Halfway milestone reached for 10.3-kilometre Mianya Tunnel on Xichang-Shangri-La motorway

According to Sichuan Provincial State-owned Assets Supervision and Administration Commission, 28 October 2026, tunnelling work on Mianya Tunnel, a key control structure of the G7611 Xichang‑Shangri‑La Expressway (Sichuan section), has passed the halfway mark.

Mianya Tunnel sits in Yanyuan County, Liangshan Yi Autonomous Prefecture, and ranks among the scheme’s nine mega engineering works. It forms a vital route linking Xichang with Lugu Lake, Shangri‑La scenic sites and Muli Tibetan Autonomous County. The separated dual two‑lane tunnel stretches 10.3 kilometres, with a maximum overburden depth exceeding 1,400 metres. The ground along its alignment is geologically complex, containing abundant groundwater, fractured fault zones, karst formations and high‑stress strata. Works face risks including seismic activity, collapse, karst incidents, mud and water surges, and rock bursts.

Multiple control tunnels including Mianya Tunnel and Yanyuan Tunnel have passed the halfway tunnelling stage this year. The main pylon of Lugu Lake Extra Large Bridge has been topped out. Total investment completed across the whole line exceeds 36 billion yuan, accounting for more than 60 per cent of the overall budget. The nine mega projects, grouped as three bridges, five tunnels and one interchange, advance to schedule.

Shudao Expressway Group leads investment for the expressway, while Sichuan Road and Bridge undertakes construction. Two highway design institutes carry out design services. The full route runs 233.13 kilometres, with a bridge‑tunnel ratio of 73.4 per cent. Built to dual two‑lane motorway standards with a design speed of 80 kilometres per hour, the scheme carries an estimated total budget of around 58.7 billion yuan and is scheduled for full opening in 2029.

The motorway forms part of the Greater Shangri‑La tourism loop. It creates a direct route connecting the inland southwest with the Yangtze River Economic Belt, Chengdu‑Chongqing Twin‑City Economic Circle and Pearl River Delta Economic Circle. On completion, it will give Yanyuan County and Muli Tibetan Autonomous County their first motorway links, support logistics for local agricultural produce and unlock tourism resources around Lugu Lake.