Control of grouting in the bedrock and soil in vicinity of tunnels and construction pits, Case study: E18, Oslo, Norway

Abstract

Construction of open excavation pits and tunnels below groundwater level in urban areas are continuous geotechnical challenges. Reducing the water ingress to excavations is vital, to limit drawdown of the groundwater head at bedrock level and consequent consoli-dation settlements in soft clays deposits, which potentially can cause damage to nearby build-ings and infrastructure. In connection with the development of the E18 highway near the city of Oslo in Norway, a hydrogeological barrier consisting of sheet pile walls, rock mass pre- grouting and jet column grouting have been designed and executed for a deep excavation in soil and rock. This paper presents the design of the barrier and control of pre-grouting execu-tion which was required to optimize the barrier construction with respect to local ground conditions.

Control of grouting in the bedrock and soil in vicinity of tunnels and construction pits, Case study: E18, Oslo, Norway