郭长宝, 吴瑞安, 李雪, 徐正宣, 王栋, 杨志华, 孙炜锋, 钟宁. 2020: 川西日扎潜在巨型岩质滑坡发育特征与形成机理研究. 工程地质学报, 28(4): 772-783. DOI: 10.13544/j.cnki.jeg.2020-110
    引用本文: 郭长宝, 吴瑞安, 李雪, 徐正宣, 王栋, 杨志华, 孙炜锋, 钟宁. 2020: 川西日扎潜在巨型岩质滑坡发育特征与形成机理研究. 工程地质学报, 28(4): 772-783. DOI: 10.13544/j.cnki.jeg.2020-110
    GUO Changbao, WU Rui'an, LI Xue, XU Zhengxuan, WANG Dong, YANG Zhihua, SUN Weifeng, ZHONG Ning. 2020: DEVELOPMENTAL CHARACTERISTICS AND FORMATION MECHANISM OF THE RIZHA POTENTIAL GIANT ROCK LANDSLIDE, WESTERN SICHUAN PROVINCE, CHINA. JOURNAL OF ENGINEERING GEOLOGY, 28(4): 772-783. DOI: 10.13544/j.cnki.jeg.2020-110
    Citation: GUO Changbao, WU Rui'an, LI Xue, XU Zhengxuan, WANG Dong, YANG Zhihua, SUN Weifeng, ZHONG Ning. 2020: DEVELOPMENTAL CHARACTERISTICS AND FORMATION MECHANISM OF THE RIZHA POTENTIAL GIANT ROCK LANDSLIDE, WESTERN SICHUAN PROVINCE, CHINA. JOURNAL OF ENGINEERING GEOLOGY, 28(4): 772-783. DOI: 10.13544/j.cnki.jeg.2020-110

    川西日扎潜在巨型岩质滑坡发育特征与形成机理研究

    DEVELOPMENTAL CHARACTERISTICS AND FORMATION MECHANISM OF THE RIZHA POTENTIAL GIANT ROCK LANDSLIDE, WESTERN SICHUAN PROVINCE, CHINA

    • 摘要: 日扎潜在巨型岩质滑坡位于四川降曲河左岸,多高山峡谷且河流纵坡降大,晚更新世以来强烈活动的金沙江断裂带东界断裂从斜坡坡脚通过。本文在遥感解译、现场调查和物探测试分析的基础上,对日扎滑坡的发育特征和形成机理进行了分析研究,认为日扎滑坡是在断裂活动、岩溶水、长期卸荷和重力作用下形成的一个潜在巨型深层岩质滑坡,在空间上可划分为后部拉裂变形区(Ⅰ)、中部挤压变形区(Ⅱ)和坡脚应力集中区(Ⅲ)等3个分区。目前日扎潜在巨型滑坡以后部蠕滑变形为主,在其后缘发育4条拉裂缝,物探推测最大裂缝宽度达30~35 m、深度达190 m。研究认为,日扎潜在巨型滑坡存在两种主要失稳模式:(1)高位剪出失稳,推测潜在失稳体积分别为(7.9~10.2)×107 m3(H1)、(2.3~2.9)×108 m3(H2)、(4.8~7.2)×108 m3(H3)和(6~10)×108 m3(H4);(2)深部蠕滑变形,在滑体深部存在蠕变带和锁固段,最大蠕动变形体厚度约300 m(H5)。日扎滑坡在长期卸荷与重力、地震和岩溶水等作用下容易造成锁固段力学强度弱化和失稳,发生高位启动-滑动-堵江灾害链,深层蠕变带容易对建设其中的深埋隧道等重大工程造成危害。该类潜在巨型岩质滑坡在青藏高原地区具有典型性,建议对日扎潜在巨型滑坡进行深入勘察,查明其空间结构特征与稳定性,必要时进行监测预警。

       

      Abstract: The Rizha potential giant rock landslide is located on the left bank of Jiangqu River, Sichuan Province, with many alpine canyons and large vertical river slopes. The eastern boundary fault of Jinsha River fault zone, which has been active since late Pleistocene, passes through the foot of the slope. Based on remote sensing interpretation, field investigation and geophysical test analysis, the development characteristics and formation mechanism of the Rizha giant rock landslide are analyzed in this paper. It is considered that the Rizha landslide is a large deep giant potential rock landslide, which was formed under the influence of fault activity, karst water, long-term unloading and gravity. The Rizha landslide could be divided into three sub-zones spatially, i.e., the rear tensile deformation zone(Ⅰ), middle compression deformation zone(Ⅱ) and slope foot stress concentration zone(Ⅲ). The Rizha potential giant landslide is currently dominated by creeping deformation. There are four large tensile cracks developed well at its rear edge, with the maximum crack width up to 20~35 m and the depth up to 190 m by the geophysical data interpretation. The study result revealed that there were two main instability types of the Rizha giant potential landslide, the first one is the high shear instability type, with potential instability volumes of 7.9~10.2×107 m3(H1), 2.3~2.9×108 m3(H2), 4.8~7.2×108 m3(H3) and 6~10×108 m3(H4), and the other is deep-buried creeping deformation type, with deep-buried creep sliding zone and locking section in the deepen part of the sliding body. The maximum deformation thickness of the creeping body is 300 m(H5). The locking section of the Rizha landslide is likely to fail under the long-term unloading and gravity, earthquake activity, karst water activity, and the geo-hazard chain of the high-level rock falling-sliding-blocking the river is likely to occur. The deep creeping sliding might have great influence on the stability of major projects built in the slope, such as deep-buried tunnels. This kind of potential giant rock landslides are typically developed on the Tibetan Plateau. It is recommended to make further investigation of the Rizha potential giant landslide, to find out the spatial structural characteristics and stability, as well as monitoring and early warning if necessary.

       

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