【摘要】：黑方臺(tái)為劉家峽庫(kù)區(qū)移民安置點(diǎn),近年來(lái),由于提水灌溉誘發(fā)大量的滑坡、崩塌、泥流等災(zāi)害,造成重大經(jīng)濟(jì)損失,嚴(yán)重威脅著當(dāng)?shù)鼐用竦纳?cái)產(chǎn)安全,引起了廣泛的關(guān)注。所以對(duì)黑方臺(tái)地區(qū)災(zāi)害的研究及防治迫在眉睫,而構(gòu)造地貌條件在一定程度上控制了災(zāi)害的發(fā)育。通過(guò)野外調(diào)查臺(tái)地周圍的構(gòu)造現(xiàn)象(斷層、褶皺、節(jié)理、巖層剖面等)、卵石層發(fā)育特征(卵石層厚度、位置、卵石產(chǎn)狀、形態(tài)大小、巖性等)、滑坡后壁發(fā)育情況等,結(jié)合DEM數(shù)據(jù)及地質(zhì)圖資料,用疊加計(jì)算的方法分析了臺(tái)塬邊坡的演化過(guò)程；用地形廊帶法分析了災(zāi)害的分布及發(fā)育過(guò)程；用分形分維的方法分析了臺(tái)地周圍38處滑坡的形態(tài)特征；基于卵石形態(tài)及排列特征分析了地下水的徑流及古河流環(huán)境。分析結(jié)果表明：(1)臺(tái)地周圍主要發(fā)育有7條斷層,以逆斷層居多,虎狼溝斷層(FH)和焦家斷層(FJ)第四紀(jì)以來(lái)曾發(fā)生過(guò)小幅度錯(cuò)動(dòng),處于活動(dòng)狀態(tài),對(duì)臺(tái)地下伏粘土層有較大的影響。斷層面及節(jié)理發(fā)育特征所反映的斷層露頭處局部地應(yīng)力場(chǎng)與現(xiàn)代大地構(gòu)造應(yīng)力場(chǎng)近一致。(2)黑方臺(tái)緣邊主要發(fā)育有兩大類滑坡,在空間分布上具有分區(qū)段發(fā)育的特征,不同區(qū)段滑坡規(guī)模各異,危害程度也不同。黃土滑坡規(guī)模較小,滑距較長(zhǎng),分維值平均為1.75,黃土基巖滑坡規(guī)模較大,分維值為1.82。(3)黃河Ⅳ級(jí)階地形成時(shí)的古河道水流方向與現(xiàn)今黃河流向近一致,古河道對(duì)地下水的徑流排泄特征產(chǎn)生了一定的導(dǎo)向性。粘土層具有弱透水性,灌溉水入滲至粘土層頂面后易匯集并沿頂面高程較低的東北方向徑流。(4)臺(tái)地緣邊發(fā)生了明顯的后退及下沉現(xiàn)象,前緣部位則在不斷堆積上升,最大下沉幅度達(dá)35 m,堆積最厚處到37 m；黑臺(tái)臺(tái)面自1977年到2010年的33年間,地面平均沉降幅度達(dá)1.5 m左右,臺(tái)緣邊坡高陡斜坡(滑坡后壁)數(shù)量有所減少,尤其大于55。邊坡數(shù)量明顯減少。
[Abstract]:Heifangtai is a resettlement site in the Liujiaxia reservoir area. In recent years, a large number of landslides, collapses, mudflows and other disasters caused by carrying water irrigation have caused great economic losses, seriously threatened the safety of local residents' lives and property, and caused widespread concern. Therefore, it is urgent to study and prevent the disasters in Heifangtai area, and the tectonic geomorphological conditions control the development of disasters to a certain extent. Through field investigation of the structural phenomena (faults, folds, joints, rock sections, etc.) around the platform, the developmental characteristics of the pebbles (thickness, location, occurrence, size, lithology, etc.) of the pebble layer, the development of the back wall of the landslide, etc. Combined with DEM data and geological map data, the evolution process of tableland slope is analyzed by superposition calculation method. The distribution and development process of disasters are analyzed by using the topographic corridor method, the morphological characteristics of 38 landslides around the platform are analyzed by fractal dimension method, and the runoff of groundwater and the environment of ancient rivers are analyzed based on the morphology and arrangement of pebbles. The results show that: (1) there are mainly 7 faults around the platform, most of which are reverse faults. The fault (FH) and (FJ) of the Hulanggou fault and Jiaojia fault have been staggered by a small margin since the Quaternary, and they are in active state. It has great influence on the underground clay bed. The local geostress field at outcrop of faults reflected by fault plane and joint development is nearly identical with that of modern geotectonic stress field. (2) there are two kinds of landslides in the margin of the Hei square platform, and the spatial distribution has the characteristics of segmental development. The scale of landslide is different and the degree of damage is different. The scale of loess landslide is smaller, the slip distance is longer, the average fractal dimension is 1.75, the scale of loess bedrock landslide is larger, and the fractal dimension is 1.82. (3) the direction of paleochannel flow is close to that of the present Yellow River when the Yellow River 鈪，

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