边坡岩块体崩塌破坏的振动特征前兆识别研究

Rock mass collapse has been a hot issue in the study of geological hazards for many years，and it is difficult to prevent because of its sudden disintegration, which is a serious threaten to human life and property safety. The traditional conventional monitoring technique can only identify the damage, but cannot provide the early warning. Therefore, the further study on advance warning of rock block collapse is required. The rock-block collapse is caused by the dynamic failure of the system instability, so it can be more effective to apply the vibration characteristic parameters for the scientific early warning. Previous studies found that the early warning of collapse based on vibration characteristics is superior to that based on displacement, and vibration characteristics are effective to the damage identification of the rock mass. Based on the laser Doppler vibration testing technology and new physical model experiment, the study aims to monitor the whole process of rock collapse and obtain multiple time domain and frequency domain vibration indexes. For early warning of rock failure, the project will focus on the identification of rock failure precursors by the vibration indexes, and form an early warning evaluation method by failure precursor recognition under multiple vibration features. The results of the project will provide scientific basis for the early warning of rock block collapse, improve the current passive prevention situation of rock-blocks monitoring, and reduce casualties and property losses caused by the instantaneous rock collapse.

岩块体崩塌一直是岩土工程灾害研究的热点问题，然而崩塌破坏的突发性使其成为最难预防的灾害，严重威胁人类的生命财产安全。目前常规监测指标只能识别破坏的发生，而不能提早预报预警，因此对岩体崩塌早期预警研究还有待进一步深入。岩体崩塌破坏多是系统不稳定导致的动力破坏，而用振动特征参数监测来进行预警更为有效。前期研究发现振动特征参数在崩塌破坏的早期预警方面优于常规位移监测，并且在岩体力学参数的损伤识别方面具有指示作用。本课题应用激光多普勒测振技术和新型物理模型实验，通过对多种时域和频域振动特征监测，进行岩块体崩塌破坏全过程实验研究，通过综合分析振动特征参数指标，开展岩块体崩塌破坏前兆识别研究的工作，旨在实现岩块体崩塌破坏的主动监测预警。项目成果将为岩块体崩塌破坏早期预警提供科学依据，改变目前岩块体崩塌监测预警被动预防的态势，减少因崩塌等瞬时破坏造成的人员伤亡和财产损失。

作为我国常见的一种地质灾害，崩塌成因复杂，分布范围广，隐蔽性和突发性强，危害性大，其早期预警技术一直难以实现。通过本项目研究总结得出，开展崩塌灾害发生的主控因素岩桥的定量识别与模糊评价，是未来岩体崩塌灾害预警预防的关键所在，而固有振动频率等动力学指标在岩桥损伤分析、危岩快速识别以及崩塌早期预警等方面具有明显的应用优势。此外，关注分离阶段及其分离破坏前兆是提高岩块体崩塌灾害早期预警时效性的有效手段之一，建立基于分离破坏前兆识别的岩体崩塌灾害预警方法并健全三位一体的监测预警指标体系可改变目前崩塌灾害被动预防的态势。与此同时还需同步开展国产高精度遥感振动监测技术装备研发，这是满足我国崩塌灾害早期预警核心技术创新发展与国家工程安全建设战略需要的必然选择。此外，项目研究还进行了振动特征与岩体稳定性的动态关系研究，确定了岩体稳定性的定性评价指标，并进一步的确定了危岩体固有振动频率与岩体粘结面积、安全系数等之间的定量关系，推导了严格意义上的基于动力特征参量的岩体稳定性定量评价模型，并在此基础上开展了基于分离破坏前兆识别的崩塌灾害早期预警方法研究。这些研究成果无论是在一带一路等工程安全需求方面，还是在全国地质灾害预警预防方面，都将具有极强的理论意义与应用价值。