陡倾互层斜坡动力损伤能量特征识别方法研究

Study on the characteristic identification method of dynamic damage energy of steeply inclined interbedded slopes

为研究强震作用下软硬互层斜坡变形破坏过程中坡内损伤演化特征,进而为斜坡地震稳定评估提供技术支持,通过对离心机振动台试验中采集的加速度监测数据进行降噪、信号重构及HHT变换处理,分析边际谱峰值以及熵值与坡体损伤发育之间的规律,提出根据边际谱累积熵值识别陡倾互层斜坡动力损伤的方法。结果表明:(1)软硬互层斜坡在强震作用下变形破坏模式为动力滑移–弯曲型,该类斜坡强震破坏位置较浅且其动力响应呈现显著的近坡面效应。(2)随地震波作用的增强,坡内损伤破坏部位的边际谱峰值及熵值均会出现突变,但仅边际谱熵值可量化反映坡体损伤程度。(3)相对于采用边际谱峰值或其熵值变化识别斜坡损伤的方法,边际谱累积熵值云图具有可直观反映坡内损伤破坏过程、坡体不同位置受损程度,并可识别锁固段及破坏面位置的优点。

For studying the damage evolution features of the interbedded slopes during the process of destruction under strong earthquake,and providing technical support for the slope seismic stability assessment,a centrifuge shaking table is conducted.The monitored acceleration data collected in model test is denoised,signal reconstruction and processed by HHT transformation.The relationships between the peak value of marginal spectrum,the entropy value and the development of slope damage are analyzed.A new method for identifying dynamic damage of steep interbedded slope by using the cumulative entropy of marginal spectrum is proposed.The results show that:(1)the deformation and failure mode of interbedded slope under strong earthquake is dynamic sliding-bending type,and the failure area of this kind of slope is shallow under strong earthquake.Its dynamic response presents significant near-slope effect.(2)The peak value and entropy value of marginalspectrum of the damaged parts in a slope will change suddenly with increased seismic motion;however,only the entropy of marginal spectrum can quantify the damage degree of slope.(3)Compared with the two methods of the peak value variation and entropy value of marginal spectrum,the cumulative-entropy field chart of marginal spectrum can directly reflect the development process of damage and failure in slope,the damage degree of slope at different positions,the location of locking section and failure plane.