Seismic response of high concrete face rockfill dams subjected to non-uniform input motion     

Yao  Yu  Wang  Rui  Liu  Tianyun  Zhang  Jian-Min 《Acta Geotechnica》2019,14(1):83-100

Analysis of the seismic response of high CFRDs under non-uniform ground motion input is conducted using a novel non-uniform input motion calculation method combined with nonlinear FEM. The non-uniform input motion calculation method and its basic assumption are validated. The response of CFRDs under uniform and non-uniform input is compared to discuss the necessity of conducting seismic analysis of high CFRDs under realistic non-uniform ground motion input. When the acceleration at the surface of the free field for dynamic simulations with uniform and non-uniform input is kept consistent, the seismic response of CFRDs under non-uniform input is in general significantly smaller, while the dynamic tensile stress around the edges of the concrete face slab is greater. The simulation results suggest that non-uniformity of the ground motion input has important effects on the seismic response of high CFRDs and should be considered in the seismic design of CFRDs. The influence of the incident angle of seismic waves is also investigated, with results indicating that the influence is waveform dependent, while being frequency independent.

  相似文献   

Pore pressure in deep bore-holes: Its measurement and relation with seismic activities     

Jian-Li Gao  Shi-Zong Sun  Jian-Min Ding  Guo-Ping Liang 《地震学报(英文版)》1997,10(1):71-79

The method of measuring the pore pressure of stratum fluid in deep bore-holes is presented. Taking the sedimentary basins in North China as an example, the variation law of pore pressure measured in strata within the depth range of 0 to 4 km is analyzed. Furthermore, the relation between the regional distribution of abnormal pore pressures in 3 000 m depth and seismic activities is discussed in connection with the earthquakes of M _S5.0 that occurred after 1 900 in the studied region. The study result indicates that the strata pore pressure P ₀ measured in deep bore-holes is not exactly the same as the hydrostatic pressure PH. Ultra pore pressure does exist, though not commonly. The relation that the pore pressures (P ₀₁, P ₀₂ and P ₀₃) measured in exploration, evaluation and exploitation wells in Oil-fields and the hydrostatic pressuree (P _H) of the above wells is as follows: 1 P ₀₁>P ₀₂>P _H>P ₀₃ in areas with ultra pore pressures; 2 P _H>P ₀₁>P ₀₂>P ₀₃ in areas where the pore pressures are normal or on the lower side. The relation between the regional distribution of ultra pore pressures and the activity of earthquakes of M _S5.0 has been analyzed. The result shows that, with latitudes 36.0°–36.5°N as a demarcation, pore pressures are ultra-high in the south and are normal or lower in the north. In the south, the measured pore pressure is obviously higher than the hydrostatic pressure below the depth of about 2 000 m and it increases as a power function with increasing depth; meanwhile, the earthquake activity there is weaker. In the north, however, the measured pore pressure increases as a linear function with increasing depth; meanwhile, the earthquake activity there is stronger. This project sponsored by the Chinese Joint Seismological Science Foundation.  相似文献   

Centrifuge shaking table tests on 4 × 4 pile groups in liquefiable ground     

Xing Liu  Rui Wang  Jian-Min Zhang 《Acta Geotechnica》2018,13(6):1405-1418

A series of centrifuge shaking table model tests are conducted on 4?×?4 pile groups in liquefiable ground in this study, achieving horizontal–vertical bidirectional shaking in centrifuge tests on piles for the first time. The dynamic distribution of forces on piles within the pile groups is analysed, showing the internal piles to be subjected to greater bending moment compared with external piles, the mechanism of which is discussed. The roles of superstructure–pile inertial interaction and soil–pile kinematic interaction in the seismic response of the piles within the pile groups are investigated through cross-correlation analysis between pile bending moment, soil displacement, and structure acceleration time histories and by comparing the test results on pile groups with and without superstructures. Soil–pile kinematic interaction is shown to have a dominant effect on the seismic response of pile groups in liquefiable ground. Comparison of the pile response in two tests with and without vertical input ground motion shows that the vertical ground motion does not significantly influence the pile bending moment in liquefiable ground, as the dynamic vertical total stress increment is mainly carried by the excess pore water pressure. The influence of previous liquefaction history during a sequence of seismic events is also analysed, suggesting that liquefaction history could in certain cases lead to an increase in liquefaction susceptibility of sand and also an increase in dynamic forces on the piles.  相似文献   

A dual-mechanism tensile failure criterion for transversely isotropic rocks     

Zhao  Yang  Wang  Rui  Zhang  Jian-Min 《Acta Geotechnica》2022,17(11):5187-5200

Acta Geotechnica - We propose a tensile failure criterion for transversely isotropic rocks that distinguishes tensile fracturing mechanisms either through the anisotropic rock matrix or along the...  相似文献   

利用互相关函数求地震波衰减   总被引：13，自引：0，他引：13       下载免费PDF全文

徐平  王宝善  张尉  林建民  陈颙 《地球物理学报》2006,49(6):1738-1744

与传统利用单事件波形求介质衰减的方法不同,我们提出一种以一系列事件为源,以源与远处记录波形的互相关函数为基础计算介质品质因子的方法.依据野外现场实验的数据,我们分别以单次和多次激发为源,讨论了事件波形和互相关函数波形的振幅变化及相应的介质品质因子,结果发现,与事件波形一样,互相关函数波形也可以用于计算介质的衰减系数.计算结果表明：（1）实验场地浅层介质在原场条件下的品质因子Q值在40左右;（2）互相关函数的最大幅度与事件波形的振幅随距离具有相同的衰减规律.  相似文献   

边坡破坏过程离心模型试验的应力位移场研究   总被引：6，自引：2，他引：4  

张嘎  王爱霞  牟太平  张建民 《岩土力学》2008,29(10):2637-2641

提出了一种确定离心模型试验过程中边坡的应力和位移场及其变化过程的方法。基于物理测量与数值模拟相结合的思路,首先采用离心场非接触位移测量技术测量出边坡的位移场;然后通过数值模拟和反演分析等途径算出边坡的应力场。该方法已成功用于多个边坡离心模型试验中的应力位移场的确定,表明了该方法可以较好地得出离心模型试验过程中边坡的应力和位移场。边坡离心模型试验结果表明,边坡的破坏过程与应变局部化和应力集中的过程有着密切联系。  相似文献   

2018年烟台四十里湾及其邻近海域网采浮游植物群落结构的时空变化     

张文静  董志军  孙西艳  张晨  刘永亮  侯朝伟  赵建民 《海洋与湖沼》2020,51(5):1151-1161

本文基于2018年5月（春季）、8月（夏季）、11月（秋季）和2019年1月（冬季）季度航次调查,采用冗余分析（RDA）和Bray-Curtis相似性聚类分析方法,讨论了烟台四十里湾及其邻近海域网采浮游植物丰度、优势种组成、多样性指数、均匀度指数的分布特征以及浮游植物与环境因子的关系。本年度调查共发现浮游植物4门69属116种,其中硅藻门50属85种,甲藻门15属27种,着色鞭毛藻门3属3种,未定类1种（三深碎裂藻,Ebria tripartita）。浮游植物丰度在8月份达到年度最高值,为2.89×10⁸cells/m³,秋季次之,春季最低,春、秋、冬季浮游植物丰度均为~10⁵cells/m³。硅藻门在4个季节中均占绝对优势,除春季出现甲藻门（夜光藻）优势种外,其余季节浮游植物优势种均为硅藻门。相邻季节浮游植物优势种更替明显,未出现4个季节共有的优势种。浮游植物多样性和均匀度指数均在夏季达到最低值,分别为1.58和0.31。RDA排序分析显示,不同季节影响浮游植物群落分布的环境因子不同,总体来讲,温度、溶解氧浓度、SiO₃^2-浓度和NO₃^-浓度对浮游植物的丰度和平面分布有显著影响。Bray-Curtis相似性聚类结果显示,2018年每个季节浮游植物群落分布均可分为两个类群,其分布受营养盐分布的影响较为明显。  相似文献   

海水酸化和热应激对日本鼓虾氧化应激和能量代谢的影响     

李笑  曲艺  张倩倩  张天宇  曹瑞文  赵建民 《海洋与湖沼》2020,51(6):1412-1421

伴随着全球气候变化的日益加剧,过量CO₂排放所导致的海洋酸化和暖化现象已引起广泛关注。本研究设置了两个pH水平（pH 8.1和pH 7.6）和两个温度梯度（20.0和23.0℃）,以探讨海水酸化和温度升高对日本鼓虾（Alpheus japonicus Miers）氧化应激和能量代谢过程的影响。结果发现,海水酸化、热应激以及海水酸化和热应激复合胁迫能够诱导日本鼓虾产生不同程度的氧化应激现象,且海水酸化和热应激对过氧化氢酶（Catalase,CAT）活性、还原型谷胱甘肽（Glutathione,GSH）含量和还原型谷胱甘肽与氧化型谷胱甘肽比值（Glutathione/Oxidized Glutathione,GSH/GSSG）有交互作用;其中,海水酸化和热应激复合暴露导致鼓虾GSH含量较对照组水平降低了66.0%,GSH/GSSG比值降低为对照组水平的20.8%,而脂质过氧化水平则较对照组显著增加了51.4%。此外,海水酸化和热应激复合暴露能够导致日本鼓虾己糖激酶（Hexokinase,HK）活性的显著增强和蛋白质含量的显著降低,提示鼓虾通过调节糖酵解过程和能量储备来满足机体的能量代谢需求。上述结果表明,短期海水酸化和热应激暴露能够影响日本鼓虾的抗氧化防御体系、能量代谢过程以及能量储备能力,长期持续暴露可能会对其种群维持构成潜在威胁。  相似文献   

基于互信息量的地震信号检测和初至提取方法   总被引：8，自引：2，他引：6       下载免费PDF全文

李辉  戴旭初  葛洪魁  王宝善  林建民  陈颙 《地球物理学报》2007,50(4):1190-1197

本文将现代信息科学中的重要基础理论——信息论引入到地震信号的分析和处理中,提出了一种利用互信息量检测地震信号并进行初至提取的方法,给出了该方法的基本原理和具体算法.计算结果表明,互信息量随滑动窗口移动的变化情况可以明确标示出待测地震信号的存在,通过提取互信息量的突变点或峰值点,能够有效拾取地震波的初至时刻.这种方法还可以特别针对非传统的地震信号,如连续随机信号、随机脉冲序列等进行处理.在这些信号条件下,往往信噪比很低,波形随传播距离发生较大变化,传统的信号检测方法效果不佳,而这种以随机信号检测为基础的互信息量探测方法具有很好的性能,很有发展前景.  相似文献   

Fe Kα line profile in AGNs: average shape and redshift dependence     

Wei-Ming Mao  Chen Hu  Jian-Min Wang  Gang Zhao  Shu Zhang 《中国天文和天体物理学报》2010,10(9)

We collect a sample of 381(271 type Ⅰ)active galactic nuclei(AGNs)with XMM-Newton observations for an analysis of the dependence of Fe Kα profiles on redshifts to test the potential cosmological evolution of spins of supermassive black holes(SMBHs).The sample spans a redshift range of z = 0.0008-4.76,which allows us to rebin the sample into 7 redshift groups.Phenomenological analysis of the Fe profile suggested that the line width(σ)of the narrow or broad Fe line does not show significant changes in redshift range z < 0.3.Using a physical model,we significantly detect a narrow Fe Kα line at 6.4 keV with an average equivalent width(EW)= 160 eV except for the two largest redshift bins.The EW of the Fe line does not show significant changes.We also find a relativistic broad line in three redshift bins(z < 0.116,0.056 < z < 0.12 and 0.12 < z < 0.3)with an average EW = 522eV.  相似文献