TẠI LÀM
LAM CHUNG WATER SUPPLY SCHEME
Chief Resident Engineer's Report of Progress to 31st March, 1953.
Work on the Tai Lam Chung Dam officially commenced on 15th Decem- ber, 1951. For the first 2 months the work was largely confined to the pre- liminary works necessary before any of the permanent work can be done, such as providing the subsidiary ac- cess roads to various parts of the work, building the culvert to carry the water from the valley in whien the excavation for foundations has to be dumped, temporary bridges, build- ings, etc. The buildings include an office for the Chief Resident En- gineer's staff, additional staff bung- alows and a Police Station. The China Light & Power Co. completed a power line to the site at the end of January and so provided power and light for the scheme. The Contrac- tors brought to the site in January some of their own plant and erected 2 derricks- and a stone crusher, and were able to start excavating rock in the vicinity of the river bed, which they crushed for use as concrete ag- gregate for road surfaces, etc.
Work on the flume began in Jan- uary and it was finished by the end of February. This takes the average river flow, and enabled the river bed to be dried out and excavation for foundations began in that month. Boulders, tightly packed with clay. and up to 8 feet thick, were encoun- tered in the deepest part of the river bed overlaying the good rock.
and the Hon. Director of Public the final sealing of any small cracks Works visited the works and during or fissures against water pressure, a that visit it was decided that it was hole 20 feet deep was drilled in the better policy to build bungalows at main foundations and tested under the 16 mile site for the engineering 1000 lb. per square inch with excel- staff required for the tunnels, pipe- lent results. It is reasonable to as- lines and other parts of the work, sume from this that the rock at than at Tsun Wan, as they will have lower levels is at least as watertight a better disposal value on the very and that deep holes will not be ne- attractive sites there. Besides, the cessary. necessity of acquiring more land was avoided.
Many tests have been made by the engineering staff on concrete and During February and March con- mortars of various mixes and grad- siderable work was done in stripping ings of stone and sand with a view overburden from one of the quarry to determining the mix which will sites. The rock disclosed is mostly of give the greatest density and strength good quality but disappointing in of the concrete. All the crushing and quantity, and the probable yield grading tests have been made by the will be less than was at first Chief Engineer, Port Works in the estimated. A start was made in P.W.D. Laboratory. This service is March to develop the second source most useful and much appreciated by of stone supply on the right bank of the Engineers. the river, where trial pits have shown that a good supply is available. But In reviewing the work done during as the work develops and the big the first 3 months it can fairly be said demands for crushed and other stone that quite reasonable progress has arise. it is likely that a shortage of been made. Progress on excavation easily-won stone will occur and sup- for the foundations can be considered plies may have to be sought for fur- as very good, 13,000 cu.yds. of soft ther afield.
and 8,000 cu.yds. of rock having been removed for dam foundation and an- other 4,000 cu.yds. for access road to the cableway tower, but progress on quarry development, which plays such a vital part in the construction of the dam, is not so good, and a big effort is required here during the next few months. By the time the Gov- ernment plant is here and erected there will be an immediate use for it and the quarries must be in every way ready to meet the big demand for stone which will then occur.
His Excellency the Governor ac- companied by the Hon. Director of Public Works visited the site early in March, and made a full tour of the works.
By the end of March the Contrac- tors had reached good quality granite for the main foundations of the dam in the river bed. In order to obtain information as to how deep it might In February, the Colonial Secretary be necessary to drill grout holes for
At the same time excavation of the soft material on both banks was in hand and by the end of February over 8000 cu.yds. had been removed.
I
KAI TAK
AIRPORT
Progress Report to the end of March 1953 by Messrs. Scott & Wilson, Consulting Engineers.
N January work was confined to the engineering investigation of the Broadbent Proposals for the develop- ment of Kai Tak. The work under- taken comprised land survey of the existing airfield and drainage; an ap- preciation of the work involved in strengthening the present 07 runway and extending it through the R.A.F. Camp, including the provision of a road tunnel under the runway: and a start on sea borings in Kowloon Bay.
tion of the hills to the north of La Salle College which would have to be removed to improve the flying ap- proach to the runway.
been prepared for the new main run- the boring barge was moved to the way. and for a secondary runway area between this runway site and from Channel Rock to Kun Tong Tai Wan, from where it is hoped to (should such a secondary runway dredge the material for the runway ever be required); a model has been reclamation. A second boring barge constructed of the northern section is now being rigged out. A series of of the Kowloon Peninsular over drill holes were put down in the sec- which aircraft would approach to the new main runway: information has been collected to enable a tidal model of the harbour to be made to ensure that a new runway in this position would not cause scour or silting in In the soil mechanics laboratory the harbour: and agreement has been samples of soil and sand from the reached with the Director of Civil marine and land borings have been Aviation and airline operators on the tested for their strength as a founda- most suitable siting and overall lay- tion for the runway, and alternative out of the terminal building area. runway pavements have been design- The architects, Messrs. Ramsey, Mur- ed: the materials in the sea bed have ray & White, have submitted line been subjected to consolidation tests which estimates have been drawings of their initial proposals for from the terminal building.
made of the amounts that they will settle; further tests on the sea bed Marine borings along the centre materials have been undertaken for line of the proposed runway were stability calculations in the design of Since that date, layout plans have completed by mid-March, after which the sea walls.
In mid-January alternative рго- posals for the runway layout were formulated by Messrs. Scott & Wil- son in conjunction with the Director of Civil Aviation, and at the begin- ning of February their terms of re- ference were amended to cover the investigation of the new proposal for a runway extending to Channel Rock. in place of the former Broadbent runways.
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