Changes of precipitation extremes over South Korea projected by the 5 RCMs under RCP scenarios

The change of extreme precipitation is assessed with the HadGEM2-AO - 5 Regional Climate Models (RCMs) chain, which is a national downscaling project undertaken cooperatively by several South Korean institutes aimed at producing regional climate change projection with fine resolution (12.5 km) around the Korean Peninsula. The downscaling domain, resolution and lateral boundary conditions are held the same among the 5 RCMs to minimize the uncertainties from model configuration. Climatological changes reveal a statistically significant increase in the mid-21st century (2046- 2070; Fut1) and the late-21st century (2076-2100; Fut2) precipitation properties related to extreme precipitation, such as precipitation intensity and average of upper 5 percentile daily precipitation, with respect to the reference period (1981-2005). Changes depending on the intensity categories also present a clear trend of decreasing light rain and increasing heavy rain. In accordance with these results, the change of 1-in-50 year maximum precipitation intensity over South Korea is estimated by the GEV method. The result suggests that the 50-year return value (RV50) will change from -32.69% to 72.7% and from -31.6% to 96.32% in Fut1 and from -31.97% to 86.25% and from -19.45% to 134.88% in Fut2 under representative concentration pathway (RCP) 4.5 and 8.5 scenarios, respectively, at the 90% confidence level. This study suggests that multi-RCMs can be used to reduce uncertainties and assess the future change of extreme precipitation more reliably. Moreover, future projection of the regional climate change contains uncertainties evoked from not only driving GCM but also RCM. Therefore, multi-GCM and multi-RCM studies are expected to provide more robust projection.     

A robust algorithm for ellipse-based discrete element modelling of granular materials

With recent research indicating the importance of the rolling mechanism of deformation in granular systems consisting of perfectly round particles, it has become popular to use ellipse-shaped particles in the Discrete Element Method (DEM) numerical model. Inherent in this technique is the need for accurately computing ellipse to ellipse intersection, in order to properly detect contact formation and compute relative contact velocities. However, the commonly used algorithms for computing ellipse-ellipse intersection are generally poorly conditioned and can be inaccurate. An alternate method for computing ellipse-ellipse intersection is developed and presented which results in a well-conditioned, stable and accurate contact detection method. These modification are incorporated into the general DEM algorithm.     

岩体中泥化夹层的流变试验及其长期强度的确定

文中首先介绍两种室内试验设备--单剪流变仪和剪应力松弛仪（松弛流变仪）及其试验方法,然后根根岩体中泥化夹层的试验成果,证实陈宗基教授提出的最高屈服值f3--强度的临界值即长期强度值,工程设计要重视它。     

“95.8”川西大暴雨成因分析

通过对“９５．８”大暴雨过程的全面技术总结，揭示了多种尺度系统间相互作用对产生大暴雨过程的贡献，并指出了云团的发生及其发展源于北方冷空气和南方低空急流持续影响所形成的两个中间尺度垂直环流。     

云南南洞地下河系统及水资源开发利用

南洞地下河系统,流域面积986km2。年迳流总量2.988亿m3,是南盘江支流——芦江河的重要补给水源,流域由岩溶高原、断陷盆地,盆间丘陵几部分组成。中三叠统个旧组（T2g）灰岩是主要含水层位。地下河系统由多条地下河组成,是早期南洞地下河与大黑水洞地下河经后期发展、演化、归并袭夺而形成。虽水文地质条件十分复杂,但资源丰富,开采潜力巨大,磨石沟地下筑坝,是最优的开发方案。     

煤岩的显微构造特征及其与瓦斯突出的关系——以南桐鱼田堡煤矿为例

煤瓦斯突出与煤岩显微结构构造密切相关。除部分显微结构构造与成煤阶段的环境等有关外,大部分都是构造变形的结果。因此,我们从构造变形类型和特点来划分煤岩显徽构造类型,既简便又利于应用。根据四川南桐鱼田堡煤矿4号及6号煤层的扫描电子显微镜研究,可将煤岩划分成5类:非构造煤、微裂隙煤、微劈理煤、碎裂构造煤和糜棱构造煤。文中详述了各类煤的特点,指出它们所代表的构造意义,并讨论了它们与瓦斯突出的关系。还特别提出糜棱构造煤的一系列塑性变形特征。得出结论:若其他条件均具备,有糜棱构造煤产出的地段,就可能是瓦斯突出最危险的部位。此外,根据观察煤瓦斯突出后的煤岩显微构造变化,提出有关瓦斯突出的过程,并探讨了煤瓦斯突出机理。在瓦斯突出过程中,已经历过塑性变形的煤岩又叠加了脆性变形,因而发生大量煤“粉尘”随突出而抛出。     

黑河出山径流量年际变化特征和趋势研究

根据有关水文气象台站的观测数据,利用定级分类,滑动平均和波谱分析等方法,对黑河出山径流（莺落峡水文站）年际变化特征进行了分析研究,发现黑河出出径流的多年变化具有持续性,周期性和丰枯水变化较平稳,波幅不大等特性,并在此基础上对其未来变化的趋势进行了预测和分析。     

建筑结构监测与抗震韧性评估

建筑结构响应是有效反映结构动力特性的最直接参数,开展结构动力响应实时监测可为结构抗震韧性评估提供准确的地震动输入。本文基于非结构构件损失构建结构抗震韧性评估方法,研究确定位移敏感型和加速度敏感型非结构构件的易损性模型。选择某六层钢筋混凝土框架结构进行实时监测系统建设,基于监测数据开展结构抗震韧性评估。通过构建建筑信息模型（BIM）,并在有限元分析软件OpenSees中建立结构弹塑性分析模型,利用实时监测数据实现结构模型更新,直至监测数据与模型分析结果一致。由于实时监测数据峰值较低,结构不会发生塑性变形,因此选择10条双向非脉冲地震动模拟实时监测地震记录。根据层间位移角和楼面加速度分布,开展结构功能损失评估,得到该建筑结构的抗震韧性得分。分析表明,该结构抗震性能较好,在遭受地震破坏后,会发生非结构构件脱落,需要采取有效措施进一步提升建筑抗震韧性水平。