Mold assembly of large-section pipe joint and upper angle mold splicing and fixing method thereof

The invention relates to a mold assembly of a large-section pipe joint for construction of pouring a top pipe. The mold assembly comprises an outer mold assembly used for forming a pouring groove, aninner mold assembly, a bottom mold and a buried pipe; the outer mold assembly is used for forming a rectangular inner mold wall with chamfered round angles; the inner mold assembly comprises a pipe joint lower angle mold, a pipe joint upper angle mold assembly and an angle mold connector; the pipe joint upper angle mold assembly comprises a first 45-degree chamfering mold, a second inner right angle mold, a third inner right angle mold and a fixing shelf, and the buried pipe is used for being arranged in an inner right angle of the second inner right angle mold or the third inner right angle mold, and the first chamfering mold, the second inner right angle mold can be formed by assembling the third inner right angle mold, a first splicing mold and/or a second splicing mold. An upper anglemold splicing and fixing m