The multi-time-scale structures of an annual sediment discharge series of debris flow in the Jiangjia Ravine and the Southern Oscillation index are analysed using the method of Morlet wavelet transformations. The possible effects of E1 Nirio episodes on the annual sediment discharge are discussed by comparing the period variations of ENSO and the discharge. The results show that the annual sediment discharge series of debris flow is related to E1 Nifio episodes. Generally, the annual sediment discharge of debris flow is less than usual during an E1 Nifio episode and debris flow is less active. On the contrary, the annual sediment discharge of debris flows is greater than usual during a La Nifia episode and debris flows are more frequent. There is a relationship between the annual sediment discharges of debris flow in the Jiangjia Ravine and the summer Southern Oscillation index, with both having quasi-periodic variations of 2 and 5-6 years. 相似文献
Steps are distinctive features for estimating the movement of the upper and lower block of faults. However, studies about the influence of steps as a special type of discontinuity on cracking behaviors and strength of rock masses are limited. In this research, rock-like samples with steps and preexisting flaws were fabricated. Step height h and the inclination angle of gentle slope of the step α were set to different values. Direct shear tests were conducted on these samples under different normal stresses. The experimental results reveal that the inclination angle of the gentle slope of the step α, step height h, and normal stress have an influence on the strength, crack initiation, and crack propagation of the samples. The experimental results show that crack behaviors and shear strength were affected by step inclination angles α and step height h. As the normal stress increases, the improvement of the strength of samples with a large step height is larger than that of samples with a small step height, the improvement of the strength of samples with α of 10° is larger than that of samples with α of 0° and-10°. The discrete element method was used to simulate the shear test. Numerical results show five different types of displacement vectors, which can be used to determine whether the cracks are tensile cracks or shear cracks. The above conclusions can provide help for estimating mechanical properties and failure modes of rock masses with steps of different geometries. 相似文献
传统的海洋环境数据集成与共享存在共享模式单一、数据服务效果不明显等突出问题。随着云计算等技术的出现,数据共享模式发生了巨大的变化。提出基于云计算的海洋环境数据共享体系,通过基础设施即服务(infrastructure as a service,IaaS)、数据资源即服务(data as a service,DaaS)及软件即服务(software as a service,SaaS)实现海洋环境数据共享模式的转变。在海洋环境数据云中,用户既是数据的使用者也是数据的提供者,通过数据发布与发现、数据需求发布与发现等功能,解决数据共享中“用户-数据”之间的矛盾,并激励普通海洋科研工作者贡献自己的数据,保障数据资源有效、可持续利用。以南海海域为实验区,以表层漂流浮标数据及中尺度涡旋数据为实验数据,构建了原型系统验证该方法。 相似文献