All tunnels have complex cross section with circular, rectangle, arch, ellipse shape, in accordance with the length of the tunnel is divided into short, medium length of the tunnel, long tunnel.

隧道按截面分为圆形、矩形、拱形、椭圆等形状，按照长度分为短隧道、中等长度隧道、长隧道。

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All tunnels have complex cross section with circular, rectangle, arch, ellipse shape, in accordance with the length of the tunnel is divided into short, medium length of the tunnel, long tunnel.

隧道按截面分为圆形、矩形、拱形、椭圆等形状，按照长度分为短隧道、中等长度隧道、长隧道。

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