栗子坪水电站南桠村沟泥石流运动特征研究

南桠村沟位于南桠河栗子坪水电站首部枢纽区左岸，是水电站工程区内规模较大的一条泥石流冲沟，历史上曾经发生过较大规模的泥石流。水电站调节池位于南桠村沟的出口台地上，沟内第四纪松散堆积物及人工堆积物丰富，在暴雨，地震等自然因素的触发下，时有较大规模的泥石流发生的可能，对调节池的运行安全带来不利影响。笔者根据国内外有关研究成果，结合南桠村沟泥石流的具体特征，分析研究了南桠村沟泥石流的运动特征，包括泥石流的流速、流量、和冲击力，这一研究对评价南桠村沟泥石流对栗子坪水电站调节池的影响具有现实意义。     

黏土颗粒含量对蒋家沟泥石流启动影响分析

黏土颗粒在泥石流中的含量并不大,但却显著地影响着泥石流的启动。在室内通过筛分配成9种不同黏粒含量级配的土体,在自行设计的模型槽内以1.64 g/cm3（松散干密度）,1.79、1.94 g/cm3（天然干密度）3种干密度堆成边坡模型,在雨强为85 mm/h下进行人工降雨试验,初步探讨了黏土颗粒含量对泥石流启动的影响,得到：黏粒含量在5%～18%时可以形成泥石流,其中黏粒含量10%时所需时间最短,低于5%或大于18%难以形成泥石流,黏粒含量具有临界性;填筑干密度越大,泥石流启动越困难,表现在启动时间长、深度浅、规模小、且填筑干密度不改变黏粒含量临界性;降雨条件下土体入渗率越高,泥石流越容易启动产流。通过试验的研究,可以深入揭示泥石流形成的内在机制,黏粒含量临界性为泥石流预测、预报提供了新思路。     

泥石流异重流入海的研究

1999年委内瑞拉瓦加斯（Vargas)乌里亚（Uria)发生的大规模泥石流将海岸线向海中推进了200m。这是一种异重流现象。泥石流流入海中并在海中沉积下来，其头部沉积位置距原海岸线已远大于200m，泥石流在海中的沉积物还将改变海底地貌。本通过实验研究得出了异重流的潜入点规律，水面和水下堆积扇规律。     

西藏浪卡子至洛扎公路沿线的泥石流及其防治

特殊的地理位置,复杂的地质构造,丰富的松散固体物质,陡峭的地形加上降水集中的气候,为泥石流的发生创造了客观条件。西藏浪卡子至洛扎公路沿线发育泥石流42条,影响线路总长3 611 m,为山坡、粘性、稀性或过渡型泥石流,其危害主要是淤埋公路。结合当地的环境和公路的等级,主要采用过水路面、涵洞等疏排措施进行治理。     

河南卢氏县罗家沟泥石流灾害及其防治

通过对罗家沟地形地貌、暴雨特征、流域面积、地层岩性、地质构造、水文地质条件、泥石流物源的调查与分析研究,针对该泥石流具有危险性高、流量大、流速缓的特点,结合受灾害对象及其分布区域与整体布局的关系,按照防治结合、因地制宜、重点突出的原则设置了以排为主、挡土墙、排导槽、防护堤加板涵的综合治理方案。     

交叉隧道塑性区分布规律、成因及支护探讨

在既有隧道区间上方近距离进行新车站的施工,是地下工程研究中难度较大的问题。本文运用数值模拟方法对北京市地铁五号线东单站上跨地铁一号线,采用浅埋暗挖法施工过程中隧道塑性区分布问题进行了研究,得出在杂填土、砂土、粘土互层条件下大跨度车站底板受既有线存在的影响其塑性区基本以车站轴线为对称轴的矩形分布、既有隧道区间塑性区不同部位的变化幅度,其中以两侧壁最大,并进行了锚杆支护模拟,保证了土体的稳定。     

地震灾区新建蒲虹公路弃土泥石流成灾特征与防治建议

蒲虹公路是地震灾区的一条灾后新建公路。公路外边坡堆放有大量的弃土,在强降雨的作用下易转化为泥石流。此类现象受到研究者的关注。本文通过对弃土场的分布、组成及成灾特征的研究,提出了科学合理的处理方法。弃土泥石流形成模式包括:(1)沟道内弃土场在沟道洪水侵蚀作用下产生泥石流或土体溜滑形成泥石流;(2)坡面上弃土场滑动,表面液化形成局部坡面泥石流;(3)沟道两侧弃土场的基脚被侵蚀,形成滑坡堵河后溃决形成泥石流。弃土泥石流的成灾特征主要为弃土泥石流翻越挡墙或摧毁挡墙,堵塞涵洞或排水口,淤埋公路,威胁居民点等,它的处置需要特别注意排水,并平整压实,恢复生态。     

Organic pollutants in microplastics from two beaches of the Portuguese coast

Microplastics pose a threat to coastal environments due to their capacity to adsorb persistent organic pollutants (POPs). These particles (less than 5 mm in size) are potentially dangerous to marine species due to magnification risk over the food chain. Samples were collected from two Portuguese beaches and sorted in four classes to relate the adsorption capacity of pollutants with color and age. Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and DDTs were analysed on pellets through gas chromatography mass spectrometry (GC-MS), and types of plastic were identified using Fourier transformed infra-red spectroscopy (micro-FTIR). Microplastics were mostly polyethylene and polypropylene. Regarding sizes, some fibres ranged from 1 to 5 μm in diameter and were 500 μm in length. The majority of samples collected had sizes above 200 μm. Black pellets, unlike aged pellets, had the highest concentrations of POPs except for PAHs in Fonte da Telha beach. PAHs with higher concentrations were pyrene, phenantrene, chrysene and fluoranthene. Higher concentrations of PCBs were found for congeners 18, 31, 138 and 187. Further investigation is necessary to understand the relationship between plastic degradation and adsorption for different pollutants.     

Potential Flank-Collapse of Soufrière Volcano, Guadeloupe, Lesser Antilles? Numerical Simulation and Hazards

The past history of recurrent flank collapses of la Soufrière volcano of Guadeloupe, its structure, its well-developed hydrothermal system and the current activity constitute factors that could promote a future flank collapse, particularly in the case of a significant increase of activity, with or without shallow magmatic input. To address the hazards associated with such a collapse, we model the emplacement of the debris avalanche generated by a flank-collapse event in 1,250 BC (3,100 years B.P.). We use a finite-difference grain-flow model solving mass and momentum conservation equations that are depth-averaged over the slide thickness, and a Coulomb-type friction law with a variable basal (minimum) friction angle. Using the parameter values determined from this simulation, we then simulate the debris avalanche which could be generated by a potential collapse of the present lava dome. We then discuss the region which could be affected by such a future collapse, and additional associated hazards of concern.