地震研究

以金沙江上游贡扎村滑坡为研究对象,对滑坡滑床及堆积体进行现场调查,研究结果表明:①该区滑坡主要受岩层层面和两组共轭节理控制,岩层倾向与坡向相反,属于反倾边坡; 堆积体内块石体积较大、形状规整,大部分保留母岩产状,在物质组成和结构上与滑床基岩存在较高相似性,判断贡扎滑坡为整体倾倒滑坡。②滑坡规模巨大,堆积体体积约4.5×107 m3,结合川藏地区金沙江流域地震活动特点,推测造成边坡大规模倾倒的主要原因是地震作用。③根据两级堆积体分布特点和滑坡后壁结构面发育特点,认为滑坡变形分为4个阶段:坡脚岩土体滑移、陡倾面拉裂、板梁弯曲折断和碎屑岩块堆积。地震是诱发滑坡的重要因素,坡内单一的岩性和岩层密集的节理是发生倾倒的内部原因,坡脚处岩土体滑移是倾倒发生的必要条件。

In this paper,we conduct a field investigation of the slide bed and the accumulation body of a landslide in Gonza village in the upper Jinsha River,Tibet and find that the landslide is mainly controlled by the rock layer and two sets of conjugate joints.The dip direction of the rock layer is opposite to the sliding direction,and the slope is anti-inclined.The blocks of the deposit body are large and regular-shaped,and most of them still retain the occurrence of the parent rock.And the composition and structure of the deposit rock are highly-similar with those of the rock of the slide bed.All these suggest that the Gonza landslide is a holistic toppling landslide.The landslide is in huge scale,with a volume of about 4.5×107 m3.In the light of the characteristics of seismic activities in the Jinsha River basin,we speculate that the main reason for the large-scale toppling of the slope is earthquake effect.According to the distribution of the two-stage accumulation bodies and the characteristics of the development of the structural surface on the back wall,we conclude that the landslide deformation consists of four stages:slope toe sliding,steeply-inclined surface cracking,cantilever beam bending and breaking,and clastic rock accumulating.Earthquakes serve as an important factor in inducing landslides.The single lithology and dense joints in the rock layers make up intrinsic factors causing toppling,while the toe slippage is a necessary condition.

引言
1 贡扎滑坡的工程地质条件
2 滑坡的发育特征
3 滑坡变形破坏模式
4 结论

表1 贡扎滑坡附近区域晚更新世断裂活动性特征表<br/>Tab.1 Characteristics of the fault activity in the late pleistocene in the surrounding area of Gongza landslide

表1 贡扎滑坡附近区域晚更新世断裂活动性特征表
Tab.1 Characteristics of the fault activity in the late pleistocene in the surrounding area of Gongza landslide

图1 滑坡区周围破坏性地震分布<br/>Fig.1 Destructive earthquakes around the landslide area

图1 滑坡区周围破坏性地震分布
Fig.1 Destructive earthquakes around the landslide area

图2 贡扎滑坡平面图<br/>Fig.2 Plan view of the Gonza landslide

图2 贡扎滑坡平面图
Fig.2 Plan view of the Gonza landslide

图3 贡扎滑坡剖面图<br/>Fig.3 A section of the Gonza landslide

图3 贡扎滑坡剖面图
Fig.3 A section of the Gonza landslide

图4 研究区节理等密度图<br/>Fig.4 Isometric map of regional joints

图4 研究区节理等密度图
Fig.4 Isometric map of regional joints

图5 滑坡边界处(a)及坡内(b)结构面产状<br/>Fig.5 Structural planes at the boundary of the landslide(a)and within the slope(b)

图5 滑坡边界处(a)及坡内(b)结构面产状
Fig.5 Structural planes at the boundary of the landslide(a)and within the slope(b)

图6 堆积体前缘出露原岩(a)及原岩原始产状(b)<br/>Fig.6 The original rock in the front edge of the deposit(a)and its occurrence(b)

图6 堆积体前缘出露原岩(a)及原岩原始产状(b)
Fig.6 The original rock in the front edge of the deposit(a)and its occurrence(b)

图7 堆积体原岩节理等密图<br/>Fig.7 Isometric map of the original rock joints in the accumulation body

图7 堆积体原岩节理等密图
Fig.7 Isometric map of the original rock joints in the accumulation body

图8 堆积体出露原岩<br/>Fig.8 Raw rocks exposed in the accumulation body

图8 堆积体出露原岩
Fig.8 Raw rocks exposed in the accumulation body

图9 堆积体临江横截面上游侧(a)和下游侧(b)<br/>Fig.9 The upstream(a)and downstream(b)sides of the riverside cross section of the accumulation body

图9 堆积体临江横截面上游侧(a)和下游侧(b)
Fig.9 The upstream(a)and downstream(b)sides of the riverside cross section of the accumulation body

表2 贡扎村滑坡堆积体钻孔资料统计表<br/>Tab.2 Statistics of the drilling data of the landslide accumulation body in Gonza village

表2 贡扎村滑坡堆积体钻孔资料统计表
Tab.2 Statistics of the drilling data of the landslide accumulation body in Gonza village

图10 夏季(a)和冬季(b)坡脚与堆积体之间的空缺带<br/>Fig.10 The vacancy zone between the toe of the slope and the accumulation body in Summer(a)and Winter(b)

图10 夏季(a)和冬季(b)坡脚与堆积体之间的空缺带
Fig.10 The vacancy zone between the toe of the slope and the accumulation body in Summer(a)and Winter(b)

$图11 滑床视倾角60°(a)和滑坡后缘的断裂面(b)<br/>Fig.11 The apparent inclination angle of the slide bed is 60°(a)and the fracture surface of the trailing edge of the landslide(b)$

图11 滑床视倾角60°(a)和滑坡后缘的断裂面(b)
Fig.11 The apparent inclination angle of the slide bed is 60°(a)and the fracture surface of the trailing edge of the landslide(b)

图12 贡扎滑坡滑动过程示意图<br/>Fig.12 Schematic diagram of the sliding process of the Gongza landslide

图12 贡扎滑坡滑动过程示意图
Fig.12 Schematic diagram of the sliding process of the Gongza landslide

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备注

引言

1 贡扎滑坡的工程地质条件

2 滑坡的发育特征

3 滑坡变形破坏模式

4 结论

期刊信息