Geomembrane spreading roller with adjustable pre-tightening force

The utility model relates to the technical field of membrane spreading rollers, and discloses a pretightening force adjustable geomembrane spreading roller which comprises a workbench, a first fixing frame is fixedly connected to the outer side of the workbench, a membrane spreading roller body is arranged on the inner side of the first fixing frame, a first mounting frame is fixedly connected to the top of the workbench, and a second mounting frame is fixedly connected to the top of the workbench. A fixing rod is fixedly connected to the interior of the first mounting frame, the outer surface of the fixing rod is movably sleeved with a first movable block, a notch is formed in the top of the first movable block, a round rod is fixedly connected to the interior of the notch, and the outer surface of the round rod is movably sleeved with a first spring and a limiting block; a tooth groove is formed in the top of the first mounting frame, and a round roller is movably connected to the inner side of the first mo