应变软化边坡渐进破坏模式及稳定性可靠度

针对现有考虑应变软化效应的边坡渐进破坏分析模型中计算假定条件不符合实际情况的不足,以三峡库区赵树岭滑坡为研究对象,考虑地下水位波动和地震力的影响,提出用于分析多场耦合条件下应变软化边坡渐进破坏模式及稳定性可靠度的方法.结果表明,地下水位波动和地震力会不同程度地影响滑坡的渐进破坏模式和破坏概率.滑坡在145 m、175 ...     

关于青藏高原2485年温度的季节和空间代表性问题

利用树轮宽度重建的青藏高原东北部2485年年均温度曲线一经发表就引起了学界很大关注.本文就该温度曲线的空间代表性问题进行了再次分析,该研究的样本来自青海乌兰和都兰地区,有一定的空间覆盖度.尽管宽度年表用于年均温度重建,但是我们也指出,它与冬半年(上年9月～当年3月)平均温度也显著高相关(r=0.686,p＜0.0001).重建温度曲线不仅与青藏高原东北部地区,而且与我国中北部地区的气象台站同期平均温度记录显著相关.本文进一步通过重建曲线与不同时空尺度CRU TS3.1网格点资料的相关分析,证明2485年年均温度曲线具有一定的全球空间代表性.     

Displacement prediction model of landslide based on a modified ensemble empirical mode decomposition and extreme learning machine

In this paper, an M–EEMD–ELM model (modified ensemble empirical mode decomposition (EEMD)-based extreme learning machine (ELM) ensemble learning paradigm) is proposed for landslide displacement prediction. The nonlinear original surface displacement deformation monitoring time series of landslide is first decomposed into a limited number of intrinsic mode functions (IMFs) and one residual series using EEMD technique for a deep insight into the data structure. Then, these sub-series except the high frequency are forecasted, respectively, by establishing appropriate ELM models. At last, the prediction results of the modeled IMFs and residual series are summed to formulate an ensemble forecast for the original landslide displacement series. A case study of Baishuihe landslide in the Three Gorges reservoir area of China is presented to illustrate the capability and merit of our model. Empirical results reveal that the prediction using M–EEMD–ELM model is consistently better than basic artificial neural networks (ANNs) and unmodified EEMD–ELM in terms of the same measurements.     

东南亚国家海洋保护区发展探析

为促进区域海洋生态环境和海洋生物多样性保护,文章分析东南亚9个沿海国家海洋保护区的发展状况,提出其发展特点和困境,并针对我国开展相关合作提出建议。研究结果表明：越南、马来西亚、柬埔寨、菲律宾、缅甸、文莱、印度尼西亚、新加坡和泰国海洋保护区的法律框架、管理方式和发展现状各有不同;新冠肺炎疫情和国家政治局势在不同程度上影响东南亚海洋保护区的发展;我国可在已有框架基础上,加强与东南亚国家开展海洋生物多样性保护合作。     

分布式能源系统与电网的区域合作仿真

电网对分布式能源系统的态度很大程度上是出于利益的考虑,如果能够实现双赢,则二者共同合作满足区域用电将是缓解能源危机和供电压力的有效途径.应用Agent技术,将分布式能源系统和电网看作区域内的两类Agent,以实现各自预期利润为目标建立区域合作仿真模型,通过"调整策略-实现利润"的迭代过程获取二者双赢的边界条件及合作轨迹.最后以上海浦东国际机场能源中心热电联产系统为研究对象,验证该方法的有效性.     

西北太平洋热带气旋历史信息查询与显示系统的设计与实现

为了较为准确地预测热带气旋对我国的影响,掌握热带气旋历史活动规律与特征,设计开发了西北太平洋热带气旋历史信息查询与显示系统.该系统能够根据用户需求实现热带气旋历史信息可视化查询、检索与显示,为分析登陆我国的热带气旋活动规律提供重要的气象信息,也可为舰船安全航行提供及时准确的海洋气象辅助决策.     

安徽安庆M_S4.8级地震现场调查启示与震害特征分析

本文通过安庆MS4.8级地震现场调查和震害特征分析,探讨了5.0级左右中强地震现场调查的自身安全保障、灾民恐惧心理安抚,以及震害分布、震害损失、人员伤亡等,旨在为将来5.0级左右中强破坏性地震开展现场调查和研究震害特征等提供参考。     

Evaluation of rock slope stability for Yujian River dam site by kinematic and block theory analyses

Lithological information, rock mass fracture data and discontinuity shear strength obtained through field investigations have been used to conduct kinematic and block theory analyses for the rock slopes that exist in the dam site to evaluate the stability of the slopes. The analyses were performed using mean discontinuity set orientations for each rock mass region under gravitational loading to calculate the maximum safe slope angles (MSSA) for different cut slope directions. Results show that final MSSAs obtained from kinematic analysis are less than or equal to that obtained from block theory analysis. The following conclusions have been made based on the block theory analysis results, which are closer to the reality: (1) The final MSSA range between 30° and 47°, 44° and 70°, 47° and 69° for cut slope dip directions of 20–30°, 105–210°, and 270–355°, respectively; (2) For cut slope dip directions of 20–30°, 200–210° and 275–315°, wide ranges of values have been obtained for the final MSSA reflecting the influence of variability of fracture orientations on MSSA; (3) Apart from the region R-d-1 for slope dip directions in the range 20–30°, rest of the regions at the dam site seem to be stable for slope angles less than 40°. Detailed comparisons are given between the kinematic and block theory analyses covering both the theoretical concepts and application results. Also a brief comparison is included between the laboratory and in situ discontinuity shear strength results.     

基于T639数值模式产品的雷电预报效果分析

本文应用闪电定位资料,采用TS评分方法对基于T639模式产品的雷电预报产品进行检验,得出以下结论:(1)雷电预报产品的准确率随着预报概率的提高而增加;(2)随着预报时效的提高,预报准确率有所降低,但变化幅度较小;(3)预报概率在70%的时候,预报准确率可以达到75%,预报效果较好;(4)高原地区的雷电预报产品预报准确率较平原地区要低,预报效果相比而言较差。