Shaking Table Tests on Bridge Foundation Reinforced by Anti-slide Piles on Slope     

ZHOU Heng  SU Qian  LIU Jie  YUE Fei 《中国地震研究》2019,33(3):514-524

Based on the requirement of seismic reinforcement of bridge foundation on slope in the Chengdu-Lanzhou railway project, a shaking table model test of anti-slide pile protecting bridge foundation in landslide section is designed and completed. By applying Wenchuan seismic waves with different acceleration peaks, the stress and deformation characteristics of bridge pile foundation and anti-slide pile are analyzed, and the failure mode is discussed. Results show that the dynamic response of bridge pile and anti-slide pile are affected by the peak value of seismic acceleration of earthquake, with which the stress and deformation of the structure increase. The maximum dynamic earth pressure and the moment of anti-slide piles are located near the sliding surface, while that of bridge piles are located at the top of the pile. Based on the dynamic response of structure, local reinforcement needs to be carried out to meet the requirement of the seismic design. The PGA amplification factor of the surface is greater than the inside, and it decreases with the increase of the input seismic acceleration peak. When the slope failure occurs, the tension cracks are mainly produced in the shallow sliding zone and the coarse particles at the foot of the slope are accumulated.  相似文献   

A quantitative estimation of the energetic cost of brown ring disease in the Manila clam using Dynamic Energy Budget theory     

Jonathan Flye-Sainte-Marie  Fred Jean  Christine Paillard  Sebastiaan A.L.M. Kooijman 《Journal of Sea Research》2009,62(2-3):114

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Dynamic response of a slope reinforced by double-row antisliding piles and pre-stressed anchor cables     

FAN Gang  ZHANG Jian-jing  QI Shun-chao  WU Jin-biao 《山地科学学报》2019,(1):226-241

Large-scale shaking table tests were conducted to study the dynamic response of a slope reinforced by double-row anti-sliding piles and prestressed anchor cables. The test results show that the reinforcement suppressed the acceleration amplification effectively. The axial force time histories are decomposed into a baseline part and a vibration part in this study. The baseline part of axial force well revealed the seismic slope stability, the peak vibration values of axial force of the anchor cables changed significantly in different area of the slope under seismic excitations. The peak lateral earth pressure acting on the back of the anti-sliding pile located at the slope toe was much larger than that acting on the back of the anti-sliding pile located at the slope waist. The test results indicate an obvious load sharing ratio difference between these two anti-slide piles, the load sharing ratio between the two anti-sliding piles located at the slope toe and the slope waist varied mainly in a range of 2-5. The anti-slide pile at the slope waist suppressed the horizontal displacement of the slope surface.  相似文献   

广州“5·21”新冠肺炎疫情时空演化与防控管理     

李文辉  陈丽茹  冼楚盈  孙彩歌 《热带地理》2022,42(10):1713-1723

广州“5·21”新冠肺炎疫情是境内首起由新冠病毒“德尔塔”（Delta）变异毒株引发的本土疫情。以广州“5·21”疫情感染者为对象,采用统计分析、文本分析和社会网络分析方法,分析本土境外输入关联疫情的统计特征、扩散网络与防控管理。研究结论主要有：1）广州“5·21”疫情感染者以老年人居多,感染者潜伏期较短,病毒传播速度快。核酸检测筛查可将病毒传播的风险精准控制在已知范围;行程轨迹可以辅助及时厘清病毒传播链条,切断传播途径。2）感染者所在区和镇街、重点防控区域、分级分类防控管理区域呈片状和点状分布,感染者在少数镇街呈集聚分布特征,疫情传播以接触扩散为主、兼具跳跃扩散的特征。3）疫情扩散传播网络以“簇状”和“链状”为主,网络整体呈现一定“小世界”特征;网络节点层面指标值较高的节点处于疫情接触扩散传播网络的关键路径,是疫情分级分类防控管理的重点对象。4）疫情分级分类防控管理应做好出入管理、社区管控、居家隔离、需求保障、生活垃圾处理、环境消杀、健康监测和服务、核酸检测、宣传引导和管控解除等工作。  相似文献   

新冠肺炎疫情在广东省的扩散特征     

刘逸  李源  黎卓灵  韩芳菲 《热带地理》2020,40(3):367-374

基于广东省各地市卫健委官网披露的新型冠状病毒肺炎确诊病例的详细信息，对新冠病例在广东省的时空扩散特征以及各地级市疫情传播和变动的空间差异进行分析。研究结果表明：1）广东省确诊病例具有中年人最多、青年人其次、老年人第三的年龄结构特点，与全国统计特征较为相似。2）广东省的疫情扩散比率为0.198，表明其防疫措施卓有成效，有效地抑制了疫情的扩散。3）广东省的疫情扩散格局和综合风险格局存在显著差异。三四线中型城市的扩散风险较高但综合风险处于中等水平，发达城市的扩散风险较低但综合风险最高，粤东西部的欠发达地区较为安全。文章建议可积极宣传广东抗疫防疫成果，适度缓解民众焦虑，但仍需重点防范因返工返学带来的二次冲击。在防疫的中后期，应根据各地市的疫情风险等级，在省内科学划分风险防控区域，实施分级管控，有序恢复社会生产生活，避免过度防疫对社会民生造成的负面冲击，并需特别关注原本经济韧性较为脆弱的欠发达地区。  相似文献   

云南耿马孟定盆地高砷水成因及其危害   总被引：2，自引：0，他引：2  

李燕  王强  蒋成兴  李丽辉  李庆生 《云南地质》2009,28(4):367-373

孟定盆地出现水砷异常由三类因素共同作用引发：汇水区砷背景高,有色金属采选冶过程排放含砷重金属导致砷二次污染,盆地地球化学环境利于砷积累。形成环境具一定的代表性,区别于我国已发生的饮水型盆地砷病病区。  相似文献   

Growth anomalies on Acropora cytherea corals     

Irikawa A  Casareto BE  Suzuki Y  Agostini S  Hidaka M  van Woesik R 《Marine pollution bulletin》2011,62(8):1702-1707

This ten-year study examined the morphological, physiological, and ecological characteristics of coral growth anomalies on Acropora cytherea on Amuro Island, Okinawa, Japan. The objectives of the study were to assess whether the growth anomalies, identified as diffuse disruptions on the skeleton: (i) were more prevalent on large colonies than on small colonies, (ii) were more common near the center of the colonies than peripherally, (iii) affected colony growth and mortality, and (iv) affected coral-colony fecundity and photosynthetic capacity. We hypothesized that the growth anomalies were signs of the onset of aging. The growth anomalies were more prevalent on colonies >2 m diameter, and were concentrated near the central (older) portions of the colonies. The growth anomalies were also associated with reduced productivity and dysfunctional gametogenesis. Still, the growth anomalies did not appear to affect colony survival. The contact experiments showed that the growth anomalies were not contagious, and were most likely a sign of aging that was exacerbated by thermal stress.  相似文献   

新疆康家石门子岩画病害调查及保护措施     

郑云峰  谌文武  张景科 《地震工程学报》2011,33(Z1)

位于新疆昌吉州呼图壁县的天山腹地的康家石门子岩画是一幅世界罕见的生殖崇拜岩画,绘在新近纪粉砂岩壁上,位于单斜砂砾岩崖体最下方。经过对岩画区域及载体的全面病害调查与分析,发现整个崖体被冲蚀的非常严重,其中较大的危害为雨水冲刷和裂隙的存在。通过多道瞬态面波勘探方法进行岩画内部裂隙的探测,依据文物保护的基本要求和现有的保护手段,初步提出了对康家石门子岩画的保护与防治措施的对策。  相似文献   

可液化场地桥梁桩基改进m值法研究          下载免费PDF全文

唐亮  凌贤长  苏雷  高霞  李青华 《地震工程学报》2011,33(Z1)

为了合理分析可液化场地桥梁桩基侧向承载力进行了改进m值法的研究。基于振动台试验和m值法,建立了桩-土相互作用体系有限元分析模型;引入反映可液化砂层侧向承载力衰减状态的孔压比指标值Ru;将不同时刻对应墩顶配重惯性力作为体系外部激励施加于墩顶;通过不断试算液化过程中砂土的m值,保证桩的弯矩计算值与试验值吻合较好。建立了考虑孔压比效应的砂土m值衰减因子p与Ru之间关系式。最后,推荐给出可液化场地桥梁桩基侧向承载性能分析的改进m值法。  相似文献   

粤西沿海震动图的生成和研究     

熊厚  叶春明  黄文辉  丘学林  卫小冬 《华南地震》2011,31(4):85-97

震动图是描绘地震产生的地面运动和可能破坏情况的有效工具,主要包括峰值地面速度(PGV)等值线图、峰值地面加速度(PGA)等值线图和仪器烈度分布图等.基于华南数字地震台网记录到的2010年7月9日MS3.7级阳江地震的数据资料,利用SAC和GMT软件从记录到的地震波形数据提取地面运动参数,生成了PGV和PGA等值线图,并...  相似文献