Vertical prestressing force opening mud jacking construction method and construction device

The present invention discloses construction process and apparatus for extruding mortar to vertical prestressed hole canal. The twice mortar extruding process includes the following steps: 1. the first mortar extruding including the first gravitational flowing and the subsequent low pressure extruding after some mortar begins bursting out through the exhaust hole; 2. blocking the exhaust hole, and extruding mortar for the second time until reaching fullness; and 3. erecting the exhaust pipe for it to become higher than the corrugated pipe. The construction apparatus includes one upper anchoring back plate with mortar extruding hole canal. The present invention has the advantages of no jamming of mortar extruding hole, saving in mortar extruding pipe material, low cost, etc.