Construction method for root-type foundation anchorage and bored, root-type cast in-situ pile with anchor bolts

Abstract

The invention discloses a construction method for rooted foundation anchorage, comprising the following steps: precasting a concrete caisson in sections, excavate or bore hole for the caisson sinking, reserving holes for projection of anchor roots in the wall of caisson; cleaning the bottom of the bore hole, and sealing the bottom with concrete; precasting the beam type concrete roots and, within the bore hole, projecting the roots into the earth around the caisson; sealing a concrete cover over the bore hole to form a flat cap, which can be used as the cap of a bridge foundation. The invention also discloses a construction method for a root-type cast in-situ bored pile with anchor roots, comprising the following steps: placing a reinforcement cage in a bored hole; each guide framework is internally provided with anchor roots; using a vibration extruder to squeeze the roots in the reinforcement cage; using the squeezing head of the vibration extruder to squeeze the anchor roots from top to bottom gradually. The invention greatly improves the traditional foundation structure. The anchor roots increases friction and structural stability greatly, thus making it possible to reduce gravity of the structure.

1 . A construction method for rooted foundation anchorage wherein comprising the following steps:
 precasting a concrete caisson in sections, excavate or bore hole for the caisson sinking, reserving holes for projection of anchor roots in the wall of caisson, and sinking the caisson into the earth by its self-weight, which stops sinking when the bottom runs into rocks; the anchor root has a cusp at one end, and a flat head at the other end;   cleaning the bottom of the bore hole, and sealing the bottom with concrete;   precasting the beam type concrete roots and, within the bore hole, projecting the roots into the earth around the caisson;   and sealing a concrete cover over the bore hole to form a flat cap, which can be used as the cap of a bridge foundation.   
     
     
         2 . The construction method for rooted foundation anchorage according to  claim 1 , wherein the precast beam type concrete roots are, within the bore hole, projected in to the earth around the caisson, comprising the following steps:
 the inwall of the caisson is internally provided with a vertical slide rail which is anchored to the caisson by rail anchors;   the inwall of the slide rail is provided with a diagonal bracing, on the same section of which a circular rail beam is arranged;   on the circular rail beam is provided with a pipe jacking platform, on which a steel support rod is arranged;   the anchor root is placed on the a pipe jacking platform with the cusp pointing at the anchor root hole, while the flat head at the other end jacked by a jack until the anchor root is projected into the earth.   
     
     
         3 . The construction method for rooted foundation anchorage according to  claim 2 , wherein in the process of jacking the anchor root by the jack, a crane is used to lift the anchor root so as to guarantee the anchor root to be projected into the earth in accordance with the design direction. 
     
     
         4 . The construction method for rooted foundation anchorage according to  claim 1 , wherein inside the anchor root hole is provided with a rubber water seal and a rubber water fender successively;
 the rubber water seal is provided with a crossed open pore in the middle, and the cusp end of the anchor root is successively pushed into the rubber water seal and the rubber water fender.   
     
     
         5 . The construction method for rooted foundation anchorage according to  claim 1 , wherein on the outer edge of the anchor root hole is provided with a grouting hole. 
     
     
         6 . A construction method for a root-type cast in-situ bored pile with anchor roots wherein comprising the following steps:
 a reinforcement cage is placed into a bored hole; the reinforcement cage consists of an external main reinforcement and an internal main reinforcement; a guide framework, which is manufactured by welding a guide ring at both ends by more than two reinforcing steel bars, is welded between the external main reinforcement and the internal main reinforcement; the guide framework is subject to uniform arrangement along a peripheral direction inside the external main reinforcement and the internal main reinforcement; guide frameworks are arranged one line by one line along the axial direction of the external main reinforcement and the internal main reinforcement from top to bottom, and each guide framework has an inclined horizontal plane; the main reinforcement is anchored to the internal main reinforcement by stirrups;   each guide framework is internally provided with an anchor root front end of which is shaped like a cone while the tail end an arc surface;   a vibration extruder is used to squeeze the roots in the reinforcement cage; the vibration extruder comprising a circular table-shaped squeezing head, a connecting rod and a hydrostatic rapping device connected successively;   the squeezing head is used to squeeze the anchor roots from top to bottom gradually, and is pulled out after all anchor roots are in place; pouring concrete into cast-in-situ bored pile, particularly guaranteeing adequate concrete pouring into the guide framework which serves as an anchoring point for the anchor root.   
     
     
         7 . The construction method for a root-type cast in-situ bored pile with anchor roots according to  claim 6 , wherein the circular truncated cone of the squeezing head is 1-2 times of the spacing of two adjacent guide frameworks in height. 
     
     
         8 . The construction method for a root-type cast in-situ bored pile with anchor roots according to  claim 6 , wherein the reinforcement cage is externally provided with a geotextile or a sleeving.