personally it is the bored piles with cappingbeam and lagging wall. H;tE=
the main reason for this collapse may be the shortage of bending moment resistance of the wall. the surrounding building is the critical origin of the large lateral force. 1L7^g*
from the photo it can be seen that the site soil is not so bad. H*f2fyC1\
measures may be : soil nailing between the piles to increase the wholly stability of the wall; SH8zkAA7u}
increase the embedment (if the collapse came from overturning of the wall); prop up the wall with berms or inclined wall; or tie back from the back of the wall; '+g[n
meanwhile, monitoring should be carried out very carefully.