延安宝塔山景区滑坡地质灾害风险评估

滑坡灾害易损性可分为两大类型:人口易损性和经济易损性。本文依据现场风险填图对宝塔山景区影响居民生命和财产安全的地质灾害进行了风险源的识别,认为宝塔山景区的风险源主要为潜在的滑坡及崩塌灾害,最大风险处人员伤亡总概率为2.6210-2a-1;同时,依据工程地质经验法对风险管理易损性各要素进行了定量评价,认为对宝塔山景区居民来说,100a以内居民平均每年有最大2.62%伤亡的概率存在。根据国际较通用的风险容许标准,认为目前部分宝塔山居民遭受的风险处于不可接受区,建议加强监测。     

大别山北麓侏罗系大理岩砾石的碳—氧同位素组成及地质意义

在大别山北麓、合肥盆地南缘侏罗系三尖铺组和凤凰台组地层中含有大理岩砾石, 属山麓冲积扇环境沉积。它们的δ１３ Ｃ数值范围为－ １．７‰～１．３‰, 大多数近于零值, 它们的δ１８Ｏ数值从６．５‰～２３．０‰。大别地块佛子岭群大理岩的δ１３Ｃ数值为－ ２．０‰～－ ２．５‰, δ１８Ｏ数值范围从６．３‰～１３．１‰。大别地块高压和超高压变质岩带的大理岩的δ１３ Ｃ数值为１‰～６‰,δ１８Ｏ数值为５‰～２３‰。碳同位素组成的明显差别表明现今大别地块佛子岭群和高压、超高压变质岩不是合肥盆地南缘侏罗系大理岩砾石的来源区。由于δ１３Ｃ的数值不随δ１８Ｏ值的降低而变化, 且分布在一个狭窄的范围, 合肥盆地南缘侏罗系大理岩砾石的碳同位素组成代表了它的原岩在沉积时海水的同位素记录。     

Analysis of loess landslide mechanism and numerical simulation stabilization on the Loess Plateau in Central China

Natural Hazards - Loess landslides have complicated deformation mechanisms. Accurately describing the internal failure deformation of loess landslides and establishing a theoretical method of...     

植被生态对气候变化和人类活动的响应 ——以陕西省榆林能源化工基地为例

全球气候变化和人类活动双重作用对生态环境的影响是当今研究的热点问题.本文以国家级榆林能源化工基地为研究区,以MODIS遥感数据为依据,以归一化差值植被指数NDVI为参数,研究了植被生态的时空分布规律,分析了植被生态与降水、地貌、地下水、包气带岩性等自然条件的关系,揭示了人类活动对植被生态正负两方面的影响.研究结果表明,自然条件控制着植被生态的格局,植被生态具有明显的水平分带性,由东南向西北,随着降水量的减少、蒸发量和干燥度的增加,植被状况由好变差;2000年以来区内植被状况总体呈现好转的趋势,其中71.22％的区域好转,28.43％的区域基本维持不变,0.35％的区域退化.植被生态对气候变化尤其是降水量的年际变化具有敏感的响应,煤炭和地下水资源开采等人类活动对植被生态总体上造成负面影响,退耕还林(草)、限耕禁牧政策的实施是研究区植被生态总体呈现好转趋势的根本原因.     

Mesozoic fill-sequences in Hefei Basin: Implication for Dabie Orogenesis, central China

A research on the Mesozoic fill-sequences of Hefei basin, located at the north foot of Dabie Mountains, shows two-phase evolution. The first phase, early- to mid-/late-Jurassic, is characterized by terrestrial clastic deposits, with four times of reverse-grading units at least, and forms greatly thick molass reconstruction in the mid-/late-phase, which reflects gradually strong thrusting-orogenesis in the north Dabie and flexural depression in the north foreland of Dabie Mountains. The second phase, late-Jurassic to Cretaceous, includes two-episode rifting processes. The first episode (J₃) shows calc-alkalic and alkali volcanic rocks interstratified pyroclastic rocks, which may reflect upwelling igneous magma from mantle-source due to the Yangtze continent slab breakoff induced by deep subduction process. A suite of lacustrine, fluvial and piemount facies, about 3000 –3500 m in thickness, develops in the second episode (J₃-K₁), which reflects regional extensional setting and intense elevator diversity of mountain-basin in the study area. This research renews and deepens cognition for the Mesozoic Dabie orogenesis     

Carbon isotope composition and its implications of Lower Cretaceous Aptian-Albian shallow water carbonates in the Cuoqin Basin, North Tibet

Since Schlanger and Jenkyns (1976)[1] first ad-vanced the ?oceanic anoxic events ?(OAEs) model to explain the origin of the worldwide distributed Early Cretaceous Aptian-Albian (115—103 MaBP) and Late Cretaceous Cenomanian-Turonian (95—88 MaBP) black shales, the OAEs and responses to them have been one of the 揾ot spots?in geological circles. Up till now, researchers at home and abroad have exten-sively studied the sedimentary and geochemical re-sponses to the two anoxic events, espe…     

鲁西北地区一次秋季强对流天气的雷达识别分析

利用SA雷达探测和高空探空资料,结合防雹作业数据和灾情信息,对2016年9月11日发生在鲁西北地区的强对流天气过程中两个对流单体进行雷达识别分析。结果表明:两个对流单体发展迅速,在4-7个体扫(约25-45min)内,垂直液态水含量(VIL)分别跃增了27kg·m^-2、16kg·m^-2,达到64kg·m^-2、57kg·m^-2;在反射率因子图上都具有典型的冰雹回波特征:存在较明显的强回波墙、回波穹窿、有界弱回波区;实施防雹作业后,对流单体回波顶高、VIL、风暴质心高度、冰雹概率、强冰雹概率等指标持续下降,进一步证实了开展防雹作业可有效地减小降雹灾害。     

基于人工智能(AI)的地质灾害防控体系建设

近年来,人工智能（AI）技术得到快速发展,并日益融入到经济社会各个领域,成为当代创新发展的新标志,智能防灾减灾将成为未来发展的趋势和研究的热点。在回顾AI发展现状与趋势的基础上,系统梳理出以往地质灾害风险防控的数据依据和传统技术方法,分析了可能采用的潜在AI方法,初步搭建了基于AI的地质灾害风险防控体系建设方案。研究表明,AI技术为地质灾害风险防控提供了新的技术途径,但目前尚无可照搬或可移植的成熟技术或解决方案。智能防灾减灾体系包括早期识别、风险评估、风险防控等3个主要环节,其中最重要的环节是早期识别,传统方法与AI技术融合的关键参数为斜坡失稳概率或泥石流发生概率;根据所依据的数据资料将早期识别方法归纳为图像识别、形变识别、位移识别、内因识别、诱因识别和综合识别等6种方法;提出了从数据层、方法层和应用层3个层次构建基于大数据智能混合优化的地质灾害风险防控平台。认为数据驱动的智能模型与理论驱动的物理模型融合是地质灾害风险防控发展的趋势。     

山区城市地下空间资源评价与开发利用模式——以延安市为例

山区城市受地形地貌条件的限制,面临建设用地不足、交通拥挤、人口密集的压力,地表空间严重短缺。然而,特殊的地形地貌与地质环境条件却有利于地下空间的开发利用。地下空间将成为山区城市发展中的一种宝贵资源。本文以黄土高原丘陵沟壑区的延安市为例,基于地形、岩土、水文地质和地质灾害等地质环境条件,并考虑文物保护区及城市功能设施、空间需求及经济因素,评估了延安市区376.68 km^2地下空间天然资源量、可开发资源量,对河谷以下50 m及川道两侧1 km内的地下空间资源适宜性进行了定性评估。结果表明,延安市地下空间资源丰富;地下空间天然资源量、可开发资源量约为188.35、174.48亿方;地下0^-10 m,-10^-30 m,-30^-50 m适宜开发的地下空间资源量分别为23.25、11.52、1.44亿方,较适宜开发的分别为4.18、62.44、71.65亿方,沿川道两侧适宜开发的侧向山体空间资源量为12.29亿方,较适宜开发的资源量为81.50亿方;延安市围岩类别自Ⅱ-Ⅵ级,其中Ⅱ-Ⅳ级围岩工程性质良好,有利于地下空间开发。本文提出了"垂向地下+侧向山体"地下空间组合开发的理念,同时提出了延安市地面建设和地下空间协同开发方案,这将成为延安乃至其他山区城市发展的一种新模式。     

Identification of model structure parameters via combination of AFMM and ARX from seismic response data

To identify the model structure parameters in shaking table tests from seismic response, especially from timevarying response records, this paper presents a new methodology by combining the online recursive Adaptive Forgetting through Multiple Models(AFMM) and offline Auto-Regression with eXogenous variables(ARX) model. First, the AFMM is employed to detect whether the response of model structure is time-invariant or time-varying when subjected to strong motions. Second, if the response is time-invariant, the modal parameters are identifi ed from the entire response record, such as the acceleration time-history using the ARX model. If the response is time-varying, the acceleration record is divided into three segments according to the accurate time-varying points detected by AFMM, and parameters are identifi ed by only using the tail segment data, which is time-invariant and suited for analysis by the ARX model. Finally, the changes in dynamic properties due to various strong motions are obtained using the presented methodology. The feasibility and advantages of the method are demonstrated by identifying the modal parameters of a 12-story reinforced concrete(RC) frame structure in a shaking table test.