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6. Make a list of technical aspects that you should consider when designing a deep hard rock tunnel.

7. These statements about tunnels and viaduct in Hong Kong are all false. Read the text below and correct them.

1) Kwai Tsing tunnels pass in easy geology.

2) A mixed-face earth pressure balance TBM has been used for the second time in Hong Kong to excavate a key section.

3) With an 8∙7 m diameter with a cutting head, the TBM is capable of digging only hard rock.

4) Tai Lam tunnel was excavated using shield-driven tunneling method.

5) The elevated alignment through the north-west New Territories avoids cutting across roads and disrupting the flow of water down drainage channels in flood-prone areas but doesn’t provide minimizing land take.

6) Viaduct noise preventing measures include a 1 m high parapet, train skirts and fixed slab track mounted on wood pads and resilient baseplates.

Tunnels and Viaducts

The underground sections comprise the Kwai Tsing tunnels passing under heavily built-up areas in the south, and the Tai Lam tunnel beneath the Tai Lam Country Park. To cope with mixed ground conditions and to avoid disruption to busy road traffic, a mixed-face earth pressure balance TBM (tunnel boring machine) has been used for the first time in Hong Kong to excavate a key section of the Kwai Tsing tunnels. With an 8.7 m diameter cutting head, the TBM is capable of digging through soft and waterlogged ground as well as hard rock.

Work on the southern section of tunnels is about 70 % complete.

At 5.5 km in length, the Tai Lam tunnel is the longest rail or road tunnel in Hong Kong. Excavated using traditional drill-and-blast methods, it was due to hole through last month. Application of the tunnel lining and construction of the central wall is proceeding alongside the excavation.

As well as minimizing land take, the elevated alignment (эстакадная трасса), through the north-west New Territories avoids cutting across roads and disrupting the flow of water down drainage channels in flood-prone areas. To ensure that these channels perform their vital function unobstructed (беспрепятственно), construction activity has been confined to the dry season. Special arrangements are in place for contractors to remove plant and materials from the worksites whenever there is a risk of flooding.

Despite these constraints (ограничения), substantial progress has been made in the construction of the 35 km of viaduct, which will be the longest bridge structure in Hong Kong. The viaduct decks are constructed using pre-cast methods and assembled on piers at a rate of 14 spans or 500 m per week.

Deck assembly was 70 % complete by mid-March, and we currently expect the last part of the deck structure to be erected during July.

A 1.3 m high parapet functioning as a noise barrier is being installed on both sides of the deck. This forms part of an innovative system that should make west Rail one of the quickest railways in the world. Other measures include train skirts and floating slab track mounted on rubber pads and resilient (упругие) baseplates. Together these will trap train noise at source and reduce vibration substantially.

Test 9

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