摘要:

Foundation investigations for large platforms in the harsh North Sea environment are costly, consequently, investigations are undertaken in progressive stages so that structural concepts can be developed with due regard to soil conditions. The shallow geological environment surrounding a platform site is explored by high resolution geophysical techniques, and interpretation of the seismic profiling data can be improved when results from one or two soil borings are available for correlating strati‐graphic boundaries. Geotechnical properties of soils and rocks to penetrations of 150 m are determined from laboratory testing of recovered samples and from in situ testing.

ISSN:0360-8867    

DOI:10.1080/10641198009379811

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

With the recent development of a method to transmit shear wave energy through laboratory unconsolidated sediments, an important new era of research on the dynamic properties of sediments has just begun. This, in time, will complement the vast amount of compressional wave data existent in the literature and provide the researcher with a very important tool to aid in the classification of sediments by correlating geophysical with geo‐technical parameters. A description is given of laboratory experiments in a specially designed sedimentation chamber to propagate shear waves in saturated sand sediments, using a method which employs a pair of novel design piezoelectric ceramic transducers. For comparison, similar measurements of wave velocity and amplitude were made on the sands using a pair of compressional wave transducers. Results are presented of compressional wave and shear wave velocity and amplitude versus porosity for these sands. A complete laboratory electronics testing facility necessary for acoustic measurements using both types of transducers is detailed. The performance of the shear wave transducers is also demonstrated in preliminary experiments using a plexiglass rod and then a container full of dry sand. Finally, the behavior of a transiently‐stressed saturated sand in the sedimentation cell is monitored geophysically by the continuous propagation of shear waves. It is shown that the duration of the liquefaction event in the sediment can be recognized by the temporary disappearance of shear waves from the record.

ISSN:0360-8867    

DOI:10.1080/10641198009379812

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

"Crust”; zones, as defined by shear strength profiles, have been delineated in Mississippi prodelta sediments since the advent of the remote wire‐line probe. Attempts to map the distribution of the “crust”; on the prodelta have been hampered by sparsity of in situ measurements and its apparent lateral discontinuity. Evidence based on clay fabric, geotechnical properties, and the location of selected cores within certain geomorphic zones, suggests the “crusts”; are associated with zones of shearing during an episode of submarine sediment movement on the prodelta.

ISSN:0360-8867    

DOI:10.1080/10641198009379813

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The continental margin of northern Sinai and Israel consists of a seaward‐inclined wedge, made up predominantly of foreset beds of mainly Nile‐derived clastics. They overlie seaward‐thickening Messinian (Upper Miocene) evaporites. Detailed bathymetric and seismic surveys reveal large areas of sea floor disturbances off northern Sinai and in several places off Israel, expressed by a complex block topography of the outer continental shelf and slope. These disturbed areas appear to be gigantic, deep‐seated, compound rotational slumps over down‐slope flowing evaporites. Many of the disturbances are above landward lobes of evaporites which fill buried Late Miocene erosion channels of the pre‐Messinian retreat of the sea. Flowage of the evaporites was presumably caused by excessive pore pressures, generated by the Pliocene‐Quaternary overload, in confined layers of the elastics interbedded within the evaporites.

ISSN:0360-8867    

DOI:10.1080/10641198009379814

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

ISSN:0360-8867    

DOI:10.1080/10641198009379815

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

ISSN:0360-8867    

DOI:10.1080/10641198009379810

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor