Excavation difficulties in a stiff fissured clay and a reinforced earth wall solution

Five long highways are under construction in Greece which will significantly update the country's infrastructure when completed. One of these highways is the Ionia Odos, located in the western part of the country. The focus of this paper is the technical presentation a) of the reasons of instability of a stiff - fissured clay cut with a height of 30-35m and b) an innovative solution for the remediation of the problem and permanent support of the cut. During the excavation of the initial part of the cut and after heavy rainfall, superficial slides occurred. The initial remediation plan proposed to reduce the slope inclination. This proposal could not materialize due to expropriation limits and long litigations with the owner of the adjacent property. An innovative solution with a geosynthetically reinforced slope was proposed which utilized the available space, allowed for steep short term excavation and provided a permanent retaining structure for the cut.