地下工程中的正交有限元分析方法及其应用

介绍了正交有限元试验分析方法的基本思想,并将其应用到地下工程设计方案优化中,得到了许多对工程有意义的结论;用该方法分析了某矿大洞室的锚喷参数优化和地下采场回采方案选取两个实际问题,证明该方法可以应用于处理地下工程设计中的方案优化问题。     

岩石圈塑性流动网络与多层构造变形的物理模拟

采用塑化松香作为岩石圈延性下层的相似材料，进行了板内塑性流动网络及多层构造变形的物理模拟实验。延性单层模型的实验表明，在边界挤压或“高原”重力势的作用下，依赖于延性层粘度的高低不同，主要形成剪切网络、压性褶皱以及二者过渡型式等一级构造。在延性／脆性双层模型中（脆性上层和延性下层分别相当于岩石圈上、下层），边界驱动力的远程传递，主要借助于延性下层的网络状流动，岩石圈下层（含下地壳和岩石圈地幔）的剪切网络，即塑性流动网络，控制着板内构造变形，导致脆性上层内剪切破裂网络、逆推断裂、纵向张裂以及其它次级断裂和褶皱的发育。实验还表明，上、下层之间非连续分布的软弱夹层（模拟壳内低速、高导层）并不妨碍下层塑性流动网络的扩展，但影响牵引力的向上传递及上层构造变形的强弱分布     

Structural design of buried pipelines for severe earthquakes

In order to realistically assess the seismic risk of a pipeline system, the accurate estimate of the pipe strains which depend upon structural details, pipe material, properties of the surrounding soil, the nature of the propagating wave, etc. is critical. Emphasis in this study, therefore has been placed on the analysis of a structural strain for several types of piping elements unique to the buried pipeline and also the provision of a simplified design formula which can be used practically. The purpose of this study is (a) to define the slippage factor in order to estimate the decrease in pipe strain resulting from the slippage effect, (b) to propose a simplified method to evaluate the plastic deformation of the pipeline for severe earthquakes, and (c) to derive a practical design formula for the structural strains of bent pipes.     

塑性混凝土防渗墙在山神庙水库中的应用

山神庙水库建成后一直带病运行。为解决水库的安全隐患，对水库大坝进行塑性混凝土防渗除险加固，彻底解决了水库大坝长期存在的渗漏问题，确保水库安全运行。     

Is the plastic flow uniformly distributed below the seismogenic region?

We compared the cutoff depth of seismicity in and around the Nojima fault broken by the 1995 Kobe earthquake occurring in intraplate Japan with the brittle–ductile transition depth of the widely accepted strength profile model of the crust. We successfully determined the temperature profile from borehole measurements, since almost the same geothermal gradients were observed at two boreholes located about 4 km apart from each other, and the thermal conductivity and heat production were also measured by taking numerous core samples. We found that the cutoff depth was much deeper than the transition depth under the assumption that wet granite is deformed at a strain rate of 3×10⁻¹⁵ s⁻¹. This small strain rate implies, however, that plastic flow is uniformly distributed below the seismogenic region. When the strain rate is assumed to be greater than 10⁻¹³ s⁻¹, the cutoff depth can be attributed to the transition depth. This suggests that deformation is localized in a narrow fault zone below the seismogenic region, even in the intraplate region.     

中东亚大陆塑性流动网络控制下构造变形的物理模拟

以塑化松香和干凝滑石粉浆分别作为岩石圈延性下层（下地壳及岩石圈地幔）和脆性上层（上部地壳）的相似材料,就亚洲中东部大陆在板块边界推挤作用下的构造变形进行了模拟实验。初步结果表明,本地区在印度板块和菲律宾海板块的推挤下,形成两个塑性流动网络系统,它们控制了岩石圈上层构造变形,在分布格局上大致与地震的网络状分布相对应;东北部可能存在另一规模较小、作用较弱的驱动边界及相应的网络系统,由于它的影响,导致华北北部构造带和地震带的扭曲。实验还表明,大型压性盆地的形成与岩石圈下层稳定块体的存在有关     

Prey and plastic ingestion of Pacific Northern Fulmars (Fulmarus glacialis rogersii) from Monterey Bay,California

Marine plastic pollution affects seabirds, including Pacific Northern Fulmars (Fulmarus glacialis rodgersii), that feed at the surface and mistake plastic for prey or incidentally ingest it. Direct and indirect health issues can result, including satiety and possibly leading to inefficient foraging. Our objective was to examine fulmar body condition, identify cephalopod diet to species, enumerate and weigh ingested plastic, and determine if prey number and size were correlated with ingested plastics in beach-cast fulmars wintering in Monterey Bay California (2003, n = 178: 2007, n = 185). Fulmars consumed mostly Gonatus pyros, G. onyx, and G. californiensis of similar size for both years. We found a significant negative correlation between pectoral muscle index and average size of cephalopod beaks per stomach; a significant increase in plastic categories between 2003 and 2007; and no significant correlation between number and mass of plastic compared with number and size of prey for either year.     

The red swamp crayfish Procambarus clarkii in Europe: Impacts on aquatic ecosystems and human well-being

Procambarus clarkii is currently recorded from 16 European territories. On top of being a vector of crayfish plague, which is responsible for large-scale disappearance of native crayfish species, it causes severe impacts on diverse aquatic ecosystems, due to its rapid life cycle, dispersal capacities, burrowing activities and high population densities. The species has even been recently discovered in caves. This invasive crayfish is a polytrophic keystone species that can exert multiple pressures on ecosystems. Most studies deal with the decline of macrophytes and predation on several species (amphibians, molluscs, and macroinvertebrates), highlighting how this biodiversity loss leads to unbalanced food chains. At a management level, the species is considered as (a) a devastating digger of the water drainage systems in southern and central Europe, (b) an agricultural pest in Mediterranean territories, consuming, for example, young rice plants, and (c) a threat to the restoration of water bodies in north-western Europe. Indeed, among the high-risk species, P. clarkii consistently attained the highest risk rating. Its negative impacts on ecosystem services were evaluated. These may include the loss of provisioning services such as reductions in valued edible native species of regulatory and supporting services, inducing wide changes in ecological communities and increased costs to agriculture and water management. Finally, cultural services may be lost. The species fulfils the criteria of the Article 4(3) of Regulation (EU) No 1143/2014 of the European Parliament (species widely spread in Europe and impossible to eradicate in a cost-effective manner) and has been included in the “Union List”. Particularly, awareness of the ornamental trade through the internet must be reinforced within the European Community and import and trade regulations should be imposed to reduce the availability of this high-risk species.     

岩石塑性变形条件下的Mohr-Coulomb屈服准则

传统的Mohr-Coulomb强度准则仅描述了峰值强度状态下正应力和剪应力之间的关系,作为岩石破坏的判据.本文拓展概念,提出Mohr-Coulomb屈服准则表述岩石发生塑性变形后不同应力状态下屈服面的应力应变关系.在总结实验研究的基础上建立了使用三轴压缩试验数据确定塑性参数c和φ随内变量κ变化的实验技术方法,给出了评价各向同性模型精度的参量表达以及某些测试结果.采用具有各向同性强(软)化规律的Mohr-Coulomb屈服准则,利用岩石的初始屈服、峰值屈服和残余屈服三组参数可以将全过程应力应变曲线简化表征为四直线模型,它比三线性模型有更广泛的适用性.本文的结果为工程地质数值模拟提供了理论和实验基础,具有指导意义.     

Seabirds indicate changes in the composition of plastic litter in the Atlantic and south-western Indian Oceans

I compare plastic ingested by five species of seabirds sampled in the 1980s and again in 1999-2006. The numbers of ingested plastic particles have not changed significantly, but the proportion of virgin pellets has decreased 44-79% in all five species: great shearwater Puffinus gravis, white-chinned petrel Procellaria aequinoctialis, broad-billed prion Pachyptila vittata, white-faced storm petrel Pelagodroma marina and white-bellied storm petrel Fregetta grallaria. The populations sampled range widely in the South Atlantic and western Indian Oceans. The most marked reduction occurred in great shearwaters, where the average number of pellets per bird decreased from 10.5 to 1.6. This species migrates between the South and North Atlantic each year. Similar decreases in virgin pellets have been recorded in short-tailed shearwaters Puffinus tenuirostris in the Pacific Ocean and northern fulmars Fulmarus glacialis in the North Sea. More data are needed on the relationship between plastic loads in seabirds and the density of plastic at sea in their foraging areas, but the consistent decrease in pellets in birds suggests there has been a global change in the composition of small plastic debris at sea over the last two decades.