Construction method for foundation pit support utilizing prefabricated large-diameter pipe pile

Abstract

Provided is a construction method for foundation pit support utilizing prefabricated large-diameter pipe pile, through this method the pipe pile can be sunk into a hole being drilled. The method applies to a large-diameter pipe pile being sunk. All of components, such as the prefabricated capping beam configured to fix all pile heads and the prefabricated waist beam configured to secure the pile bodies, can ensure the excellent fixture of the pipe piles during the construction of the foundation pit. This method has a good retaining and protecting effect when applied to construction of a deep foundation pit requiring large-diameter pipe pile. It can reduce the environmental impact caused by waste soil and mud discharge in traditional cast-in-place construction, and the use of prefabricated components decreased the construction period and improved the construction efficiency.

1 . A construction method for foundation pit utilizing prefabricated large-diameter pipe pile, comprising:
 drilling a hole for pipe pile at a preset position, while sinking a prefabricated pipe pile into the hole;   repeating said drilling the hole to obtain an array of the prefabricated pipe piles which each is buried in the respective hole drilled;   fixing each head of the prefabricated pipe piles on a prefabricated capping beam;   fixing a first horizontal support rod to the prefabricated capping beam at a side of foundation pit;   excavating the foundation pit surrounded by the prefabricated pipe piles; when the foundation pit reaches a preset depth, fixing a prefabricated waist beam to the pile bodies of the plurality of the prefabricated pipe piles, while fixing a second horizontal support rod to the prefabricated waist beam; and   removing part or all of prefabricated components when the foundation pit was reached to the desired bottom,   wherein, during said drilling the hole, a retractable drill bit is configured below the prefabricated pipe pile, and is powered by a power supply device through a spiral drill rod set inside the prefabricated pipe pile; when the retractable drill bit works for drilling, the hole is produced for accommodating the prefabricated pipe pile, and an angle controller is used to adjust the drill rod and the prefabricated pipe pile to incline an angle.   
     
     
         2 . (canceled) 
     
     
         3 . The construction method of  claim 1 , the step  1  further includes:
 grouting a gap between an outer wall of the prefabricated pipe pile and an wall of the hole. 
 
     
     
         4 . (canceled) 
     
     
         5 . The construction method of  claim 1 , during said drilling the hole while the prefabricated pipe pile was sunk to the hole but not long enough, a quick joint is used for connecting the pipe pile to another prefabricated pipe pile such that the construction of sinking the prefabricated pipe pile can go on. 
     
     
         6 . The pile construction method of  claim 1 , wherein the prefabricated capping beam includes a first capping beam and a second capping beam which both are disposed on both sides of each head of the prefabricated pipe piles, and a plurality of groove pairs are symmetrically set in opposite sides of both the first capping beam and the second capping beam, each groove pair corresponds to each head of the prefabricated pipe piles; the first capping beam and the second capping beam are connected by detachable bolts. 
     
     
         7 . The construction method of  claim 6 , wherein the first horizontal support rod is fixed to the second capping beam through a first support rod joint, and the second horizontal support rod is fixed to the waist beam through a second support rod joint. 
     
     
         8 . The construction method of  claim 1 , wherein a lock member is provided between the waist beam and the prefabricated pipe piles, and an expansion bolt penetrates through the prefabricated waist beam and the lock member to fix the prefabricated waist beam to the prefabricated pipe piles. 
     
     
         9 . The construction method of  claim 8 , wherein brackets are configured underneath positions where the prefabricated pipe piles and the prefabricated waist beam are joined. 
     
     
         10 . The construction method of  claim 1 , wherein during said removing part or all of prefabricated components, part or all of prefabricated components are gradually removed and recycled.