【作者】 何淑军；

【导师】 廖椿庭； 吴树仁； 张春山；

【作者基本信息】 中国地质科学院 ， 地质工程， 2009， 博士

【摘要】 地质灾害风险评估与管理一直是近年来的研究热点与难点,尽管在研究方法、内容和程序上,国内外一直有着不同争论与差异,但是,不断在实践中改进完善、并逐步推广应用地质灾害风险评估管理技术方法成为主流和共识。陕西省宝鸡市是西北黄土高原地质灾害发育严重的地区之一,特别是宝鸡市城区周围和铁路干线地质灾害潜在危害大,是进行地质灾害风险评估研究的良好试验基地。为了结合实例探索区域地质灾害不同层次风险评估技术方法,本文以陕西省宝鸡市渭滨区地质灾害风险评估为例,依托国家科技支撑项目课题“地质灾害风险评估技术研究”和中国地质调查局项目“陕西宝鸡地区地质灾害详细调查”,在渭滨区地质灾害详细调查编录和数据库建设的基础上,简要分析地质灾害风险评估国内外研究现状和进展,系统研究宝鸡市渭滨区地质灾害发育条件、地质环境背景、分布规律及其主要影响因素,利用面上统计分析与典型滑坡解剖研究相结合,野外调查、勘察与室内测试、模拟计算相结合,定性分析与定量模型评价相结合的方法,分区域(1:5万调查资料)、重点地段(1:1万调查资料)和单体(1:2000勘察资料)3个层次进行渭滨区地质灾害易发性、危险性和风险评估区划,取得了下列主要进展和成果:1、初步揭示宝鸡市渭滨区地质灾害类型及分布特征:①受秦岭山脉和渭河谷地控制,渭滨区地质灾害总体上呈东西向—北西向带状展布,大多数地质灾害集中分布于秦岭山脉北坡中低山丘陵—黄土梁峁过渡地段:②地质灾害二级分带明显受渭河支流控制呈南北向群带分布,渭滨区大多数地质灾害主要沿秦岭山脉南北向冲沟两侧分布,即主要沿渭河支流岸坡发育,而不是沿渭河岸坡发育,宏观上类似于“立交桥”式分布特征:③渭滨区地质灾害分布密度最大地段是八渔镇清水河的支沟—滩家洼沟两侧。在不到2km的长度内分布9个黄土滑坡,小冲沟流域最大面密度达到20%。这主要是由于滩家洼沟紧临南部的秦岭基岩山前断裂,黄土覆盖厚度较大,沟谷狭窄、流程短,纵坡降大,使得水流冲蚀作用强烈,造成两侧斜坡自然坡度和坡高大,易于形成滑坡。④地质灾害发育类型以滑坡为主(中小型黄土滑坡),崩塌、泥石流次之,潜在危害较大的灾害是中小滑坡和居民房屋周围的黄土崩塌,易于发生滑坡灾害的斜坡是黄土斜坡(包括纯黄土斜坡、黄土+红层斜坡、黄土+基岩斜坡等)。2、初步揭示渭滨区地质灾害分布的主要控制因素是构造地形地貌与工程岩土体组合特征,90%左右的滑坡、崩塌集中发生在秦岭山脉与渭河河谷斜坡中下部地带。秦岭北缘断裂带控制秦岭北坡地形地貌特征,断裂带两盘的差异升降,使秦岭北坡中下部斜坡基岩表层分布薄层黄土,秦岭北坡南北向冲沟水系冲蚀下切,造成渭河高阶地和黄土塬边及支流河谷两侧斜坡陡峻,沟谷发育,为滑坡、崩塌的形成提供了有利的地形条件。3、通过对典型滑坡的大比例尺调查、工程勘察、室内测试分析和稳定性模拟计算,初步揭示潜在多级叠置滑坡和对冲黄土滑坡群形成演化过程:①夏呀河滑坡和高家河滑坡分别是4级和3级潜在滑面的大型黄土-粘土砂砾石混层滑坡,是多期活动形成的。目前仍然存在局部变形滑动的危险性,它们属于典型的分层扩展式滑坡。利用蒙特卡罗模拟法对滑坡进行可靠性分析,初步认为:可靠性分析可以实现定量表达滑坡的安全度,它给出了滑坡的可靠度和失稳概率,可以为单体滑坡定量风险评估提供基础参数,有利于对比分析滑坡的危险性,揭示其滑动风险的概率。②通过对夏呀河滑坡和高家河滑坡的数值模拟分析,研究表明:夏呀河四级滑坡在天然状态下均处于稳定状态,而在降雨条件下,一二级滑坡则出现失稳可能。三维数值模拟图显示其滑面上的剪切应变率一级滑面最高,其次为二级,而三四级滑面基本没有剪切应变,说明一二级滑坡稳定性差,三四级滑坡处于稳定状态。高家河滑坡二维模拟结果显示:在降雨状态下,压应力、拉应力最大值均明显增大,塑性应变变化值要比在天然条件下增大约一倍以上。塑性变化趋势是一级滑坡在降雨条件下有整体变形破坏的趋势,三级滑坡后缘有变形破坏趋势。③渭滨区密度最大的滩家洼滑坡群是由9个滑坡组合而成,属于典型对冲黄土滑坡群,滑坡叠次毗邻发生,相互影响,构成冲沟两侧密集分布的滑坡群;其中,4、5和7号滑坡是对滑式滑坡,最早是左岸7号滑坡下滑,冲击对岸边坡,使冲沟沿对岸坡脚冲刷,经长期切割冲蚀,临空面加大,对岸斜坡堆积体坡脚松动,在降雨等触发因素的作用下引起了4、5号滑坡的下滑。4、5号滑坡下滑撞击对岸,由于同样的原因,引起7号滑坡局部再次的下滑,造成7-1滑坡前缘河流向对岸弯曲。目前,4、5号滑坡存在局部活动的可能性,属于高危险区,应注意加强监测预警。4、运用定性分析和综合信息量模型、因子权重叠加模型相结合的评价方法,完成3个层次渭滨区地质灾害易发性、危险性和风险评估区划,结果显示:①渭滨区地质灾害高易发区占14.96%,主要分布在渭滨区南部的基岩山区到黄土台原的过渡区内及神农镇附近的清姜河两岸;中易发区占27.02%,主要分布在渭滨区西南部清姜河两岸以及其支流深沙河、李家河一带,西部晁峪乡沿渭河两岸以及渭滨区南部基岩山地,渭河南岸的黄土台塬、梁、峁的中部地区:其余为低易发区和不易发区,分别占31.57%和26.45%。②渭滨区地质灾害极高危险区和高危险区分别占10.34%和16.99%,主要分布在晁峪乡甘峪村—高家镇堡子山一带,神农镇东峪口—陈家村一带的清姜河两岸,石鼓镇至八渔镇的高家河村—燃灯寺—张家岭—带的黄土梁峁区;其余为中等危险区、低危险区和极低危险区,分别占25.69%、30.79%和16.18%。③渭滨区地质灾害极高风险区和高危险区分别占3.65%、9.10%,主要分布于晁峪乡和高家镇的孔柯槽—黑山湾—寺沟岭—带,神农镇的东峪口—偏桥—石家营一带的清姜河两岸以及晁峪乡渭河北岸的北嘴村附近;在这些极高—中等风险区,应对沿线的公路、铁路加强监测预报,采取风险减缓措施。其余为中等危险区、低危险区和极低危险区,分别占21.61%、34.04%和31.41%。④渭滨区重点地段地质灾害风险评估结果揭示,极高风险区、高风险区合计占5.92%,主要分布神农镇大湾堡—朱家沟—益门堡一带的清姜河两岸。在这一地区需要引起注意和加强监测预报、采取风险减缓措施。总体分析,渭滨区区域地质灾害总体危险和风险不是很高,需要注意居民房屋周围和重要铁路、公路干线两侧的单体灾害危险性和风险。5、通过对夏呀河单体四级滑坡的定量风险评估的探讨分析,初步揭示:①初步估算了夏呀河4级潜在滑面滑坡在不同工况条件下潜在的经济损失和人员伤亡的总风险值及其存在的差异,提出了沿不同滑面滑动滑坡所具有的潜在威胁,可以为当地政府对该滑坡进行灾害风险管理提供科学依据。②夏呀河2级潜在滑面滑坡属于高风险滑坡,与国际上暂定的社会容许标准相比,其总风险值处于不可接受范围内,应该采取风险减缓措施,或者是滑坡防治措施降低滑坡风险。6、根据国内外地质灾害风险管理的一些经验和做法,初步探索渭滨区地质灾害风险管理体系和风险减缓措施,有针对性地提出渭滨区滑坡、崩塌、泥石流防治的一般方法。更多还原

【Abstract】 In recent years, geo-hazard risk assessment and management has been a hot and difficult topic in research field. Although there are still many different views on the research methods, content, procedures home and abroad nowadays, the geo-hazard risk assessment techniques and management methods became the mainstream because of its improving in practice and gradual promoting in use. Baoji City in Shaanxi Province is one of the serious geological hazards regions in the northwest loess plateau, especially the potential geo-hazards are very serious around Baoji City and along railway, and it is a good testing field for studying the geohazard risk assessment. In order to explore different levels risk assessment technique method on geological hazard in the combination of examples, taking geological hazard risk assessment in Weibin district of Baoji City in Shaanxi Province as example in this paper, relying on the national science and technology support project" Geo-hazards risk assessment technology research" and on the China Geological Survey Project" Geo-hazard detailed investigation in the region of Baoji City in Shaanxi Province ", based on detailed catalog and database construction of geological hazard investigation in Weibin district, the status and progress of research on geo-hazard risk assessment at home and abroad was analyzed briefly and geological hazard development conditions, geo-environmental background, distribution regularity and the main impact factors in Weibin Disrict of Baoji City were systematically studied. Geo-hazard susceptibility, hazard and risk assessment zone in Weibin district were finished by three levels such as region (1:5 million survey data), the key area (1:1 million survey data) and monomer (1:2000 reconnaissance data) by using statistical analysis of the surface in combination of anatomy research of typical landslides, field survey and reconnaissance in combination of simulated calculation, qualitative analysis and in combination of quantitative model. Through these studies, the major progress and conclusions are obtained in this thesis as follows:1) The main types and distribution characteristics of geological hazard in Weibin district were preliminarily revealed as below:①Distribution of geological hazard was generally east to west - northwest to the zonal distribution controlled by Qingling Mountains and the Weihe River valley in Weibin district. The majority of geo-hazards are concentrated between the hilly - loess hilly beam hillside in the northern slope of Qingling Mountain.②Sub-band of geo-hazards was significantly affected by controlling of the tributary of the Weihe River and was a distribution of the North-South bands. The majority of geo-hazards in Weibin district are concentrated along the north-south gullies in Qingling Mountain. That is, geo-hazards are mainly developed along banks of Weihe River branches and not developed along banks of Weihe River.③The most dense area of geo-hazards in Weibin district is the branch of Qingshuihe River in Bayu town—both banks of Tanjiawa gully. There are nine loess landslides lying in less than 2km length of the gully and the largest surface density is up to 20% in the small gully basin. This area was easy to form landslides mainly due to Tanjiawa gully is close to Qingling southern bedrock piedmont fault, covered by thick loess, narrow valley, short process, longitudinal big drop, which lead to a strong role in water erosion , result in the natural slope angle and slope height of both gully sides tall.④The main type of geo-hazard is landslide (small and medium-sized loess landslides) and the second is landfalls and debris flows. The potential hazards that are more harmful are small and medium-sized landslides and loess collapse around the resident houses. The slope that is prone to landslide hazards is loess slope (including pure loess slopes, loess and red bed slope, loess and bedrock slope, etc.).2) The main factors which control the distribution of geo-hazards in Weibin area are structure terrain geomorphic and characteristics of rock and soil composition. About 90% of the landslides, landfalls occurred in the mid-lower slope zone between Qingling Mountains and the Weihe River valley. The terrain features of Qingling Mountains northern slope is controlled by the northern margin fault zone of the Qingling Mountains. Thin layer loess covered bedrock surface in the mid-lower part of the northern slope of Qingling because of the differential uplift between two side of the fault. The north-south gullies of the Qingling northern slope is incised by water which resulted in the steep slopes on both sides of the tributary valley of Weihe River high-terrace and the side of the loess plateau and gully development. These formations of the terrain conditions are a favorable environment for landslides, landfalls development3) The formation and evolution of the process of multi-levels overlay landslide and opposed loess landslides are initial revealed by the large-scale surveys, engineering investigations, indoor testing analysis, and stability simulation of typical landslide:①Xiayahe landslide and Gaojiahe landslide are large-scale loess - clay -sand mixed-layer landslide which have 4-level and 3-level potential sliding surfaces respectively and they are multi-period formation. By yet, they are still deforming and sliding somewhere. They belong to typical landslides with extended stratification. By reliability analysis for the landslide by using Monte-Carlo simulation method, the preliminary view is as follows:Landslide safety can be quantitative expressed by reliability analysis and the landslide reliability and its instability probability can be obtained by reliability analysis, which can provide basis parameters for quantitative risk assessment of monomer landslide and is conducive to comparative analysis of landslides hazard, revealing risk probability of landslide slide. At the same working conditions, the stability of landslide (Safety) and its reliability value (or failure probability) does not have one-to-one relationship.②Through numerical simulation analysis for Xiayahe landslide and Gaojiahe landslides, the research shows that: in natural conditions, 4 levels landslide of Xiayahe landslide are all in steady state, in the rain conditions , instability possibility of the 1, 2 level landslide may occur. 3-dimension numerical simulation shows that the shear strain rate of the first sliding surface is the highest, followed by the second sliding surface, and there are little shear strain on the third, fourth sliding surface. The poor stability of 1, 2 level landslide and 3,4 level landslide in steady state are confirmed. 2-dimension simulation results of Gaojiahe landslide show that maximum value of compressive stress and tensile stress in the rain state was significantly increased and changes value of plastic strain was more than double level of plastic changes in natural conditions.1 level Landslide in the rain conditions would be failure of the overall trend and the back margin of 3 level landslide would be failure of the trend.③Tanjiawa landslide group with largest density in Weibin area is a combination of nine landslides, which belongs to a typical hedge loess landslide group. Landslides occurred in the adjacent and mutual influence, which constitute landslide-intensive group lying on both sides of the gully. 4, 5 and 7 landslides in the group are hedge landslide, and 7 landslide on the left bank first slid down to impact the slope foot of the other side, and then accumulated at the bottom of the gully to form accumulation dam. Water diffuse above the dam to wash the slope foot on the other side of the gully which leads to invading face up through the long-term cutting erosion and leads to slope foot loose of the previous accumulation body on the opposite banks.4,5 landslide slid down due to the role of triggering factors such as rainning.4,5 landslide slid down to hit the other side, for the same reason, causing portion of 7 landslides sliding again, which result in river bend to the other side in front of 7-1 landslide. Other hedge landslides have similar characteristics, too. At present, 4, 5 landslides have the possibility of local activities, belong to high-risk areas, should be paid attention to strengthening the monitoring and early warning.4) Geological hazard susceptibility zoning, hazard zoning and risk assessment zoning were respectively completed at 3 levels in Weibin areas by using evaluation methods in combination of qualitative analysis, synthesis information model and factor right overlap model. The results showed that: ①The geo-hazard high susceptibility zones in Weibin area accounted for 14.96 %, and the geo-hazards mainly distributed in the districts from the southern bedrock mountain zones to the loess plateau, and at the two sides of Qingjianghe River nearby Shengnong Town; The middle susceptibility zones accounted for 27.02%, which were mainly distributed at the two sides of Qingjianghe River in the south-west of Weibin district and its affluent, such as Shenshahe River, Lijiahe River, etc., and at the two banks of Weihe River in Chaoyu Town and the southern bedrock mountain zones, and in the middle of the loess plateau, the loess ridges and loess knolls at the southern bank of Weihe River; others were low susceptibility zones and non-susceptibility zones, accounting for 31.57% and 26.45%, respectively.②The geo-hazard extremely high and high dangerous zones in Weibin area accounted for 10.34 % and 16.99 %, respectively. And they mainly distributed in the zone of Gangu Village, Chaoyu Country -Puzishan, Gaojia Town, at the banks of Qingjianghe River from Dongyukou to Chenjia Village, Shennong Town, in the area of the loess ridges and loess knolls along the zones of Gaojiahe Village - Randengsi Temple - Zhangjialing Village in Shugu Town and Bayu Town; and others were middle dangerous zone, low dangerous zones and non-dangerous zones, accounting for 25.69 %, 30.79% and 16.18 %, respectively.③The extremely high risk zones and the high risk zones accounted for 3.65 % and 9.10 % respectively in Weibin district. And they mainly distributed in the zones of Kongkecao -Heishanwan -Sigouling in Chaoyu Country and Gaojia Town, at the two banks of Qingjianghe River from Dongyukou -Pianqiao -Shijiaying in Shengnong Town and nearby Beizui Village at the north bank of Weihe River in Chaoyu Country. The geo-hazard forecast along the road and railway should be strengthened in these extremely high and high risk areas and some slowing up measures should be taken. Others were the middle risk areas, low risk areas and extremely low risk areas, accounting for 21.61 %, 34.04% and 31.41%, respectively.④The geo-hazard risk assessment results of the key area in Weibin district showed that, the extremely high risk and high risk areas totally accounted for 5.92%, mainly distributed along the two banks of Qingjianghe River from Dawanbu -Zhujiagou -Yimenbu in Shengnong Town, These extremely high and high risk areas should be paid more attention, the forecast should be strengthened and some slowing up measures should be taken.In a word, the geo-hazard hazard and risk in Weibin district were not very high, but the areas around domestic architectures and the single geo-hazard risk at the two sides of important railways and highways should be paid attention.5) According to the discussion and analysis on the qualitative risk evaluation of the four layers landslide in Xiayahe monomer landslide, the followings could be indicated:①The total values of potential economy loss and personal casualty of each level potential sliding surface of Xiayahe landslide under different working conditions were preliminarily quantitatively calculated and different. The latent risk of different potential sliding surface of Xiayahe landslide was proposed, which could supply scientific gist of geo-hazard risk management for the local government.②The landslide with the second level potential sliding surface of Xiayahe landslide belongs to the high riskone, comparing with the international tentative society tolerable risk criterion. Its risk value lies in the non- acceptable range. Therefore, the slowing up measures should be taken or the prevention measures should be strengthened so as to decrease the landslide risk.6) According to some experiences and methods of geo-hazards risk management home and abroad, the geo-hazard risk management system and some slowing up measures for risk of Weibin district were preliminary studied. Meanwhile, the general method for decreasing and preventing the landslide, landfall and debris flow in Weibin district was put forward.更多还原