bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small Cone Penetrometer Tests and Piezocone Tests in Laboratory Consolidated Clays
Authors: Almeida MSS , Parry RHG 
Published: February 2009

Abstract
Small vane, 10-mm-diameter cone penetrometer and 12.7-mm-diameter piezocone devices have been developed to measure soil properties in centrifuge models during flight. This paper presents tests with these devices on kaolin and Gault clay in a normal gravity field. Empirical cone factors were shown to increase with increasing overconsolidation ratio but were found to depend on other factors such as cone size and testing rates. The values also differed considerably between the two clays used. Tests with the small piezocone have shown that the ratio of pore pressure to point resistance decreases slightly with the overconsolidation ratio, but not enough for this ratio be used as a method for determining overconsolidation ratio (OCR). As shown by other workers, pore pressures acting around the tip influence measured tip resistance and should be taken into account when interpreting cone resistances in clays. Dissipation tests with the piezocone have yielded values of coefficient of consolidation agreeing very well with those from swelling tests on clay cakes.
Prediction of Pore-Water Pressure Buildup During Undrained Resonant Column Testing of Virgin Sand Specimens
Authors: Chung RM , Yokel FY 
Published: February 2009

Abstract
Prediction of pore-water pressure buildup of a saturated sand deposit subjected to dynamic load is important for dynamic stability analysis of the deposit. Empirical equations, proposed by Drnevich to correlate the predicted pore-water pressure buildup with that measured during undrained resonant column tests on saturated Ottawa silica sand, were used to predict the results of tests on virgin Monterey No. 0 sand specimens. It was found that, with a modification of the coefficient in the empirical equation, there is good correlation between predicted and measured excess pore-water pressures when a high degree of saturation (B ≥ 0.96) was achieved in the specimen preparation. The correlation is poor for specimens with a lower degree of saturation (B &lt; 0.96).
Methods for Predicting Shale Durability in the Field
Authors: Santi PM , Higgins JD 
Published: February 2009

Abstract
Durability of shales and other weak rock is an important parameter describing the material's susceptibility to breakdown upon exposure to water or during construction work. While laboratory methods have been developed to measure durability, no correlations between laboratory results and simple field tests have been determined.
The results of this study show that certain field parameters can predict slake durability with acceptable accuracy. The recommended field tests, in order of desirability, are slake index, jar slake, hammer rebound, and NGI “Q” value. Single variable and multiple variable linear regression equations are given, including equations conservatively modified so that 95% of the slake durability values are underpredicted.
Application of Bender Elements in Measuring Gmax of Sand Under K Condition
Authors: Zeng X , Ni B 
Published: February 2009

Abstract
A new application of bender elements to measure the small strain shear modulus of sand in multiple shear planes under anisotropic loading is developed. The tests were conducted in a specially designed oedometer with the side of the ring smoothed by a Teflon sheet. The soil used in the tests is clean angular pool filter sand. The effects of size of bender elements on the results of shear wave velocity measurement are discussed. Shear modulus in four different shear planes during a loading-unloading cycle is presented. The results of experiments are compared with the Hardin-Blanford equation on Gmax, which shows good agreement. The influence of side friction of the oedometer is investigated.
Procedure for Determining the Segregation Potential of Freezing Soils
Authors: Konrad J-M 
Published: February 2009

Abstract
Basic frost heave data obtained from various types of laboratory freezing tests, using computerized ramp temperature generation and temperature control at both warm and cold ends of a soil specimen, are analyzed to determine the segregation potential. Automatic volume change measurements provide fair values of cumulative water intake, but not accurate water intake rates. A method based on accurate measurements of total heave, taking into account the amount of heave from in-situ freezing of pore-water, yields relevant freezing characteristics of soils. Precise and automatic acquisition of temperature measurements and of total heave during an open-system freezing test enables accurate definition of the segregation potential, the suction at the frozen-unfrozen interface and the rate of cooling of the frozen fringe, immediately after testing. Examples of freezing test results are given to emphasize the influence of various factors such as the temperature at the segregation-freezing front, the soils porosity, and the unfrozen water content on the segregation potential of freezing soils.
Directional Shear Cell Experiments on a Dry Cohesionless Soil
Authors: Sture S , Budiman JS , Ontuna AK , Ko H-Y 
Published: February 2009

AbstractThe directional shear cell has become an important tool for investigating anisotropic soil behavior, especially effects caused by rotation of principal stress directions during monotonic, cyclic, proportional, and nonproportional loading. This paper describes a newly developed directional shear cell and typical stress-strain response curves from two groups of experiments on a cohesionless soil where the principal stress directions either rotate discretely in a jump-like manner or continuously rotate at constant magnitude. It is shown that stiffness moduli are significantly reduced when principal stresses rotate with respect to the soil fabric and that substantial shear strains occur when principal stresses rotate while their magnitudes remain constant.
A Low-Cost Electrolytic Tiltmeter for Measuring Slope Deformation
Authors: Zhang X 
Published: February 2009

Abstract
The tiltmeter described consists of an electrolytic sensor (a glass jar containing an electrolyte and six electrodes) and a portable AC digital conductivity meter, which reads conductivity changes resulting from tilting deflections. The tiltmeter has a sensitivity of 2 to 8 min of arc/cmu (conductivity meter unit), with a measurement range of more than 45°. This tiltmeter measured earth flow subsurface movements reliably. It was easy to install and read.
Undrained Deformability and Strength Characteristics of Soft Bangkok Clay By the Screw Plate Test
Authors: Bergado DT , Huan NM 
Published: February 2009

Abstract
Eighteen screw plate tests were carried out using 10-in. 25.4-cm diameter plate, and three types of laboratory test were performed, namely, 18 unconfined tests, 31 unconsolidated-undrained triaxial tests, and 18 one-dimensional consolidation tests. The sampling and testing were carried out at three sites inside the campus of the Asian Institute of Technology in the soft clay layer. At each site, six screw plate tests were performed at depths of 2.50, 4.50, and 6.00 m, and three boreholes were made to take 60-cm-long Shelby tube samples at the test levels. The screw plate test results were calibrated with unconsolidated-undrained (UU) triaxial test results and the bearing capacity factor Nc was found to be 11.00 while the undrained modulus factor K was found to be 0.61. The screw plate test results were also correlated with the unconfined compression (UC) test and one-dimensional consolidation test in this study as well as with the vane shear test and pressuremeter test results from previous investigations. Furthermore, the pressuremeter-settlement-time relationship was evaluated, and it was found that the logarithm of settlement rate, log s, decreased linearly with the logarithm of time, log t, and increased linearly with the logarithm of the stress level, log P′.
Liquid Limit Determination—Further Simplified
Authors: Nagaraj TS , Murthy BRS , Bindumadhava  
Published: February 2009

Abstract
In recent years the cone penetration method to determine liquid limit of soils has gained popularity and acceptance. This paper advances two more specific potentials of this method by which (1) the liquid limit can be determined almost instantaneously and (2) the liquid limit of soils, also having particles coarser than 425 µm can be directly determined. The interrelation between water content and bulk density at known degree of saturation and specific gravity of soil solids has been used to compute the water content. In the cone penetrometer method, availability of a cup of standard volume is shown to be helpful in determining the bulk density of the soil for different penetration values. In the range of water contents around liquid limit it is further shown that the degree of saturation of the bulk soil in the cup is around 98%. Using this, the water content at different penetrations can be computed. The floating matrix concept has been used to demonstrate the ability of this method to determine the liquid limit of soils also having particles coarser than 425 µm. The limiting size and percent of coarse particles have been indicated.
Determining Preconsolidation Stress and Penetration Pore Pressures from DMT Contact Pressures
Authors: Mayne PW 
Published: February 2009

AbstractOver recent years, several geotechnical explorations in clay deposits have shown the flat dilatometer test (DMT) to provide reasonable estimates of in-situ overconsolidation ratio with depth. Why should the horizontal stress index (KD = initial contact pressure minus hydrostatic pressure normalized to the effective overburden stress) show an empirical trend with over consolidation ratio (OCR)? It is postulated that, since the closing pressure and contact pressures are nearly equal, the initial contact pressure in clay is an approximate measure of the total pore pressure induced during penetration of the dilatometer blade. Published data from a clay site tested by a special DMT having a pore-pressure sensor, as well as piezocone/dilatometer data from seven other sites, support this hypothesis. Since the pore-pressure response of clay is influenced by the in-situ OCR, the initial effective DMT contact pressure can be used to profile the stress history.
Chemical Mass Transport Measurements to Determine Flexible Membrane Liner Lifetime
Authors: Lord AE , Koerner RM , Swan RH 
Published: February 2009

Abstract
The prediction of the service life of flexible membrane liners (FMLs) when exposed to chemicals has usually been by way of testing for physical or mechanical property changes after periodic exposure times. This paper presents an alternate approach by evaluating the chemical properties via five different mass transport related measurements of the exposed FML. These tests are water vapor transmission (WVT), radioactive tracer transmission (RT), water absorption (WA), water vapor absorption (WVA), and benzene absorption (BA).
This approach was tested for exposures of up to 15 months. The FMLs used were polyvinyl chloride (PVC), ethylene-propylene-diene monomer (EPDM), chlorinated polyethylene (CPE), and high density polyethylene (HDPE). The chemicals used were 10% sodium hydroxide (NaOH) (in water), 10% sulfuric acid (H2SO4) (in water), 10% phenol (in water), 100% xylene, and water (as a control). The WVT and RT were found to be quite reliable test methods, whereas the WA and WVA techniques experienced serious problems in regard to obeying simple one-dimensional diffusion theory. The BA method worked well for HDPE. The various transport coefficients showed all the expected types of behavior with chemical exposure: (1) constancy with exposure (acids and bases on most all FMLs and all chemicals on HDPE), (2) decrease with exposure (plasticizers leaching from FMLs), and (3) increase with exposure (Phenol-treated CPE). The WVT and RT results were generally complimentary to one another. The transport approach was quite successful in predicting the instability of CPE exposed to phenol. This instability was further verified by differential scanning calorimetry measurements.
The work reported herein lends credence to the use of mass transport measurements to determine structural change in FMLs. Thus the monitoring of transport properties, over a reasonable exposure time to particular chemicals, could serve as the basis for a predictive method for FML lifetime.
Servo-Controlled Cuboidal Shear Device
Authors: Sivakugan N , Chameau J-L , Holtz RD , Altschaeffl AG 
Published: February 2009

Abstract
A servo-controlled cuboidal shear device with automatic data acquisition system is described. Provisions are made for pore-pressure measurements with specially designed “needle” piezometers. Complete stress-strain curves can be obtained with strains up to 20%. The application of servo-control in Ko consolidation and strain controlled loading is illustrated with flow charts and experimental data.
Multistage Direct Shear Testing of Unsaturated Soils
Authors: Gan KJ , Fredlund DG 
Published: February 2009

AbstractA conventional direct shear box was modified to accommodate the testing of an unsaturated soil. The design concepts and necessary modifications to the apparatus are described. A multistage testing procedure is outlined. Typical results from direct shear tests are presented. The results illustrate the relationship between suction and shear strength for a glacial till soil.
Profiling OCR in Stiff Clays by CPT and SPT
Authors: Mayne PW , Kemper JB 
Published: February 2009

Abstract
Standard penetration tests (SPT) and cone penetration tests (CPT) have conventionally been used to index profiles of undrained shear strength su in clay deposits. Since su is related to stress history, an alternative use of penetration resistances is the profiling of in-situ overconsolidation ratio (OCR). An empirical methodology is developed based on compiled data bases from 50 sites investigated by SPTs and 40 sites tested by CPTs. The study indicates general trends occur between the in-situ OCR and penetration resistances normalized to effective overburden stress in clays. Site specific calibration with laboratory consolidation tests is required, however, for profiling. Electric CPTs are preferable over SPTs and mechanical CPTs for profiling stress history because they are more repeatable and less subject to operator influence.
An Electromagnetic Connection for Triaxial Testing
Authors: de Gijt JG , Pronk WD 
Published: February 2009

Abstract
This paper describes a new tensile connection for transmitting tensile forces to triaxial test specimens. Comparative tests show that the loading and frequency characteristics of this electromagnetic connection are considerably better than those of commercially available screw and vacuum type connections. This means that two-way cyclic triaxial tests can be controlled with much greater precision. Also the procedures for specimen preparation are considerably simplified.
Effect of Dissolved Oxygen (and Bubbles) on the Measured Permittivity of Geotextiles
Authors: Halse YH , Lord AE , Koerner RM 
Published: February 2009

Abstract
Measurements are made of the permittivity in a heat set, nonwoven staple filament polypropylene as a function of the dissolved oxygen content (DOC) of the water. Vacuum deairing of the water to a DOC of 5 ppm or below insures that the measured permittivity will not be lowered by oxygen effects. Careful long-term measurements show that the measured permittivity is reduced very significantly if the DOC rises above 6 ppm. However as long as bubbles are not observed in the water, reasonably good values of the permittivity can usually be achieved, provided the measurements are performed rather quickly.
The Role of Jute Geotextile/Slurry Interface Friction on the Bearing Capacity of Clay Slurry
Authors: Tan S-A , Muhammad N , Karunaratne G-P 
Published: February 2009

Abstract
The layered clay-sand scheme of land reclamation depends on the successful formation of sand seams sandwiched between hydraulically placed layers of marine clay slurry to provide shorter drainage paths for rapid clay consolidation during surcharge application. It is anticipated that a low-cost jute geotextile placed on a clay slurry surface without anchorage will expedite construction of sand seams by providing support for the thin sand layers and preventing penetration of sand into the clay slurry. In this application, the interface friction between the very soft clay slurry and the jute geotextile plays a major role in determining the support for the thin sand seam. This paper discusses measurement of the jute/slurry interface friction by incremental vertical penetration of a thin, end-weighted jute sheet under an incremental load to obtain the interface stress value under a quasistatic condition. The effects of sheet width and sheet type were investigated and found to be negligible on the measured interface friction for the clay slurry water content range tested. The results of the interface friction for the 500 g/m2 jute geotextile is then applied to a rectangular loaded area with a jute base on clay slurries of 150 to 300% water content. These water contents are the likely range of values to be encountered in field applications. The load test results indicate that the measured bearing capacity for the jute on clay slurry is about 5.5 to 6.5 times the interface friction, which is in close agreement with typical bearing-capacity factors used in a shallow foundation on clays.
Model Study on the Failure Mechanism of Soil-Nailed Structure Under Surcharge Loading
Authors: Kim D-S , Juran I , Nasimov R , Drabkin S 
Published: February 2009

Abstract
To investigate the effects of surcharge loading on the failure mechanism of soil-nailed structures, reduced scale-model tests were performed. The main variables for this study were the bending stiffness and tension resistance of nails and applied surcharge loading levels. In addition, two different testing sequences were used to simulate, respectively, the application of soil nailing in both new construction and rehabilitation or widening of earth-retaining systems under surcharge loading. To effectively assess the loading effects on the failure mechanism, failure tests without surcharge loading were performed, and the results were used as reference data. When applying surcharge loading, the failure of the system occurred through a progressive breakage of the nails initiated at the top nails. Under low surcharge loading, the state of stress in the upper nails is close to the stress state for the unloaded wall. As the surcharge loading increases, the equivalent earth pressure coefficient in the upper nails tends to increase toward the atrest value. The locus of nail breakage points under surcharge loading is fairly close to that obtained with flexible nails without surcharge loading regardless of bending stiffness and construction sequence.
Factors Affecting the Performance of a Pneumatic Earth Pressure Cell
Authors: Felio GY , Bauer GE 
Published: February 2009

Abstract
Twenty pneumatic total earth pressure transducers of type SOLINST were installed on a bridge abutment. It was found that their performance was affected considerably by temperature, and to a lesser extent, by the installation procedure and the type of soil in contact with the pressure cells. In order to quantify these influences, an extensive laboratory investigation was undertaken. From this experimental study, correction factors were obtained and applied to the field data. It is suspected that other pneumatic pressure cells will be affected similarly and field measurements need to be corrected.
Imaging of Rock Fractures with Low-Frequency Ultrasonic Reflection/Diffraction
Authors: Glaser SD , Hand MK 
Published: February 2009

Abstract
This paper documents the development of a method for imaging millimeter-scale fractures in rock with low-frequency ultrasound and seismic algorithms developed originally for kilometer-scale geologic structures. Low-frequency ultrasonic reflection/diffraction imaging provides detailed images of an impedance contrast in terms of two-way travel time from the surface to the fracture, which produces a geometrically distorted representation. Several seismic methods were used to sharpen the images, including migration, which greatly enhances horizontal resolution and inverts the image from the travel time domain back into the depth domain. The resulting images allow quantitative analysis of the geometry and location of the fracture.
Computer-based parametric modeling indicates that velocity changes as small as 5% of the rock matrix velocity can be resolved, and fracture length and thickness less than 1 mm can be resolved. Laboratory-scale tests were run on a cast rock-like block with a known flaw (150-mm disk “sandwich” of oil-separated polyethylene, total thickness 1.5 mm). The processed data allowed quantification of the known flaw as well as revealing a sub-millimeter-thick crack that was created during construction of the block. As a final test, the method successfully imaged the failure crack in a rock beam under static loading.
Development of an Axisymmetric Field Simulator for Cone Penetration Tests in Sand
Authors: Hsu H-H , Huang A-B 
Published: February 2009

Abstract
An experimental system capable of simulating axisymmetric field conditions has been developed. This system, as an improvement over conventional calibration chambers, enables cone penetration tests (CPT) to be calibrated under minimal boundary effects. The new simulator consists of a stack of 20 rings to house the sand specimen. These rings are lined with an inflatable silicone rubber membrane on the inside. The boundary expansion and stress are measured and individually controlled, respectively, at each ring level during the CPT. The soil from physical boundary to infinity is simulated using a nonlinear cavity expansion curve derived from a lateral compression test on the specimen. Results from a series of CPTs show that at relative densities of approximately 80%, the cone tip resistance values agree within 4% as the diameter ratio of the physical specimen over cone varies from 18 to 22. This paper describes unique features of this field simulator, presents available CPT data performed in the simulator, and discusses its implications on future calibration tests.
An Automated Apparatus for Three-Dimensional Monotonic and Cyclic Testing of Interfaces
Authors: Fakharian K , Evgin E 
Published: February 2009

Abstract
A new computer-controlled apparatus has been developed to study the behavior of interfaces between two materials under three-dimensional monotonic and cyclic loading conditions. The interface can be subjected to a normal stress, σn, and two shear stresses, τx, and τy, acting simultaneously on the interface plane. The normal stress is applied by a pneumatic actuator that is operated by a motorized regulator. Shear stresses, which are perpendicular to each other, are applied by two stepper motors. Tests can be either displacement or load controlled.
The results of an experimental program that includes two series of tests to study the behavior of an interface between a dry coarse sand and a rough surface are presented. In the first series, two-dimensional monotonic and cyclic tests were carried out to verify the performance of the apparatus. The effects of surface roughness, initial relative density of sand, and the magnitude of normal stress on the shear stress-shear displacement and volume change behavior of the interface are presented. In the second series, the loading was three-dimensional and monotonic. First, the interface was sheared in one tangential direction up to a shear stress level less than the peak value. Then, the interface was sheared in a perpendicular direction, while the shear stress in the previous direction was maintained at a constant level. Shear stress and shear displacement increments experienced different paths, while the resultant shear stress-shear displacement curves remained the same irrespective of stress paths.