Thrust estimation in small diameter tunnel excavation using slurry pipe-jacking method

In order to protect the safety of workers during construction, as well as for environmental and cost reasons, small-diameter shallow tunneling methods have recently become increasingly important in regards to outside plant such as for supplying of water, electricity, telecommunications and gas. The effects of the above projects in overcrowded urban areas are significant and often result in substantial impact in traffic delays associated with a loss of travel time. The solution of these utility placement problems, if the full impact of trench excavation is avoided, is trenchless technology. In particular, for construction work near existing facilities, underground tunnels that are excavated by slurry pipe-jacking are increasingly employed in order to avoid problems. Slurry pipe-jacking was firmly established as a special method for the non-disruptive construction of the underground pipelines of sewage systems. Pipe-jacking, in its traditional form, has occasionally been used for short railways, roads, rivers, and other projects. Basically the system involves the pushing or thrusting concrete pipes into the ground by a number of jacks. This method utilizes mud slurry that is formed around the pipes in order to stabilize the surrounding soil. In slurry pipe-jacking, the performance of the mud slurry plays an important role in the pushing process. Thrust in slurry pipe-jacking can be predicted by evaluating the resistance between the mud slurry and the concrete pipes and the resistance between the soil and the pipes in linear and curved jacking area. This paper discussed about this point.