四川盆地中二叠统栖霞组、茅口组岩相古地理及勘探方向

通过地层剥蚀关系分析,四川盆地中二叠统沉积前的古构造格局具有"三隆一洼"的特点。基于野外剖面、岩心和薄片观察,结合录井、测井相和地震相分析,明确了栖霞组和茅口组发育镶边碳酸盐岩台地沉积,包含一级台缘带、二级台缘带、开阔台地和台盆等4种亚相以及一级台缘滩、二级台缘滩、台内滩和硅质台盆等微相。栖霞组、茅口组岩相古地理受控于沉积前古构造:一级台缘带分布于古隆起与斜坡—盆地过渡地带;开阔台地分布于古隆起区和低隆起区;台盆分布于低洼区;二级台缘带分布于开阔台地和台盆之间的过渡地带。类比上二叠统长兴组和下三叠统飞仙关组油气勘探,栖霞组、茅口组台地内部的二级台缘带可作为下一步油气勘探的有利领域。     

Three-dimensional DEM analysis of single geogrid-encased stone columns under unconfined compression: a parametric study

Three-dimensional discrete element method (DEM) was employed in this study to analyze the behavior of single geogrid-encased stone columns under unconfined compression. Four important parameters were investigated to understand and evaluate their effects on the behavior of the encased columns by seven DEM models. The biaxial geogrid used as an encasement material for stone columns was simulated using parallel-bonded particles, and the aggregate in the stone column was simulated using graded particles. Both the macroscopic responses (e.g., vertical pressure–strain curves) and the microscopic interactions (e.g., contact force, coordination number, and sliding fraction) of the columns under unconfined compression were analyzed and are presented in this paper. The numerical results show that the geogrid encasement with high tensile stiffness could provide high confining stresses and then effectively increased the bearing capacity of the column. The short column yielded quickly even though its column modulus at a small deformation was relatively high. The modulus of the column slightly decreased with an increase in the column diameter due to high circumferential strains mobilized in the geogrid encasement. The column with large aggregate was stiffer and deformed less than the column with small aggregate. Selecting aggregate with a size larger than the geogrid aperture size was an effective way to achieve better interlocking between the aggregate and the geogrid and to minimize mass loss for the geogrid-encased stone column under loading. Due to limited deformation allowed by the geogrid encasement, a coefficient of radial stress equal to half of the coefficient of passive earth pressure was suggested to estimate the ultimate bearing capacity of the geosynthetic-encased stone column.     

Evaluation of ecological effectiveness of protected areas in Northwest China

Protected areas (PAs) have experienced explosive growth in Northwest China over the last three decades, but their effectiveness in representing regional ecological system diversity has not attracted considerable attention. Low effectiveness would exacerbate the conservation-development conflicts, particularly those that arise as a result of the Great Western Development Strategy (GWDS). Thus, an assessment of the effectiveness of the PA network has become quite important. We proposed natural vegetation communities to represent regional ecological system diversities, and proposed Global 200 Priority Ecoregions, Important Bird Areas, and ecosystem function regions to represent important conservation areas. To determine their effectiveness, we studied the extent to which ecological system diversities and important conservation areas are represented by the existing 96 PAs. Our results indicated that the total coverage of vegetation communities in PAs in Northwest China is not sufficiently comprehensive. As the PA system has expanded, the growth in the total area of the PAs has been greater than that of their vegetation community richness. While most of the important conservation areas are covered by PAs, some regions have not yet reached the 10% threshold; further, PAs are distributed unevenly and conservation gaps remain in the region. Therefore, these regions should receive more attention when planning new PAs. It is vital that more biodiversity datasets and assessment of ecosystem function regions are integrated in order to provide a basis for the government to formulate appropriate protection and development strategies.     

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不同配筋形式钢筋混凝土框架变梁节点抗震性能试验研究

完成6个1/3比例钢筋混凝土框架变梁中节点试件低周反复荷载试验,重点研究了小梁交叉弯折纵筋(即"X"筋)、梁垂直加腋等配筋构造措施对变梁节点抗震性能的影响。研究结果表明:增加节点区配箍率和小梁采用交叉弯折纵筋后节点组合体仍发生了核心区剪切破坏,表明此种配筋方式对该类非常规节点抗震性能的改善不明显;小梁底部垂直加腋后,在小梁与加腋界面处发生破坏,避免了节点区的剪切破坏,从而改善了变梁节点的抗震性能。此外,轴压比变化对变梁节点抗震性能的影响不显著,增加核心区配箍率则可以增大节点组合体剪力、减小核心区裂缝间距和宽度,从而改善变梁中节点的抗震性能。     

欧亚大陆及西太平洋边缘海地区瑞雷波群速度结构与各向异性分布

根据欧亚大陆及西太平洋地区102个数字化台站记录的近万次地震事件的长周期垂直向瑞雷波资料,利用时频分析方法测量并筛选后共得到11213条质量较高的基阶瑞雷波群速度频散资料.纯路径频散的反演中同时计算方位各向异性,反演获得了欧亚大陆及西太平洋边缘海地区(10°E—150°E,10°S—80°N)8—200s共28个周期的瑞雷波群速度及各向异性空间分布图象.瑞雷波高分辨率层析成像表明,30—60s周期,以青藏高原为中心呈极低速分布;100—120s周期,速度差异幅度较大,在东亚东部及西太平洋边缘海,自北向南显示出一条宽2500—4000km,长约8000km的巨型低速异常带.相对海洋来说,欧亚大陆各向异性强度较弱且快波方向较复杂.由于受到印度板块与欧亚板块的碰撞,中国大陆西部的各向异性强度明显大于东部.     

华北1999—2009年水平形变应变场特征

根据华北地区GPS观测数据计算了华北活动块体的运动速度和应变率,以及块体边界带的活动速率和应变率,研究了华北块体的运动和应变率特征,以及边界断裂带的应力作用特征。形变揭示出华北亚板块从西向东运动方向由东向偏转为南东向,NE NNE向断裂带呈现右旋,NWW EW向断裂带呈现左旋。各个次级块体的主压应变应力轴方向存在一定的差异。边界断裂带现今应变应力状态页不相同,郯庐断裂带北段和山西断陷带以压性为主,具有应变能积累显示,但是应变率相对较小,应变能积累缓慢。     

Conditioning temperature‐index model parameters on synoptic weather types for glacier melt simulations

Temperature‐index models are widely favoured as a pragmatic means of simulating glacier melt because of their generally good performance, computational simplicity and limited demands for in situ data. However, their coefficients are normally treated as temporally stationary, unrealistically assuming a constancy of the prevailing weather. We address this simplification by prescribing model coefficients as a function of synoptic weather type, in a procedure that utilizes reanalysis data and preserves the minimal data requirements of temperature‐index models. Using a cross‐validation procedure at Vestari Hagafellsjökull, Iceland, and Storglaciären, Sweden, we demonstrate that applying transient model coefficients, for three temperature‐index models, results in statistically significant increases in the skill with which melt is modelled: Median simulation improvements in the Nash–Sutcliffe efficiency coefficient of 7.3 and 23.6% are achieved when hourly and daily melt totals are evaluated respectively. Our weather‐type modelling approach also yields insight to processes driving parameter variability, revealing dependence that is consistent with a priori considerations of the surface energy balance. We conclude that incorporating weather types into temperature‐index models holds promise for improving their performance, as well as enhancing understanding variability in coefficient values. Copyright © 2014 John Wiley & Sons, Ltd.     

地理国情普查数据协同生产系统开发与应用

随着测绘地理信息技术及计算机软硬件的发展,在地理信息数据生产过程中,大量的工序都已采用模块化、并行化的方式处理,目前进行中的全国地理国情普查工作更需要大量业务人员分批分片开展。然而,该种作业方式经常需要将阶段性成果进行集成,用于统一处理或检查,完成之后又需要化整为零。因此,针对目前地理国情并行作业方式,迫切需要一套协同化的地理国情普查数据生产平台和体系来支撑多人在线、协同采集、网络化处理的业务。本文设计开发了地理国情普查数据协同生产系统,为地理国情普查内外业数据管理、质检和处理提供了一整套完整的解决方案。此系统实现和验证了地理国情普查数据协同生产的思想,在地理国情普查青岛区域中已经得到广泛的应用,取得了良好应用效果。