Fumito YAMAUCHI

Experimental Grasp of flow resistance characteristic of grease by element experiment

Supervisor  Mitsutaka SUGIMOTO

Today, shield tunnels have been constructed in deeper underground with sharp curve, as underground structures in urban area become congested. Furthermore, segment become thinner and wider for saving its cost. Consequently, stress in segment during construction tends to be increased and then segment damage during construction occurred increasingly
The predominant component of construction loads is tail force. To make clear the of flow resistance characteristic and Frictional drag characteristic of grease and steel segment grease for tail force quantitatively when grease passes wire brush, this study carried out the elementary tests on grease and wire brush.
The experiment was conducted with a testing machine of the box type sealing up. In this study, the width of wire brush, the flow of grease through wire brush, the piston intrusive speed, the tail clearance, and the hydraulic pressure behind wire brush were adopted as test parameters.
As a result, the followings were concluded: 
1) Piston intrusive pressure and the grease pressure become 100mm in widthƒ300mm in width. The pressure difference is small for Tc35mm with 6`35kPa, and the difference is great for Tc5mm with 1470`1873kPa.
2) The peak of the grease pressure regardless of flowing quantity of grease q for Tc35mm and 25mm are almost constant. On the other hand, The peak of the grease pressure increases with an increase in flowing quantity q for Tc15mm and 5mm.
3) Grease flow resistance power f becomes Tc35mmàTc25mm<Tc15mm<<Tc5mm. 
4) Grease flow resistance power f(peak value) is almost constant for Tc35 and 25mm regardless of flowing quantity q and the hydraulic pressure behind wire brush. On the other hand, f increases with an increase in flowing quantity q for Tc15mm and 5mm.
5) Based on the above results, the empirical equation about flow resistance of grease f and flowing quantity of grease q was proposed.