Field Permeability Tests Research Articles

What maximum permeability can be measured with a monitoring well?

The PVC screens of recent monitoring wells (MWs) have thin slots and a low open area, usually in the 2–8% range. The MW screen and filter pack may cause important head losses which are not taken into account when interpreting the data of permeability tests performed using the MW. The equivalent hydraulic conductivity K of usual PVC screens was defined by hydraulic tests in a water tank, which have shown that gas micro-bubbles, a common problem in MWs and filter packs, contribute to increase the parasitic head losses. Closed-form equations and numerical models are used to explain by how much a field permeability test in a MW under evaluates an aquifer K value due to parasitic head losses in the screen and filter pack. The MW can properly measure the local soil K value only if it is markedly lower than the maximum MW value as obtained in a water tank. The MW measuring capacity can reach 5×10−3m/s for large slots and deaired water, but is most often between 10−5 and 10−4m/s for small slots in field conditions, and it can be only 10−6m/s for poorly designed and installed MWs. The limited measuring capacity may yield artificial permeability scale effects as often registered in environmental studies.

Evaluating the Relationship between Permeability and Moisture Damage of Asphalt Concrete Pavements

AbstractLimiting the presence of water inside an asphalt concrete (AC) pavement can slow down the process involved in water diffusion, hydration, adhesion loss, and other mechanisms of moisture damage. In the past, numerous studies have been conducted on the topic of moisture damage and permeability, but very few studies have related permeability with moisture damage in AC. This study evaluates whether such relation exists. In essence, a field survey is conducted to identify a set of pavements (bad) that suffer from moisture damage and a set of pavements (good) that do not exhibit moisture damage. Field permeability tests and coring are conducted on the pavements. Laboratory permeability tests are performed on the field cores. An indirect tensile strength ratio (TSR) of wet- to dry-conditioned core samples is determined in the laboratory and used as a moisture damage potential parameter. Wet conditioning is performed by using a recently developed moisture-induced sensitivity test (MIST) device and a well-...

A coupled analysis of cavity and pore volume changes for pulse tests conducted in soft clay deposits

SUMMARYThis paper presents a new interpretation method for pulse tests, a field permeability test that allows for rapid measurements of hydraulic conductivity k in aquitards. This new method applies to soft clay deposits. To initiate a pulse test, a known volume of water is injected into the sand filter of a monitoring well isolated by a packer. The resulting pressure increase yields an outward movement of the sand filter cavity wall. After presenting the usual interpretation methods and their limits, this paper proposes a new interpretation method based on a coupled analysis of the pressure and displacement fields in the soil using the Biot–Darcy formulation. A series of analytical and numerical non‐dimensional velocity graphs, normalized plots of the mean hydraulic head difference versus its rate of change, are given. For a linear elastic material, these type curves show relatively small variations with the sand filter aspect ratio and the Poisson ratio of the tested clay. The type curves are also found to be independent of the clay compressibility (mv) and k, an important result. A series of pulse tests conducted in a soft marine clay deposit near Montreal, Canada, are interpreted with the proposed method. The hydraulic conductivity values calculated from these tests are closely correlated with independent estimates obtained using long‐duration variable‐head tests. Compared with previous interpretation methods, the proposed method allows soil volume changes to be reconciled with cavity expansion phenomena and the range of type curves available for the interpretation of test data to be constrained. Copyright © 2013 John Wiley & Sons, Ltd.

W-tube system with bi-exponential response – A model for permeability tests in heterogeneous aquifers

Summary This article presents the results of a search for a laboratory (physical) and the corresponding mathematical model of bi-exponential water level movement in a W-tube (triple-columned) system. Water level movement in this laboratory system resembles the behavior of the water level in piezometers installed in heterogeneous aquifers during field permeability tests, where a response to the initial disturbances is recorded. The configuration of the W-tube was set to ensure the bi-exponential return of the water level to its initial position. Throughout laboratory experiments, four types of sand samples were analyzed. The shape of the recorded rate-of-rise curve depended on hydraulic conductivities of the sands in the branches of the W-tube system. Results of the analytical mathematical model and the experiments were compared, good convergence was obtained.

Quality control/quality assurance testing for longitudinal joint density and segregation of asphalt mixtures

Longitudinal joint quality control/assurance is essential to the successful performance of asphalt pavement and it has received considerable amount of attention in recent years. Five paving projects were selected for sampling and evaluation in Iowa. For each project, joint quality is compared with regard to the “center” of the pavement mat (6′ right of joint). Field densities and permeability test were made. Cores were obtained for subsequent lab permeability, density and indirect tensile (IDT) strength testing. Asphalt content and gradations were also obtained to determine the joint segregation.In general, this study found that methods providing the most reliable measurements of joint quality are the AASHTO T166, AASHTO T331 (CoreLok) density tests and the permeability test by Karol-Warner Permeameter. The minimum required joint density for quality control should be around 90.0% and 88.5% of theoretical maximum density based on the AASHTO T166 and AASHTO T331 method respectively. Based on various mix design and longitudinal joint construction methods, the joints show differences in asphalt content and level of segregation. Results of this study indicate that poor quality of longitudinal joint should be a combination of segregation, asphalt content variation and insufficient density.

A Leaky Aquifer below Champlain Sea Clay: Closed‐Form Solutions for Natural Seepage

Closed-form solutions are proposed for natural seepage in semiconfined (leaky) aquifers such as those existing below the massive Champlain Sea clay layers in the Saint-Lawrence River Valley. The solutions are for an ideal horizontal leaky aquifer below an ideal aquitard that may have either a constant thickness and a constant hydraulic head at its surface, or a variable thickness and a variable hydraulic head at its surface. A few simplifying assumptions were needed to obtain the closed-form solutions. These have been verified using a finite element method, which did not make any of the assumptions but gave an excellent agreement for hydraulic heads and groundwater velocities. For example, the difference between the two solutions was smaller than 1 mm for variations in the 5 to 8 m range for the hydraulic head in the semiconfined aquifer. Note that fitting the hydraulic head data of monitoring wells to the theoretical solutions gives only the ratio of the aquifer and aquitard hydraulic conductivities, a clear case of multiple solutions for an inverse problem. Consequently, field permeability tests in the aquitard and the aquifer, and pumping tests in the aquifer, are still needed to determine the hydraulic conductivity values.

Field evaluation of permeability of concrete linings and rock masses around underground lined rock caverns by a novel in-situ measurement system

In this paper, we introduce a novel in-situ permeability measurement system and present the results of field permeability testing using the developed system. Using a modular structural design and wide measurement range from low to high permeability, the developed system was capable of measuring in-situ scale permeabilities of concrete linings, construction joints and rock mass around excavated rock caverns. Such measurements have been extremely limited so far but are essentially required in estimating the sealing performance of underground storage caverns. The experimental results of a concrete block model test as well as field permeability measurements of concrete linings and the excavation damaged zone (EDZ) around a lined rock cavern (LRC) in a pilot plant for underground compressed air energy storage (CAES) were presented. From these experimental measurements, we could verify the effective applicability of the developed system to a wide range of measurement conditions, from the low permeability concrete lining matrix to the highly permeable construction joints and fractured rock masses around underground rock storage caverns.

N.D.S공법과 S.M.I공법을 이용한 지반차수 방법에 관한 연구

This paper describes a study on the permeability reduction of the riverbed ground during urban railway tunnel construction. The research is mainly concentrated on the study of the grouting or injection methods among permeability reduction methods which can be adapted in the riverbed ground. The design technology of grouting methods considering the long term hydro-geological behaviour in the riverbed, was suggested. Two injection methods namely, Natural Durable Stabilizer (N.D.S) and Space-Multi Injection Grouting (S.M.I) methods, were introduced as new approach methods which could be adapted to modify the riverbed ground. In order to evaluate the performance of the improved ground by the N.D.S and S.M.I method, a series of pilot tests including the field and laboratory permeability tests, were carried out in the river crossing tunnel construction sites. The results obtained from pilot test program, were also reviewed. The results, the grouting efficiency of the S.M.I method using the non-alkalimeter silica sol is better than that of N.D.S method using cement. In addition, it is anticipated that the current research results are contributed to develop the grouting design technology.

自動現場透水試験システム(平 主水)の開発

自動現場透水試験システム(平 主水)の開発

Sample Size Requirements for Field Permeability Measurements of Hot-Mix Asphalt Pavements

The permeability of coarse-graded asphalt mixtures has been of great concern in recent years. Asphalt mixes that are permeable are susceptible to a number of distresses, such as moisture damage, raveling, cracking, and binder oxidation. In this study, seven sites were mapped according to the vacuum permeameter method to determine the location and distribution of permeable voids. The variability of the sites was evaluated to determine an appropriate sample size for permeability testing. Relatively impermeable pavements were consistent; pavements with moderate or high permeability were more variable. Relationships between sample size, reliability, and testing discrimination are presented. Based on the range of standard deviations measured in this project, a minimum sample size of 10 is recommended for pavements with marginal densities or variable consistency. On the basis of the results of this study, permeability test results are highly dependent on the placement of the permeameter during testing, the effective testing area of the permeameter, and the variability of the pavement. Field permeability testing may have value as a forensic tool, but the large sample size required is not conducive to standard quality control procedures.

Comparative Analysis of Field Permeability Testing of Compacted Hot-Mix Asphalt Pavements: Using Air and Water Permeameters

The in-place permeability of asphalt pavements has been the focus of recent research as investigators try to establish links between pavement permeability and performance. Previous research concluded that pavements with in-place air voids exceeding 8% to 10% may be considered as excessively permeable, and it is generally accepted that excessively permeable pavements are more prone to oxidation and stripping of the asphalt binder, as well as more susceptible to freeze-thaw degradation. As the use of the Superpave® design procedures has increased, numerous questions have arisen regarding the effect of certain mix design parameters on the in-place density and permeability of compacted asphalt pavements. A recent investigation into this issue has generated the need for reliable test methods and equipment that can be used to assess the field permeability of in-place pavements. Results of field permeability tests conducted on newly constructed asphalt pavements by using both water and air permeameters are prese...

Comparative Analysis of Field Permeability Testing of Compacted Hot-Mix Asphalt Pavements

The in-place permeability of asphalt pavements has been the focus of recent research as investigators try to establish links between pavement permeability and performance. Previous research concluded that pavements with in-place air voids exceeding 8% to 10% may be considered as excessively permeable, and it is generally accepted that excessively permeable pavements are more prone to oxidation and stripping of the asphalt binder, as well as more susceptible to freeze–thaw degradation. As the use of the Superpave® design procedures has increased, numerous questions have arisen regarding the effect of certain mix design parameters on the in-place density and permeability of compacted asphalt pavements. A recent investigation into this issue has generated the need for reliable test methods and equipment that can be used to assess the field permeability of in-place pavements. Results of field permeability tests conducted on newly constructed asphalt pavements by using both water and air permeameters are presented. The data obtained indicate that currently accepted test methods based on the water permeameter may not produce repeatable results for all pavement types investigated. In contrast, test data obtained with the air permeameter indicate good repeatability for all included pavement types.

Influence of the presence of a partially saturated layer on the interpretation in field permeability tests

This paper concerns the determination of the soil permeability from water tests performed in the proximity of a partially saturated layer. The objective of the study is the determination of the influence of the presence of a partially saturated zone on the shape factor. The latter is a key parameter for the interpretation of soil permeability from in situ tests. The paper is composed of three parts. The first part describes the water test generally used in the measurement of the permeability in saturated soils, and we discuss difficulties of its use in the presence of unsaturated soils. The second part includes the numerical model used to study the flow of water in partially saturated soils. The last part involves a study of the influence of the presence of a partially saturated soil on the interpretation of the water test.

Predicting Field Permeability from Testing Hot-Mix Asphalt Specimens Produced by Superpave Gyratory Compactor

This study was conducted to develop laboratory and field permeability testing procedures for design and quality control of Superpave® mixtures in Wisconsin. Sixteen mixes including fine-graded and coarse-graded mixes were evaluated. The in-place field permeability was measured by using the National Center for Asphalt Technology (NCAT) device, field cores were taken for measuring permeability in the laboratory by using the ASTM D5084 method, and laboratory compaction was used to prepare and test samples from loose mixtures recovered from the field. Two compaction procedures called Method A and Method B were used in this study to produce Superpave gyratory compacted (SGC) specimens that have thickness, air voids, and aggregate orientation similar to the field cores. Result indicates that Method B, based on the use of Ndesign gyrations for different sample sizes, can be used to produce samples that give permeability values similar to values measured for field cores. Results of this study also indicate a good relationship between field permeability (using the NCAT device) and lab permeability measured on field cores of fine-graded mixes with the amount passing No. 8 sieve (P8) higher than 45%. However, the relationship between field permeability and lab permeability measured on field cores of coarse-graded mix (P8 lower than 40%) is poor. It is concluded that the NCAT permeability device could possibly be used in the field for fine-graded mix (with P8 higher than 45%). However, to measure the field permeability of coarse-graded mix (P8 lower than 40%), there appears to be no current alternative better than taking field cores and testing them in the laboratory. For estimating permeability during mixture design, a simple method for preparing and testing permeability of SGC specimens and interpolating based on expected field density is introduced.

Predicting Field Permeability from Testing Hot-Mix Asphalt Specimens Produced by Superpave Gyratory Compactor

This study was conducted to develop laboratory and field permeability testing procedures for design and quality control of Superpave® mixtures in Wisconsin. Sixteen mixes including fine-graded and coarse-graded mixes were evaluated. The in-place field permeability was measured by using the National Center for Asphalt Technology (NCAT) device, field cores were taken for measuring permeability in the laboratory by using the ASTM D5084 method, and laboratory compaction was used to prepare and test samples from loose mixtures recovered from the field. Two compaction procedures called Method A and Method B were used in this study to produce Superpave gyratory compacted (SGC) specimens that have thickness, air voids, and aggregate orientation similar to the field cores. Result indicates that Method B, based on the use of Ndesign gyrations for different sample sizes, can be used to produce samples that give permeability values similar to values measured for field cores. Results of this study also indicate a good relationship between field permeability (using the NCAT device) and lab permeability measured on field cores of fine-graded mixes with the amount passing No. 8 sieve (P8) higher than 45%. However, the relationship between field permeability and lab permeability measured on field cores of coarse-graded mix (P8 lower than 40%) is poor. It is concluded that the NCAT permeability device could possibly be used in the field for fine-graded mix (with P8 higher than 45%). However, to measure the field permeability of coarse-graded mix (P8 lower than 40%), there appears to be no current alternative better than taking field cores and testing them in the laboratory. For estimating permeability during mixture design, a simple method for preparing and testing permeability of SGC specimens and interpolating based on expected field density is introduced.

Fracture hydraulic conductivity in the Mexico City clayey aquitard: Field piezometer rising-head tests

A regional lacustrine aquitard covers the main aquifer of the metropolitan area of Mexico City. The aquitard’s hydraulic conductivity (K′) is fundamental for evaluating the natural protection of the aquifer against a variety of contaminants present on the surface and its hydraulic response. This study analyzes the distribution and variation of K′ in the plains of Chalco, Texcoco and Mexico City (three of the six former lakes that existed in the Basin of Mexico), on the basis of 225 field-permeability tests, in nests of existing piezometers located at depths of 2–85 m. Tests were interpreted using the Hvorslev method and some by the Bouwer-Rice method. Results indicate that the distribution of K’ fits log-Gaussian regression models. Dominant frequencies for K’ in the Chalco and Texcoco plains range between 1E−09 and 1E−08 m/s, with similar population means of 1.19E−09 and 1.7E−09 m/s, respectively, which are one to two orders of magnitude higher than the matrix conductivity. In the Mexico City Plain the population mean is near by one order of magnitude lower; K’=2.6E−10 m/s. The contrast between the measured K’ and that of the matrix is attributed to the presence of fractures in the upper 25–40 m, which is consistent with the findings of previous studies on solute migration in the aquitard.

Comparison of Falling-Head and Constant-Head Techniques: Estimating Field Permeability of Hot-Mix Asphalt Pavements

Permeability of hot-mix asphalt continues to generate considerable interest in the asphalt materials, design, and construction community. Ongoing studies of permeability report advances in permeability testing techniques for both laboratory-based and field-based testing methods. The University of Arkansas (UAF) has developed a constant-head field permeability test device for use on in-place asphalt pavements. One constructed test section and 16 in-service pavements, including both new construction and overlays of existing pavements, were tested with the UAF device and a falling-head field permeameter originally developed by the National Center for Asphalt Technology. At each field test site, cores were taken from the pavement and tested in the laboratory by the falling-head, constant-tail method described in ASTM PS-129. At a minimum, two field permeability measurements were taken at each site with each permeability device; at least three cores were taken from each test site for testing in the laboratory. The total data set for this study includes more than 40 direct comparisons of each field method and the laboratory results. The data indicate that falling-head and constant-head field methods yield significantly different permeability results but display similar test variability (based on replicate tests). Further, field permeability measured by the falling-head method was significantly different from corresponding laboratory results, while constant-head field results were not significantly different from laboratory results. Relative differences between field devices in the initial applied hydraulic head and the test area footprint may contribute to observed differences.

Variable-Head Field Permeability Tests in Driven Flush-Joint Casings: Physical and Numerical Modeling

Abstract Two types of variable-head permeability tests in driven flush-joint casings, the end-of-casing test and the lateral injection test (Lefranc test), were performed in two sand tanks. Hydraulic conditions in the sand tanks included a constant vertical hydraulic gradient that was null, positive, or negative. The gradients were monitored by lateral piezometers, which confirmed that the large-scale hydraulic conductivity (k) value of the sand layer remained constant throughout the test program. Any interpretation method for these variable-head tests implicitly requires an assumed piezometric level (APL) for analysis. According to a common practice, the elevation of the ponded water surface above the sand deposit was taken as the APL to plot the test results as the logarithm of the difference in total head versus time. After each casing installation, permeability tests were performed for the three gradient conditions. When the vertical gradient was null in the tank, the test data provided straight lines as assumed in theory. When the gradient was positive or negative, the test data provided curved graphs that may be interpreted as giving k values that vary with time. The velocity graph method, however, provided the same constant k value for the three gradient conditions. It also detected the error in the APL and provided in all cases a local piezometric level (PL) equal to that given by lateral piezometer monitoring. Thus, the velocity graph method, a graphical representation of the conservation equation, eliminated the potential for misanalysis of variable-head tests. The experimental k values, as determined by the two types of tests, usually ranged between 0.5 and 2 times the larger-scale values determined independently by the monitored flow rates and gradients in the sand tanks. The variability in experimental k values was partly due to the local variations of void ratio and effective diameter of the sand, and partly due to the influence of casing installation. Numerical simulations of the tests confirmed the validity of the velocity graph method for providing k and the local piezometric level for a test.

Assessing subsoil permeability for groundwater vulnerability

Groundwater vulnerability assessment is a key element of any groundwater protection scheme. In Ireland, groundwater vulnerability is determined mainly according to the thickness and permeability of the subsoils (glacial tills and other superficial deposits). The relative permeabilities of the subsoils are assessed qualitatively as high, moderate or low. To improve the robustness of the groundwater protection scheme, research was carried out into subsoil properties with the aims of refining the permeability ratings, and of improving the way in which subsoil permeability classes are assigned. This research focused on subsoils in the low and moderate permeability categories, mainly tills. Important issues investigated were the relationship between permeability and the grain size distribution of the subsoil, description of subsoils for permeability classification, correlation between permeability and indicators of aquifer recharge, and suitable field and laboratory methods for measuring subsoil permeability. A standard system for describing subsoils was selected, namely BS5930:1999, the choice being influenced by the familiarity of this system among the main users of the vulnerability maps. Analysis of subsoil field descriptions and grain size data indicate that those samples identified as ‘CLAY’ on the basis of BS 5930 correspond to the low permeability category, and tend to have more than 13% clay size particles. The permeability values obtained from each method are compared and indicate that the numerical boundary between moderate and low permeability lies in the region of 10 −9 m/s. Differences between the results from laboratory and various field permeability test methods can be explained by differences in scale and by the presence of discontinuities. The research was successful in refining the permeability ratings and thereby in making the vulnerability maps more defensible against possible challenges. This research has improved the way permeability maps are produced in Ireland, and may prove useful in other countries where permeability data are scarce and mapping relies largely on field assessment of subsoils.

Round-Robin Study for Field Permeability Test

Recently, a field permeability device and test procedure have been developed and tested by the National Center for Asphalt Technology (NCAT) that have shown the ability to identify pavement areas with high permeability to water. This device works by measuring the amount of water that flows into a pavement over a given time period by using a falling-head approach. Based on work conducted by NCAT, the use of this field permeability device has many potential benefits to the hot-mix asphalt industry. The field permeability device can be used as an almost real-time estimate of mat density and may be a good indicator of longitudinal joint quality. Because of the success NCAT has had with the device to date, a study was needed to evaluate the repeatability and reproducibility of the test method. Results of the round-robin study indicated that an estimate of permeameter–operator reproducibility was 10.0 × 10−5 cm/s. An overall standard deviation on permeability measurements was found to be 24.4 × 10−5 cm/s. Additionally, criteria were developed based on the variability of test results to specify field permeability testing for quality control type testing to ensure impermeable pavements.