崔圣华, 裴向军, 黄润秋, 朱凌, 孟祥瑞. 2019: 汶川地震黄洞子沟右岸大型滑坡地质构造特征及成因. 工程地质学报, 27(2): 437-450. DOI: 10.13544/j.cnki.jeg.2017-179
    引用本文: 崔圣华, 裴向军, 黄润秋, 朱凌, 孟祥瑞. 2019: 汶川地震黄洞子沟右岸大型滑坡地质构造特征及成因. 工程地质学报, 27(2): 437-450. DOI: 10.13544/j.cnki.jeg.2017-179
    CUI Shenghua, PEI Xiangjun, HUANG Runqiu, ZHU Ling, MENG Xiangrui. 2019: GEOLOGICAL FEATURES AND CAUSES OF THE WENCHUAN EARTHQUAKE TRIGGERED LARGE LANDSLIDES ON RIGHT BANK OF HUANGDONGZI GULLY. JOURNAL OF ENGINEERING GEOLOGY, 27(2): 437-450. DOI: 10.13544/j.cnki.jeg.2017-179
    Citation: CUI Shenghua, PEI Xiangjun, HUANG Runqiu, ZHU Ling, MENG Xiangrui. 2019: GEOLOGICAL FEATURES AND CAUSES OF THE WENCHUAN EARTHQUAKE TRIGGERED LARGE LANDSLIDES ON RIGHT BANK OF HUANGDONGZI GULLY. JOURNAL OF ENGINEERING GEOLOGY, 27(2): 437-450. DOI: 10.13544/j.cnki.jeg.2017-179

    汶川地震黄洞子沟右岸大型滑坡地质构造特征及成因

    GEOLOGICAL FEATURES AND CAUSES OF THE WENCHUAN EARTHQUAKE TRIGGERED LARGE LANDSLIDES ON RIGHT BANK OF HUANGDONGZI GULLY

    • 摘要: "5·12"汶川地震发生于龙门山逆冲构造带映秀-北川断裂,此次地震沿约300 km地表破裂带触发了大型滑坡百余处,其中大光包滑坡、红石沟滑坡和老鹰岩滑坡发育于绵阳安州区黄洞子沟右岸不到5 km区段内,规模均超过千万方,且大光包滑坡是此次地震中最大滑坡,也是世界罕见的巨型滑坡。本研究通过大量现场照片、遥感影像和实地测绘,结合XRD、岩石薄片手段在此3个滑坡滑源区展开了详细的地质调查。结果表明:(1)先期深埋的中-缓倾构造层带为大光包滑坡提供了潜在侧滑面,与岩体结构面组合触发了大光包大型楔形体破坏;(2)红石沟滑坡发育于含多级角砾、糜棱质次级错动带的碎裂结构坡体,地震中这些倾坡外的次级错动带快速贯通形成滑坡底滑面;(3)老鹰岩滑坡主控于厚层陡倾构造带,地震中该带沿走向拉裂破坏,加之两侧陡倾结构面组合切割触发了老鹰岩大型楔形体破坏。研究进一步发现,红石沟斜坡紧临大水闸背斜轴部、老鹰岩和大光包斜坡位于其两翼,认为该背斜构造对研究区斜坡地震稳定性有较大影响。本研究仅揭示了3个典型地质构造滑坡类型,汶川地震百余处大型滑坡地质构造成因有待进一步研究。

       

      Abstract: Wenchuan earthquake ruptured the Yinxiu-Beichuan fault in Longmenshan thrust zone. More than 100 large-scale landslides were triggered during earthquake along the 300 km fault rupture. Three landslides with volume larger than 1000×104 m3 were developed within 5 km at the right bank of Huangdongzi River in Mianyan City. There are Daguangbao landslide, Hongshigou landslide and Laoyingyan landslide. The Daguangbao landslide was the largest landslide during the earthquake. Geological investigations were conducted in landslide areas and the results showed that the study area was located not only between imbricated thrust belts but also on an anticline. The Hongshigou landslide was close to its axis, while the others were on each wing. Several joint sets and weak interlayers were developed in slopes. The three landslides were triggered with special geology. A bedding fault with breccia rock formed landslide potential boundary. The shear resistance reduced rapidly during earthquake which triggered the landslide initiation. The Hongshigou landslide was located on a cataclastic slope with many breccia shear bands. The landslide was triggered resulting from the shear bands failure which formed the basal shear surface rapidly during the earthquake. A weak interlayer of almost 100 m developed in Laoyingyan slope. The weak layer tensioned rapidly due to strong horizontal seismic shaking which triggered the slope collapse.

       

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