Field-observed phenomena of seismic liquefaction and subsidence during the 2008 Wenchuan earthquake in China

In the 2008 Wenchuan earthquake in Sichuan Province, a large number of buildings, water conservancy facilities, and transportation facilities were severely damaged. The damage caused by liquefaction and earthquake-induced soil subsidence was widely distributed, diverse, and extensive. Typical liquefaction and earthquake-induced subsidence damage for this region has been described by investigations of soils and foundations in the earthquake-stricken area. Factors that influenced the liquefaction of soils in Dujiangyan County were analyzed, accounting for regional geological conditions. The results identify several factors that may affect the process of liquefaction and general damage to buildings, roads, levees, and dams. Such factors could serve as the basis for further research into mitigating the damage caused by earthquake-induced liquefaction and subsidence. The importance of detailed ground reconnaissance and the implementation of reasonable and effective measures to improve soft soil are proposed for earthquake hazard reduction in similar areas.     

Petrogenesis and tectonic implications of Late Jurassic shoshonitic lamprophyre dikes from the Liaodong Peninsula, NE China

This paper presents detailed mineral chemical, element geochemical and Sr–Nd–Hf isotopic data for the Late Jurassic (155?±?4 Ma) lamprophyre dikes in the Liaodong Peninsula, NE China. The lamprophyres are shoshonitic and geochemically fall into three groups: Group I has relatively high SiO₂ (52.5–57.0 wt.%), low MgO (5.5–8.3 wt.%) and compatible trace element (e.g. Cr?=?128–470 ppm) contents, high initial ⁸⁷Sr/⁸⁶Sr ratios (0.7093–0.7117), and low ε_Nd (T) values (?9.6 to ?12.1); Group II has relatively low SiO₂ (44.8–50.0 wt.%), high MgO (10.8–14.2 wt.%) and compatible trace element (e.g. Cr?=?456–1,041 ppm) contents, low initial ⁸⁷Sr/⁸⁶Sr ratios (0.7073–0.7087), and high ε_Nd (T) values (?1.4 to ?2.9); Group III is transitional between the two in all elemental and isotopic compositions. Interpretation of the elemental and isotopic data suggests that the lamprophyric melts were derived by partial melting of subcontinental lithospheric mantle (SCLM) at a depth of 60–80 km (group I), decompression melting of upwelling asthenosphere at 60–100 km (group II), and mixing between the SCLM-derived and asthenosphere-derived melts (group III). It is assumed that the local SCLM was detached at a depth of 60–80 km by the 155 Ma ago. A continental arc-rifting related to the Palaeo-Pacific plate subduction is favored as a geodynamic force for such a cratonic lithosphere detachment.     

HGP桩在地基处理中的应用

通过工程实例,介绍HGP桩复合地基的设计计算及施工工艺,根据现场检测结果,说明采用HGP桩能有效提高地基强度、控制地基变形,而且HGP桩具有施工机具简单、可操作性强、造价低、不受场地条件限制等优点。HGP桩在地基处理中具有很好的推广应用价值。     

美国印第安纳州宾夕法尼亚系含煤地层和煤层简介

美国中部伊利诺伊煤田(跨伊利诺伊、印第安纳、肯塔基等三个州)的含煤地层为上石炭统宾夕法尼亚系。美国印第安纳地质研究所2006年编制的印第安纳州基岩综合地层柱状图建立了宾夕法尼亚系含煤地层的岩相层序,现将此岩相层序介绍到国内,对我们了解美国晚古生代煤田地质及阅读国外文献资料颇有帮助。     

安阳矿区煤与瓦斯突出预测模型的建立与应用

利用灰色关联分析法确定控制矿井煤与瓦斯突出的主导因素,根据人工神经网络建立煤与瓦斯突出危险性预测的系统结构,在此基础上,选用突出矿井的15个煤与瓦斯突出实例作为学习样本对网络进行训练,最后运用3个煤与瓦斯突出实例作为预测样本对所建模型进行验证。结果表明利用灰色理论—神经网络方法建立的预测模型能够满足煤与瓦斯突出预测的要求。通过分析和计算安阳矿区煤层的开采深度、地质构造(尤其是断层)与突出危险程度关系密切,在煤与瓦斯突出的预测、防治工作中可以作为首选指标来考虑。     

Contamination levels assessment of potential toxic metals in road dust deposited in different types of urban environment

A total of 42 samples of road dust were collected along ring road, city centre, city side, and freeway in Urumqi, China. Total concentrations of Cd, Cr, Cu, Ni, Pb, Mn, Be, Co, Zn, and U were determined by using the inductively coupled plasma-mass spectrometry in order to assess and to compare road dust contamination levels of metals among the four roads. The results show that, among the four categories of roads, mean concentrations of Co and U vary little. City centre locations show strong enrichments of Cd, Cu, Pb, and Be. Along the ring road, the highest mean concentrations were found for Cr, Ni, Mn, and Co. However, the highest concentrations of Zn and U were found along the freeway. The cluster analysis shows that three main groups can be distinguished. Every group may be associated with different main sources and concentrations of the metals. The results of contamination assessment reveal that, among all of the potential toxic metals, Cd, Cu, and Zn pollution were obviously heavier with moderate or high contamination indices for most road dust samples, while Cr, Ni, and Pb contamination were lower along the four categories of roads. Compared with the city side, Cd, Cu, Pb, Ni, and Zn contamination were heavier along the ring road, the city centre, and the freeway with high traffic density. Low Pb contamination or no contamination in all the road dust samples may be related to the increasing usage of lead-free petrol.     

Spatiotemporal variation and mechanisms of temperature inversion in the Bay of Bengal and the eastern equatorial Indian Ocean

In the northern Bay of Bengal, the existence of intense temperature inversion during winter is a widely accepted phenomenon. However, occurrences of temperature inversion during other seasons and the spatial distribution within and adjacent to the Bay of Bengal are not well understood. In this study, a higher resolution spatiotemporal variation of temperature inversion and its mechanisms are examined with mixed layer heat and salt budget analysis utilizing long-term Argo（2004 to 2020） and RAMA（2...     

Dynamic Response Analysis and Vibration Control for A Fixed-Bottom Offshore Wind Turbine Subjected to Multiple External Excitations

For the offshore wind turbines installed in earthquake areas, their operation is affected by seismic loads in addition to wind and wave loads. Therefore, it is necessary to study the dynamic responses and vibration control of the wind turbines. In previous studies, the structural responses of offshore wind turbines are usually investigated in the parked case, while the blade rotation effect is usually not considered. The evaluation on the structural responses may be inaccurate under this conditi...     

“海翼号”水下滑翔机盐度数据的热滞后效应偏差订正方法探讨

水下滑翔机可以高效地观测海水的温度、盐度和压强等海洋参数,但由于热滞后效应,盐度数据,特别是在温度梯度较大的温跃层,会出现一定程度的偏差。本研究选取了3种目前常用的盐度热滞后订正方法,对带泵的“海翼号”水下滑翔机,于2019年8月在中北太平洋所观测的盐度数据因热滞后效应引起的偏差进行订正处理,与船载911型温盐深测量仪(Instrument for Measuring Conductivity Temperature and Depth,CTD)观测盐度进行对比,在比较了3种方法对滑翔机盐度订正前后下降和上升剖面偏差的减少程度、订正后剖面与船载CTD观测剖面的偏差大小和下降上升温盐曲线(T-S曲线)的一致程度后,得出了水下滑翔机盐度订正的最优方法,即在订正电导池中实际温度的前提下,采用计算机图形分割方法,最小化滑翔机机载CTD测得的下降和上升两个剖面T-S曲线围成面积所确定的目标函数,来确定合适的热滞后修正振幅和时间常数,从而修正下降和上升两个剖面之间盐度偏差。     

邻避设施空间分布特征及其与周边住宅价格的关系——广州案例

随着中国城镇的快速发展以及市民环境意识的提高,由邻避设施引发的矛盾日益增多。合理规划邻避设施,是促进环境正义、推动社会和谐的重要课题。论文从“规划云平台”获取广州主城区邻避设施的地理信息数据,通过Python语句编码收集广州主城区小区平均房价数据,运用克里金插值法分析邻避设施的空间分布特征,构建多元线性回归模型和地理加权回归模型研究邻避设施与周边住宅价格的关系。研究发现,广州主城区邻避设施的布局与低收入住宅区的分布在空间上具有一致性,邻避设施主要分布在房价较低的住宅区周边;邻避设施对周边小区房价的影响与邻避设施的类型和所在区位相关,城市边缘区的邻避设施对房价造成了显著的负面影响,而城市中心良好的区位条件、基础设施与公共服务配套一定程度上抵消了邻避设施的负外部性;污名化类的邻避设施对房价的影响程度明显小于污染类、风险聚集类和心理不悦类邻避设施。本研究对有关城市邻避设施的科学规划布点具有一定的借鉴和指导意义。