True Triaxial Apparatus With Rigid-Flexible-Flexible Boundary and Remolded Loess Testing PDF Download

Author: S. Shao
Publisher:
ISBN:
Category : Failure strength
Languages : en
Pages : 10

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Book Description
Several kinds of true triaxial apparatuses have been devised and applied to obtaining the strength and deformability behavior of soils under different stress paths. However, for these true triaxial apparatuses with flexible loading boundaries boundary interference is still not solved. This paper presents a new type of true triaxial apparatus, with rigid-flexible-flexible boundaries, which addresses the boundary interference using four division strip-platens. This apparatus applies three principal stresses on a 70-mm cuboidal specimen from two rigid platens along the vertical direction and four hydraulic rubber bags around four side faces of the cuboidal specimen. The rigid platens and hydraulic rubber bags were assembled in a true triaxial chamber and driven by three servo-hydraulic cylinders. Four division strip-platens are installed along the lateral edges of the confining side wall of the chamber to separate adjacent rubber hydraulic bags and can adjust themselves to accommodate dimensional changes in the deforming specimen. Therefore, this apparatus does not only allow independent control of stresses applied in three dimensions to a cuboidal specimen but also resolve the boundary interferences. The effectiveness of this apparatus was confirmed by tests on remolded loess under five stress paths with the intermediate principal stress parameter b = 0, 0.25, 0.5, 0.75, and 1. The test results show that the stress-strain relationship, volume strain, and failure strength of remolded loess depend on the stress path.

Author: KR. Reddy
Publisher:
ISBN:
Category : Cementation
Languages : en
Pages : 17

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Book Description
A stress-controlled, flexible boundary, true (or cubical) triaxial apparatus has been developed to investigate the behavior of cemented sand under various stress paths which are not achievable using conventional axisymmetric triaxial apparatus. The apparatus components, specimen preparation, and test procedure are described. Tests were performed on cemented sand along different stress paths which included hydrostatic compression, conventional triaxial compression, and along different directions on octahedral planes. The test results indicate that stress-strain and volumetric response of cemented sand depends on stress path.

Author: Jae Hyun Park
Publisher:
ISBN: 9780542226946
Category : Civil engineering
Languages : en
Pages :

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Book Description
A stress-controlled, flexible boundary, true triaxial (cubical) testing apparatus has been developed to test 3-inch cubical specimen of partially saturated soil under different moisture contents and for a wide range of multiaxial stress paths. A series of HC, CTC, TC, TE, and SS tests were conducted in order to perform a thorough performance and check-out verification testing of the newly developed device by investigating the multiaxial stress-strain response of partially saturated silty sand specimens artificially prepared in the laboratory. The development of the apparatus, specimen preparation process, test procedure, and the corresponding validation of its suitability for testing partially saturated sandy soils are described. In this work, specimens were prepared using a dual-mesh pluviation technique at four different moisture contents: w = 2.0, 4.5, 5.3, and 6.1%. In all cases, initial total soil suction was induced and found to exert a paramount influence on the stress-strain-strength behavior of partially saturated silty sand.

Author: Changho Choi
Publisher:
ISBN:
Category : Coarse-grained soil
Languages : en
Pages : 13

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Book Description
This paper presents a recently developed true triaxial apparatus and a series of verification studies. The apparatus is capable of handling 241-mm cubical specimens providing the means for testing specimens under a wide variety of stress paths under drained and undrained conditions. It uses flexible boundaries to apply three independently controlled principal stresses with back pressure. The apparatus also uses a fully computer-controlled electro-pneumatic loading system with advanced technology for data control. A testing program is presented for the purpose of verification. Pea-gravel specimens with D50=6.6 mm were tested under fully stress-controlled loading conditions. Stress paths used in this verification study include undrained and drained constant total mean stress paths and conventional triaxial compression and extension stress paths. Results from this study indicate that the newly developed apparatus is capable of capturing the stress-strain characteristics of coarse-grained soils.

Author: LR. Hoyos
Publisher:
ISBN:
Category : Axis-translation technique
Languages : en
Pages : 9

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Book Description
A servo-controlled, true triaxial (cubical) testing apparatus has been modified to test 10-cm cubical specimens of unsaturated soil under suction-controlled conditions and for a wide range of stress paths. The equipment is a mixed-boundary type of device, with the specimen seated on top of a saturated high-air-entry disk and between five flexible membranes on the remaining sides of the cube. This paper describes the development of the device, including details of main apparatus components, specimen preparation, step-by-step assembling procedure, and the corresponding validation of its suitability for testing unsaturated soils. The device features two independent pore-air pressure and pore-water pressure control/monitoring systems. Matric suction states in the specimens are induced and maintained constant during testing by using the axis-translation technique. A companion paper (Macari and Hoyos Jr. 2001) presents the results from a comprehensive experimental study of the stress-strain response of a recompacted silty sand following simple-to-complex stress paths under suction-controlled conditions.

Author: Jay Ameratunga
Publisher: Springer
ISBN: 8132226291
Category : Science
Languages : en
Pages : 236

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Book Description
This book presents a one-stop reference to the empirical correlations used extensively in geotechnical engineering. Empirical correlations play a key role in geotechnical engineering designs and analysis. Laboratory and in situ testing of soils can add significant cost to a civil engineering project. By using appropriate empirical correlations, it is possible to derive many design parameters, thus limiting our reliance on these soil tests. The authors have decades of experience in geotechnical engineering, as professional engineers or researchers. The objective of this book is to present a critical evaluation of a wide range of empirical correlations reported in the literature, along with typical values of soil parameters, in the light of their experience and knowledge. This book will be a one-stop-shop for the practising professionals, geotechnical researchers and academics looking for specific correlations for estimating certain geotechnical parameters. The empirical correlations in the forms of equations and charts and typical values are collated from extensive literature review, and from the authors' database.

Author: P. J. Sabatini
Publisher:
ISBN: 9781410217615
Category : Technology & Engineering
Languages : en
Pages : 392

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Book Description
This document presents state-of-the-practice information on the evaluation of soil and rock properties for geotechnical design applications. This document addresses the entire range of materials potentially encountered in highway engineering practice, from soft clay to intact rock and variations of materials that fall between these two extremes. Information is presented on parameters measured, evaluation of data quality, and interpretation of properties for conventional soil and rock laboratory testing, as well as in situ devices such as field vane testing, cone penetration testing, dilatometer, pressuremeter, and borehole jack. This document provides the design engineer with information that can be used to develop a rationale for accepting or rejecting data and for resolving inconsistencies between data provided by different laboratories and field tests. This document also includes information on: (1) the use of Geographical Information Systems (GIS) and Personal Data Assistance devices for the collection and interpretation of subsurface information; (2) quantitative measures for evaluating disturbance of laboratory soil samples; and (3) the use of measurements from geophysical testing techniques to obtain information on the modulus of soil. Also included are chapters on evaluating properties of special soil materials (e.g., loess, cemented sands, peats and organic soils, etc.) and the use of statistical information in evaluating anomalous data and obtaining design values for soil and rock properties. An appendix of three detailed soil and rock property selection examples is provided which illustrate the application of the methods described in the document.

Author: Delwyn G. Fredlund
Publisher: John Wiley & Sons
ISBN: 047185008X
Category : Technology & Engineering
Languages : en
Pages : 542

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Book Description
The principles and concepts for unsaturated soils are developed as extensions of saturated soils. Addresses problems where soils have a matric suction or where pore-water pressure is negative. Covers theory, measurement and use of the fundamental properties of unsaturated soils--permeability, shear strength and volume change. Includes a significant amount of case studies.

Author: Delwyn G. Fredlund
Publisher: John Wiley & Sons
ISBN: 1118280504
Category : Technology & Engineering
Languages : en
Pages : 946

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Book Description
The definitive guide to unsaturated soil— from the world's experts on the subject This book builds upon and substantially updates Fredlund and Rahardjo's publication, Soil Mechanics for Unsaturated Soils, the current standard in the field of unsaturated soils. It provides readers with more thorough coverage of the state of the art of unsaturated soil behavior and better reflects the manner in which practical unsaturated soil engineering problems are solved. Retaining the fundamental physics of unsaturated soil behavior presented in the earlier book, this new publication places greater emphasis on the importance of the "soil-water characteristic curve" in solving practical engineering problems, as well as the quantification of thermal and moisture boundary conditions based on the use of weather data. Topics covered include: Theory to Practice of Unsaturated Soil Mechanics Nature and Phase Properties of Unsaturated Soil State Variables for Unsaturated Soils Measurement and Estimation of State Variables Soil-Water Characteristic Curves for Unsaturated Soils Ground Surface Moisture Flux Boundary Conditions Theory of Water Flow through Unsaturated Soils Solving Saturated/Unsaturated Water Flow Problems Air Flow through Unsaturated Soils Heat Flow Analysis for Unsaturated Soils Shear Strength of Unsaturated Soils Shear Strength Applications in Plastic and Limit Equilibrium Stress-Deformation Analysis for Unsaturated Soils Solving Stress-Deformation Problems with Unsaturated Soils Compressibility and Pore Pressure Parameters Consolidation and Swelling Processes in Unsaturated Soils Unsaturated Soil Mechanics in Engineering Practice is essential reading for geotechnical engineers, civil engineers, and undergraduate- and graduate-level civil engineering students with a focus on soil mechanics.

Author: Fu Hua Chen
Publisher: CRC Press
ISBN: 142004981X
Category : Science
Languages : en
Pages : 298

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Book Description
In the last forty years, at least fifty books have been written on the subject of soil mechanics, most of them textbooks. Only a few touch on practical applications. Soil Engineering: Testing, Design, and Remediation supplies the information needed to fill the gap between textbook learning and practical know-how. When engineers deal with major p