摘要:研究目的:艰险山区高速铁路隧道洞口坡面落石防护问题是制约安全运营的重要因素，本文以西安至成 都高速铁路项目为依托，结合地形特点，提出两种新型棚洞结构#桥隧一体化柔性钢网棚洞及柱、梁支撑式钢 筋混凝土棚洞，分析各自特点，并提出适用条件。研究结论:( 1)柱、梁支撑式钢筋混凝土棚洞的上部结构自重大，需单独设置基础，工序复杂，施工难度 大，投资大，但耐久性好，后期维护成本低，在轨面标高与地面高差较大、高地震区采用时，务必进行详细检算 分析;（2)桥隧一体化柔性钢网棚洞可以与桥设为一体，不需单独设置基础，具有制作安装方便、经济美观等 优点，但钢材耐久性差，需定期防锈处理，后期维护成本高；（3)轨面距沟心地面高差是影响两种新型棚洞型 式选取的重要因素，一般高差小于15 m时优先选用柱、梁支撑式钢筋混凝土棚洞；（4)该研究成果可在铁路 隧道洞口落石防护中推广使用。

Abstract : Research purposes : The purpose of this paper is to study the rockfall protection of the high speed railway tunnel entrance in the mountainous area，which is an important factor restricting the safe operation. This paper is based on the high - speed railway project from Xi an to Chengdu，combined witli terrain features，proposes two new types of shed structure of the integration of flexible steel net shed tunnel tunnel，column and beam supported reinforced concrete shed，and analyzes their characteristics，puts forward the applicable conditions. Research conclusions ：( 1) Column and beam supported reinforced concrete shed tunnel superstructure has large self - weight，need to set the foundation alone，and has complex process， construction difficulty，large investment，but good durability，lowmaintenance cost，when the elevation difference between the surface of the orbit and the ground is higher， the detailed analysis and calculation of the high seismic zone must be carried out. (2) The integration of flexible steel net shed tunnel can be integrated with the bridge， the utility model has the advantages of convenient manufacture and installation，beautiful appearance，but has the disadvantage of poor durability of steel， the need for regular anti rust treatment and high maintenance costs. (3)The elevation difference between the surface and the center of the channel is an important factor influencing the selection of two new types of shed tunnel，when the height difference is less than 15 m，the column and beam supported reinforced concrete shed is prefered. (4 ) The research results can be widely used in rockfall protection of railway tunnel portal.