基于自振频率的监测预警指标确定方法

Methods for determining early warning indices Based on natural frequency monitoring

强震、极端气候条件和人类活动是滑坡发生的主要诱发因素。这些强扰动会使滑坡的物理参数和软弱结构面力学参数发生变化,从而影响滑坡的有效预警。在监测中如何直接有效分析滑坡在地震及降雨作用下力学参数的变化,是工程中亟需解决的一大难题。提出了地震等强扰动作用下一种新的识别滑坡安全指标的快速评价方法;运用激光测振技术,测定滑坡等不良地质体的自振频率;根据结构动力学理论,基于测得的自振频率,可定量反映出内部结构参数变化。根据简化的滑坡体模型,模拟滑坡在地震或强降雨等条件下潜在滑移面的抗滑应力损失。结果表明:由自振频率可以得到滑坡在受到较大扰动情况下的应力折减系数等监测指标;非接触式的快速监测能快速实现对滑坡体的评价。激光测振技术将会在防灾、减灾和抢险救灾等工程实际中发挥重要作用。

Strong earthquakes, extreme weather conditions and human activities are among the major factors triggering landslides. These strong disturbances can change the physical properties of the landslides and the mechanical properties of the weak surfaces, which are responsible for the failure of the early warning. A new method is examined for quickly evaluating the safety of the landslides after a disturbance, such as an earthquake. The natural frequency of harmful geological structures are measured using the laser measurement technology. The measured natural frequency can quantitatively reflect the parameters of the internal structure. Using the simplified model of the landslide body, the stress loss of the slope surface due to an earthquake or heavy rain can be determined. The experimental results show that the natural frequency can be used to infer the monitoring indices such as the stress loss coefficient when the landslide subjected to a large disturbance. Rapid and remote monitoring can be effectively used to quickly evaluate a landslide. The laser vibration technology will play an important role in disaster prevention and disaster mitigation in the engineering practice.