1,721,251 research outputs found
The effect of membrane and area corrections on triaxial shear characteristics of London clay
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Tube sampling disturbance - forgotten truths and new perspectives
No full textThe past decade has seen a considerable improvement in the understanding of the causes of tube sampling disturbance, as a result both of comparative studies of the performance of different sampling methods, and the development of new analytical techniques. This has built on the pioneering work carried out in the 1930s and 1940s, reviewed and interpreted in the seminal works of Hvorslev. Much of this knowledge, both old and new, has yet to be used widely in engineering practice, both in the UK and elsewhere. This paper reviews some of the major issues which must be addressed if samples of acceptable quality are to be obtained for laboratory soil testing, and draws on both old and new sources
Mechanical properties of reconstituted soft London clay
No full textUndrained triaxial compression and extension tests, and one-dimensional incremental loading oedometer tests were carried out to evaluate the stress-strain-strength, stiffness, compressibility and permeability properties of K0-normally consolidated reconstituted soft London clay
Disturbance due to tube sampling in coastal soils
No full textThe effects of tube sampling disturbances on undrained shear characteristics of reconstituted samples of three coastal soils were investigated. The values of undrained shear strength su and initial tangent modulus Ei were reduced, whereas axial strain at peak deviator stress εp increased because of a disturbance caused by penetration of samplers. Disturbances also reduced initial effective stress σ'i and pore pressure changes considerably. The changes in soil parameters between the “in situ” and “tube” samples depended markedly on the geometry of samplers used to retrieve tube samples. Values of su, Ei, and σ'i of samples were reduced, whereas the values of εp increased with an increasing area ratio (or decreasing external diameter to thickness ratio) and an increasing outside cutting edge angle of the samplers. Different reconsolidation procedures were adopted to assess the suitability of reconsolidation of tube samples to recover in situ properties. It was found that the K0-reconsolidation of tube samples to vertical effective stresses equal to 1.5 and 2.5 times the in situ vertical effective stress produced the best overall estimate of in situ characteristics
Effects of sampler design on tube sampling disturbance - numerical and analytical investigation
No full textThe detailed features of the design of a sampling tube, such as area ratio, inside clearance, cutting edge taper angle, etc., have an important influence on the disturbance caused when a tube sampler is pushed into cohesive soil. Currently, most tube sampler designs have evolved on the basis of empirical design rules, and local good practices, developed for particular soil conditions. The strain path method provides a basis upon which the influence and importance of different features of tube sampler design can be evaluated, and the design of future samplers optimized. This paper examines the use of Baligh's strain path method for the assessment of tube sampling disturbance, and implements the method via a finite-element approach to assess the influence of area ratio, cutting-edge angles and inside clearance, on sample disturbance evaluated on the basis of the strains imposed on the centre-line of a soil sample.The detailed features of the design of a sampling tube, such as area ratio, inside clearance, cutting edge taper angle, etc., have an important influence on the disturbance caused when a tube sampler is pushed into cohesive soil. Currently, most tube sampler designs have evolved on the basis of empirical design rules, and local good practices, developed for particular soil conditions. The strain path method provides a basis upon which the influence and importance of different features of tube sampler design can be evaluated, and the design of future samplers optimized. This paper examines the use of Baligh's strain path method for the assessment of tube sampling disturbance, and implements the method via a finite-element approach to assess the influence of area ratio, cutting-edge angles and inside clearance, on sample disturbance evaluated on the basis of the strains imposed on the centre-line of a soil sample
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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