Pressure-reducing flow-stabilizing device applied to engineering investigation pump-in test and construction method of device

The invention discloses a pressure-reducing flow-stabilizing device applied to an engineering investigation pump-in test and a construction method of the device. The device comprises a pressure-reducing flow-stabilizing pipeline, wherein one end of the pressure-reducing flow-stabilizing pipeline is provided with a water inlet, and the water inlet is connected with a simplex pump through a water inlet pipe; the other end of the pressure-reducing flow-stabilizing pipeline is provided with a water outlet, the water outlet is connected with a drill rod through a water outlet pipe, and the drill rod extends into a test segment to perform the pump-in test; and a plurality of equidistant or non-equidistant first partition plates and second partition plates are further arranged in an inner cavityof the pressure-reducing flow-stabilizing pipeline, and the first partition plates, the second partition plates and the interior of the pressure-reducing flow-stabilizing pipeline form water flow buffer regions. The device is