Tangential Heave Stress Acting on Deep Foundations in Cold Regions

US Transportation Collection2019PDFTech ReportSeo, HoyoungLi, LiangLawson, William D.Jayawickrama, Priyantha W.Texas Tech University. Center for Multidisciplinary Research in TransportationUnited States. Department of Transportation. Office of the Assistant Secretary for Research and TechnologyUnited States. Department of Transportation. University Transportation Centers (UTC) ProgramSouthern Plains Transportation CenterSouthern Plains Transportation CenterUnited StatesFrigid regionsFrost heavingFrost heaving soilsLaboratory testsPile foundationsSoil structure interactionStressesTest proceduresCold weatherTangential heave testDeep foundationsCold regions engineeringSPTC15.1-17-FDTRT13-G-UTC36Final, June 2016 \u2013 May 2019In this study, the research team performed an experimental investigation of the effect of frost heave during soil freezing on the development of tangential heave force acting on deep foundations. A novel, laboratory-scale tangential heave testing system, instrumented with a model pile, moisture sensors and thermocouples, was developed in this study. The model pile was specially manufactured by bonding two vertically-cut half piles into a single, closed ended pipe pile and instrumented with strain gages and thermocouples on inner surface of the pile. The test soil was subjected to a temperature gradient of 0.082\ub0C/mm between the top (-10 \ub0C) and bottom (15 \ub0C) of the soil sample in an environmental chamber. The maximum heave amounts at the center and corner of the soil surface were about 18 mm and 14 mm, respectively. The pile top reached a peak upward movement of 0.533 mm at 24 hours, and no significant change was observed thereafter. The tangential heave stress measured in this study varied from about 66 kPa to 280 kPa. The tangential heave tests using the instrumented model pile and image acquisition system provided a wealth of information that can improve fundamental understanding of ice-soil-pile interaction. Furthermore, the testing system and procedure developed in this study may contribute to establish a test standard for tangential heave testing.111