Short- and long-term effects on upheaval buckling of blinding struts

Significant economies can be achieved by using concrete blinding as struts in cut and cover excavations. This paper identifies the key issues which need to be addressed in the design of blinding struts in cut and cover excavations. It is shown that blinding struts can fail in upheaval buckling. The main parameters affecting the buckling load are identified and comparisons are made between numerical and analytical predictions of the failure load. Comparisons are also made between the measured and predicted strengths of ¼ scale blinding struts tested by the authors. The paper also discusses the effect of creep of concrete on the failure load of blinding struts. The paper concludes with a brief overview of the geotechnical numerical analysis undertaken to date which gives useful insights into the nature of the soil-structure interaction.