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利用有限单元法模拟二维MT倾子响应 总被引:1,自引:0,他引:1
在二维地电模型中,考虑到大地电磁测深(MT)倾子响应依赖于横电(TE)模式的数值模拟问题,笔者采用矩形网格单元和双二次插值对MT的倾子响应进行求解。首先,给出了二维地电条件下的边值问题和变分问题,并通过有限单元法对模型进行单元剖分、插值、积分和整体合成;其次,通过求解复系数方程组得到了每个节点的电场值;最后,采用差分方法求得电场沿横向和垂向的偏导数值,从而计算出二维MT的倾子响应。通过对2个二维地电模型的倾子响应进行数值模拟,获得了倾子响应的实部、虚部和振幅,结果很好地反映了不均匀体的横向分布情况。 相似文献
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Analysis of an anti-dip landslide triggered by the 2008 Wenchuan earthquake in China 总被引:2,自引:0,他引:2
Runqiu Huang Jianjun Zhao Nengpan Ju Guo Li Min Lee Lee Yanrong Li 《Natural Hazards》2013,68(2):1021-1039
The Guantan landslide, with a total displaced mass of about 468 × 104 m3, was triggered by the 2008 Wenchuan earthquake and succeeding rainfall in Jushui Town, Sichuan Province, China. The landslide occurred on an anti-dip hard rock slope with a weak rock founding stratum of 200 m in thickness. To investigate the failure mechanism of the Guantan landslide, dynamic behaviors of hard and soft rock slopes were investigated by means of large scale shaking table tests. The laboratory models attempted to simulate the field geological conditions of the Guantan landslide. Sinusoidal waves and actual seismic waves measured from the Wenchuan Earthquake were applied on the slope models under 37 loading configurations. The experimental results indicated that deformation mainly developed at a shallow depth in the upper part of the hard rock slope and in the upper (near the crest) and lower (near the toe) parts of the soft rock slope. An equation for predicting the depth of sliding plane was proposed based on the location of the maximum horizontal acceleration. Finally, it was concluded that the failure process of the Guantan landslide occurred in three stages: (1) toppling failure caused by compression of the underlying soft rock strata, (2) formation of crushed hard rock and sliding surface in soft rock as the result of seismic shocks, particularly in the horizontal direction, and (3) aftershock rainfall accelerates the process of mass movement along the sliding plane. 相似文献
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Kecun Zhang Jianjun Qu Qinghe Niu Zhefan Jing Zhishan An 《Environmental Earth Sciences》2013,70(7):3107-3113
Based on the detailed wind data, this paper aims to investigate wind regime, drift potential and the movement of mega-dunes at the Crescent Moon Spring, an important scenic spot in western China and to clarify the dominant factors that control sand transport in this region. The results of this paper revealed that the dominant wind directions at the spring were NW and SW. The spring region belonged to a low-energy wind environment. The wind regime and sand drift potential were hugely influenced by local topography, and the regional atmospheric circulation intensified the complexity of their variations. Besides, the movement of the southern and northern mega-dune towards the spring greatly endangered the preservation of this scenic spot. These results provide insights into the characteristics of wind-blown sand at the Crescent Moon Spring that will guide efforts to control sand damages. 相似文献
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缓倾煤层采空区上覆山体滑坡形成机制分析 总被引:4,自引:0,他引:4
下伏采空区的缓倾斜坡,由于采空区大小、方位不同和斜坡结构特征的差异,多存在地表沉陷、拉裂、局部崩塌、滑坡等工程地质问题,常常会诱发大规模的地质灾害。马达岭滑坡发育于存在软弱夹层和煤层采空区的缓倾斜坡中,由采空区的破坏和降雨诱发形成,体积达190104m3。调查和分析表明,脆弱的地质结构和坡体下伏采空区的破坏是滑坡形成的主要原因,降雨的促进作用加速了滑坡的发生; 马达岭滑坡的破坏模式为塌落-拉裂-剪切滑移,滑坡的形成机制和发展过程可以分为以下3个阶段: 斜坡后缘拉裂阶段,滑面贯通阶段和滑坡整体破坏阶段。崩滑体崩解后顺着沟谷向下游流动,形成长1.5km的泥石流碎屑堆积区,淹没大量农田。 相似文献
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