危岩失稳模式分类研究

近年来,重庆地区开展的大量危岩防治工作表明,现有的危岩分类方案缺乏统一的定义和内涵,使用中容易出现混淆和争议,同时,还存在危岩无类可归的现象。针对现有危岩分类方案的不足,本文在分析和总结国内主要危岩分类方案的基础上,结合近年来发生的典型危岩崩塌事件的调查成果,对危岩分类问题进行了研究。首先,根据危岩破坏时的初始运动方式,将危岩分为倾倒式、滑移式、错断式、悬挑式、坐落式和坠落式等6类,并根据危岩结构面组合特征及影响因素的差异,进一步细分为11个亚类;其次,对各类危岩的定义、主控结构面位置及发育特征、形成条件及影响因素、变形机理进行了细致的界定和总结,最后,结合典型危岩崩塌实例进行简要的分析和说明。新的危岩分类方案类型全面,定义明确,界限清晰,实用性较强,可以有效地指导危岩勘查评价、监测预警以及防治工作的开展。     

对“白加白”改造旧水泥砼路面实施方案的探讨

G318怀宁段路面改善工程设计方案为旧水泥砼路面加铺水泥砼路面(简称"白加白"),在安庆市公路系统尚属首次实施,在我省亦无成功的实践经验可直接借鉴。为此,安庆市公路局专门成立了科研小组,并与浙江大学合作,以"白加白改造旧水泥砼路面方案的研究"为课题,将G318怀宁段作为实践项目,申报2010年度安徽省交通科技项目。笔者作为小组三位主要成员之一,全过程参与该项目的建设与管理。现就该方案的实践成果进行一次全面系统的总结,并就有关技术问题进行探讨。     

The Best Natural Boundary:a New Concept Developed by Combining the Sequence Boundary with the GSSP

Through a detailed study of sequence boundaries, it is concluded that sequence stratigraphy is an independent regional and transitional stratigraphic system between local lithostratigraphy and global chronostratigraphy. Therefore, a new tripartite stratigraphic classification scheme has been proposed. By combining organically the concept of sequence boundaries with the GSSP, it is suggested that the GSSP should be chosen in a conformale portion of a related sequence boundary, and the boundary established in light of this concept is defined as the Best Natural Boundary (BNB). The definition of the BNB points out the working area and stratigraphic level for the GSSP. By referring to a case study of the Permian Guadalupian/Lopingian boundary, the concept of the BNB has been elaborated in detail, and it is proposed that the BNB of the Guadalupian and the Lopingian lies between the Mesogondolella granti Zone and the Ctarkina postbitteri Zone, which is also the sequence chronostratigraphic boundary between th     

Mesoscale numerical simulation study of warm fog dissipation by salt particles seeding

Based on the dynamic framework of WRF and Morrison 2-moment explicit cloud scheme, a salt-seeding scheme was developed and used to simulate the dissipation of a warm fog event during 6–7 November 2009 in the Beijing and Tianjin area. The seeding effect and its physical mechanism were studied. The results indicate that when seeding fog with salt particles sized 80 μm and at a quantity of 6 gm~(-2) at the fog top, the seeding effect near the ground surface layer is negative in the beginning period, and then a positive seeding effect begins to appear at 18 min, with the best effect appearing at 21 min after seeding operation. The positive effect can last about 35 min. The microphysical mechanism of the warm fog dissipation is because of the evaporation due to the water vapor condensation on the salt particles and coalescence with salt particles.The process of fog water coalescence with salt particles contributed mostly to this warm fog dissipation. Furthermore, two series of sensitivity experiments were performed to study the seeding effect under different seeding amounts and salt particles sizes. The results show that seeding fog with salt particles sized of 80 μm can have the best seeding effect, and the seeding effect is negative when the salt particle size is less than 10 μm. For salt particles sized 80 μm, the best seeding effect, with corresponding visibility of 380 m, can be achieved when the seeding amount is 30 g m~(-2).     

EOF迭代方案恢复夏季大气环流场的试验

本文设计了一种恢复夏季大气环流场的EOF(经验正交函数)迭代方案,并利用1951～1984年中国夏季降水距平场和北半球500hPa夏季高度距平场作镢复试验,数值试验效果较好.此项工作表明:利用某些长时间序列的资料通过EOF迭代方案恢复历史时期大气环流是可行的.     

回溯时间积分格式的有效性研究

采月正压准地转模式作为动力核,用Rossby-Haurwitz波函数作为理想场,同时使用回溯时间积分格式和普通中央差格式进行数值试验.结果表明,在短时积分的情况下,回溯格式能减小数值解误差1～2个量级,而且它对时间步长的增大不敏感.因此使用回溯格式可以减少积分计算量,延长积分时效.     

面向大区域遥感专题制图的自动化策略

如何消除相邻影像间的信息冗余是实现大区域遥感自动化制图的关键。本文提出了一种基于约束接缝线的区域分块自动化制图方法,首先采用全球通用墨卡托投影-UTM投影的网格带将研究区分为若干小区域;然后,针对每个UTM投影带内的遥感影像,采用影像镶嵌的原理和湖泊边界约束条件计算其接缝线网络,以确定每景遥感数据制图范围;最后,根据其制图范围生成对应的无冗余专题信息,减少计算量和相邻影像重复信息的编辑时间。本文以亚洲中部干旱区为例开展湖泊制图试验,结果证明该方法能够生成顾及湖泊的有效制图范围,提高了遥感大区域制图的效率。     

Introducing a transferable fishing day management regime for Pacific Island countries

On 1 December 2007, eight ‘Small Island Developing States’ in the Western and Central Pacific Ocean implemented a management regime restricting the total number of days fished by tuna purse seine vessels within their waters, commonly referred to as the Vessel Day Scheme (VDS). The VDS is seen as one component of management arrangements to reduce fishing mortality on bigeye and yellowfin tuna, constrain fishing effort, and increase the rate of return from access fees by Distant Water Fishing Nations.     

地震与强降雨作用下堆积体滑坡变形破坏机理及防治方案分析

位于西南山地堆积体滑坡常受到地震和强降雨的双重作用,查明此类滑坡变形破坏机理是地质灾害防治和风险防控的基础。文章的研究对象是鲜水河断裂带附近的炉霍县马居滑坡。研究表明,地震作用对位于斜坡地带堆积体滑坡体结构损伤明显,不但使滑坡整体稳定性下降,还促使坡体内裂隙大量发育,利于降雨入渗,进一步恶化滑坡的水文地质条件。强降雨形成的大规模洪水和泥石流下切坡脚沟道,牵引滑坡体整体向下。长历时强降雨入渗影响坡体稳定性,且在降雨结束后较长时间持续影响坡体稳定性。因此,对此类滑坡防治的对策应考虑坡脚防护和抗滑支挡设置。在对防治方案的有效性分析后,表明防护方案在极端条件下仍然能保障安全性,达防治和风险管控的目的。