Zhongnanshan vs Jinpingshan: length, opening date and class compared

• 5entries listed

Side by side

Zhongnanshan is recorded on data/tun10.html and Jinpingshan on data/tun10.html, compiled to the same convention, which is what makes the two figures comparable at all.

How this archive measures: lengths, bores, dates and ordering

How this table is compiled

Zhongnanshan and Jinpingshan are compared here on the figures this archive records for each, taken from the same sources and the same measurement convention. Zhongnanshan belongs to the 2000s and Jinpingshan to the 2010s, two decades in which what a tunnel had to provide by way of escape and ventilation was not the same thing.

Zhongnanshan is the longer of the two at 18.04 km, ahead of Jinpingshan at 17.5 km, a difference of 0.54 km. Driven end to end the two would run 35.54 km, which is the figure to hold against the 24.51 km of the longest single road tunnel in the record.

That gap is about 3 per cent of the longer bore, which is the figure worth holding on to rather than the raw metres. Both rows are reachable from the road tunnel table they were taken from, where the note column carries the tube count, the gradient and any reconstruction Zhongnanshan or Jinpingshan has had.

Across every class this archive records, Zhongnanshan stands 44th by length and Jinpingshan 48th, so the pair sits inside the top 48 of 244 structures. 58 other structures in this record opened within two years of Jinpingshan, which is the cohort it was designed alongside and the fairer comparison for how it was built.

Counting every class, 3 recorded structures fall between these two by length; the comparison is a window on that part of the record rather than a gap in it. Both pass ten kilometres, which 161 of the 244 structures recorded here manage, so this is a comparison inside a small group rather than across the field.

Reading the figures

The 2000s account for 53 entries in this archive, and Zhongnanshan is one of them, which is the context a single opening date does not carry on its own. A length quoted to the metre implies a survey that was actually carried out, and not every published figure carries one.

Both are recorded in this archive as road tunnels, so the measurement convention is identical and the comparison is direct. Smoke moves uphill, so the two portals of a burning tunnel are not equally dangerous. Nothing in either row is estimated: a value that could not be corroborated is left blank rather than filled in.

Jinpingshan was designed under the modern regime, with cross-passage spacing and emergency ventilation specified from the outset. Among the road tunnels this archive records, Zhongnanshan stands 4th by length and Jinpingshan 5th, adjacent in the ranking. Opening dates refer to the admission of traffic, not to breakthrough, which normally falls a year or two earlier.

43 recorded structures are longer than Zhongnanshan, the nearest of them Taihangshan at 18.13 km. A single-bore crossing has to be closed to be maintained, which turns routine work into a route closure. Comparing two national records says as much about how each country documents its infrastructure as about the infrastructure.

Linings are inspected on a cycle of years and repaired in windows of hours. Height above sea level is a separate record from length. Round figures in an old record are usually estimates that hardened into fact. Rock cover above the bore governs a subsea design, not the depth of water above that.