本文關(guān)鍵詞：南海北部陸坡白云凹陷區(qū)海底滑坡的識別與特征分析　出處：《國家海洋局第一海洋研究所》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 南海北部 海底滑坡 識別分析 聲學(xué)結(jié)構(gòu) 觸發(fā)機(jī)制

【摘要】：海底滑坡是陸坡區(qū)廣泛發(fā)育的地質(zhì)災(zāi)害類型之一,既是塑造海底地形地貌的主導(dǎo)因素,也是大陸坡上沉積物向深海盆地搬運(yùn)的重要方式。我國南海北部陸坡區(qū)存在豐富的天然氣水合物和油氣資源,同時也是滑坡等地質(zhì)災(zāi)害極為發(fā)育的區(qū)域。本文以南海北部陸坡白云凹陷為研究區(qū),開展海底滑坡的分布、滑坡特征及成因機(jī)制研究,結(jié)果對于評價深水油氣鉆探及海底管道安全有較強(qiáng)的指導(dǎo)意義,對于認(rèn)識陸坡區(qū)沉積物質(zhì)搬運(yùn)也有一定的科學(xué)意義。研究區(qū)位于南海北部陸坡白云凹陷區(qū),水深約200~1700m,水深和地貌類型變化較大。本文綜合利用多波束水深資料、淺地層剖面以及側(cè)掃聲吶資料,對研究區(qū)的海底滑坡的類型、規(guī)模、分布和成因機(jī)制進(jìn)行了分析與研究,得到如下結(jié)論:(1)基于多波束地形數(shù)據(jù),利用編制海底陡坡自動識別程序?qū)５谆逻M(jìn)行了識別,并通過地震剖面資料和側(cè)掃聲吶資料對識別的滑坡進(jìn)行對比驗證,結(jié)果表明利用海底陡坡自動識別程序快速識別海底滑坡是可行的,但識別結(jié)果主要受水深數(shù)據(jù)精度的影響。(2)研究區(qū)海底滑坡主要分布在海底峽谷區(qū),其中峽谷的頭部和峽谷兩側(cè)的谷壁是海底滑坡集中分布區(qū)。在研究區(qū)共識別出145個海底滑坡,統(tǒng)計的結(jié)果顯示,滑坡面積大小在0.04~15.88km2之間不等,其中91.7%的滑坡面積小于4km2;大約有110個海底滑坡(約占76%)分布在海底峽谷的谷壁及其附近區(qū)域。(3)對不同位置(上陸坡、中陸坡和下陸坡)的典型滑坡的內(nèi)部聲學(xué)結(jié)構(gòu)的分析結(jié)果表明,上陸坡滑坡體屬于脆性滑坡體,其特征是內(nèi)部基本保持了原來的結(jié)構(gòu)和層理;中陸坡海底滑坡具有明顯的弧形滑動面,峽谷壁上的滑坡體屬于塑性滑坡體,內(nèi)部結(jié)構(gòu)和層理雜亂;兩峽谷中脊上的滑坡體屬于脆性滑坡體;下陸坡峽谷尾部濁流堆積扇區(qū)的滑坡體主要是塑性滑坡體,且滑坡底部的滑動面不十分明顯。(4)海底坡度和土體力學(xué)強(qiáng)度是研究區(qū)海底滑坡的主要控制因素。基于Geo Slope數(shù)值分析軟件,構(gòu)造了3°、6°、8°、9°、12°和15°六種坡度海底斜坡模型。計算結(jié)果表明,地震作用和斜坡坡度都是影響海底斜坡穩(wěn)定性的重要因素,坡度較小的穩(wěn)定斜坡,地震作用對斜坡穩(wěn)定性的影響比較明顯;隨著斜坡坡度的增大,大于臨界坡度時斜坡就會處于不穩(wěn)定狀態(tài),此時地震作用的影響變得不再那么明顯;通過8°和9°斜坡模型的對比,結(jié)合研究區(qū)海底坡度及滑坡分布特征,該研究區(qū)的斜坡穩(wěn)定性臨界坡度與數(shù)值模擬結(jié)果一致均約為9°。
[Abstract]:Submarine landslide is one of the widely developed geological hazards in the continental slope area, which is the dominant factor in shaping the topography and landform of the seabed. It is also an important way to transport sediments on the continental slope to deep-sea basins. There are abundant natural gas hydrates and oil and gas resources in the northern slope of the South China Sea. This paper takes Baiyun Sag on the northern slope of the South China Sea as the research area to study the distribution, characteristics and genetic mechanism of submarine landslides. The results are of great significance for evaluating the safety of deep water oil and gas drilling and submarine pipelines, as well as for the understanding of sediment transport in the continental slope. The study area is located in Baiyun sag on the northern slope of the South China Sea. The depth of water is about 200 ~ 1700m, and the water depth and geomorphologic types vary greatly. In this paper, the types and scale of submarine landslides in the study area are analyzed by using multi-beam bathymetric data, shallow stratum profile and lateral sonar data. The distribution and genetic mechanism are analyzed and studied. The following conclusions are obtained: 1) based on multi-beam topographic data, the submarine landslide is identified by compiling an automatic identification program for submarine steep slope. The results show that it is feasible to identify the submarine landslide quickly by using the automatic recognition program of submarine steep slope through seismic profile data and side scan sonar data. However, the identification results are mainly affected by the accuracy of the depth data. 2) the submarine landslides in the study area are mainly distributed in the submarine canyon area. The head of the canyon and the valley wall on both sides of the canyon are the concentrated distribution areas of submarine landslides. 145 submarine landslides have been identified in the study area, and the statistical results show that. The area of landslide varies from 0.04 ~ 15.88 km ~ 2, of which 91.7% is less than 4 km ~ 2; There are about 110 submarine landslides (about 76 parts) distributed in the valley wall of the submarine canyon and its adjacent area. The results of the analysis of the internal acoustic structure of the typical landslide on the middle and lower slopes show that the upper slope landslide belongs to the brittle landslide, and its characteristics are that the internal structure and stratification are basically maintained. The submarine landslide on the middle slope has obvious arc sliding surface, the landslide body on the valley wall belongs to the plastic landslide body, the internal structure and stratification are chaotic. The landslide on the middle ridge of the two canyons belongs to the brittle landslide. The slope body in the turbidity accumulation sector at the tail of the downslope canyon is mainly plastic landslide. The slope of the bottom of the landslide and the mechanical strength of the soil are the main controlling factors of the landslide. Based on the software of Geo Slope numerical analysis, 3 擄is constructed. 6 擄/ 8 擄/ 9 擄/ 12 擄and 15 擄/ 6 slope models. The calculated results show that seismic action and slope gradient are important factors affecting the stability of submarine slope, and the slope with low slope is stable. The effect of earthquake on slope stability is obvious. With the increase of slope gradient, the slope will be unstable when the slope is larger than the critical slope, and the effect of earthquake becomes less obvious. Based on the comparison of 8 擄and 9 擄slope models and the characteristics of submarine slope and landslide distribution in the study area, the critical slope of slope stability in the study area is about 9 擄consistent with the numerical simulation results.
【學(xué)位授予單位】：國家海洋局第一海洋研究所
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P736;P642.22

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 陳維濤;杜家元;龍更生;張尚鋒;李向陽;;珠江口盆地海相層序地層發(fā)育的控制因素分析[J];沉積學(xué)報;2012年01期

2 王磊;吳時國;李偉;;人機(jī)交互地貌解釋技術(shù)在海底滑坡研究中的應(yīng)用[J];地球物理學(xué)進(jìn)展;2013年06期

3 寇養(yǎng)琦;;南海北部的海底滑坡[J];海洋與海岸帶開發(fā);1990年03期

4 尹延鴻;海岸侵蝕和海底滑坡[J];海洋地質(zhì)動態(tài);1995年08期

5 欒錫武;張亮;;南海構(gòu)造演化模式:綜合作用下的被動擴(kuò)張[J];海洋地質(zhì)與第四紀(jì)地質(zhì);2009年06期

6 馮文科，石要紅，陳玲輝;南海北部外陸架和上陸坡海底滑坡穩(wěn)定性研究[J];海洋地質(zhì)與第四紀(jì)地質(zhì);1994年02期

7 楊作升,陳衛(wèi)民,陳彰榕,吳光華,曹立華,沈渭銓;黃河口水下滑坡體系[J];海洋與湖沼;1994年06期

8 李家鋼;修宗祥;申宏;江鳳鳴;;海底滑坡塊體運(yùn)動研究綜述[J];海岸工程;2012年04期

9 許浚遠(yuǎn),張凌云;西北太平洋邊緣新生代盆地成因(中):連鎖右行拉分裂谷系統(tǒng)[J];石油與天然氣地質(zhì);2000年03期

10 施和生;秦成崗;高鵬;張忠濤;朱俊章;趙仁永;;珠江口盆地番禺低隆起—白云凹陷北坡天然氣晚期成藏特征[J];中國海上油氣;2008年02期

，

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