You can proceed as follows :

import torch

torch.manual_seed(0)

x = torch.rand(1, 25200, 11)

i=80*80*3#= 19200

j=40*40*3#= 4800

#k=20*20*3#=1200

x1=x[:,:i,:].reshape(1, 3, 80, 80, 11)

x2=x[:,i:i+j,:].reshape(1, 3, 40, 40 , 11)

x3=x[:,i+j:,:].reshape(1, 3, 20, 20, 11)

"""
x1=x[:,:i].reshape(1, 3, 80, 80, 11)
x2=x[:,i:i+j].reshape(1, 3, 40, 40 , 11)
x3=x[:,i+j:].reshape(1, 3, 20, 20, 11)
"""