Meaning, measurement and field application of swelling pressure of clay shales

PROPERTIES:COMPRESSION, SWELLING, CONSOLIDATION and karstificarion phenomena within the aquifer matrix. -from Author

Compression, swelling and consolidation 944124 Penetration resistance value along compaction curves A. G. Fanre & J. D. Viana da Mata, Journal of Geotechnical Engineering - ASCE, 120(1), 1994, pp 46-59. Complete compaction curves of miscellaneous natural soils and sandy-clay mixtures were determined. The simple compression resistances or the penetration resistances were simultaneously determined. O n compaction curves a particular water content appeared, the compaction sensitivity threshold (CST), linked to the clay content, me compactive force value, and the clay mineralogy. It is shown that this CST appeared also as a particular water-content value on resistance curves. These results showed that the maximum dry density had no effect on variations in these resistances. It is shown that when the water content was lower than the CST aggregates remained individualized and then the hypothesis that the clay content still did not have its lubrication action was reinforced. -from Authors 944125 On the indentation of a poroelastic layer A. P. S. Selvadural & Z. Q. Yue, International Journal for Numerical & Analytical Methods in Geomechanics, 18(3), 1994, pp 161-175. The paper examines the axisymmetric contact problem related to the indentation of a fluid saturated poroelasric layer by a smooth rigid punch. The layer rests in bonded contact with a rigid impermeable base and the surface of the layer is considered to be either permeable or impermeable. The paper develops the integral equations governing the problem for the generalized case where the pore fluid exhi~bits compressibility. The numerical results presented in the paper illustrate the influence of the relative layer thickness, drainage conditions and the compressibility of the pore fluid on the degree of consolidation settlement of the indenting punch. -Authors 944126 Pressures exerted on soil due to rocking of liquid ~lOara~e tanks Lun C.S. Chang, Journal of Geotechnical Engineering - ASCE, 119(i 1), 1993, pp 1679-1695. Large pressure exerting on soil due to dynamic response of a liquid storage tank may cause excessive settlement of the supporting soil. In this study, a sim~le numerical model is proposed to model the effect of liquid sloshing in tank. The dynamic response of the system is examined for various tank sizes, height-radius ratios, and soil properties. It is found that resonance of such a system occurs due to sloshing of liquid under slow excitation. Under higher fre.quency excitation, such as that of earthquakes, the effect of hquid also plays an important role in the response of the liquid-tank-soil system. -from Authors 944127 M o d e r n technology and equipment for manufacturing and sinking t u b u l a r drains E. V. Svetinskii, Soil Mechanics & Foundation Engineering, 30(5), 1994, pp 201-203; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 30(5), 1993, pp 14-15. This article considers new designs of verrical drains recommended for compaction of soft, water-saturated soils. The advantages and fields of application of tubular drains are pointed out. Technical characteristics of the equipment for manufacturing and sinking them are given. -Journal summary 944128 Results of investigations of the process of consolidation of drained multilayered peaty bases (joint Soviet-Finnish experiment) P . A . Konovalov, V. G. Goncharov, Yu. N. Platonov & F. F. Zekhniev, Soil Mechanics & Foundation Engineering, 30(5), 1994, pp 207-213; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 30(5), 1993, pp 18-23. Results axe given from many years of experiments to reveal efficient technology and compaction of a mulrilay-

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ered peaty base with the help of various drains: factorymade (the 'geodrain' type), and sand ones made directly on the site, with cylindrical (round) and fiat cross sections o! equal area. -Journal summary 944129 T h e r m o d y n a m i c s of phase transitions in swelling/shrinking surficial soil layers T. K. Karalis, Materials Science & Engineering A, A175(1-2), 1994, pp 247-260. An expansive soil is used as an example to explain transitions of consistency in surficial soil layers where swelling/shrinking is required to proceed in a n umher of domains and ways. The aim of the present work is twofold. First, to explain swelling/shrinking and consistency change by contmuons or second-order transitions ana secondly to provide a simpler interpretation of this particular hehaviour by considering successive first order transitions at moisture ratio lower than the void ratio. Second order transitions evidently produced between the swelling/shrinking parts of an expansive soil layer are based on experiments on swelling upon wetting under different constraints. -from Author 944130 Study on the performance of calcareous expansive clays S . N . Abduljauwad, Bulletin - Association of Engineering Geologists, 30(4), 1993, pp 481-498. Geology, sedimentation and arid climate influence the formarion of the calcareous clay in the Eastern Province of Saudi Arabia. This study discusses the geotechnical and physicochemical properties, mineralogical composition and swelling characteristics of this soil. The estimation ot swell potential was obtained based on laboratory and field swelling tests. A major difference between the two approaches was observed. -Author 944131 Swelling of shale a r o u n d a cylindrical wellbore J . D . Sherwood & L. Bailey, Proceedings - Royal Society of London, A, A.A.A.(1920),1994, pp 161-184. A modified form of Blot's linear theory of poroelasticity is applied to shale swelling in contact with an aqueous electrolyte. It is predicted that swelling is prevented if the chemical potential of water within the shale equals that within the wellbore. The predictions of the analysis are compared with experimental results obtained when drained outcrop shale swelled in contact with aqueous solutions of KCI or NaCI. -from Authors 944132 Development o f K a in soft soils C. M. R. Ting, G. C. S'flls & D. C. Wijeyesekera, Geotechnique, 44(1), 1994, pp 101-109. This paper ipresents observations of the development of K o, the coefficient of lateral earth ~pressure at rest, in a soft kaolin undergoing one-dimensional consolidation up to 150 kPa. Experimental observations indicate that K 0 is not a constant but varies linearly with void ratio. It is suggested that the traditional empirical correlations between K0 and friction ankle ~' may be applicable at low stress levels, given that ~ may be higher at low effective stress levels than at higher values. -from Authors 944133 Meaning, m e a s u r e m e n t and field application of swelling pressure of clay shales G. Mesri, M. C. Pakbaz & A. F. Cepeda-Diaz, Geotechnique, 44(I), 1994, pp 129-145. The meaning and laboratory measurement of swelling pressure are examined by swelling and swelling pressure tests on undisturbed specimens of Taylor shale from San Antonio, Texas. Swelling pressure response of a shale element is defined in terms of a void ratio against swelling pressure relationship, rather than a single value of swelling pressure, and is interpreted by means of constant volume, free swell, and controlled load or controlled deformation unloading, tests. A concept of unsaturated fissured shale is introduced and is used to explain the magnitude and timerate of swelling pressures measured in laboratory tests and mobilized in the field. The magnitude of swelling pressure that a shale suffac~ exposed in an excavation mobilizes against a stiff support Is expressed in terms of an expansion of the shale mass adjacent to the excavation. T h e

PROPERTIES:DYNAMICS

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expansion of shale is mainly through the opening of joints and fissures during excavation and before installation of the lining. -Authors 944134

P r o c e d u r e for predictinig settlements of thaw.

ing bases for engineering calculations

V. D. Kazamovskii & E. S. Pshenichnikova, Soil Mechanics & Foundation Engineering, 30(4), 1994, pp 145-148; translated from: Osnovaniya, Fundamenty i Mekhanika Grunter, 30(4), 1993, pp 5-7. It was shown that in order to compute the settlement of thawing cohesive soft under a load m time it is necessary ~ experimentally determine the consolidation coefficient. procedure is suggested for determining this coefficient, as well as use of the classical solution of a differential equation for seepage consolidation to describe the settlement of soft, thawing of which can occur according to any law. -Journal summary

Dynamic properties 944135 Soil dynamics and geotcchnical earthquake

engineering. Proceedings of a seminar, Lisboa, July 1992 od P. Seco e Pinto, (A. A. Balkema), ISBN (hardback) 90 5410 310 8, price £50.00 (Dr 135.00), 1993, 501 pp. This volume contains 10 papers (abstracted separately) covering topics including laboratory tests on the dynamic properties of softs and gravels, evaluation of liquefaction potential, dynamic analysis of embankment dams, soft/structure interactions, seismic design and monitoring of geotechnical structures and the damage distribution in the 1992 Emincan earthquake. The book is intended as a contribution to the International Decade for Natural Disaster Reduction. -G.E.Hodgson 944136 Dynamic properties of soils and gravels from l a b o r a t o r y tests K. Ishihara, in: Soil dynamics and geotechnical earthquake engineering. Prec. seminar, Lisboa, 1992, ed P. Seco e Pinto, (Balkema), 1993, pp 1-17. Dynamic analyses to evaluate the response of soft deposits and earth structures to seismic load applications have been finding increased application in geotechnical engineering. Various idealized models and analytical techniques are used to re l~resent a soil deposit and to evaluate its response, whatever procedure is used, it is necessary to determine the appropriate stress-strain and energy absorbing properties o f the material in the deposit. Many attempts have been made to evaluate the dynamic properties of soft materials in the laboratory and in the field. I n this paper, information of the dynamic properties of materials recently reported in Japan is briefly reviewed with emphasis on the shear modulus and damping values obtained for coarsegrained materials. -from Author 944137 Evaluation of liquefaction potential W. D. L. Finn, in: Soil dynamics and geotechnical earthquake engineering. Prec. seminar, Lisboa, 1992, ed P. Seco e Pinto, (Balkema), 1993, pp 127-157. One of the more significant factors leading to ground failure during earthquakes is the liquefaction of loose to medium-dense sands below the water table. The mechanics of liquefaction are now well understood and the potential for occurrence can be estimated with a reasonable degree of confidence. The magnitude of potential deformations at a liquefied site with contractive behaviour depends on the extent to which the driving shear stresses exceed the residual strength. The residual strength therefore is a key parameter controlling the extent and cost of remedial measures to limit deformations to tolerable levels. In this paper, procedures are presented for dete .m~dn~ the potential for triggering liquefaction and for estimattng residual strength. -from Author 944138 Dynamic elastic tests for rock engineering A . F . Siggins, in: Comprehensive rock engineering. Vol. 3, ed J.A. Hudson, (Pergamon), 1993, pp 601-618. This chapter is concerned with the practicalities of the dynamic testing of rock specimens prepared from core samples. Both pulse vetocity and reasonance methods are

included, together with a discussion of the influence of specimen geometry on the test results. In addition, a techtuque for the measurement of specific attenuation, Q, or internal friction, is mentioned. This parameter is a measure of the departure of the rock material from pure elastic behavior, and is known to be sensitive to the degree of microcracking in the sample. -from Author 944139 Seismic investigation for rock engineering P. W. McDowell, in: Comprehensive rock engineering. Vol. 3, ed J.A. Hudson, (Pergamon), 1993, pp 619-634. This chapter first summarises the basic principles of seismic surveying. Evaluation of rock fracture state by analysis of seismic wave propagation is detailed with other factors affecting wave velocxty, such as water content and in situ stress. The assessment of elastic moduli is discussed before 'a case study is presented to highlight the principles discussed. -R.Gower 944140 Dynamic indications of rock mass failure T. Vladut, in: Comprehensive rock engineering. Vol. 4, ed J.A. Hudson, (Pergamon), 1993, pp 695-714. This chapter presents some of the microseismic contributions in relation to ground control for engineering practice both on rock and in rock (surface and underground). Engineering practice requires the evaluation of the pattern of failure development which, when intensive, may affect the purpose of the project. Estimation of hazardous releases of energy confronts a number of unknowns in which neither the state of stress nor the properties of rock materials are fully known. The monitoring of rock masses is an observational method in which the dynamic elements cannot be disassociated from the traditional rock engineering assessment. -from Author 944141 Cumulative deformation of soft clay under cyclic loading Yan Shuwang, Yan Chi & Zhang Jianguo, China Ocean Engineering, 7(3), 1993, pp 341-348. Reconstituted specimens are prepared by means of vacuum preloading. Both static and cyclic triaxial tests are carried out, with the specimens consolidated under different principal stress raUos. A finite element method is put forward for calculating the cumulative deformation of soft clay under cyclic loading. -Authors 944142 Liquefaction potential of reinforced sand N. R. Krishnaswamy & N. T. Isaac, Geotextiles & Geomembranes, 13(1), 1994, pp 23-41. A simple stress-controlled cyclic triaxial testing system developed for liquefaction testing is described. Using this system, a series of cyclic undrained triaxial tests were performed on sands with different densities and with different es of reinforcements to investigate the effect of reinrcement in enhancing resistance to liquefaction. It was found that the inclusion of reinforcement significantly increased liquefaction resistance. The reinforcement effect was more pronounced at lower relative densities and with reinforcements having higher stiffness and interface friction. Coir, a natural fibre, was found to be a good substitute for geosynthetics. -from Authors

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944143 Effect of dynamic loading on compressionai behaviour ofspunbonded nonwoven fabrics V . K . Kothari & A. Das, Geotextiles & Geomembranes, 13(1), 1994, pp 55-64. The compressional behaviour of these types of fabrics changes with the dynamic loading cycles. 'l'he change in compressional behaviour with dynamic loading has been studied using laboratory equip.ment. After the application of a known dynamic load wxth a particular frequency for different durations, the needle punched spunbonded nonwoven fabrics show a very prominent change in their compressional behaviour, while the changes in the ~omp~ssional behaviour in the case of the thermally onaea spunoonded nonwoven fabrics is relatively small. -from Authors