为解决特长公路隧道升级改造困难问题，以折多山公路隧道项目为依托，创新性地提出远、近期合建的总体设计方案。通过交通量预测、工程造价、运营通风及逃生救援等方面综合比较，得出可实施的合建方案： 先期建设二级公路隧道主洞，设2段非贯通平导，后期直接将二级公路隧道作为高速公路隧道右洞，并贯通二级公路隧道平导作为高速公路隧道左洞。合建方案能有效节约工程造价，降低社会耗能。

The extralong tunnel is difficult to upgrade and transform. Hence, an joint construction plan in both longterm and shortterm is creatively presented for Zheduoshan Tunnel project. The construction schemes are compared and analyzed from the aspects of traffic volume prediction, construction cost, ventilation and escaperescue design, and a practical construction plan, i.e. the national Grade 2 road tunnel main tunnel is constructed and 2 sections of breakthrough parallel heading are set firstly, and then the main tunnel is taken as right tunnel of highspeed tunnel and the brokenthrough parallel heading is taken as left tunnel of highspeed tunnel, is put forward. The results show that the joint construction scheme can effectively reduce the construction cost and social consumption.