南极中山站地区航空飞行的天气条件

随着中国南极考察事业的不断发展,科考工作进一步深入,南极地区不同机型的各类飞行活动将日益增多。开展南极航空气象服务是确保飞行安全,提高科考效率的迫切需求。南极冰雪高原的地形复杂,天气多变且局地性强,但是航路和场站的气象资料积累很少,航空气象服务的困难较大。本文对南极中山站地区影响飞行安全的主要天气现象,中山站地区的适航时间,天气条件等进行了初步探讨。     

北极东北航道海冰变化特征分析研究

21世纪以来,北极海冰正在发生快速变化,海冰覆盖范围明显减小,厚度显著变薄,在此背景下,东北航道的提前开通成为可能.本文对多年来北极东北航道内的海冰变化特征和近几年东北航道的开通情况进行了分析研究,认为东北航道在9月份开通的可能性最大,8月份次之,10月份通航的困难较大;历年的航道开通起始时间变化较大,俄罗斯新西伯利亚群岛和北地群岛,与大陆之间的海冰对东北航道的开通起着关键作用.东北航道的海冰年际变化较大,这给未来东北航道使用带来了较大挑战.     

New magnetic data of the southern East China Sea and some geological interpretations

In September and October of 2011, a marine magnetic survey was conducted in the southern East China Sea between 120° and 126°E, 26° and 28°N with the research vessel Kexue-3. New magnetic maps with 5 × 5 km grid spacing were generated after meticulous data processing. Based on an analysis of magnetic anomaly features and further calculation results, including the total horizontal derivatives (THD), second order vertical derivatives (SVD) and analytic signal amplitude (ASA), several new tectonic insights on magnetic sources, basement structures and fault properties were obtained. The NE-SW or NNE-SSW oriented magnetic anomaly highs have different sources: (1) The high amplitude, short wavelength magnetic anomalies of the Zhemin Uplift are caused by shallow buried igneous rocks intruded along NE-NEE oriented faults. (2) The high amplitude, moderate wavelength magnetic anomalies of the Diaoyudao Uplift are caused by the metamorphic basement intruded by magmatic rocks. (3) The magnetic sources of the Yandang Uplift and Taibei Uplift in the shelf basin are shallow buried metamorphic basements and deep buried volcanic bodies, respectively. Several NW-SE or NWW-SEE oriented dextral strike-slip fault belts were identified as important tectonic boundaries. Each is composed of several en echelon and partly overlapping secondary faults. Initially formed in the Cretaceous, these fault belts have evolved through multiple periods, propagated seaward with the migration of the basement rifting and accommodated local stress fields in the Cenozoic.     

Deposition rate and interaction of human-riverine from height increase and permanent function of an 1180 years weir in Southeast China

This paper is to present an efficient approach to enriching the quantification model of human-riverine interactions and its anthropogenic impact by a retrospective study on one of the four most famous historical hydraulic projects in China,the Tuoshan Weir.It was constructed in 833 AD and had trajectories of natural resilience and hydraulic engineering maturity more than thousand years.Extensive historical data and maturation procedure of the hydraulic system were used judiciously to examine the spatial patterns of the long-term water conservancy system with agriculture,urbanization and civilization of Ningbo City in Zhejiang Province,Southeast China.Interaction framework is assessed from historical perspective and the deposition rate(DR)is calculated by analyzing the continuous increase of the Tuoshan Weir height.The results show that the declining DR during the 1180 years guaranteed the beneficial role the Tuoshan Weir played in spite of some negative river responses caused by the increase of sediment deposition and decrease of fresh water-retention capacity.The following up revamped workings and well matured hydraulic system around the Tuoshan Weir also contribute a lot to the designed mission of the weir.We conclude that hydraulic system maturation is very important for the proper function and life span of huge hydraulic projects.     

高地应力区砂岩在卸荷条件下的变形参数劣化试验研究

以锦屏某高边坡砂岩所赋存的高地应力环境为基础,开展峰前卸围压力学特性试验,研究了应力-应变全过程曲线、变形特征及参数劣化效应。试验结果表明,相对于加载试验,岩样卸荷破坏表现出明显的脆性特征,相同初始围压下卸荷破坏所需偏应力较加载试验少;卸荷过程横向应变和体积应变急剧增大,卸荷方向表现出明显的扩容特征;当初始围压小于某一值（30 MPa）,岩样破坏所需卸荷量随初始围压增大而增大,当初始围压达到一定值（40 MPa时）,脆性特征更加明显,很少的卸荷量即可引起岩样破坏。以表征岩石卸荷程度的卸荷量H为参变量,分别对高、低围压下卸荷过程中变形参数（变形模量和泊松比）随卸荷量变化关系进行拟合,得到高、低地应力区卸荷过程中变形劣化参数的关系式。试验结果和计算方法对高应力区边坡开挖的稳定性评价具有一定指导意义。     

滑坡治理稳定状态的耦合权重综合评价方法

针对滑坡治理以后的稳定状态综合评价问题,从影响因素多因子多层次角度出发,构建综合评价决策模型,提出了滑坡治理稳定状态综合评价的耦合权重确定方法,即基于优先关系排序-二元相对比较的权重计算确定方法,以避免一致性检验,减少评判的主观性,还采用程序编程语言编制了相应计算分析程序。在此基础上,结合杭金衢K103滑坡的地形地质条件和工程治理情况,采用基于耦合权重的滑坡治理稳定状态综合评判方法,进行其历经治理的稳定状态分析和效果评价。研究结果表明：滑坡历经综合治理,所处的稳定状态等级区间为基本稳定状态（E_II）;各项工程措施充分发挥功能效应,稳定系数由0.98提高至1.20,滑坡整体稳定,安全储备充足。     

从水井岩大型滑坡表面高温降解喷出物特征到汶川地震天然气体溢出爆炸模型

汶川大地震中XI级烈度区内水井岩滑坡现场等地爆炸声、特大型滑坡现场巨大环形坑和远距离抛射碎石等记录和现象,需给出科学解释。在地震发生后多次现场地质调查和走访、样品采集和多项分析测试及其结果比较等基础上,对主中央断裂F₂控制的下盘陈家坝水井岩大型滑坡体上环形坑周边不同距离范围内散落烧焦残留的硅酸盐和碳酸岩等采样后,开展了物质成分和微观结构分析。结果发现：与原生溶蚀灰岩、薄层煤岩结构和有机质成分不同,这些抛散在滑体表面的样品中富含经强烈高温作用的块石,一些成分以锰碳酸盐岩等为主的暗棕色样品中稠环芳烃是其经历过强烈热作用过程而使有机质发生环化芳构化反应的结果,即样品经过了强烈热降解作用,显示其形成时出现强烈热作用过程和高温裂解现象。结合本区地质构造特征和煤层气分布情况、地震后实施的汶川地震带深钻在穿越主中央断裂带F₂深度处监测到余震过程中甲烷含量异常增高、东河口地震遗址公园发现温泉及天然气溢出等资料和研究结果,讨论了地震诱发的富含甲烷的天然气爆炸,其加剧或伴生着地震次生地质灾害。由此推测：与碳质岩或煤系共存的喀斯特溶洞中封闭煤层气在地震过程中突溢和爆炸燃烧,叠加或放大了地震作用,结果在滑坡堆积体表面残留了多处环形爆炸坑,引发了一些岩块大规模长距离水平抛撒等。研究结果对监测和认识发震断层带在地震过程中天然气爆炸诱发和加剧滑坡灾害有重要意义。     

平推式滑坡启动判据的修正

对平推式滑坡启动判据的传统研究往往忽略滑块后缘的静水压力沿滑面法向的分力及承压水作用的具体范围,因而导致计算结果不准确。通过对平推式滑坡进行全面的受力分析,同时引入了承压水作用范围的概念,最终推导出修正后的平推式滑坡启动判据公式。将所得的修正判据应用于模型试验的结果分析,发现修正方法计算结果比传统方法大6.0%～15.5%,更加接近于试验观测值,验证了修正判据的准确性。同时对平推式滑坡启动临界水头的模型试验结果和修正计算值之间的差异进行了机理分析：当边坡模型滑动面倾角小于等于8°时,渗流的时滞性和渗透层的不均匀性导致启动临界水头实测值大于修正计算结果;当倾角大于8°时,模型稳定性随试验时间增加而逐步降低,导致启动临界水头实测值小于修正计算结果。     

从南水北调中线文物与地貌关系看全新世以来沿线人聚居条件变化

早期先民聚居和活动遗址及古墓分布受地貌类型及其与河流关系影响,在跨流域不同地区表现关系如何?本文以沿伏牛山和太行山山前地带线性展布的南水北调中线干渠两侧各3 km宽度带为个案,研究干渠沿线唐白河、淮河、黄河北、滏阳河和海河等5个区段的362处文物分布随水系及地貌单元的变化。结果发现,干渠沿线先人多聚居在缓坡地和岗地,其次是冲洪积扇和微倾斜平原。石器时代遗址基本在大河二级支流、河流二级阶地上,高出河床10~20 m左右。文物总数与调查干渠线路长度大致成正比,沿线路分布密度约0.5处/km。淮河-黄河北区段文物较集中且新石器遗址数量与线路长度大致成正比,沿线路分布密度约0.2处/km;海河区段文物密度相对较低。不同时代(7个时期)文物占比表现出一些共性特征,如战国至南北朝文物占比最高的在黄河北和滏阳河区段,分别为30%和41%,而明清文物占比较高的为海河和唐白河区段,分别为32%和44%。战国后太行山山麓带渐变干旱,黄河以北海河以南的华北平原西部湖区与山麓之间聚居遗址增多。上述结果为南水北调中线干渠规划设计中合理避让、科学保护和适量发掘文物供了一定依据.     

基于遥感影像的祁连山区俄博岭热融滑塌发育特征

热融滑塌是山地多年冻土退化最直接的表现形式之一,通过解译祁连山俄博岭地区遥感影像,结合实地考察,对俄博岭热融滑塌的空间分布和时间变化进行了研究,明确了热融滑塌的发育特征。结果表明,俄博岭热融滑塌发育活跃,1997~2015年热融滑塌数量增加(11~13个),面积增大(7765~20605m^2),其中1997~2009年面积增加速率为679.9m^2/a,2009~2015年面积增加速率为780.2m^2/a。通过分析热融滑塌景观分布与地形因子的关系,发现俄博岭热融滑塌在海拔3570~3700m,坡度3°~10°的富冰多年冻土区北向斜坡发育;通过对典型热融滑塌溯源后退速率分析发现,1997~2009年其平均后退速率为2m/a,2009~2015年平均后退速率为5m/a,呈明显增大趋势,且其后退速率主要与坡度、地下冰含量和地表径流相关。