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黄土震陷是广大黄土地区在进行工程建设时避免不了的一种主要地震灾害。许多年来,黄土震陷研究是以室内试验为主要手段,天然地震黄土震陷现象的例证与现场试验的研究较为罕见。在典型震陷性黄土场地通过爆破方法模拟实际地震动的现场试验能够直观地了解黄土震陷发生的真实过程和分布特征和影响因素。试验结果表明,较强的地震动可以诱发黄土震陷的发生;场地内黄土震陷的最大量值可达33 mm,最小值约为13 mm;通过分析场地内黄土震陷分布特征和地震动强度分布特征可知,地震动强度与频谱H/V值是影响黄土震陷的决定性因素,地形也对震陷分布具有一定的影响;因为离爆破点较近,场地下部土层沉降贡献率大于上部土层。
Loess seismic subsidence is a major earthquake disaster in the vast loess areas that can not be avoided during construction. For many years, the study of loess seismic subsidence is mainly based on laboratory tests. The researches on the loess subsidence of natural earthquakes and field tests are rare. In the typical collapsible loess site by blasting method to simulate the actual ground motion field test can intuitively understand the loess earthquakes occurred in the true process and distribution characteristics and influencing factors. The results show that strong earthquakes can induce the occurrence of loess seismic subsidence. The maximum value of loess seismic subsidence within the site is up to 33 mm and the minimum value is about 13 mm. By analyzing the distribution characteristics of loess seismic subsidence and ground motion The results show that the intensity of ground motion and H / V value of the spectrum are the decisive factors affecting the loess seismic subsidence. The topography also has some influence on the seismic subsidence distribution. Because of the closer detonation point, the contribution rate of soil subsidence in the lower part of the site is larger than that of the upper part Soil layer.