Pile load test results - glacial clay till and clay shale near Regina, Saskatchewan

Gene Froc, Ramy Saadeldin

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Earth Walls and Foundations

ABSTRACT: test results glacial clay till and clay shale near Regina, Saskatchewan Gene Froc., P.Eng. & Ramy Saadeldin, M.Sc., P.Eng. AMEC Environment & Infrastructure, Regina, Saskatchewan, Canada ABSTRACT A compression pile load test was completed in conjunction with a proposed facility expansion at the Mosaic Potash Belle Plaine mine complex which is located approximately 45 km west of Regina, Saskatchewan. The pile load test program resulted in a more accurate understanding of pile load settlement characteristics which, in turn, were used for Serviceability Limit State reference and for other design purposes. This site specific pile load test also reduced prediction uncertainty and, in accordance with the National Building Code of Canada, allows foundation designers to use a reduced geotechnical resistance factor when calculating factored pile resistance (to satisfy Ultimate Limit State criteria). The pile load test was performed during the fall of September 2011 on three, drilled cast-in-place concrete piles installed within the northeast sector of the Mosaic Potash Belle Plaine mine site. Two of the test piles consisted of 610 mm diameter friction piles, individually supported by glacial clay till and clay shale deposits, respectively, and one consisted of a 760 mm diameter end bearing pile supported by the clay shale deposit. Both the glacial clay till and underlying clay shale deposits are significantly over-consolidated and have undrained shear strengths that range from 100 to 150 kPa and 250 to 400 kPa, respectively. The average ultimate skin friction resistance was determined to be in the approximate order of 85 kPa and 200 kPa for piles supported by the glacial clay till and clay shale, respectively. Corresponding settlements at the compressive failure loads were in the order of 13 mm and 28 mm, respectively. The back calculated adhesion values for both friction piles are in the order of 0.65 to 0.70. The ultimate end bearing resistance for the clay shale was determined to be in the order of 1800 kPa at 38 mm of settlement. Settlements for skin friction piles at service load conditions are predicted to be 5 mm or less. Settlements of end bearing piles at service loads and for the range of design bell diameters expected (1.2 m to 3 m) are predicted to range from 5 mm to 15 mm. RÉSUMÉ Un test de compression de pilier a été réalisé agrandissement de l'installation proposée au complexe minier MosaicPotash de Belle Plaine situé à environ 45 km à l'ouest de Regina, en Saskatchewan. Le programme de test à charge a abouti à une compréhension plus précise de la charge de la pile. Les caractéristiques du tassement du sol, à leurs tour, ont été utilisées pour la référence limite de service et à d'autres fins de conception et de design. Ce test de charge de pile spécifique au site a également réduit l'incertitude des prévisions et, en conformité avec le code national du bâtiment du Canada, permet aux concepteurs de la fondation à utiliser un facteur de résistance géotechnique réduit lors du calcul de la résistance pondéréedu tablier (pour satisfaire les critères tat limite ultime).Le test de charge du pilier a été réalisé en Septembre 2011 sur trois, tabliers forés en béton coulé et installés dans le secteur nord-est du site de la mine MosaicPotash Belle Plaine. Deux des piliers d'essai se composaient de 610 mm de diamètre de pilier de friction, soutenus individuellement par des dépôts d'argile et d'argile de schiste, respectivement, et un se composait d'un pilier de 760 mm de diamètre soutenu par un dépôt de schiste argileux (socle). Autant l'argile que le dépôt argileux de schiste, sous-jacents, sont nettement plus consolidés et ayant des résistances au cisaillement non drainé de 100 à 150 kPa et de 250 à 400 kPa, respectivement. La résistance ultime moyenne de friction de surface a été déterminée à être de l'ordre d'environ 85 kPa et 200 kPa pour les pilierssupportés par l'argile et argile schiste, respectivement. Les tassements correspondants aux charges de rupture de compression étaient de l'ordre de 13 mm et 28 mm, respectivement. Les valeurs d'adhésion calculé pour les deux piliers de frottement sont de l'ordre de 0,65 à 0,70. La résistance de roulement argile de schiste a été déterminée à être de l'ordre de 1800 kPa à 38 mm de tassement. Les tassements pour les piliers de friction en surface à des conditions de charge de service sont prévus pour être de 5 mm ou moins. Les tassements des derniers piliers à charges de service et pour la gamme de diamètres prévus (1,2 m à 3 m) sont estimés à atteindre de 5 à 15 mm. 1 INTRODUCTION This pile load test project was conducted at the Mosaic Potash Belle Plaine site as part of AMEC Environment & geotechnical investigation for the Mosaic Compaction Expansion and Stage 2 projects. The pile load test was expected to provide benefits to Mosaic in terms of potential cost savings, improved design accuracy for future piles foundations and a better understanding of existing and future pile foundation performance at the mine site. The test program was arranged, coordinated and supervised by AMEC Environment & Infrastructure with the support of Mosaic. The piles were installed and loaded to failure by North American Caisson Ltd (NACL) of Regina, Saskatchewan.

RÉSUMÉ: load test results glacial clay till and clay shale near Regina, Saskatchewan Gene Froc., P.Eng. & Ramy Saadeldin, M.Sc., P.Eng. AMEC Environment & Infrastructure, Regina, Saskatchewan, Canada ABSTRACT A compression pile load test was completed in conjunction with a proposed facility expansion at the Mosaic Potash Belle Plaine mine complex which is located approximately 45 km west of Regina, Saskatchewan. The pile load test program resulted in a more accurate understanding of pile load

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Cite this article:
Gene Froc; Ramy Saadeldin (2014) Pile load test results - glacial clay till and clay shale near Regina, Saskatchewan in GEO2014. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoRegina14Paper397,author = Gene Froc; Ramy Saadeldin,title = Pile load test results - glacial clay till and clay shale near Regina, Saskatchewan ,year = 2014}