TNAG-0273-FCO40-309-Scheme-for-development-of-container-terminal-at-Hong-Kong-1970 — Page 49

FT. OR

$/SQ.

FT.

4

10

(68) 8

FIG. 1: SETTLEMENT & COST / REPLACEMENT DEPTH

KEY

(23) — No. OF YEARS FOR 90% CONSOLIDATION OF CLAY

FINAL SETTLEMENT

"90%

SETTLEMENT

(23)

(9)

2-YEAR

SETTLEMENT

2

UNIT COST

5

10

15

20

25

DEPTH - FT.

10.14 Fig. 1 indicates that irrespective of what depth of clay is replaced, about 3 ft. of settlement can be expected in the first two years after completion of filling. It also indicates that if only 15 ft. of the clay layer is replaced, the amount of settlement to be expected after consolidation of the fill is complete would be comparatively small. This would mean that if would be necessary only occasionally to make up levels thereafter. The estimated cost of replacing 15 ft. is $4.50 per sq. ft.

10.15 It would seem therefore, that expenditure for replacing more than 15 ft. of clay would not be justified. On the other hand, if this method is to be adopted, removal of that depth would be needed in order to reduce the amount of settlement after consolidation of fill to a reasonable amount.

10.16 It is concluded therefore, that replacement of very soft clay to reduce it to a 10-ft. thickness would enable the reclamation to be brought into use as soon as the majority of consolida- tion of the filling had taken place i.e. in the course of about 2 years.

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