MUD PREPARATION SYSTEM AND MUD PREPARATION METHOD IN MUD CONSTRUCTION METHOD

摘要

PROBLEM TO BE SOLVED: To make a static mixer general-purpose without impairing mud preparing effect by adding to mix an additive in split mud diverged from a mud feed path for feeding mud to a working face, and uniting the split mud with non-split mud to feed the united mud to the working face. SOLUTION: A mud feeding system 43 feeds mud from a ground installation to a chamber through a mud feed pipe. The mud feed pipe 44a is diverged to a main flow pipe 102 and a branch pipe 106. An additive is added to the split mud by an additive feeder 55 and agitated and mixed by a static mixer 104 which is an agitating-mixing device 54 to prepare mud, and the prepared mud joins the main flow pipe 102. A connection part between the main flow pipe 102 and the mud feed pipe 44b can be connected using reducers 80. 82 of tapered shape even in case of different pipe diameters. The viscosity of the united mud is measured by a viscometer 60, and a flow meter 62 is provided at the main flow pipe 102 to measure the flow rate of non-split mud. The flow rate is regulated by a valve 78 to control the split flow of the fed mud.