "Field measurement of soil sorptivity and hydraulic conductivity". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/192028.
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Four methods were applied at four experimental sites following a two-factor completely randomized design for field soil infiltration measurements at the University of Arizona Maricopa Agricultural Center. The Cassel ring and the disc permeameter at a 2 cm positive head provided saturated measurements whereas the 10 cm and the 5 cm tension disc permeameters provided unsaturated measurements which excluded pores ^ 0.03 and 0.06 cm in diameter, respectively. Sorptivity, hydraulic conductivity and characteristic mean pore size were calculated by the method given by White, Sully and Perroux (1989). Both sorptivity and hydraulic conductivity showed dependence on the method applied. The high sorptivity and hydraulic conductivity values obtained by saturated measurements were associated with the unavoidable presence of root channels and cracks at field hence provided large variation and poor repeatability. On the contrary, the disc permeameter at 5 cm tension demonstrated reliable repeatability and reasonable results.
6
Zafar, Saleem. "Strength and hydraulic conductivity characteristics of roller compacted concrete". Ohio : Ohio University, 1997. http://www.ohiolink.edu/etd/view.cgi?ohiou1184617589.
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Bansal, S. P. "Sludge dewatering in terms of structure and hydraulic conductivity". Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382265.
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Britton, Jeremy Paul. "Soil-Bentonite Cutoff Walls: Hydraulic Conductivity and Contaminant Transport". Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28642.
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Soil-bentonite cutoff walls are commonly used to contain contaminants in the subsurface. A key property in determining the effectiveness of a cutoff wall is its hydraulic conductivity. There are important difficulties and uncertainties regarding the accuracy of commonly used methods of measuring the hydraulic conductivity of cutoff walls.
When predicting contaminant transport through cutoff walls, common practice is to use the average hydraulic conductivity of the wall. There are some cases, however, such as circumferential cutoff walls with inward hydraulic gradients, where it is also important to consider the variability in hydraulic conductivity from point to point in the wall in contaminant transport studies.
A pilot-scale facility was envisioned where subsurface barrier issues such as those mentioned above could be studied. In 1998, the Subsurface Barrier Test Facility (SBTF) was constructed. In this facility, pilot-scale subsurface barriers can be installed using real construction equipment and tested in a controlled environment.
The effectiveness of various methods of measuring the hydraulic conductivity of cutoff walls was studied by building and testing three pilot-scale soil-bentonite cutoff walls at the SBTF. The following currently used test methods were evaluated: API tests on grab samples, lab tests on undisturbed samples, piezometer tests (slug tests), and piezocone soundings. The use of slug tests in cutoff walls was improved in this research in the areas of avoiding hydraulic fracture and accounting for the close proximity of the trench walls. The SBTF allows for measurement of the global, average hydraulic conductivity of an installed pilot-scale cutoff wall, which is a useful value to compare to the results of the above-mentioned tests. The two main factors differentiating the results of the different test methods used for the pilot-scale walls were remolding and sample size. Remolding of the API samples significantly reduced the hydraulic conductivity of these samples compared to the hydraulic conductivity measured in lab tests on undisturbed samples, which were of similar size. For the other tests, the degree and extent of remolding were less significant compared to in the API tests. For these tests, the scale of the measurement is believed to be the main factor differentiating the results. Hydraulic conductivity was found to increase as the sample volume increased, with the global measurement of the average hydraulic conductivity producing the highest value.
The influence of variability in hydraulic conductivity on contaminant transport through cutoff walls was studied from a theoretical standpoint using the one-dimensional advection-diffusion equation. Charts were developed that can be used to estimate the flux through a cutoff wall based on knowledge of the average hydraulic conductivity of the wall and an estimate of the variability in hydraulic conductivity. Data sets of hydraulic conductivity from lab tests on soil-bentonite samples from four cutoff wall case histories were used to estimate typical values of variability. The contaminant transport analyses showed that the effect of variability may be significant when the hydraulic gradient opposes the concentration gradient, which is the case for a circumferential cutoff wall with an inward hydraulic gradient. The goal of a circumferential cutoff wall with an inward hydraulic gradient is to reduce the outward diffusive flux of contaminant by inducing an inward advective flux. The effect of variability in hydraulic conductivity is to reduce the effectiveness of this scheme.Ph. D.
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Paleologos, Evangelos Konstantinos 1958. "Effective hydraulic conductivity of bounded, strongly heterogeneous porous media". Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/191184.
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This dissertation develops analytical expressions for the effective hydraulic conductivity Kₑ of a three-dimensional porous medium bounded by two parallel planes of infinite extent separated by a distance 2a. Head varies randomly along each boundary about a uniform mean value. The log hydraulic conductivity Y forms a homogeneous, statistically anisotropic random field having a variance σᵧ² and principal integral scales λ₁, λ₂, λ₃. Flow is uniform in the mean parallel to the principal coordinate χ₁. A solution is first derived for mildly nonuniform media with σᵧ² ≪ 1 via an approximate form of the 1993 residual flux theory by Neuman and Orr. It is then extended to strongly nonuniform media with arbitrarily large σᵧ² by invoking the Landau-Lifshitz conjecture as Kₑ = KG exp {σᵧ² [1/2 — (D + S)]} . Here, K(G) is the geometric mean of hydraulic conductivities and D and S are domain and surface integrals, respectively. Based on a rigorous limiting analysis we show that when the length scale ratio p = a / λ₁ → 0, Kₑ is equal to the arithmetic mean hydraulic conductivity K(A). This supports the theoretical finding of Neuman and Orr and the numerical result by Desbarats. When ρ → ∞ we obtain expressions for Kₑ that have been previously derived in the stochastic literature for infinite flow domains. For strongly anisotropic media with integral scale ratios ε₂ = λ₂ / λ₁ and ε₃ = λ₃ / λ₁ equal to each other and tending to zero or infinity ( ) i 0) we obtain the closed form solution Kₑ = K(G) exp {σᵧ²[exp(—p) — 0 .5]} . The latter reduces to K(A) when ρ → 0 and tends to the harmonic mean K(H) as ρ → ∞. One can think of the case ε₂ = ε₃ = 0 as mean flow along parallel channels having mutually uncorrelated hydraulic conductivities, and of the case ε₂ = ε₃ → ∞ as mean flow normal to layers having uniform hydraulic conductivities. For statistically isotropic media we show numerically that Kₑ equals K(A) when ρ = 0.01; when ρ ≥ 4, Kₑ = K(G) exp(σᵧ²/6) the three-dimensional infinite domain solution. Our results support the analytical finding of Rubin and Dagan, and predict and explain all related bounded domain numerical results. Finally, contrary to Dagan's assertion, we show that for small ρ boundary effects are extremely important; the absolute value of the surface integral S equals the value of the domain integral D.
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Rahi, Khayyun Amtair 1954. "Hydraulic conductivity assessment for a variably-saturated rock matrix". Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/191883.
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Water flow through unsaturated rock has received increasing attention recently. In order to solve unsaturated flow problems, it is necessary to determine the unsaturated hydraulic conductivity, K. A model which predicts K from water retention data was evaluated for rock matrices. It includes three unknown parameters to be determined from experimental data. To verify the model, K was measured by the outflow method. Water retention data were determined by two methods, the pressure plate extractor and the psychrometer. Near saturation, the water retention curve was best estimated by the pressure extractor method. The outflow method gave reliable measurements of K at low negative pressure heads (≥ -1000 cm of water). The predicted K deviated from the experimental values when only the water retention data were used to estimate the model parameters. When the measured K was incorporated in the parameter estimation process, the deviation was reduced considerably.
11
Marpaung, Fivman. "Investigation of the effect of gel residue on hydraulic fracture conductivity using dynamic fracture conductivity test". Texas A&M University, 2007. http://hdl.handle.net/1969.1/85866.
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The key to producing gas from tight gas reservoirs is to create a long, highly
conductive flow path, via the placement of a hydraulic fracture, to stimulate flow from the
reservoir to the wellbore. Viscous fluid is used to transport proppant into the fracture.
However, these same viscous fluids need to break to a thin fluid after the treatment is over
so that the fracture fluid can be cleaned up. In shallower, lower temperature (less than
250°F) reservoirs, the choice of a fracture fluid is very critical to the success of the
treatment. Current hydraulic fracturing methods in unconventional tight gas reservoirs
have been developed largely through ad-hoc application of low-cost water fracs, with little
optimization of the process. It seems clear that some of the standard tests and models are
missing some of the physics of the fracturing process in low-permeability environments.
A series of the extensive laboratory "dynamic fracture conductivity" tests have
been conducted. Dynamic fracture conductivity is created when proppant slurry is
pumped into a hydraulic fracture in low permeability rock. Unlike conventional fracture
conductivity tests in which proppant is loaded into the fracture artificially, we pump
proppant/ fracturing fluid slurries into a fracture cell, dynamically placing the proppant
just as it occurs in the field.
Test results indicate that increasing gel concentration decreases retained fracture
conductivity for a constant gas flow rate and decreasing gas flow rate decreases retained
fracture conductivity. Without breaker, the damaging effect of viscous hydraulic
fracturing fluids on the conductivity of proppant packs is significant at temperature of
150°F. Static conductivity testing results in higher retained fracture conductivity when
compared to dynamic conductivity testing.
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DiFrenna, Vincent J. "Effect of scaling on hydraulic conductivity in a Karst Aquifer". FIU Digital Commons, 2005. http://digitalcommons.fiu.edu/etd/2819.
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Hydraulic conductivity was determined for samples from the Biscayne Aquifer in Miami Florida at bench and field scales. Hydraulic conductivity values obtained were examined for increase due to scale and for anisotropy. Bench scale testing was performed on Key Largo Limestone cubes for total porosity, effective porosity, and hydraulic conductivity. Total porosity was determined by drying and weighing, while effective porosity was determined by submersion. Hydraulic conductivity was determined in a permeameter for each axis of each cube. Field scale testing of hydraulic conductivity was performed with slug tests in the Miami Oolite Formation at the Homestead General Airport. Aquifer scale values for hydraulic conductivity were taken from the literature. Hydraulic conductivity was found to increase with scale in the - Biscayne Aquifer. Furthermore, it increased greatly above an effective porosity of 33 percent. Anisotropy was found to vary in cubes with depth and in proximity to a dense laminated layer.
13
Foster-Reid, Grace Harriet. "Variability of hydraulic conductivity and sorption in a heterogeneous aquifer". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/38355.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1994.Includes bibliographical references (leaves [131]-[132]).
by Grace Harriet Foster-Reid.
M.S.
14
Blank, L. Aaron Jr. "Models of Disordered Media and Predictions of Associated Hydraulic Conductivity". Wright State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=wright1164985765.
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Petroutson, William D., Jeffery B. Bennett, Roderic A. Parnell i Abraham E. Springer. "Hydraulic-Conductivity Measurements of Reattachment Bars on the Colorado River". Arizona-Nevada Academy of Science, 1995. http://hdl.handle.net/10150/296453.
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From the Proceedings of the 1995 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 22, 1995, Northern Arizona University, Flagstaff, Arizona
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Shea, Michael Scott. "Hydraulic Conductivity of Cement-Treated Soils and Aggregates after Freezing". BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2434.
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Improvements in the strength and durability of frost-susceptible soils and aggregates can be achieved through chemical stabilization using portland cement, where the efficacy of cement stabilization for improving durability depends on the degree to which hydraulic conductivity is reduced. Hydraulic conductivity is commonly estimated from basic soil properties using Moulton's empirical equation. However, the hydraulic conductivity estimation does not consider the detrimental effects of freezing or the benefits of cement stabilization. The purpose of this research was to derive new equations relating hydraulic conductivity after freezing to specific material properties of cement-treated soils and aggregates stabilized with different concentrations of cement. This research included material samples from two locations in Alaska and from single locations in Minnesota, Montana, Texas, and Utah, for a total of six material samples. Each soil or aggregate type was subjected to material characterization by the Unified Soil Classification System (USCS) and the American Association of State Highway and Transportation Officials (AASHTO) classification system. Moisture-density curves were developed, and unconfined compressive strength (UCS) testing was performed to determine cement concentrations generally corresponding to low, medium, and high 7-day UCS values of 200, 400, and 600 psi, respectively. After being cured for 28 days at 100 percent relative humidity, the prepared specimens were subjected to frost conditioning and hydraulic conductivity testing. The Alaska-Elliott, Minnesota, Montana, and Utah materials exhibit decreasing hydraulic conductivity with increasing UCS, the Texas material exhibits increasing hydraulic conductivity with increasing strength from the low to medium cement concentration levels but decreasing hydraulic conductivity from the medium to high cement concentration levels, and the Alaska-Dalton material exhibits increasing hydraulic conductivity with increasing strength. Multivariable regression analyses were performed to investigate relationships between hydraulic conductivity and several material properties, including soil gradation and classification, fineness modulus, specific gravity, cement content, porosity, compaction method, dry density, and 7-day UCS for each specimen. The R2 values computed for the six-parameter, four-parameter, USCS, and AASHTO-classification models are 0.795, 0.767, 0.930, and 0.782, respectively. Further research is recommended to investigate the effects of cement on hydraulic conductivity for USCS and AASHTO soil types not covered in this research.
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Agyei, Festus O. "TEMPORAL AND SPATIAL VARIABILITY OF RIVERBED CONDUCTANCE AT THE BOLTON WELLFIELD ALONG THE GREAT MIAMI RIVER, SOUTHWEST OHIO". Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1166069378.
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Hartz, Andrew Scott. "Lab Scale Hydraulic Parameter Estimation". Thesis, The University of Arizona, 2011. http://hdl.handle.net/10150/203499.
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Hydraulic tomography has been tested at the field scale, lab scale and in synthetic experiments. Recently Illman and Berg have conducted studies at the lab scale. Using their data hydraulic tomography can be compared to homogeneous anisotropic solutions using one pumping well or multiple pumping wells. It has been found that hydraulic tomography out performs homogenous methods at predicting hydraulic head for validation pumping experiments. Also it has been shown in this study that homogenous anisotropic tests exhibit scenario dependent behavior. Additional tests performed to further validate the conclusions made in this experiment include spatial moment analysis, response surface analysis, and synthetic hydraulic tomography and show consistent results providing additional validation of these findings. Additional study examining the principle of reciprocity has proven inconclusive.
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Pongthunya, Potcharaporn. "Development, setup and testing of a dynamic hydraulic fracture conductivity apparatus". Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1960.
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Špongrová, Kamila. "Design of an automated tension infiltrometer for unsaturated hydraulic conductivity measurement". Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1420.
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A tension infiltrometer for field use, where both water level changes measurement and tension settings could be automated, was built in-house. Differential pressure
transducers were used to automate the water level measurement in the reservoir. The
Mariotte bottle was automated by a set of solenoid valves which were connected via
tubing to pre-defined depths in the Mariotte bottle. Based on design parameters tested in the laboratory (sensor sensitivity, water reservoir diameter, and bubbling
rate) three identical tension infiltrometers connected to a single Mariotte bottle were
built. A new reservoir system made of two plexiglass tubes of different diameter
slotted in each other was found to reduce the measurement fluctuations caused by the
disturbance created to rising bubbles in the reservoir.
The new system was tested on a uniform sandy loam profile prepared in the soil bin
laboratory and different analytical and numerical data analysis methods were
compared. The measured steady state data were used to determine K(h) at different
suctions using the analytical method proposed by Reynolds and Elrick (1991). The
K(h) points obtained were fitted with the van Genuchten’s equation (van Genuchten,
1980) using the RETC program to calculate the best fit parameters Ks, and n. These
parameters were used as initial estimates of the soil hydraulic parameters in the
numerical models HYDRUS 1D and 2D, in which transient cumulative flow data was used to determine the soil hydraulic functions via inverse modelling. The analysis of variance determined significantly higher K(h) values calculated by HYDRUS 1D while the other methods did not differ from each other.
Finally, the tension infiltrometer was used in the field on a sandy loam soil to
characterise five different tillage treatments (conventional plough, shallow plough, minimum tillage, direct drill, and no-tillage). The effect of wheel traffic was also evaluated by measuring the infiltration rates in the wheel-marks. The fully automated
system allowed the measurement of infiltration rates for 8 tensions in triplicate per day with hardly any human intervention apart for refilling the reservoir. The results show that the tillage practices and wheel-traffic have a significant influence on the soil hydraulic function K(h).
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Dorsey, Jay Dunton Ward Andrew D. "A comparison of three field methods for measuring saturated hydraulic conductivity /". Connect to resource, 1989. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1145374211.
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Dorsey, Jay Dunton. "A comparison of three field methods for measuring saturated hydraulic conductivity". The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1145374211.
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Xu, Teng. "Ensemble Kalman filtering for hydraulic conductivity characterization: Parallelization and non-Gaussianity". Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/43769.
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The ensemble Kalman filter (EnKF) is nowadays recognized as an excellent inverse method for hydraulic
conductivity characterization using transient piezometric head data. and it is proved that the EnKF is
computationally efficient and capable of handling large fields compared to other inverse methods. However,
it is needed a large ensemble size (Chen and Zhang, 2006) to get a high quality estimation, which means a
lots of computation time. Parallel computing is an efficient alterative method to reduce the commutation
time.
Besides, although the EnKF is good accounting for the non linearities of the state equation, it fails when
dealing with non-Gaussian distribution fields. Recently, many methods are developed trying to adapt the
EnKF to non-Gaussian distributions(detailed in the History and present state chapter). Zhou et al. (2011,
2012) have proposed a Normal-Score Ensemble Kalman Filter (NS-EnKF) to character the non-Gaussian
distributed conductivity fields, and already showed that transient piezometric head was enough for hydraulic
conductivity characterization if a training image for the hydraulic conductivity was available. Then in
this work, we will show that, when without such a training image but with enough transient piezometric
head information, the performance of the updated ensemble of realizations in the characterization of the
non-Gaussian reference field.
In the end, we will introduce a new method for parameterizing geostatistical models coupling with the
NS-EnKF in the characterization of a Heterogenous non-Gaussian hydraulic conductivity field.
So, this doctor thesis is mainly including three parts, and the name of the parts as below.
1, Parallelized Ensemble Kalman Filter for Hydraulic Conductivity Characterization.
2, The Power of Transient Piezometric Head Data in Inverse Modeling: An Application of the Localized
Normal-score EnKF with Covariance Inflation in a Heterogenous Bimodal Hydraulic Conductivity Field.
3, Parameterizing geostatistical models coupling with the NS-EnKF for Heterogenous Bimodal Hydraulic
Conductivity characterization.Xu, T. (2014). Ensemble Kalman filtering for hydraulic conductivity characterization: Parallelization and non-Gaussianity [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43769
TESIS
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Alvarado, Blohm Fernando Jose. "Determination of Hydraulic Conductivities through Grain-Size Analysis". Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:106982.
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Thesis advisor: Alfredo UrzuaThesis advisor: John Ebel
Nine empirical equations that estimate saturated hydraulic conductivity as a func- tion of grain size in well-graded sands with gravels having large uniformity coecients (U > 50) are evaluated by comparing their accuracy when predicting observed conduc- tivities in constant head permeability tests. According to the ndings of this thesis, in decreasing order of accuracy these equations are: USBR (Vukovic and Soro, 1992; USBR, 1978), Hazen (Hazen, 1892), Slichter (Slichter, 1898), Kozeny-Carman (Carrier, 2003), Fair and Hatch (Fair and Hatch, 1933), Terzaghi (Vukovic and Soro, 1992), Beyer (Beyer, 1966), Kruger (Vukovic and Soro, 1992), and Zunker (Zunker, 1932). These re- sults are based on multiple constant head permeability tests on two samples of granular material corresponding to well-graded sands with gravels. Using the USBR equation sat- urated hydraulic conductivities for a statistical population of 874 samples of well-graded sands with gravels forming 29 loads from a heap leaching mine in northern Chile are calculated. Results indicate that, using the USBR equation, on average the hydraulic conductivity of the leaching heaps has a two standard deviation range between 0.18 and 0.15 cm/s. Permeability tests on the actual material used in the heaps provided by the mine shows that the results presented in this thesis are consistent with actual observa- tions and represent saturated conductivities in heaps up to 3 m high under a pressures of up to 62 Kpa. In future work hydraulic conductivities can be combined with water retention curves, discharge rates, irrigation rates, porosities, and consolidation so as to evaluate the relationship between copper yields and the hydraulic conductivities of the heap
Thesis (MS) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Geology and Geophysics
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Abou-Arab, A. A. A. "Some effects of trapped air in wet soils". Thesis, University of Aberdeen, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378082.
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The effects of air trapped in soils at zero or small negative values of matric potential were studied in relation to saturated and unsaturated hydraulic conductivity, the water release characteristic, and root growth. A reliable method was developed for measuring the trapped air porosity of 'saturated' soils. Using this method, the surface layer of three soils of contrasting texture, in a relatively undisturbed state, was found to have similar amounts of trapped air (5 to 7% of total soil volulme). After digging, the amount of air trapped by ponding water on the surface increased to a value of about 10%. Values of trapped air porosity below a stationary water-table were very low (1%) and this can be attributed to opportunity which the trapped air has to go into solution and diffuse to the water-table. The effects of trapped air on the water release characteristic were investigated in both field and laboratory studies using the neutron-probe and both the neutron-probe and the gamma-probe to measure the water content in the field soil and in a tank packed with sand in the laboratory, respectively. The presence of trapped air had an effect on the field water release characteristic. This effect was more pronounced in dug soil than in undisturbed soil. In the laboratory, the amount of trapped air differed according to the method of wetting, less trapped air occurred when wetting was from the bottom upwards compared to wetting by ponding water from the top. Amounts of trapped air decreased with increasing depth of sand. The water release characteristic was found to depend not only on the method of wetting but also on the previous history of wetting. In a comparison between a tension-table water release and the water release characteristic measured in a sand tank, they were found to be closely similar except at zero and small negative values of matric potential, where effects due to varying amounts of trapped air with depth and wetting history caused differences. Unsaturated hydraulic conductivity measured in the field was affected by the presence of trapped air but only at potentials close to zero. In the laboratory, the values of saturated hydraulic conductivity measured in the sand tank and the values calculated from the water release characteristic using Marshall's theory agreed to within the limits of experimental accuracy. Unsaturated hydraulic conductivity values were found to be not only dependent on the method of wetting but also on the previous history of wetting. The results suggested that once dry sand has been wetted and allowed to drain, that rewetting leads to trapping of air in large pores which reduces the flow during the next drainage period. There was an agreement between unsaturated hydraulic conductivity variation with matric potential obtained from the instantaneous profile method in the sand tank and that using Marshall's theory, however, it is not to be expected that such an agreement will be found for most soils which are not comparable to the relatively homogenous sand used here. In a laboratory experiment with winter barley, the relationship between the presence of trapped air, soil aeration and root growth was studied at 9 and 15°C. The techniques of measuring redox potential with bare platinum electrodes, measuring exygen flux with the same platinum electrodes, and measuring the concentrations of O2, CO2 and N2O in samples extracted through a hypodermic needle gave results which were consistent with one another and with observed root growth rates. Root extension rate was much slower in the saturated soil than in the freely-drained soil. At both temperatures, root growth during 'daytime' (the time of illumination) was about 3 times greater than at night. At 15°C, there was a greater rate of root growth in soil cores which had been flooded rather than vacuum saturated which was related to a slightly greater measured rate of oxygen flux from air trapped by the flooding procedure.
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Elsenbeer, Helmut, Keith Cassel i Jorge Castro. "Spatial analysis of soil hydraulic conductivity in a tropical rain forest catchment". Universität Potsdam, 1992. http://opus.kobv.de/ubp/volltexte/2008/1697/.
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The topography of first-order catchments in a region of western Amazonia was found to exhibit distinctive, recurrent features: a steep, straight lower side slope, a flat or nearly flat terrace at an intermediate elevation between valley floor and interfluve, and an upper side slope connecting interfluve and intermediate terrace. A detailed survey of soil-saturated hydraulic conductivity (K sat)-depth relationships, involving 740 undisturbed soil cores, was conducted in a 0.75-ha first-order catchment. The sampling approach was stratified with respect to the above slope units. Exploratory data analysis suggested fourth-root transformation of batches from the 0–0.1 m depth interval, log transformation of batches from the subsequent 0.1 m depth increments, and the use of robust estimators of location and scale. The K sat of the steep lower side slope decreased from 46 to 0.1 mm/h over the overall sampling depth of 0.4 m. The corresponding decrease was from 46 to 0.1 mm/h on the intermediate terrace, from 335 to 0.01 mm/h on the upper side slope, and from 550 to 0.015 mm/h on the interfluve. A depthwise comparison of these slope units led to the formulation of several hypotheses concerning the link between K sat and topography.
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Naseri, Abd Ali. "The hydraulic conductivity of aggregated clay soils under loading, leaching and reclamation". Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244980.
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Bagour, Mohammed H., i Donald F. Post. "An Evaluation of Methods to Measure the Saturated Hydraulic Conductivity of Soils". Arizona-Nevada Academy of Science, 2000. http://hdl.handle.net/10150/296564.
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Chang, Yi-Jia. "Predictions of saturated hydraulic conductivity dynamics in a midwestern agricultural watershed, Iowa". Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/476.
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In this study, a physically-based, modeling framework was developed to predict saturated hydraulic conductivity Ksat) dynamics in the Clear Creek Watershed (CCW), IA. The modeling framework integrated selected pedotransfer functions (PTFs) and watershed models with geospatial tools. A number of PTFs and watershed models were examined to select the appropriate models that represent the study site conditions. Models selection was based on statistical measures of the models' errors compared to the Ksat field measurements conducted in CCW under different soil, climatic and land use conditions. The study has shown that combined Rosetta and the Water Erosion Prediction Project (WEPP) predictions provided the best agreement to the measured Ksat values in the CCW compared to the other tested models. Therefore, Rosetta and WEPP were integrated with the Geographic Information System (GIS) tools by developing a program for data registries. The modeling framework allowed for visualization of the data in forms of geospatial maps and prediction of Ksat variability in CCW due to the seasonal changes in climate and land use activities.
Two seasons were selected to demonstrate K sat dynamics; specifically, the months of October and April, which corresponded to the before harvesting and before planting conditions, respectively. Baseline saturated hydraulic conductivity (K b) exhibited higher values on the northern part of the CCW compared to the southern part due to differences in soil texture. For bare saturated hydraulic conductivity (Kbr), the month of April had overall higher values than the month of October, because Kbr is inversely proportional to cumulative rainfall kinetic energy and spring season in Iowa are characterized by lower precipitation compared to the fall season.
Except for the ungrazed grassland areas, effective Ksat that accounts for land cover only (Ke-nr) did not change significantly with season, exhibiting the lowest values at the forest and urbanized areas in the CCW. The corn fields showed lower Ke-nr values than soybean fields due to different characteristics of the crops. The effects of rainfall on effective saturated hydraulic conductivity (Ke) were demonstrated by the single storm events of October 17th, 2007 and April 18th, 2008. The former showed higher Ke in CCW, because Ke is linearly proportional to rainfall depth and the October event had higher precipitation than the April event.
Statistical analysis of the Ksat data in CCW has shown that the geometric mean or median was more representative for the distributions of different expressions of saturated hydraulic conductivities due to their wide ranges. The values of Kb were the highest values among the other expressions of Ksat. Ke-nr values were smaller than Kb values, while Ke values were higher than Ke-nr.
The applicability of the pedotransfer functions and watershed models used within the developed modeling framework is limited to the investigated watershed and other watersheds in Iowa having similar soils, management practices, and climatic conditions, mostly in the semihumid region of eastern Iowa. As the proposed modeling framework was able to successfully capture the spatial and temporal variability of Ksat at the watershed scale, it would be advisable to repeat this study in different counties or even in other parts of the country, where arid or semi-arid conditions are ubiquitous, using different pedotransfer functions and watershed models. This can contribute to the development of ratings for many of the soil interpretations incorporated into the National Cooperative Soil Survey (NCSS) and update the Ksat data stored in the National Soil Information System (NASIS) database.
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Tsai, Jui-Pin, Tian-Chyi Jim Yeh, Ching-Chung Cheng, Yuanyuan Zha, Liang-Cheng Chang, Cheinway Hwang, Yu-Li Wang i Yonghong Hao. "Fusion of Time-Lapse Gravity Survey and Hydraulic Tomography for Estimating Spatially Varying Hydraulic Conductivity and Specific Yield Fields". AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/626482.
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Hydraulic conductivity (K) and specific yield (S-y) are important aquifer parameters, pertinent to groundwater resources management and protection. These parameters are commonly estimated through a traditional cross-well pumping test. Employing the traditional approach to obtain detailed spatial distributions of the parameters over a large area is generally formidable. For this reason, this study proposes a stochastic method that integrates hydraulic head and time-lapse gravity based on hydraulic tomography (HT) to efficiently derive the spatial distribution of K and Sy over a large area. This method is demonstrated using several synthetic experiments. Results of these experiments show that the K and Sy fields estimated by joint inversion of the gravity and head data set from sequential injection tests in unconfined aquifers are superior to those from the HT based on head data alone. We attribute this advantage to the mass constraint imposed on HT by gravity measurements. Besides, we find that gravity measurement can detect the change of aquifer's groundwater storage at kilometer scale, as such they can extend HT's effectiveness over greater volumes of the aquifer. Furthermore, we find that the accuracy of the estimated fields is improved as the number of the gravity stations is increased. The gravity station's location, however, has minor effects on the estimates if its effective gravity integration radius covers the well field.
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Dikinya, Oagile. "The effects of self-filtration on saturated hydraulic conductivity in sodic sandy soils". University of Western Australia. School of Earth and Geographical Sciences, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0051.
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[Truncated abstract] Self-filtration is here defined as particle detachment and re-deposition causing re-arrangement of the particles and therefore pore space which affects water flow in soil by decreasing hydraulic conductivity. This is of particular important in soils which are susceptible to structural breakdown. The objective of this thesis was to examine the dynamics of the self-filtration process in sodic sandy soils as affected by ionic strength and soil solution composition. The temporal changes of hydraulic conductivity and the elution of fine particles from soil columns were used as the main criteria to assess selffiltration. Two porous media exhibiting significantly different structural cohesion were examined, one a loamy sand (Balkuling soil) from agricultural land use and the second a mining residue from mineral sands operations . . . The effects of the composition of mixed calcium (Ca) and sodium (Na) ions in solution (sodium adsorption ratio (SAR)) on the exchange behaviour and saturated hydraulic conductivity were examined by carrying out batch binary exchange and saturated column transport experiments. A strong preference for Ca2+ ions in the exchange complex was observed for both soils. Generally K/Ko was found to decrease with increasing sodium adsorption ratio with the more structured Balkuling soil maintaining K/Ko for SARs 3 and 5 at an electrolyte concentration of 100 mmol/L. However measurements at the critical threshold and turbidity concentrations at a SAR of 15 revealed structural breakdown of the pore matrix system attributed to various extents of slaking, swelling, dispersion and decreases of pore radii as a result of selffiltration during leaching. These experiments illustrate the wide range of complex interactions involving clay mineralogy, solution composition and structural factors which can influence the extent of mobilization, transport and re-deposition of colloidal particles during the leaching process in soil profiles.
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Bennett, Claire. "An experimental study on the hydraulic conductivity of compacted bentonites in geoenvironmental applications". Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/58665/.
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Compacted bentonites and compacted sand-bentonite mixtures have been proposed as suitable barrier and backfill materials for the disposal of municipal solid waste and high level radioactive waste. Although unsaturated on placement, the barrier and backfill materials can become saturated subject to the availability of fluid. Detailed understanding of the saturated hydraulic conductivity of compacted bentonites and sand-bentonite mixtures is essential to ensuring the integrity of the waste disposal facility and the long-term protection of the geoenvironment. This thesis is concerned with the experimental determination of the hydraulic conductivity of compacted MX80 bentonite and sand-bentonite mixtures (30% MX80 bentonite to 70% sand). A high capacity fixed ring modified swelling pressure cell was used for carrying out the hydraulic conductivity tests. High precision pressure-volume controllers were used to apply a range of hydraulic gradients between about 1250 and 12500 under constant head conditions. The expansion of the measuring system was studied to account for differences between inflow and outflow water volumes during the hydraulic conductivity tests. The hydraulic gradient was increased and decreased during the hydraulic conductivity tests. Chemical analysis of fluid samples collected from the inflow and outflow reservoirs after each hydraulic conductivity tests provided information about the type and amount of exchangeable cations expelled from the specimens. The inflow volume was calculated based on the system expansions. The hydraulic conductivities were calculated from Darcy’s law. The saturated hydraulic conductivity of compacted bentonite and sand-bentonite specimens were also calculated based on the consolidation tests results. The gas permeability of compacted unsaturated bentonites was determined. The saturated hydraulic conductivity of compacted bentonites was assessed using various existing models. A model based on parallel plate flow was proposed in the current study. The proposed model considered the viscosity of water in the inter-platelet region and its influence on the hydraulic conductivity of compacted bentonites. The correction of the water inflow volume by accounting for the system expansion during the hydraulic conductivity tests provided good compatibility between the inflow and outflow water volumes. The equilibrated inflow and outflow rates were found to be similar during the hydraulic conductivity tests. A linear relationship was noted between hydraulic gradient and hydraulic flux indicating the validity of Darcy’s law for calculating the hydraulic conductivity of compacted bentonites. An expulsion of exchangeable cations from the compacted bentonite specimens occurred during the hydraulic conductivity tests. The amount of expelled cations was found to be less than about 6% of the total exchangeable cations present in the bentonite. The gas permeability of compacted unsaturated bentonite was found to decrease within an increase in compaction dry density. The calculated hydraulic conductivity of compacted unsaturated bentonite based on the measured gas permeability was found to be greater than the measured hydraulic conductivity of compacted saturated bentonite indicating that swelling reduces the hydraulic flow paths. The saturated hydraulic conductivities calculated from the Kozeny-Carman model were found to better describe the measured saturated hydraulic conductivities than the other available models. The model proposed in this study did not satisfactorily establish the hydraulic conductivity of compacted saturated bentonite due to uncertainties associated with the assumptions made regarding the viscosity of the bulk fluid.
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Trast, John Mathew. "Hydraulic conductivity of thirteen compacted clays". 1993. http://catalog.hathitrust.org/api/volumes/oclc/32679505.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 148-151).
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Lai, Wei-Yu, i 賴威宇. "Analysis of In-situ Hydraulic Conductivity Tests". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/psmhzz.
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碩士國立交通大學
土木工程系所
92
In-situ hydraulic conductivity tests have been widely used in field investigations for construction project nowadays. In this study, in order to estimate the cause of various outcomes, in-situ hydraulic testes such as Double-Ring Infiltrometer, Two-Stage Borehole Permeameter, Guelph Permeameter, and Simplified Borehole Test were conducted to compare their applicability in silty and clayey soils. In addition, numerical analysis was performed with a finite-element program, FEMWATER, to further analyze the results of the in-situ tests. The tests were simulated with FEMWATER by using the hydraulic conductivity and soil water characteristic curves obtained from laboratory experiment. The effect of anisotropy of hydraulic conductivity was also studied. Due to the difficulty of quantifying the influence of macropores and fissures in the soils on the hydraulic conductivity, the soils were assumed to be homogeneous. The study showed that the in-situ hydraulic conductivity obtained by the Guelph Permeameter was the lowest and the closest to that from the laboratory tests. On the other hand, the hydraulic conductivity measured by the Double-Ring Infiltrometer tests and Simplified Borehole tests difference were much greater. However, considering the effect of anisotropy and macropores of soil, Double-Ring Infiltrometer test could give more reliable results than Guelph Permeameter and Simplified Borehole Test.
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Dillin, Matthew F. "Wavelet analysis of the spatial variability of hydraulic conductivity on hydraulic head". Thesis, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464492.
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Romero, Lugo Jose 1985. "Experimental Investigation of Propped Fracture Conductivity in Tight Gas Reservoirs Using The Dynamic Conductivity Test". Thesis, 2012. http://hdl.handle.net/1969.1/148364.
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Hydraulic Fracturing stimulation technology is used to increase the amount of oil and gas produced from low permeability reservoirs. The primary objective of the process is to increase the conductivity of the reservoir by the creation of fractures deep into the formation, changing the flow pattern from radial to linear flow. The dynamic conductivity test was used for this research to evaluate the effect of closure stress, temperature, proppant concentration, and flow back rates on fracture conductivity. The objective of performing a dynamic conductivity test is to be able to mimic actual field conditions by pumping fracturing fluid/proppant slurry fluid into a conductivity cell, and applying closure stress afterwards. In addition, a factorial design was implemented in order to determine the main effect of each of the investigated factors and to minimize the number of experimental runs. Due to the stochastic nature of the dynamic conductivity test, each experiment was repeated several times to evaluate the consistency of the results.
Experimental results indicate that the increase in closure stress has a detrimental effect on fracture conductivity. This effect can be attributed to the reduction in fracture width as closure stress was increased. Moreover, the formation of channels at low proppant concentration plays a significant role in determining the final conductivity of a fracture. The presence of these channels created an additional flow path for nitrogen, resulting in a significant increase in the conductivity of the fracture. In addition, experiments performed at high temperatures and stresses exhibited a reduction in fracture conductivity. The formation of a polymer cake due to unbroken gel dried up at high temperatures further impeded the propped conductivity.
The effect of nitrogen rate was observed to be inversely proportional to fracture conductivity. The significant reduction in fracture conductivity could possibly be due to the effect of polymer dehydration at higher flow rates and temperatures. However, there is no certainty from experimental results that this conductivity reduction is an effect that occurs in real fractures or whether it is an effect that is only significant in laboratory conditions.
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Lien, Bob Kuochuan. "Field measurement of soil sorptivity and hydraulic conductivity". 1989. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1989_664_sip1_w.pdf&type=application/pdf.
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Harvey, Donald John. "The effective hydraulic conductivity of unsaturated layered sands". 1989. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1989_170_sip1_w.pdf&type=application/pdf.
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Shyu, Ing-Shiou, i 徐英修. "Hydraulic conductivity of compacted clay to oxalic acid". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/50073906837700876135.
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碩士國立臺灣大學
環境工程研究所
84
Because of its low permeability, compacted clay is often used as liners in landfills. Under certain conditions clays may be subject to organic contamination, resulting in the change in hydraulic conductivity. This study tries to explore the dissolution of kaolinite in the presence of oxalic acid in terms of hydraulic conductivity of compacted kaolinite and bentonite-field soil mixtures. Compaction test was performed by the standard Proctor methods, and flexible-wall permeameter was used. Specimens werefirst permeated with 0.01 N CaCl2 until a stable hydraulic conductivity was observed and the oxalic acid was then introduced. Batch dissolution results show that both increasing surface protonation and decreasing surface protonation enhance thedissolution rate, and the dissolution rate was affected by the concentration of oxalic acid. Furthermore, the dissolution of kaolinite is surface controlled. Permeability test results show that in the kaolinite and bentonite-field soil mixtures systems, with the introduction of oxalic acid, hydraulic conductivities slightly decrease. The decrease is attributed to the dissolution of clods, which in turn clogged the soil pores and reduced the hydraulic conductivity. With the ratio of bentonite to field soil 12 %, the hydraulic conductivity is close to 10-8 cm/sec. In the mixtures, field soil forms the load-supporting framework and bentonite acts as a seepage barrier, and the mixture was not influenced by permeating with oxalic acid.
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Lai, Yi-Chiu, i 賴宜秋. "FUZZY PROPERTY OF HYDRAULIC CONDUCTIVITY IN PINGTUNG PLAIN". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/65120424119030781681.
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碩士國立屏東科技大學
土木工程系碩士班
90
While groundwater flows through an unconfined aquifer due to heterogeneity, the vertical average saturated hydraulic conductivity is a function of hydraulic head. In this study, the MODFLOW model was used to calculate the relationship between hydraulic head and hydraulic conductivity in Pingtung Plain. In the model, the hydrology stress and boundary conditions were adopted study by other researches. The hydraulic conductivity was transformed with exponential function to examine the distribution properties of fuzzy membership function of the fuzzy theory. The result shows that hydraulic conductivity had fuzzy properties following the changes of groundwater head in observation wells in Pingtung Plain. This analysis indicated that the hydraulic conductivity could not be assumed as a constant value when in situ groundwater flow was simulated with numerical model. Key word : Pingtung plain, hydraulic conductivity, fuzzy theory
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Tseng, Yu-Hsin, i 曾禹昕. "Uncertainty of Hydraulic Conductivity of Fractured Rock Mass". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/ynnwy9.
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碩士國立中央大學
土木工程學系
107
The property of fractured rock is highly spatial variable, and the directionality of fractures has a great influence on the hydraulic conductivity. This study presents the representative elementary volume (REV) of hydraulic conductivity of fractured rock mass. When the rock sample is smaller than the representative elementary volume (REV), the sampled hydraulic conductivity would be discrete, variable and not representative. Then use the REV to investigate the effect of the fracture orientation and Fisher constant on the hydraulic conductivity. Finally, the relationship of the connectivity is defined by the influence parameters of the fractured rock mass. Due to the research of hydraulic conductivity of fractured rock mass usually needs a large number of specimens to do the test, which is difficult to conduct due to high time-consuming and cost. In recent studies, the discrete fracture network (DFN) was widely used to simulate the fractured rock. FracMan was used to generate DFN in rock mass models and execute the systematical sampling in this study. Conventional Oda and Oda gold were adopted to estimate the hydraulic conductivity of the fractured rock mass. A series parametric study including size of rock mass model, specimen volume, dip angle, dip direction, Fisher constant κ, fracture diameter, and fracture intensity was conducted in this study. The quantized model of mean and coefficient of variance of hydraulic conductivity was established based on the results of parametric study. And consolidated the quantized result of the parameters which influence on the connectivity. Then, integrated these results to represent the quantized model of the connectivity. Finally, according to the results of the quantized model, the hydraulic conductivity and the connectivity of the fractured rock mass can be determined, which is applied to the local assessment and prediction of the flow and transmission behavior in the fractured rock mass. It has effective prevention and benefits to the engineering.
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Schulz, Eric Clinton. "Conductivity of proppant mixtures". Thesis, 2014. http://hdl.handle.net/2152/26439.
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Hydraulic fracturing is a physically complex phenomenon, and there are many variables, both environmental and operational, that affect the overall success of a fracture treatment. Amongst the operational variables, the process of proppant selection is key to ensuring that the induced fractures remain open and permeable. A variety of physical mechanisms act to degrade the permeability of a given proppant packing after deposition in a fracture, the most important of which is the magnitude of the confining stress. The goal of this work is to understand how mixtures of unlike proppants behave under various stress conditions. Specifically, the permeability and conductivity of various mixtures of unlike proppants are measured as a function of confining stress. A secondary investigation is also made into the dependence of permeability on the areal concentration of proppant. Choices of proppants are restricted to those which are currently most common in industry, in terms of both material and size. To that end, mixtures consisted of primarily ceramics and sands with appropriate grain size distributions. Additionally, a light-weight plastic proppant was included in the study. Simple laboratory methods are employed to measure the permeability of the various proppant packings. Values obtained from direct experimentation are compared with values obtained from an independent analytical model. Given the assumptions which are inherent in the analytical model, the experimental and analytical results are in satisfactory agreement. Also, a correlation is developed for single proppants and binary mixtures which predicts permeability as a function of stress, grain size, material, and weight fraction. One key conclusion is that for a binary mixture of proppants, the mixture permeability will not generally be a weighted linear combination of the pure proppant permeabilities. In other words, the permeability of a mixture comprised of 50% (by weight) of one component and 50% of the second component will generally not be halfway between the permeabilities of the single components. A hypothesis is presented which posits that there are threshold weight fractions for each proppant pair that control the permeability of the mixture.text
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Rahi, Khayyun Amtair. "Hydraulic conductivity assessment for a variably-saturated rock matrix". 1986. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1986_161_sip1_w.pdf&type=application/pdf.
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Paleologos, Evangelos Konstantinos. "Effective hydraulic conductivity of bounded, strongly heterogeneous porous media". 1994. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1994_71_sip1_w.pdf&type=application/pdf.
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San, Hui-Hsuan, i 三慧瑄. "Estimation of the Hydraulic Conductivity by Using Field Test". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/92407456468679789388.
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碩士中原大學
土木工程研究所
97
Bouwer and Rice is one of the estimation methods of slug test of obtaining the hydraulic conductivity, but it’s a synthetic value of fully drilling, do not know the hydraulic conductivity of each layers. Because of the phenomenon of the delaminated aquifer, so the Bouwer and Rice is the main method discussed in this research that purpose improving the synthetic value, because that can’t know the values of each layers. This research was based on the different circulating area of the recharge and recovery to get two formulas, use Newton-Raphson method to obtain the hydraulic conductivity values in double-layers aquifer. After verification we use the data of Dong Ju to apply to this model. According to the different ratio of transmissivity to discuss the variance, and execute the sensitivity analysis of the parameters to discuss the identifiability. Pumping test is another field test that estimating the hydraulic conductivity, it’s a large scale test that can get the hydro-geological parameters of wide range. Pumping test effected by boundary easily, according to Cooper-Jacob method, use the data of pumping test to draft the semi-log graph and obtain the hydro-geological parameters. When the pumping test encountered the boundary effect, the graph will show two different lines. If there is only one observation data, this method only knew the distance between the observation and boundary. In order to find the location of the boundary, we suggest using the data of one pumping well and two observations to determine the position of boundary, using the pumping test data of Dong Ju to discuss it.
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Rockhold, Mark L. "Characterization of unsaturated hydraulic conductivity at the Hanford Site". 1988. http://hdl.handle.net/2097/22241.
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Huang, Yi-Tzu, i 黃懿慈. "Effect of Gravel Content on Soil Saturated Hydraulic Conductivity". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/43129435714818451815.
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碩士國立中興大學
水土保持學系
93
Due to geological characteristic and high rainfall, soil erosion is generally quite serious in Taiwan. The fine soil particles were eroded easily and the gravel content in soil increased gradually. It will affect the water movement in the soil and change soil saturated hydraulic conductivity. Sieved soil sample with eight treatments, namely, 0%, 5%, 10%, 20%, 30%, 40%, 50% and 60% of volumetric content gravel in soil column were packed to measure soil saturated hydraulic conductivity using constant-head apparatus. Field experiment were measured by Guelph permeameter and cores. Relationship between repacted and in situ saturated hydraulic conductivity was developed, and saturated hydraulic conductivity of repacked soil was fitted by the concept of Kozeny-Carman formula. Experimental results indicated that, bulk density increased with increasing of soil gravel content. On the other hand, porosity decreased with increasing of soil gravel content. The change of soil saturated hydraulic conductivity may divide into three stages: ( ), when 0% < < 10% (1) ( ), when 10% < < 30% (2) ( ), when 30% < < 60% (3) where, is gravel volume content (%). Guelph permeameter and cores cannot be used in high gravel content locations. Only Guelph permeameter results were fitted with the first stage of repacked soil and the relationship function is： ( ), when 0% < <12% where, is gravel weight content (%). and is the saturated hydraulic conductivity measured by Guelph permeameter and the predicted value from equation(1).
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Pang, Zhengyu. "Effects of hemodynamic forces on endothelial cell hydraulic conductivity". 2003. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-372/index.html.
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Hardianto, Fransiscus S. "Representative sample size for hydraulic conductivity of compacted clay". 1992. http://catalog.hathitrust.org/api/volumes/oclc/26102542.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1992.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 112-115).
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Sangita, Sushree. "Hydraulic Conductivity and Leachate Characteristics of Lime Stabilized Flyash". Thesis, 2015. http://ethesis.nitrkl.ac.in/6880/1/Sushree_Mtech(r)_2015.pdf.
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Coal based thermal power plants have been the backbone of a country due to its major contribution in electricity generation for the developmental purposes. Due to indomitable rise in demand of the electricity, the increase in generation of fly ash has become inevitable now-a-days. Moreover, the disposal of fly ash has become a major issue for coal based thermal power plants as it requires a vast disposal area and gives rise to a lot of problems like shortage of useful land, increase in disposal cost and dusting of atmospheric air. Fly ash generated from the coal fired thermal power plants is mostly sluiced into ash ponds by wet disposal method. This fly ash contains a number of soluble major and trace elements such as As, Fe, Cd, Hg, Zn, Pb and Cu, etc. There is possibility that leachate emanating from this fly ash bed may contaminate the ground and pose a threat to the human as well as aquatic life. Therefore, stabilization of fly ash by some chemical additives like lime/cement is an excellent method to mitigate the leachate characteristics of fly ash in addition to improve the strength and stability of the structure.
The leaching of metals mainly depends on two factor such as pH and hydraulic conductivity. The pH plays a pivotal role in reducing the concentration of the elements. Hydraulic conductivity also has a major effect in preventing the leachate from contaminating the ground water. If the material can be made less permeable, the leachate can be confined at the source of generation and thus the ground water can be protected from being contaminated.
A thorough study of the previous research works reveals that lime stabilization is an effective means of reducing the permeability and concentration of metals in the leachate emanating from ash ponds. In the present research work an effort has been taken to study the effect of lime on hydraulic conductivity and leaching characteristics of fly ash by varying the mix-proportion and curing period.
In addition to this, an experimental set up has been developed to investigate the efficacy of lime column in mitigating the leachate characteristics of compacted and sedimented ash beds.
The experiments were performed in two phases. At first, the compaction characteristics of fly ash mixed with different lime content such as 0%, 2%, 4%, 8%, 12% and 15% were found out from light and heavy compaction tests. The hydraulic conductivity and leachate characteristics of compacted fly ash-lime mixes were determined after 0, 7, 15, 30, 60 and 90 days of curing. All these samples were prepared corresponding to their respective MDD and OMC and cured for the specified curing periods as mentioned above. The concentration of the major and trace elements like Cu, Fe, Zn, Ca, Ni, Pb and Cr were found out by atomic absorption spectrometer. The effects of lime content and curing period on microstructure, morphology and hydration products in the stabilized specimens were studied by various microanalyses such as XRD and SEM tests.
Further, large scale laboratory models of sediment and compacted fly ash beds were prepared with a centrally installed lime column simulating a field condition as closely as possible. The samples were collected from various radial distances and depths after 7, 30, 90 and 180 days of curing period and subjected to different tests such as pH, and leachate analysis of different elements like Ca, Ni, Pb, Zn, Cu, Cr, and Fe. In addition to this, the hydraulic conductivity of treated ash deposit was measured by collecting undisturbed specimens from different radial distances and depths.
From compaction test results it is found that for light compaction test, with increase in lime content the OMC value increases up to 4% and thereafter, it decreases whereas in case of heavy compaction test, the OMC increases up to 2% lime addition and thereafter, it decreases. Similarly, the MDD in case of light compaction test decreases with increase in lime content up to 4% and thereafter it increases whereas in case of heavy compaction test the same value decreases up to 2% lime addition and thereafter, it increases.
The hydraulic conductivity value is found to depend on the lime content, compaction effort, and curing period. The samples containing higher doses of lime shows significant decrease in hydraulic conductivity value. It was found that at 90 days curing, it reduces about 10 times for samples compacted with light compaction energy whereas in case of heavy compaction, it decreases about 100 times than the unstabilized specimen. However, sample with no lime content showed marginal change in hydraulic conductivity value with curing period. XRD analysis shows the presence of compounds like ettringite, C-S-H and C-A-H gel which blocks the pore space and reduces the capillary voids. SEM analysis also confirms an interlocking network of hydration products which is responsible in reducing the hydraulic conductivity.
From the leachate analysis, it was observed that concentration of all elements was less than that of leachate sample of raw fly ash collected from acid digestion and extraction method. At 0 days curing the concentration of each metal (except Ca) is approximately same for different lime contents whereas at higher curing period, as the lime content increases, the concentration of metals in the leachate follows a decreasing trend. This is due to presence of alkaline medium which is unfavorable for metal precipitation and also due to encapsulation of metals by the hydration products. It is also observed that the concentration of all the metals was below the threshold limit of IS-10500 and WHO water quality standard.
The pH test results of the sample collected from sediment and compacted ash deposits show that the value is more in the sample collected adjacent to the lime column than that of the sample collected at a remote area from the lime column and also it increases with increase in depth. This is due to migration of lime to the periphery and downward direction of the tank. Moreover, it is observed that the pH value increases with curing period up to 180 days and thereafter, it decreases. Because with longer curing period lime is consumed in pozzolanic reaction which results in reduction of the pH value.
The permeability test result of lime column stabilized ash bed shows that during the early period of stabilization (30 days of curing) no significant variation in hydraulic conductivity value is observed in specimens collected at different locations (different radial distances and depths). However, as the curing period increases, the hydraulic conductivity follows an increasing trend with increase in radial distance whereas the same decreases with depth. In addition, it is also observed that as the curing period increases, a significant reduction in hydraulic conductivity occurs in all the layers of sedimented pond ash deposit.
The leachate analysis result shows that concentration of elements in the leachate sample collected from the test tank is much lower than the leachate sample extracted from raw fly ash. At early stage of curing the concentration of Ca is found to be more than that in the virgin fly ash, however at longer curing period, i.e at 365 days, the concentration of Ca is found to be decreased due to participation of lime in pozzolanic reaction. It is also observed from the results that the concentration of major and trace elements in the leachate sample collected adjacent to the lime column is lesser than that of the sample collected at the periphery of the test tank. This is due to higher pH value adjacent to the lime column as compared to remote areas. Moreover, the concentration of other elements in the leachate collected on 365 days curing is less than that of the sample collected on 90 and 180 days. This is due to the formation of hydration product such as C-S-H gel which encapsulates the elements and prevents leaching. The concentration of elements is found to be less than the threshold limit of WHO and IS-10500 water quality standard.Thus, it is concluded that lime treatment is an effective means of reducing the hydraulic conductivity and concentration of metals in the leachate emanating from compacted as well as sedimented fly ash specimens.