To extend the work period and shoulder half of the expenditures of the additional work in the event of unforeseen difficult ground condition in piling work performed according to the contractor s design 又或在打樁工程按承建商的設計進行而遇到不可預知復雜巖土的情況時,房委會會予以延長施工期,并承擔相關額外工程支出的半數。