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Displacement-pile behaviour in a soft marine clay
SURFACE STRUCTURES :FOUNDATIONS
945183
Importance of speed and frequency in flexible
pavement response M. S. A. Hardy & D. Cebon, Journal of Engineering Mechanics - ASCE, 120(3), 1994, pp 463-482. This paper examines the importance of structural dynamics in the primary response of flexible pavements to fluctuating, moving wheel loads. The influence of vehicle speed and loading frequency are examined first, using a validated dynamic road-response model with idealized loads. The dynamic calculation procedure is then simplified to provide a 'quasi-dynamic' calculation which accounts for vehicle speed but not the dependence of road response on loading frequency. The simplication descreases the necessary computer resources significantly and reduces the comutation time sufficiently for use on a personal computer. e validity of the simplification is tested by comparing primary road responses and fatigue damage predicted by the two methods, for dynamic wheel loads generated by two representative mathematical vehicle models, on two different roads. It is found that differences in response are observable, but in practical situations they are likely to be small. It is concluded that the simplified quasi-dynamic calculation approach is preferable. -Authors
Foundations 945184 Review of foundation testing methods and procedures M. England & W. G. K. Fleming, Proceedings - ICE: Geotechnical Engineering, 107(3), 1994, pp 135-142. This paper reviews some of the shortcomings of foundation load testing procedures, considers what would constitute an ideal test, and comments on recent developments in static load testing which increase the technical value. It is concluded that the standard maintained load test, as covered by the Institution of Civil Engineers' Specification for pilling still represents the best available method, but that it would benefit from some minor amendment. This would specifically require defined constancy of load at each load stage and would permit better interpretation of results. An available model for analysis is discussed. -Authors 945185 A case history of foundation excavation in contaminated ground R. P. Ashen & L. Waterman, Proceedings - ICE: GeotechnicalEngineering, 107(3), 1994, pp 173-184. This paper records the construction of foundations for a large asphalt plant in variable contaminated ground. The nature of the contamination encountered and how the contract was managed and constructed to deal with the contamination is described. This process included the setting up and operating of a groundwater treatment plant. The paper also indicates the arrangements adopted for testing soil, water, and gas samples, occupational hygiene, medical testing, safety procedures, industrial relations; dealing with the media and the public; construction techniques, and management systems which were implemented, and also the environmental aspects. -Authors 945186 New technologies and equipment for constructing foundations B.V. Goncharov, V. L. Kogan, A. Kh. Enikeev & V. G. Khazin, Soil Mechanics & Foundation Engineering, 30(6), 1994, pp 234-240; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 6, 1993, pp 11-15. This article discusses new technologies for constructing combined foundations under large loads, a waste-free technology with sinking of driven piles to a given level on the basis of static sounding, a jet technology for constructing supports, the use of piles with small cross sections, methods of constructing foundations on slopes and sites with mine workings, and construction of foundations in rammed pits. -Authors 945187 Risk-reduction factor for bearing capacity of shallow foundations A. A. Basma, Canadian Geotechnical Journal, 31(1), 1994, pp 12-16. An ultimate bearing capacity risk-reduction factor is pro-
247A
posed to account for the variation and randomness in soil properties. Results indicate that the risk-reduction factor F R decreases with an increase in the coefficient of variati~in of ultimate bearing capacity and a decrease in the selectedprobability of failure Pv For pf = 0.0001, however, F s was found to range between 0.20 and 1.0. A numerical example is presented to illustrate the use of the proposed reduction factor. -from Author 945188 Displacement pile behaviour in glacial clay B . M . Lehane & R. J. Jardine, Canadian Geotechnical Journal, 31(1), 1994, pp 79-90. Describes a programme of field experiments with heavily instrumented displacement piles installed in a stiff, lodgement till. Measurements of the effective stresses recorded at various levels along the pile shaft during installation, equalization, and load testing are presented. Shaft capacity is shown to be governed by an effective stress failure criterion, with the mobilized stresses depending on the clay consistency, distance from the pile tip, shaft surface texture, type of loading, installation rate, and degree of equalization. -Authors 945189 Displacement-pile behaviour in a soft marine clay B . M . Lehane & R. J. Jardine, Canadian Geotechnical Journal, 31(2), 1994, pp 181-191. The paper presents the results of field experiments performed using the Imperial College instrumented displacement pile in a soft, sensitive marine clay at Bothkennar, Scotland. These results are compared with data from similar programmes of experiments performed in other clay types with this pile so that some of the major factors controlling displacement-pile performance may be identified. -Authors 943190 Lateral load capacity of single piles in sand M. Mahmoud, Proceedings ICE: Geotechnical Engineering, 107(3), 1994, pp 155-162. A study is made of some of the parameters which influence the lateral load capacity of single model piles; these are breadth, depth of embedment and the cross-sectional shape of the pile. Variations of lateral load with the above parameters show that the behaviour of laterally loaded piles is essentially controlled by all of these parameters. In order to illustrate these relationships further, test, results are presented in terms of Broms' dimensionless groups H/y'KpB 3 and L/B for different stages of loading corresponding to different pile head lateral displacement ratios (x/B). The variation of H/T'KpB 3 and L/B is nonlinear, with the degree of nonlinearity becoming more pronounced with increasing values of x/B. Experimental curves of H/~/KpB 3 against L/B show good agreement with Broms' design chart, with the latter corresponding to an x/B value of approximately 40%. Furthermore, the experimental curves agree very well with recent field test results reported in the published literature. -from Authors 945191 A re-examination of the strain field a r o u n d a simple pile V. Silvestri & C. Tabib, Canadian Geotechnical Journal, 31(2), 1994, pp 303-308. This technical note describes the analysis of the strain field around a simple pile. The analytical solution is obtained by using a spherical coordinate system of reference. It is shown that the expressions for the various strains are very simple. Streaming motions and octahedral shear strain contours are presented in graphical forms. -Authors 945192 Stress-level effects in model tests on piles W. H. Craig & S. K. Sabagh, Canadian Geotechnical Journal, 31(1), 1994, pp 28-41. Results are presented from several series of centrifuge model tests of piles installed in beds of uniform dry sand. Using identical model geometries, but varying acceleration factors, the tests demonstrate quite clearly the nature and extent of stress-level variations on the performance of piles. The results are interpreted initially in terms of bearmg capacity coefficients N t and lateral earth pressure coefficients K , and subsequently in terms of angle of friction determined using available relationships. -from Authors
945183
Importance of speed and frequency in flexible
pavement response M. S. A. Hardy & D. Cebon, Journal of Engineering Mechanics - ASCE, 120(3), 1994, pp 463-482. This paper examines the importance of structural dynamics in the primary response of flexible pavements to fluctuating, moving wheel loads. The influence of vehicle speed and loading frequency are examined first, using a validated dynamic road-response model with idealized loads. The dynamic calculation procedure is then simplified to provide a 'quasi-dynamic' calculation which accounts for vehicle speed but not the dependence of road response on loading frequency. The simplication descreases the necessary computer resources significantly and reduces the comutation time sufficiently for use on a personal computer. e validity of the simplification is tested by comparing primary road responses and fatigue damage predicted by the two methods, for dynamic wheel loads generated by two representative mathematical vehicle models, on two different roads. It is found that differences in response are observable, but in practical situations they are likely to be small. It is concluded that the simplified quasi-dynamic calculation approach is preferable. -Authors
Foundations 945184 Review of foundation testing methods and procedures M. England & W. G. K. Fleming, Proceedings - ICE: Geotechnical Engineering, 107(3), 1994, pp 135-142. This paper reviews some of the shortcomings of foundation load testing procedures, considers what would constitute an ideal test, and comments on recent developments in static load testing which increase the technical value. It is concluded that the standard maintained load test, as covered by the Institution of Civil Engineers' Specification for pilling still represents the best available method, but that it would benefit from some minor amendment. This would specifically require defined constancy of load at each load stage and would permit better interpretation of results. An available model for analysis is discussed. -Authors 945185 A case history of foundation excavation in contaminated ground R. P. Ashen & L. Waterman, Proceedings - ICE: GeotechnicalEngineering, 107(3), 1994, pp 173-184. This paper records the construction of foundations for a large asphalt plant in variable contaminated ground. The nature of the contamination encountered and how the contract was managed and constructed to deal with the contamination is described. This process included the setting up and operating of a groundwater treatment plant. The paper also indicates the arrangements adopted for testing soil, water, and gas samples, occupational hygiene, medical testing, safety procedures, industrial relations; dealing with the media and the public; construction techniques, and management systems which were implemented, and also the environmental aspects. -Authors 945186 New technologies and equipment for constructing foundations B.V. Goncharov, V. L. Kogan, A. Kh. Enikeev & V. G. Khazin, Soil Mechanics & Foundation Engineering, 30(6), 1994, pp 234-240; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 6, 1993, pp 11-15. This article discusses new technologies for constructing combined foundations under large loads, a waste-free technology with sinking of driven piles to a given level on the basis of static sounding, a jet technology for constructing supports, the use of piles with small cross sections, methods of constructing foundations on slopes and sites with mine workings, and construction of foundations in rammed pits. -Authors 945187 Risk-reduction factor for bearing capacity of shallow foundations A. A. Basma, Canadian Geotechnical Journal, 31(1), 1994, pp 12-16. An ultimate bearing capacity risk-reduction factor is pro-
247A
posed to account for the variation and randomness in soil properties. Results indicate that the risk-reduction factor F R decreases with an increase in the coefficient of variati~in of ultimate bearing capacity and a decrease in the selectedprobability of failure Pv For pf = 0.0001, however, F s was found to range between 0.20 and 1.0. A numerical example is presented to illustrate the use of the proposed reduction factor. -from Author 945188 Displacement pile behaviour in glacial clay B . M . Lehane & R. J. Jardine, Canadian Geotechnical Journal, 31(1), 1994, pp 79-90. Describes a programme of field experiments with heavily instrumented displacement piles installed in a stiff, lodgement till. Measurements of the effective stresses recorded at various levels along the pile shaft during installation, equalization, and load testing are presented. Shaft capacity is shown to be governed by an effective stress failure criterion, with the mobilized stresses depending on the clay consistency, distance from the pile tip, shaft surface texture, type of loading, installation rate, and degree of equalization. -Authors 945189 Displacement-pile behaviour in a soft marine clay B . M . Lehane & R. J. Jardine, Canadian Geotechnical Journal, 31(2), 1994, pp 181-191. The paper presents the results of field experiments performed using the Imperial College instrumented displacement pile in a soft, sensitive marine clay at Bothkennar, Scotland. These results are compared with data from similar programmes of experiments performed in other clay types with this pile so that some of the major factors controlling displacement-pile performance may be identified. -Authors 943190 Lateral load capacity of single piles in sand M. Mahmoud, Proceedings ICE: Geotechnical Engineering, 107(3), 1994, pp 155-162. A study is made of some of the parameters which influence the lateral load capacity of single model piles; these are breadth, depth of embedment and the cross-sectional shape of the pile. Variations of lateral load with the above parameters show that the behaviour of laterally loaded piles is essentially controlled by all of these parameters. In order to illustrate these relationships further, test, results are presented in terms of Broms' dimensionless groups H/y'KpB 3 and L/B for different stages of loading corresponding to different pile head lateral displacement ratios (x/B). The variation of H/T'KpB 3 and L/B is nonlinear, with the degree of nonlinearity becoming more pronounced with increasing values of x/B. Experimental curves of H/~/KpB 3 against L/B show good agreement with Broms' design chart, with the latter corresponding to an x/B value of approximately 40%. Furthermore, the experimental curves agree very well with recent field test results reported in the published literature. -from Authors 945191 A re-examination of the strain field a r o u n d a simple pile V. Silvestri & C. Tabib, Canadian Geotechnical Journal, 31(2), 1994, pp 303-308. This technical note describes the analysis of the strain field around a simple pile. The analytical solution is obtained by using a spherical coordinate system of reference. It is shown that the expressions for the various strains are very simple. Streaming motions and octahedral shear strain contours are presented in graphical forms. -Authors 945192 Stress-level effects in model tests on piles W. H. Craig & S. K. Sabagh, Canadian Geotechnical Journal, 31(1), 1994, pp 28-41. Results are presented from several series of centrifuge model tests of piles installed in beds of uniform dry sand. Using identical model geometries, but varying acceleration factors, the tests demonstrate quite clearly the nature and extent of stress-level variations on the performance of piles. The results are interpreted initially in terms of bearmg capacity coefficients N t and lateral earth pressure coefficients K , and subsequently in terms of angle of friction determined using available relationships. -from Authors