研究目的:我国在黄土地区修建了大量的隧道工程，对隧道地基的湿陷性评价和处理没有专业规范，仅 参考《湿陷性黄土地区建筑规范》（GB 50025 —2004)的有关内容执行，在隧道内仰拱未封闭条件下进行地基 处理,速度慢，难度大,风险高。结合郑西、宝兰客专科研项目，提出黄土隧道的湿陷条件与建筑工程不同，隧道工程基底力学模型也不同于建筑工程，不能套用建筑规范，需研究适用于隧道工程的湿陷性系列技术。 研究结论:（1）新黄土发生湿陷的内因是其特殊的“峰窝状”结构，诱发因素及必要条件为外部荷载和水; (2)隧道开挖对其地基为减载作用,建筑工程结构对地基为加载作用；（3)隧道工程地基的湿陷变形从隧道底 部起算（建筑工程从地面起算），隧道两侧及顶部土层的湿陷量不计人;（4)隧道地基湿陷量计算值为隧底各 黄土层湿陷量的累计值，相应湿陷性等级划分为三级;（5)—般条件下，隧道洞门及洞口段地基需进行湿陷性 处理;（6)相应研究主要成果已纳入《铁路黄土隧道技术规范》（Q/CR 9511 —2014)，并应用于宝兰客专等线 的铁路隧道建设。

Research purposes： Although lots of tunnels have been built in loess regions, there is no professional specification or regulations were proposed yet for design of loess tunnel expect 11 code for building construction in collapsible loess regions GB 50025 - 200411. During the process of traditional tunnel foundation treatment in loess region, the construction is difficult , low and difficulty and high - risk. In terms of the study reports of Zhengzhou - Xian and Baoji - Lanzhou dedicated line , the collapsibility conditions and mechanical behavior of tunnel engineering is different from that of civil engineering. So a new collapsible mechanism and treatment of loss tunnel should be proposed more than quoting the old specification in civil engineering. Research conclusions ： (1) Internal factors of collapsible loess is determined by its special honeycomb structure. Meanwhile, its inducing factors and necessary conditions depend on applied loading and water. (2) Tunnel foundation induced by tunnel excavation is unloaded, contrary to that of civil engineering. (3) Calculation zero point of collapsible loess thickness start from the bottom of tunnel ( other than that in civil engineering start from ground) excluding from the contribution of soil from both sides and top of tunnel. (4) The calculation of collapse deformation is equal to an accumulative value of al soil layers beneath the tunnel foundation and classification of collapsibility is divided into three gradations based on collapse deformation. (5) Tunnel portal is generally necessary to be treated for collapsibility, corresponding technical principles about various tunnel foundation treatment are also subordinated to the 11 technical code for railway tunnel in loess Q/CR 9511 - 2014" and the achievements have been applied to the railway tunnel construction such as Baoji - Lanzhou dedicated line.