Field behaviour of very soft clays at the Athlone embankments

The approach road embankments to the new Shannon bridge rise up to 8·6 m above the marshlands of the River Shannon to the north of the town of Athlone in the Irish Midlands. These embankments are located on very soft glacial lake clay, highly compressible organic clay and calcareous marls, the geotechnical properties of which were largely unknown at the commencement of design in the early 1980s. Comparisons between compressibility, consolidation and shear strength parameters derived during the site investigation and those measured by monitoring the works are presented in this paper. It was found, for example, that the installation of vertical drains can significantly alter consolidation behaviour, that field compressibility was greater than that expected from laboratory testing, and that lateral movement monitoring was a useful indicator of embankment instability. Data from the construction of the Athlone embankments also confirm that the field vane strength underestimates the operational strength of the ...

[1]  H Grace,et al.  DISCUSSION ON AIRPORT PAPER NO. 35: THE PLANNING AND DESIGN OF THE NEW HONG KONG AIRPORT. , 1957 .

[2]  Jjm Powell,et al.  Initial investigations of the soft clay test site at Bothkennar , 1992 .

[3]  Serge Leroueil,et al.  In situ and laboratory stress–strain relationships , 1988 .

[4]  D. W. Hight,et al.  The undrained behaviour of clayey sands in triaxial compression and extension , 1990 .

[5]  Serge Leroueil,et al.  Construction pore pressures in clay foundations under embankments. Part I: the Saint-Alban test fills , 1978 .

[6]  F. Tavenas,et al.  Lateral displacements in clay foundations under embankments , 1979 .

[7]  S. Leroueil,et al.  The stability of stage-constructed embankments on soft clays , 1978 .

[8]  Serge Leroueil,et al.  STUDY OF THE VALIDITY OF A συ'-ευ-ευ MODEL IN IN SITU CONDITIONS , 1988 .

[9]  M. Roy,et al.  FACTORS AFFECTING THE MEASUREMENTS AND INTERPRETATION OF THE VANE STRENGTH IN SOFT SENSITIVE CLAYS , 1988 .

[10]  Peter K. Robertson,et al.  Cone-penetration testing in geotechnical practice , 1997 .

[11]  S. Leroueil.  Tenth Canadian Geotechnical Colloquium: Recent developments in consolidation of natural clays , 1988 .

[12]  Suzanne Lacasse,et al.  Use of In Situ Tests for Foundation Design on Clay , 1986 .

[13]  S. Hansbo,et al.  Aspects of vertical drain design: Darcian or non-Darcian flow , 1997 .

[14]  C.R.I. Clayton,et al.  Disturbance of the Bothkennar clay prior to laboratory testing , 1992 .

[15]  S. Leroueil,et al.  Preconsolidation pressure of Champlain clays. Part I. In-situ determination , 1983 .

[16]  C. P. Wroth,et al.  The interpretation of in situ soil tests , 1984 .

[17]  James Graham,et al.  Effects of freeze–thaw and softening on a natural clay at low stresses , 1985 .

[18]  A. Landva,et al.  EQUIPMENT FOR CUTTING AND MOUNTING UNDISTURBED SPECIMENS OF CLAY IN TESTING DEVICES , 1964 .