Development of new cyclic loading ring shear apparatus

地震引发的山体滑坡在世界范围内造成了巨大的灾害。地震的时间预报并不能减少滑坡灾害的发生。滑坡预测是非常必要的。本研究开发了一种新的装置来再现到达滑动表面的应力和应变，以及地震期间斜坡的快速剪切位移。试验步骤为：1)在剪切箱中设置试样；2)在排水条件下加载与边坡应力相似的静应力；3)在不排水条件下加载地震应力；4)监测由此产生的剪切位移和产生的孔隙压力。利用从滑坡区采集的浮石样本，再现了1984年长野根-西武地震引发的御武滑坡。我们从1980年伊朗地震引起的Galdian滑坡和Fatalok滑坡中提取了样本，并重现了观测到的滑坡。然后，我们对中国西安故宫背后的骊山进行了调查，该山体具有滑坡前兆现象和引发灾难性滑坡的可能性，并对该边坡的黄土样品进行了测试。结果给出了引起滑坡和运动过程中动员摩擦的临界地震加速度。

Landslides triggered by earthquakes have caused great disasters in the world. Time prediction of earthquakes could not reduce those landslide disasters. Prediction of landslides are very necessary. This research has developed a new apparatus to reproduce the stress and strain reaching to a sliding surface, and the resulting rapid shear displacement in slopes during earthquakes.The test procedures are 1) setting samples in the shear box, 2) loading the static stress similar to the stress in the slope under the drained condition 3) loading seismic stress under the undrained condition 4) monitoring the resulting shear displacement and the generated pore pressure.The Ontake landslide triggered by the 1984 Naganoken-Seibu earthquake was reproduced using the samples of pumice taken from the landslide area. We took samples from the Galdian landslide and the Fatalok landslide caused by 1980 Iran earthquake and also reproduced the observed landslides.Then, we investigated the Lishan mountain behind the Royal Palace in Xian, China which has a precursor landslide phenomena and the possibility to cause a catastrophic landslide, and tested the sample of loess taken from this slope. The result gave a critical seismic acceleration to cause landslides and the mobilized friction during motion.