The new extension in the COLLEGE SACRE-COEUR consists of a 7 storey concrete building with 3 basements. The main challenge in this project was the restricted time frame since the shoring works needed to be finished in a very quick way to allow the erection of the building prior to the school start in the coming fall. Technically 2 sides were of concern: the main road on one side and the Old Procurement building on the other side, which could not tolerate any movement. The planned excavation was 9m deep on the average. The Soil was Sandy and clayey fill on the top 6 meters, then a calcareous marl below. The water table was encountered at a depth of 8m. I.G.M. proposed a nailed shotcrete wall reinforced with vertical micropiles on the main road side, and an anchor/pile system on the Procurement building side. The piles were 25cm in diameter with a 70cm spacing c/c and 2 rows of active anchors tensionned against concrete waler beams
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