Forced drainage type controllable sand plate composite structure, injection equipment of construction sand plate and soft foundation treatment method

The invention discloses a forced drainage type controllable sand plate composite structure which comprises a plastic drainage plate. At least three sand plates are evenly distributed around the plastic drainage plate in the radial direction with the plastic drainage plate as the center. A vacuum pre-pressing pump drainage mechanism or a preloading pump drainage mechanism is arranged at the upper end of the plastic drainage plate. The plastic drainage plate is connected with a drainage pipe of the vacuum pre-pressing pump drainage mechanism or the preloading pump drainage mechanism. The invention further provides injection equipment of a construction sand plate and a soft foundation treatment method adopting the forced drainage type controllable sand plate composite structure. In the forced drainage type controllable sand plate composite structure, the multiple radially-distributed sand plates radiate a pumping drainage area towards the periphery, the contact area of the vertical faces of the sand plates and a