In 1986 a 4-year, $4 million research project named clouterre was initiated in france by the french minister of transport. The main objective was to develop recommendations on soil nailing for temporary and permanent nailed soil walls in excavation, with special emphasis on safety and durability. The results and the subsequent recommendations for seven selected important topics are presented. The behavior of a nailed soil wall during construction, in service, and nearfailure was studied on three full-scale experimental walls pushed to failure according to three modes of failure. A design method basedon schlosser's multicriterion is recommended to account for all possible modes of failure. The classical definition of the global factor of safety is abandoned, and a new procedure using partial safety factors and weighing factors is recommended. A new method is proposedto design the facing thickness as a function of the nail spacings. More than 450 in situ pullout tests were collected to create a unique data base allowing correlations between the nail and soil types and the soil-nail interface frictional resistance. Detailed recommendations are developed to calculate the extra thickness of steel required in permanent nailed soil structures depending on the characteristics of the soil. Limitations of soil nailing are clearly defined fordifferent situations. Clouterre recommendations are a major contribution to the status of knowledge on soil nailing in excavation. Theywill allow the increasing use of soil nailing for temporary and permanent structures. This paper appears in transportation research record no. 1330, Behavior of jointed rock masses and reinforced soil structures 1991
Abstract