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摘要: 大型高陡危岩崩塌初始失稳过程短暂，难以在现场进行及时观测并获取有效数据，为此引入离心模型试验。以重庆甑子岩陡崖高陡危岩崩塌为原型，对危岩崩塌启动机制展开研究，获取关键数据，定量化验证甑子岩危岩失稳的关键影响因素，探索危岩崩塌的离心模型试验方法。试验较好地完成了对岩质崩塌初始失稳过程的模拟，当危岩模型底部区域抗压强度为60 kPa时，失稳时刻离心加速度为73g；当抗压强度降至40 kPa时，失稳时刻离心加速度仅为18g；对照组试验证明高陡危岩底部区域强度对其整体稳定性起控制性作用。试验模型中上部岩体的失稳方式与原型具有一定差异，分析认为其原因除试验因素引入外力作用之外，主要是由于模型材料没有考虑原型的节理裂隙与抗拉强度所致，这表明高陡危岩崩塌模式除受底部岩体强度控制外，还与中上部岩体性状密切相关。研究结果可为高陡危岩压裂溃屈失稳机制提供试验依据与数据支撑，对崩塌灾害机理研究具有重要参考。Abstract: The collapse of large unstable rockmass fails suddenly with a short initial failure process. Therefore, it is different to make in-situ observation and obtain valid data timely. As a result, a centrifuge model test is introduced. In this paper the unstable rockmass at the Zengziyan cliff is taken as a case, and the collapse mechanism for this tower-shaped unstable rockmass is examined. The key influencing factors are analyzed quantitatively. Centrifugal acceleration of the Zengziyan model is 73g at failure moment when the compressive strength of the bottom zone of the unstable rockmass model is 60 kPa. The centrifugal acceleration is just 18g at the failure moment when the compressive strength of bottom zone is reduced to 40 kPa. The strength of the bottom zone can control the whole stability of the unstable rockmass, which is proved with the contrast tests. The failure mode of the middle and upper part of the high-steep rockmass model is different from the original one, and the reason is that the exogenic action is introduced due to the test factors. The other reason is the model material without considering joints and tensile strength. The results show that the collapse mode of the unstable rockmass like Zengziyan is controlled by the rockmass strength at the bottom and the properties of the overlying rockmass. These results provide experimental basis and data support for the failure mechanism of this kind of unstable rockmass, and they are also an important reference for collapse mechanism research.
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