Large-torsion temporary pile group construction method and back structure thereof

The invention discloses a large-torsion temporary pile group construction method. The method comprises the following steps of assuming the pile center distance, the pile diameter, the total pile number and pile group stress are horizontal force design values and torque design values; obtaining a horizontal force distributed by each pile according to the hypothesis; solving a torsional horizontal force according to the distance from each pile centroid to the centroid point of the pile group and the torque; combining all the forces, and calculating the horizontal thrust borne by one single pile;and finally, constructing a temporary pile group according to the horizontal thrust borne by the single pile and the reinforcing bars. According to the improved back arrangement, soil filling on oneside of the back is omitted, and the adverse effect of negative friction on the pile can be reduced; according to the calculation formula, the horizontal thrust of the single pile is obtained, and existing specifications are i