崩塌作为中国常见的一种地质灾害，分布范围广，隐蔽性高、突发性强，危害性大。在易灾地层红层广泛分布的西南地区，高切坡在后端汇水和冻融作用的共同影响下，若不及时治理，极易诱发崩塌、滑坡等灾害。以广元射箭镇场镇崩塌为对象，通过现场调查、影像分析和公式计算等方法，探究后端汇水及冻融影响下红层高切坡的破坏机制，旨在为红层区域基础设施建设中的崩塌防治提供思路。结果表明：研究区特殊的地貌和气候条件带来了丰沛的降水，崩塌后端的大面积汇水区与蓄水农田的下渗共同造就了强水环境，导致岩体长期处于饱和状态，且多年冻融循环严重削弱了岩体强度，使砂岩与泥岩抗拉强度降低至166.12 kPa和72.77 kPa，均低于红层切坡裂隙中的裂隙水压174.87 kPa，进而导致崩塌的发生。鉴于不同岩体结构的红层高切坡在后端汇水及冻融影响下的破坏模式存在差异，建议在防治过程中增加对后端汇水和冻融的考虑，加强排水措施，结合崩塌的破坏模式进行针对性的治理。

Collapse, as a common geological hazard in China, are widely distributed, highly concealed, sudden, and pose significant risks. In southwestern China, where disaster-prone red beds are extensively distributed, high cutting slopes are highly susceptible to landslides and collapses if not promptly managed, especially under the combined effects of back-end catchment and freeze-thaw cycles. Taking the collapse at Shejian Town in Guangyuan as a case study, on-site investigations, image analysis, and formula calculations were conducted to examine the failure mechanisms of red bed high cutting slopes influenced by back-end catchment and freeze-thaw effects, aiming to provide insights for disaster prevention in infrastructure development within red bed regions. The results indicate that the unique topography and climate conditions of the study area contribute to abundant rainfall, creating a waterintensive environment due to the extensive back-end catchment in the collapse area and infiltration from irrigated farmlands. The prolonged saturation of rock masses, combined with repeated freeze-thaw cycles, significantly weakens the rock strength, reducing the tensile strengths of sandstone and mudstone to 166.12 kPa and 72.77 kPa, respectively. Both values are lower than the fracture water pressure of 174.87 kPa in the fractures of the red bed cut slope, ultimately leading to the occurrence of the collapse. Given the variations in failure modes of red bed high cutting slopes with different rock structures under the effects of back-end catchment and freeze-thaw cycles, it is recommended to enhance drainage measures during prevention efforts and to implement targeted treatments based on the identified failure modes.