bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Triaxial Testing System to Evaluate Stress-Strain Behavior of Soils for Wide Range of Strain and Strain Rate
Authors: Santucci de Magistris F , Koseki J , Amaya M , Hamaya S , Sato T , Tatsuoka F 
Published: February 2009

Abstract
Some important modifications were made to an existing triaxial testing apparatus to more accurately evaluate the stress-strain behavior of geomaterials for wide ranges of strain and strain rate. An electro-mechanical loading device was specifically designed to control strain states and stress paths and to study the quasi-elastic properties of geomaterials at any given stress state. The device is now driven by an a-c servo motor, allowing for changing the strain rate about three orders of magnitude without any intermission in each test. A 16-bit A/D card has been adopted also to increase the resolution in data acquisition. The long-term stability of a local axial gage, LDT, has been ensured to evaluate creep deformations as well as post-creep behavior of geomaterials, which should be properly understood for many practical engineering applications. High performance of the system is demonstrated by presenting some typical results from undrained cyclic tests at very small strain levels for a wide range of strain rate and an undrained monotonic loading test for a wide strain range, both on a compacted silty sand. It is shown that the equivalent Young's modulus and damping ratio at very small strains have a clear sensitivity to both strain rate and ageing period. For monotonic shearing tests in a wide range of strain, the isotach property and the effects of changes in the strain rate are also presented.
Model Studies of the 1988 Kettleman Hills Landfill Slope Failure
Authors: Chang M-H , Mitchell JK , Seed RB 
Published: February 2009

Abstract
The paper describes physical model studies of the 1988 failure of Unit B-19 waste landfill at the Kettleman Hills Landfill, Kettleman City, California. Six 1/150 scale models were tested under 1-g (g = gravity) conditions. Aims of the study were to confirm the mode of failure and to provide a better understanding of the sliding mechanism. Results showed that the failure conditions (e.g., slide direction, magnitude, and surface cracking, etc.) of the models agreed very well with those of the actual landfill. The study indicated that the sliding of model fills occurred as a coherent mass, with slip surfaces located at the interface within the underlying liner system. Internal shears and surface cracks were formed in the slide mass due to the noncircular configuration of the slip surface. Displacement paths suggested the sliding of model landfill was essentially a translational movement of a three-block system. The models accurately reproduced the 1988 Kettleman Hills Landfill failure and provided information that enabled development of an analysis method for evaluating the three-dimensional stability of waste landfills against sliding along an underlying linear system (Chang 1992).
Shear Banding in a Sedimentary Soft Mudstone Subjected to Plane Strain Compression
Authors: Hayano K , Maeshiro T , Tatsuoka F , Sato T , Wang L , Kodaka T 
Published: February 2009

Abstract
A plane strain compression (PSC) testing system to observe shear banding in softrock was developed. The deformation characteristics of shear band in a sedimentary soft mudstone were evaluated by locally measuring axial and lateral deformations of specimens in drained PSC tests. Shear deformation and dilatancy of shear band that occurred between the peak stress state and the start of the residual stress state were on the order of 1 and 0.5 mm. Dilatancy of the shear band continued during the residual stress state, resulting in a high-residual friction angle mobilized along the shear band. Shear band deformation characteristics of two other sedimentary softrocks were obtained from axial strains measured locally in triaxial compression tests based on the stress-state dilatancy relationship obtained from the PSC tests.
An Innovative Method of Load Testing Deep Foundations
Authors: Ooi PSK , Frederick LL 
Published: February 2009

Abstract
Current procedures for high strain dynamic testing of piles require estimation of the dynamic resistance. This paper presents an innovative method of load testing deep foundations that estimates the pile capacity directly. By placing and monitoring sensitive force sensors near a pile head, a force-time curve can be generated when an impact load is applied. The unique stages of the impact event are captured in a force-time plot from which the ultimate pile capacity is estimated directly. Similar sensors can be placed at the pile toe to estimate end bearing. Ancillary equipment, consisting of the same force sensors sandwiched between two thin plywood boards, can be placed on top of production piles during driving for capacity estimates. Pile capacities derived have been found to be in reasonably good agreement with values from two static load tests. It also provides information on pile integrity during driving.
Specimen Size Effects for Fiber-Reinforced Silty Clay in Unconfined Compression
Authors: Ang EC , Loehr JE 
Published: February 2009

Abstract
A series of laboratory unconfined compression tests were performed on specimens of a compacted silty clay to evaluate how the size of specimens used for strength testing of fiber-reinforced soil affects the measured strength and stress-strain properties. The results of these tests indicate that there is a significant effect of sample size both in terms of the magnitudes of the measured strengths as well as in terms of the variability of the measured strengths. The effects of specimen size were found to be most important for specimens compacted dry of the optimum moisture content. While no clear threshold specimen size was identified, the data indicate that specimens of 70 mm or greater in diameter are likely to produce strengths that are reasonably representative of the “mass” properties of fiber-reinforced soils.
Evaluation of Multi-Electrode Earth Resistivity Testing in Karst
Authors: Roth MJS , Nyquist JE 
Published: February 2009

Abstract
Multi-electrode resistivity testing is quickly becoming a common tool for geotechnical site investigation in karst areas, particularly areas with clay soils. To study the effectiveness of this method, data from over 140 resistivity tests at two sites were collected and compared with the results from 51 borings. The tests were conducted to evaluate the effect of electrode arrangement and the presence of conductive utilities, to determine the repeatability of the results, and to evaluate the effectiveness of the method in determining depth to bedrock and the location and size of voids. The results demonstrated that multi-electrode resistivity can reliably map depth to bedrock with excellent repeatability, although there was some smoothing in areas where the true bedrock surface is highly irregular. Underground utilities presented the most serious problem when oriented parallel to the resistivity electrode spread. The multi-electrode resistivity method was not as effective at locating voids. The strongest indication was provided by comparison of the resistivity data from lines collected perpendicular and parallel to the geologic strike because the results tended to be very different when collected over a cavity. Recommendations for using resistivity testing as a site investigation tool are given.
A Testing Unit for Monitoring Wall Permeability In Situ
Authors: Brauns J , Bieberstein A , Reith H 
Published: February 2009

Abstract
It is difficult to prove the permeability characteristics of a cut-off wall. For this reason, a special testing unit for monitoring the wall permeability in-situ was developed. The testing unit can easily be installed at any depth of a cut-off panel by hanging it into the fresh slurry. After the installation it remains in the cut-off panel and can be used for a long period. The application and evaluation of tests results are described.
Influence of Matric Suction on the Results of Plate Load Tests Performed on a Lateritic Soil Deposit
Authors: Costa YD , Cintra JC , Zornberg JG 
Published: February 2009

Abstract
This paper evaluates the influence of soil matric suction on the results of plate load tests conducted in an unsaturated, lateritic soil deposit at a depth of 1.5 m. Soil suction was monitored during the tests with tensiometers installed at the bottom of the testing pit. Field test results show that small increases in matric suction lead to substantial increases in bearing capacity of the soil-plate system. In situ experimental loading-collapse (LC) and suction increase (SI) yield surfaces are proposed for the soil investigated. Changes in matric sucion were observed to significantly influence settlement response, particularly for high levels of surcharge load. The rate of settlement shows a non-linear decreasing trend with increasing soil matric suction.
Centrifuge Modeling for Undergraduate Geotechnical Engineering Instruction
Authors: Dewoolkar MM , Goddery T , Znidarcic D 
Published: February 2009

Abstract
A small, simple, and economical instructional centrifuge has been developed at the University of Colorado at Boulder to assist in undergraduate geotechnical engineering education. Centrifuge experiments on stability of slopes and retaining walls have been developed. These experiments are conceptually simple, yet fundamental, and do not require elaborate instrumentation and data acquisition. Classical failure patterns discussed in the class can be reproduced in the models. Experimental results can be used to verify such theories as undrained slope stability analysis and Rankine's or Coulomb's lateral earth pressure theories. Each of the tests can easily be conducted up to four to five times in a 2-h laboratory session. Comprehensive laboratory reports can be generated by students discussing both qualitative and quantitative aspects of the tests in relation to the theoretical concepts taught in the classroom. In addition to the experiments on slope stability and lateral earth pressures, demonstration experiments on footings and reinforced earth slopes have also been conducted using the instructional centrifuge.
Experimental Evaluation of Consolidation Behavior of Stiff Clay Lumps in Reclamation Fill
Authors: Leung CF , Wong JC , Manivanann R , Tan SA 
Published: February 2009

Abstract
When stiff clay dredged from the seabed is deposited by barge as fill material, large voids exist between the stiff clay lumps in the reclamation fill. One major concern is that the voids may close up upon loading, resulting in a large and sudden increase in the fill settlement. In the present study, an experimental investigation is carried out to examine the behavior of fill made up of dredged stiff clay lumps using a large one-dimensional compression apparatus and a centrifuge modeling technique. The results revealed that much of the inter-lump voids close up during the preloading stage. In addition, the rate of consolidation of the lumpy fill is significantly faster than that of homogeneous clay with the difference in consolidation rate diminishing with increase in loading pressure. The effects of lump shape and size, and original shear strength of in situ clay on the performance of lumpy fill, are also investigated.
Changes in Clay Swelling and Shear Strength Properties with Different Sample Preparation Techniques
Authors: Attom MF , Abu-Zreig MM , Obaidat MT 
Published: February 2009

Abstract
This paper presents the effect of compaction methods on soil swell pressure, unconfined compressive strength, and swell potential of three types of soils in Jordan. Undisturbed and disturbed soil samples were collected from the field and used for this study. Compacted soil specimens were prepared using dynamic compaction, static compaction, and kneading compaction. Swell potential test, swelling pressure test, and unconfined compression test were conducted on identical samples compacted by different methods, and having similar initial conditions to the undisturbed samples. Other sets of experiments were also conducted to examine the influence of initial water content on swell pressure and unconfined compressive strength under different compaction techniques. Results indicated that the undisturbed samples have the highest swelling pressure and swell potential values followed by dynamic compaction, while kneading compaction gave the lowest values for the three soils. For the same soil, it has been found that the swelling pressures of the undisturbed samples were 1.5, 1.96, and 3.07 times of that for the dynamic, static, and kneading compaction, respectively. Similar trends were obtained with regard to unconfined compressive strength and swell potential. The unconfined compressive strengths of the undisturbed samples were 1.35, 1.6, and 2.53 times higher than that of the soil specimen compacted according to the dynamic, static, and kneading procedures, respectively.
Determination of Critical State Parameters in Sandy Soils—Simple Procedure
Authors: Santamarina JC , Cho GC 
Published: February 2009

Abstract
The critical state is arguably the most robust criterion for strength design, including post liquefaction strength. The conventional triaxial test is used for the determination of critical state parameters; however, it is time-consuming and the required set of tests is relatively expensive for common geotechnical tasks. A simplified test procedure is developed to determine the critical state line in sandy soils. The procedure is reliable, economical, and fast. In order to verify the simplified test procedure, results are compared against critical state parameters determined in conventional triaxial tests. The comparison shows very good agreement between critical state parameters obtained with the suggested procedure and those gathered with triaxial testing. Limitations are identified.
Laboratory Characterization of Stress-Strain Behavior of Soils by Stress and/or Strain Path Loading
Authors: Vaid YP , Eliadorani A , Sivathayalan S , Uthayakumar M 
Published: February 2009

Abstract
Strain path control during loading in addition to the often-desired stress path control is shown to constitute a versatile method of characterizing stress-strain response of soils in the laboratory. It allows probing stress or strain increments to be applied in any direction at an ambient effective stress state to study the stress history and stress-path-dependent response. The capture of even the potential strain softening and the post peak behavior is made possible with no difficulty. Some unique capabilities of a triaxial and a multiaxial hollow cylinder torsion apparatus of these types are demonstrated by results of tests on a saturated sand.
Extracting Piezometric Level and Hydraulic Conductivity from Tests in Driven Flush-Joint Casings
Authors: Chapuis RP 
Published: February 2009

AbstractPermeability tests in borehole casings must satisfy many conditions to give reliable results. A test can be done only in a driven flush-joint casing. When a casing is rotated, its contact against the adjacent soil does not provide a seal good enough to assess the local k-value. Only water injection can be used (either falling-head or constant-head) because water extraction creates upward forces that destabilize the soil and induce either soil heave or clogging. Other conditions are explained in the paper. Interpretation methods differ mainly in their assumptions about solid matrix deformability during the test. The paper describes an interpretation method based on the equation of mass conservation: it leads to a graph of downward water velocity in the casing. This graph provides the error made in the quick field estimate of piezometric level (PL) for a tested zone. Several examples are provided, including tests that produce hydraulic separation between soil and casing. The PL obtained with this graph was always similar to that given by a monitoring well installed at the same level after borehole completion. From analysis of many tests at the same site, information can be obtained on natural water seepage conditions using a variation of PL versus depth.
Empirical Function Representing the Shear Strength of Unsaturated Soils
Authors: Miao L , Yin Z , Liu S 
Published: February 2009

Abstract
The general research situation of the shear strength of the unsaturated soils is reviewed in the paper. The hyperbola model is put forward based on the triaxial test results of the unsaturated soils. It can be used to predict the suction strength. The predicted results compare well with the measured data and show that the hyperbola model can be used to represent the shear strength of unsaturated soils.
Influence of the Loading Apparatus on the Stresses within Biaxial Specimens
Authors: Bobet A 
Published: February 2009

Abstract
The design and construction of a biaxial loading machine is presented in this paper. Two major concerns are addressed in designing the machine: alignment between the loading axes and the specimen, and shear stresses (friction) that may develop between the loading platens and the specimen. The alignment requirement is solved by constructing a multi-frame machine in which the horizontal frame hangs from the top of a 890 kN (200 Kip) Baldwin machine by cables and springs, thus allowing displacements and rotations of the horizontal loading axis with respect to the vertical axis. Shear stresses between the platens and the specimen are reduced by using brush platens. These platens are made of independent plates flexible enough to bend and thus reduce the transmitted friction. Numerical modeling of the interaction between the machine, platens, and the specimen shows the advantage of the multi-frame machine with brush platens over other combinations. With a multi-frame machine with brush platens, the stress field is uniform at the center of the specimen; differences between the applied and the obtained stresses are mostly within a 10% error, and are produced at the top boundary of the specimen. A single-frame machine with brush platens produces a nonsymmetric stress field and increases the confinement in the specimen as much as 5%. Rigid platens produce unloading within the specimen, which will cause an overprediction in the strength of the material.
Evaluation of Geomembranes Using an Ultrasonic Method
Authors: Yesiller N , Sungur S 
Published: February 2009

Abstract
An ultrasonic testing procedure was developed to evaluate geomembranes. The pulse-echo inspection technique was used on the surface of geomembranes without disturbing the material. The equipment required consists of a P-wave transducer, a pulser-receiver, and a signal acquisition system. Travel time of ultrasonic waves and waveform energy are measured to evaluate the condition of geomembranes. Laboratory tests were conducted to assess the effectiveness of the method. Defects that simulate installation damage and various in-service degradation conditions were induced on samples. The defects were identified with the ultrasonic method at a success rate higher than 98%. Changes in the thickness or the microstructure of the geomembranes were identified. Surficial and internal defects were located. Defects that were not visible from the measurement surfaces were identified. This method appears promising to monitor the condition of geomembranes in the laboratory or in the field and to assess in situ damage to geomembranes.
Properties and Behavior of Raw Sludge Mixed with Pulverized Fuel Ash and Lime
Authors: Yin JH 
Published: February 2009

Abstract
Raw sludge from a water treatment plant and pulverized fuel ash (PFA) from a coal-fired power plant are normally considered to be waste. The raw sludge is usually soft and weak, and takes a large area for storage if stockpiled on open ground, or requires a heavy dam/retaining structure if impounded. Strength and stiffness of the sludge are important parameters for the design and construction of facilities for sludge storage. This paper presents results from a series of tests on geotechnical properties and behavior of local raw sludge mixed with PFA and lime. The focus is on the improvement of the shear strength and stiffness of the sludge by mixing with different ratios of PFA and percentages of lime. Test results are presented and analyzed. Relationships between unconfined compression strength (UCS), PFA/Sludge (P/S) ratios, and lime contents are obtained. Relationships between the effective friction angle (and cohesion) and P/S ratios for 8% lime are also obtained from consolidated undrained (UC) triaxial tests. Correlation between secant Young's modulus E50 and the peak deviator stress qpeak is established.
A Multisleeve Friction Attachment for the Cone Penetrometer
Authors: DeJong JT , David Frost J 
Published: February 2009

AbstractAccurate knowledge of the strength of soil-geomaterial interfaces is becoming of increasing importance in geotechnical engineering. Systems whose performance is heavily dependent on soil-geomaterial interfaces include deep foundations, synthetic impervious liners, trenchless technologies, and an assortment of earth retaining structures. The strength of the interface is typically estimated by applying adjustment factors to values of soil or interface strength measured in laboratory tests. These adjustment factors are intended to correct for differences between the test and anticipated operating conditions such as variations in soil type and density, strain rate, surface roughness, or confining stress and are often empirically based with little theoretical underpinnings. Of these adjustment factors, the surface roughness is considered to be of utmost importance in that it has the potential to alter the interface strength by 100% or more.This paper describes the development of a new multisleeve Friction attachment for the cone penetrometer that allows for direct in situ measurement of the relationship between interface strength and surface ronghness. As discussed herein, the ability of the attachment to quantify this relationship, in conjunction with additional ongoing research, provides the opportunity to improve the design of friction dependent systems, as well as site characterization. A key characteristic of the penetrometer attachment is the ability to obtain four individual sleeve friction (fs) measurements at each elevation within a sounding, in addition to the conventional Cone Penetration Test (CPT) fs measurement. This allows for direct in situ analysis of the effects of sleeve roughness on the fs measurement. Considerations pertinent to the development of the device including assessments of the conventional CPT fs measurement and soil geomaterial interface mechanisms are first presented. A description of the new penetrometer attachment including key characteristics and capabilities follows. Finally, validation of the operation of the device through laboratory and field tests is described, and future applications of the attachment are discussed.