资源环境承载协调理论与评价方法     

李瑞敏  殷志强  李小磊  刘琼  孟晖  黄道袤  王轶  王龙平  王欣宝  刘建奎  孙超  赵德刚 《地质通报》2020,(1):80-87

资源环境承载能力评价是进行国土空间规划和用途管控的基础性工作,越来越受到国家重视。在资源环境承载能力研究实践中,以自然资源环境系统及其与社会经济系统的关系为主要研究对象,创新性提出了"资源环境承载协调理论",并基于此理论初步建立了不同空间尺度的地质资源环境承载能力评价技术方法,构建了地质环境、地下水资源、矿产资源等不同资源环境要素的承载能力评价指标体系,包括承载本底评价指标和承载状态评价指标。规范了不同尺度的资源与环境承载能力评价流程,为有序推动全国、区域及市县尺度的自然单元和行政单元的地质资源环境承载能力评价工作提供了强有力的。  相似文献   

地中海直布罗陀海峡附近内孤立波的地球物理特征          下载免费PDF全文

孙绍箐  张锟  宋海斌 《地球物理学报》2019,62(7):2622-2632

本文主要利用地震海洋学方法研究地中海直布罗陀海峡附近内孤立波的结构特征，此处内孤立波为第一模态下沉型，为中幅度和大幅度内孤立波，垂向振幅最大可达74.5 m，振幅随深度增加呈增大趋势，传播速度随振幅增大而增大，可以确定"真"最大振幅位置位于密跃层附近.由于类多普勒效应和孤立波与测量船之间存在夹角的原因，从地震剖面上得到的为视半高宽参数，需要进行校正后才能得到比较真实的半高宽参数，校正后半高宽最高可达到1721.8 m，但是校正后的半高宽与理论结果有些差距，这可能与内孤立波的发育稳定程度有关.随着内孤立波包不断向东运动，整体波宽变大，垂向速度变小.本文将地震海洋学方法拓展应用于地中海区域内孤立波分析，进一步证明了利用地震海洋学方法研究海水运动的可行性.  相似文献   

Seismic amplitude inversion for the transversely isotropic media with vertical axis of symmetry     

Feng Zhang  Tuo Zhang  Xiang-Yang Li 《Geophysical Prospecting》2019,67(9):2368-2385

Transverse isotropy with a vertical axis of symmetry is a common form of anisotropy in sedimentary basins, and it has a significant influence on the seismic amplitude variation with offset. Although exact solutions and approximations of the PP-wave reflection coefficient for the transversely isotropic media with vertical axis of symmetry have been explicitly studied, it is difficult to apply these equations to amplitude inversion, because more than three parameters need to be estimated, and such an inverse problem is highly ill-posed. In this paper, we propose a seismic amplitude inversion method for the transversely isotropic media with a vertical axis of symmetry based on a modified approximation of the reflection coefficient. This new approximation consists of only three model parameters: attribute A, the impedance (vertical phase velocity multiplied by bulk density); attribute B, shear modulus proportional to an anellipticity parameter (Thomsen's parameter ε−δ); and attribute C, the approximate horizontal P-wave phase velocity, which can be well estimated by using a Bayesian-framework-based inversion method. Using numerical tests we show that the derived approximation has similar accuracy to the existing linear approximation and much higher accuracy than isotropic approximations, especially at large angles of incidence and for strong anisotropy. The new inversion method is validated by using both synthetic data and field seismic data. We show that the inverted attributes are robust for shale-gas reservoir characterization: the shale formation can be discriminated from surrounding formations by using the crossplot of the attributes A and C, and then the gas-bearing shale can be identified through the combination of the attributes A and B. We then propose a rock-physics-based method and a stepwise-inversion-based method to estimate the P-wave anisotropy parameter (Thomsen's parameter ε). The latter is more suitable when subsurface media are strongly heterogeneous. The stepwise inversion produces a stable and accurate Thomsen's parameter ε, which is proved by using both synthetic and field data.  相似文献   

特定场地下土工构筑物的几何可靠性分析     

吴兴征  王瑞凯  辛军霞 《岩土力学》2020,41(6):2070-2080

针对特定场地下土工构筑物的正常使用极限状态，采用近年发展的几何可靠性方法计算了多种构筑物的可靠度指标。考虑同一场地下的钻孔灌注桩、抗浮锚杆和CFG桩单桩加载变形测试曲线的离散性，各曲线回归参数呈现差异并可作为随机变量，进而探讨了各曲线回归参数间的相关性及联合分布特性。基于这些回归参数的联合发散概率密度等值线，即随机变量刚好达到极限承载能力状态，该几何可靠性算法可在随机变量的原始空间求得土工构筑物的可靠度指标。通过比对该几何可靠度指标与常规的一次可靠性算法成果，验证了该几何可靠性计算技术的可行性。计算表明，几何可靠性评价模型实施简便，易于被工程技术人员接受。  相似文献   

考虑填充墙影响的钢筋混凝土厂房结构地震易损性分析     

梁志强  徐超  温增平 《震灾防御技术》2019,14(4):707-718

采用对角斜撑模拟纵向填充墙的作用，建立考虑填充墙和不考虑填充墙厂房结构模型，采用拉丁超立方抽样技术建立考虑材料不确定性的结构分析样本，基于随机Pushover分析确定结构不同破坏状态下的统计参数。综合考虑结构材料强度及输入地震动不确定性的影响，通过非线性时程分析开展单层钢筋混凝土厂房结构易损性研究，在此基础上比较结构横、纵向易损性的差异，研究填充墙对结构易损性的影响。研究结果表明:钢筋混凝土厂房结构体系横向地震易损性显著大于纵向地震易损性；对纵向结构体系而言，加入填充墙会明显降低结构易损性，但在相同强度的地震动作用下，填充墙破坏程度比主体结构严重，这与厂房结构的实际震害特征相符。  相似文献   

Undrained lower bound solutions for end bearing capacity of shallow circular piles in non-homogeneous and anisotropic clays     

Boonchai Ukritchon  Suraparb Keawsawasvong 《国际地质力学数值与分析法杂志》2020,44(5):596-632

The undrained bearing capacity of shallow circular piles in non-homogeneous and anisotropic clay is investigated by the lower bound (LB) finite element limit analysis (FELA) under two-dimensional (2D) axisymmetric condition using second-order cone programming, and the new solution of the problem is presented. Modified from the isotropic von Mises yield criterion, a cross-anisotropic undrained strength criterion of clays under the axisymmetric state of stress requiring three input shear strengths in triaxial compression, direct simple shear, and triaxial extension is employed in the 2D axisymmetric LB FELA. Parametric studies on the effects of pile embedment ratio, dimensionless strength gradient, anisotropic strength ratio, and pile roughness are investigated extensively, while the predicted failure mechanisms associated with these parameters are discussed and compared. Numerical results of undrained end bearing capacity of shallow circular piles are summarized in the form of design tables that are useful for design practice and represent a new contribution to the field of pile capacity considering the combined effects of undrained strength non-homogeneity and anisotropy.  相似文献   

Land Resource Carrying Capacity in Xilin Gol Grassland Transects: A Perspective on Food Nutritional Demand     

YANG Wanni  ZHEN Lin  LUO Qi 《资源与生态学报(英文版)》2019,10(6):614-620

Food safety is an important issue for the development of the national economy and society. Studying regional food supply and demand from the perspective of land resource carrying capacity can provide new references for regional resource sustainability. This study uses the data from farmer and herdsmen household questionnaires, statistical data, land use data, and other sources to construct a land resource carrying capacity (LCC) assessment framework, targeting the food supply and demand of residents in representative areas, specifically the typical grassland pastoral areas, sandy pastoral areas and agro-pastoral areas on the Xilin Gol grassland transects. The three food nutritional indicators of calories, protein and fat were selected for analyzing the balance of land resource carrying capacity. We found that: 1) Along the Xilin Gol grassland, the main local food supply showed a shift from meat and milk to grains, vegetables and fruits. 2) From north to south along the grassland transects, the calorie intake increased gradually, while the intake of protein and fat was highest in pastoral areas and lowest in agricultural areas. 3) The overall land resource carrying capacity of the Xilin Gol grassland transects was in a surplus state, but the land carrying capacity of typical grassland pastoral area was higher than the two other types of areas. This study provides an empirical reference for the sustainable development of regional food nutrition.  相似文献   

考虑冲刷影响的筒型基础竖向极限承载力研究     

陆罗观  刘润  练继建  陈广思 《海洋工程》2019,37(3):69-77

大直径宽浅式筒型基础,阻水宽度大,在位工作期间受波浪海流作用,其周围土体易被冲刷。为研究单侧地基土体受冲刷后筒型基础的竖向极限承载力变化,通过引进冲刷率的概念,采用有限元方法研究了不同冲刷率下筒型基础的竖向极限承载力;并基于Meyerhof理论建立了计算不同冲刷率下筒型基础竖向极限承载力的极限平衡方法。研究结果表明,随着冲刷率增大,筒型基础的极限承载力出现不同程度的下降,当冲刷率为0.8时,即筒型基础单侧土体冲刷深度达6.4 m时,筒型基础的竖向极限承载力折减率为3.28%。建立的极限平衡算法可准确计算冲刷条件下筒型基础的竖向极限承载力。  相似文献   

浅层地震剖面揭示固原市清水河东侧断裂特征     

花鑫升  姬计法  酆少英  杜鹏  宋威  刘增祺 《大地测量与地球动力学》2019,39(8):794-797

为查明清水河东侧断裂的产状、性质及其浅部构造特征，跨断裂开展高分辨率的浅层地震探测，获得高信噪比的浅层地震反射叠加剖面。根据浅层地震剖面结果并结合该区域地质资料，对该断裂的浅部构造特征进行分析和讨论。结果表明，清水河东侧断裂为一条走向近SN、倾向E的逆断层，其浅部为由2~3条断层组成的“Y”字形构造，并错断埋深约10~30 m的第四系沉积层，属第四纪以来的隐伏活动断裂。  相似文献   

基于MINA框架的应急救助与地震灾情管理平台设计与实现     

肖本夫  申源  陈维锋  毛利  格桑扎西  梁厚朗 《震灾防御技术》2020,15(4):836-845

针对不同用户群体应急救助和地震灾情需求，基于MINA框架，运用阿里云基础架构、微信组件和应用程序接口等技术方法，设计并构建集灾情信息收集与报送、应急救助服务、科普宣教等功能于一体的管理平台。该平台的设计与实现不仅有利于震后现场应急队员收集并准确报送实时灾情信息，还可为被救助人员提供防震减灾知识和地震应急避难场所空间分布等应急救助信息，实现了应急救助与地震灾情的综合管理，提升了震后应急救助、应急指挥和辅助决策等方面的服务能力。  相似文献