Radiolaria‐dated Lower Permian clastic‐rock sequence in the Fukuji area of the Hida‐gaien terrane,central Japan,and its inter‐terrane correlation across Southwest Japan

The stratigraphy and radiolarian age of the Mizuyagadani Formation in the Fukuji area of the Hida‐gaien terrane, central Japan, represent those of Lower Permian clastic‐rock sequences of the Paleozoic non‐accretionary‐wedge terranes of Southwest Japan that formed in island arc–forearc/back‐arc basin settings. The Mizuyagadani Formation consists of calcareous clastic rocks, felsic tuff, tuffaceous sandstone, tuffaceous mudstone, sandstone, mudstone, conglomerate, and lenticular limestone. Two distinctive radiolarian faunas that are newly reported from the Lower Member correspond to the zonal faunas of the Pseudoalbaillella u‐forma morphotype I assemblage zone to the Pseudoalbaillella lomentaria range zone (Asselian to Sakmarian) and the Albaillella sinuata range zone (Kungurian). In spite of a previous interpretation that the Mizuyagadani Formation is of late Middle Permian age, it consists of Asselian to Kungurian tuffaceous clastic strata in its lower part and is conformably overlain by the Middle Permian Sorayama Formation. An inter‐terrane correlation of the Mizuyagadani Formation with Lower Permian tuffaceous clastic strata in the Kurosegawa terrane and the Nagato tectonic zone of Southwest Japan indicates the presence of an extensive Early Permian magmatic arc(s) that involved almost all of the Paleozoic non‐accretionary‐wedge terranes in Japan. These new biostratigraphic data provide the key to understanding the original relationships among highly disrupted Paleozoic terranes in Japan and northeast Asia.     

Planners to the rescue: Spatial planning facilitating the development of offshore wind energy

The development of offshore wind energy has started to take place surprisingly quickly, especially in North European waters. This has taken the wind energy industry out of the territory of planning systems that usually govern the siting of wind farms on land, and into the world of departmental, sectoral regulation of marine activities. Although this has favoured the expansion of offshore wind energy in some respects, evidence suggests that the practice and principles of spatial planning can make an important contribution to the proper consideration of proposals for offshore wind arrays. This is especially so when a strategic planning process is put in place for marine areas, in which offshore wind is treated as part of the overall configuration of marine interests, so that adjustments can be made in the interests of wind energy. The current process of marine planning in the Netherlands is described as an illustration of this.     

黑石岭隧道围岩岩爆灾害的研究

地应力环境与围岩力学属性是隧道工程中引发岩爆的两大决定性因素。为了研究黑石岭隧道开挖过程中围岩岩爆灾害的潜在威胁及其表现规律,通过对岩爆里程段的现场采样、运用Kaiser效应法测量原岩应力和室内岩石力学实验,探讨了工程区内白云岩的岩性特征及其破坏规律,并基于强度理论和冲击能指标分析了发生岩爆的可能性及其发生方式。分析得知,该工程区内岩爆的潜在威胁较大,尤其是测点1和测点2处发生强岩爆的可能性最大,须在工程开挖过程中加强防治。     

土体剪切带的模拟与机理分析

采用修正剑桥模型,研究在平面应变条件下正常固结土剪切带的产生机理和剪切带形状的多样性。研究结果表明,剪切带是由材料的不均匀变形引起,并由试样局部应变能释放的冲击作用形成的;试样端部摩擦约束与试样内部初始缺陷都能够引起试样的不均匀变形进而诱发剪切带。分析了不同边界约束条件、初始缺陷设置方式及二者共同作用对剪切带形式的影响,平面应变条件下土体的剪切带有单一型、交叉型和多段型等3种形式,多段剪切带的发展具有先后顺序。     

不同构造参数对圆环耗能器性能的影响分析

设计了13组不同构造参数的圆环耗能器,采用ABAQUS软件对安装在支撑框架结构中的圆环耗能器进行参数分析,研究圆环钢板厚度、圆环外直径、支撑角度、圆环钢板局部削弱形式和削弱深度对圆环耗能器性能的影响。研究结果表明：圆环耗能器滞回曲线稳定、饱满,塑性耗能能力强;随着圆环钢板厚度的增加或者圆环外直径的减小,圆环耗能器初始刚度和屈服力增大;支撑与横梁之间的角度对圆环耗能器性能有一定影响,交叉支撑角度宜取45°左右;圆环钢板局部削弱圆环耗能器比不削弱圆环耗能器具有更好的耗能效果;圆环钢板局部削弱形式宜采用圆弧式,且钢板削弱深度宜控制在圆环钢板宽度的20%~30%。     

高强混凝土剪力墙地震损伤模型分析

在分析比较现有钢筋混凝土结构的地震损伤模型的基础上,根据高强混凝土剪力墙的滞回曲线特性及刚度退化规律,采用能量耗散系数和最大变位处的卸载刚度的退化为破坏参数,提出了适用于高强混凝土剪力墙构件的双参数地震损伤模型。依据已有的高强混凝土剪力墙构件试验研究结果,对损伤模型进行非线性回归分析,确定了相应的地震损伤模型参数,提出了高强混凝土剪力墙各性能水平的损伤指数以及相应于三水准抗震设防的损伤指数允许值。分析结果表明,按本文所提出的损伤模型计算得到的剪力墙构件最终破坏时对应的损伤指数,其平均值在合理范围内,标准差较小;损伤指数计算值对应的损伤程度基本符合试验结果,计算结果离散程度较低。     

基于光子计数探测器的能谱CT的研究

本文的目的是评估光子计数探测器对CT成像的性能的影响,我们对一款基于碲锌镉(CZT)的光子计数探测器进行了性能测试,并搭建一个成像平台。首先对探测器系统进行能量增益的校正以及坏像素点校正,以减少探测器响应的不均匀性对CT成像的影响。然后对探测器进行能量-阈值标定,以确定探测器的工作能量阈值。最终搭建成像系统,对X光能量分别大于36和45keV的数据,获得了模体的重建结果,并对结果进行了分析。     

Liquefaction potential evaluations by energy-based method and stress-based method for various ground motions

An energy-based liquefaction potential evaluation method (EBM) previously developed was applied to a uniform sand model shaken by seismic motions recorded at different sites during different magnitude earthquakes. It was also applied to actual liquefaction case histories in Urayasu city during the 2011 M9.0 Tohoku earthquake and in Tanno-cho during the 2003 M8.0 Tokachi-oki earthquake. In all these evaluations, the results were compared with those by the currently used stress-based method (SBM) under exactly the same seismic and geotechnical conditions. It was found that EBM yields similar results with SBM for several ground motions of recent earthquakes but has easier applicability without considering associated parameters. In Urayasu city, the two methods yielded nearly consistent results by using an appropriate coefficient in SBM for the M9.0 earthquake, though both overestimated the actual liquefaction performance, probably because effects of plasticity and aging on in situ liquefaction strength were not taken into account. In Tanno-cho, EBM could evaluate actual liquefaction performance due to a small-acceleration motion during a far-field large magnitude earthquake while SBM could not.     

克拉玛依科博馆倾斜结构抗震设计

结合克拉玛依市科技博物馆工程,对超限倾斜结构设定性能设计目标,并针对性能目标提出抗震措施及抗震构造措施.考虑结构材料的非线性属性,采用静力非线性分析方法,分析倾斜框架-剪力墙结构在地震作用下的响应,尤其是结构在罕遇地震作用下的非线性动力特性.结果表明,结构在罕遇地震下也是安全可靠的,剪力墙尚处在弹性范围,未出现塑性铰,...     

基于等效单自由度体系的结构地震输入能量的研究

通过对多自由度体系结构在地震作用下的能量分析,考虑地震动因素和结构自身特性,提出一种框架结构地震总输入能量的简化求解方法.实例计算结果表明:基于等效单自由度体系来估计多自由度体系的地震总输入能,是一种计算简便且较为准确的方法.