多年冻土地区机场跑道修筑技术现状

我国分布有大面积的多年冻土, 根据我国机场建设的中长期规划, 未来将在多年冻土区修建大量机场, 这些机场的修建将不能避免多年冻土问题. 国内关于冻土区机场跑道修筑的经验非常有限, 国外则开始的较早, 并积累了一些经验. 总结分析国内外多年冻土区机场跑道修筑技术的现状, 其跑道类型主要有: 基岩跑道、开挖换填法修筑的跑道、铺设隔热层的跑道、安装热管的跑道, 共4类. 由于我国多年冻土区的特殊性, 国外的跑道修筑经验只能在一定程度上参考. 由于飞机跑道不同于铁(公)路的特殊性, 近年国内在冻土区铁(公)路的修建过程中采用的稳定冻土地基的工程措施如何应用到机场跑道的建设上, 仍需进一步研究、验证和实践. 将来在我国多年冻土区修建机场跑道, 应结合国外已有的技术和经验, 并以我国在多年冻土区线性工程中已取得的经验作为基础, 进一步研究我国多年冻土区机场跑道修筑的关键技术.     

黑龙江省漠河地区土地覆被与地表温度时空变化特征研究

以我国高纬度多年冻土区漠河县城区及郊区862 km²的区域为研究对象,基于RS和GIS技术对该区地表覆被变化和地表温度进行研究。结果表明：地表类型和地表温度反演结果与现场比对结果一致;从1988年到2015年,经过火灾后重建和城镇化发展,建设用地面积增加了11.33 km²;以2015年为例,冬季由于积雪覆盖,有79.02%的区域无植被覆盖,夏季有80.91%的区域为高植被覆盖。冬季地表温度和高程具有高度相关性,高程每升高100 m,地表温度平均升高2.27℃,表明该区地表温度也存在显著的逆温现象。该区城镇热岛效应全年存在,城镇区域地表温度高于全区平均值,夏季最显著,最高温差可达6.37℃。地表温度与NDVI具有明显的负相关关系;不同土地利用类型地表温度由低到高的顺序为水体-林地-草地-裸地-建筑用地。     

Chronology and Geochemistry of the Berezitovoe Polymetallic Gold Deposit in Eastern Siberia, Russia and its Geological Significance

The Berezitovoe deposit is a large-sized Au-Ag-Zn-Pb deposit in the east of the SelengaStanovoi superterrane, Russia. Au-Ag orebodies are hosted by tourmaline-garnet-quartz-muscovite metasomatic rocks; Zn-Pb orebodies are hosted by granodiorites, porphyritic granites and tourmalinegarnet-quartz-muscovite metasomatic rocks. These orebodies are surrounded by wall rocks dominated by the Tukuringra Complex granodiorites, porphyritic granites, and gneissic granodiorites. The alteration includes silicification and garnet, sericitization chloritization, carbonatization and kaollinization. LA-ICP-MS U-Pb zircon dating indicates that the gold mineralization can be divided into two stages in the Berezitovoe polymetallic gold deposit(at 363.5 ± 1.5 Ma, and133.4± 0.5).Hornblende-plagioclase gneisses of the Mogocha Group in the study area underwent Paleoproterozoic metamorphism(at 1870 ± 7.8 and 2400 ± 13 Ma), gneissic granodiorite of the Tukuringra Complex yields a late Paleozoic magmatic age(at 379.2 ± 1.1 Ma),and subalkaline porphyritic granitoid of the Amudzhikan Complex yield late Mesozoic magmatic ages(133-139 and 150-163 Ma). Granodiorites of the Tukuringra Complex in the study area have high concentrations of SiO_2(average of 60.9 wt%), are aluminum-oversaturated(average A/CNK of 1.49), are enriched in the large ion lithophile elements(e.g.,K, Rb, and Ba), U, Th, and Pb, are depleted in high field strength elements(e.g., Ta, Nb, and Ti), and have slightly negative Eu and no Ce anomalies in chondrite-normalized rare earth element diagrams.Fluid inclusions from quartz veins include three types: aqueous two-phase, CO_2-bearing three-phase,and pure CO_2. Aqueous two-phase inclusions homogenize at 167℃-249℃ and have salinities of 4.32%-9.47% NaCl equivalent, densities of 0.86-0.95 g/cm~3, and formed at depths of 0.52-0.94 km. In comparison, the C0_2-bearing three-phase inclusions have homogenization temperatures of 265℃-346℃,salinities of 7.14%-11.57% NaCl equivalent, and total densities of 0.62-0.67 g/cm~3. The geochemical and zircon U-Pb data and the regional tectonic evolution of the study area, show that the Berezitovoe polymetallic gold deposit formed in an island arc or active continental margin setting, most probably related to late Paleozoic subduction of Okhotsk Ocean crust beneath the Siberian Plate.     

2009年日本骏河湾地震后东海俯冲带上应力转移之探讨

日本西南部位于菲律宾海俯冲板块和欧亚上冲板块交界处。1944年和1946年,东南海和南海分别发生一次8级大逆冲型地震,但与该板块边界相邻的东海却仍保持闭锁状态[1]。因此,东海地区有可能会发生一次大逆冲型地震。2009年,骏河湾发生6.4级地震,地震位于菲律宾海俯冲板块内,靠近东海地区。在此,我们利用断层滑动模型来研究由骏河湾地震引起的应力变化[2]对东海地区的影响。我们发现在这次地震之后,板块边界的地震活动发生率有所上升。东海地区推测的强闭锁地段大都位于应力逐渐增大的地区。其中一小块闭锁地段的破裂——发生在地震应力达到临界值之后——就会引起整个东海地区的破裂,最终引发一场大逆冲型地震。     

Mechanical and low-cycle fatigue behavior of stainless reinforcing steel for earthquake engineering applications

Use of stainless reinforcing steel (SRS) in reinforced concrete (RC) structures is a promising solution to corrosion issues. However, for SRS to be used in seismic applications, several mechanical properties need to be investigated. These include specified and actual yield strengths, tensile strengths, uniform elongations and low-cycle fatigue behavior. Three types of SRSs (Talley S24100, Talley 316LN and Talley 2205) were tested and the results are reported in this paper. They were compared with the properties of A706 carbon reinforcing steel (RS), which is typical for seismic applications, and MMFX II, which is a high strength, corrosion resistant RS. Low-cycle fatigue tests of the RS coupons were conducted under strain control with constant amplitude to obtain strain life models of the steels. Test results show that the SRSs have slightly lower moduli of elasticity, higher uniform elongations before necking, and better low-cycle fatigue performance than A706 and MMFX II. All five types of RSs tested satisfy the requirements of the ACI 318 code on the lower limit of the tensile to yield strength ratio. Except Talley 2205, the other four types of RSs investigated meet the ACI 318 requirement that the actual yield strength does not exceed the specified yield strength by more than 18 ksi (124 MPa). Among the three types of SRSs tested, Talley S24100 possesses the highest uniform elongation before necking, and the best low-cycle fatigue performance.     

固体废弃物管理不当对地下水产生的影响

倾倒垃圾处形成的淋漓液中包含大量的可能造成地下水污染的物质。这些区域对地下水的影响可以通过在特定监测点监测潜在的污染物浓度来判断。本研究中,我们对Chennai地区城市固体废物垃圾场周边的地下水水质进行了调查。在3年间每间隔3个月,由垃圾填埋场开始,选择不同距离的水样进行化学分析。研究表明,这些区域地下水不能满足印度标准局的饮用水标准。垃圾倾倒对地下水的影响最早表现在溶解物浓度、电导率、总体硬度、氧化物、化学需氧量、硝化剂及硫酸盐。在这些位置的淋漓液还包含重金属。在雨季后,污染物浓度趋于下降,而在雨季前,很多样品的污染浓度会增加。早期研究表明,在人口密集城市中,应该设有依据某种规范的地下水监测系统。进而,垃圾垃圾场及周边的地下水不应作为饮用水,除非满足某种特殊的标准。在发达地区,未经严格固体废物管理许可而随意倾倒垃圾的行为应到受到禁止。     

Temporal and spatial variation in the sediment volume along the beaches between Ovari and Kanyakumari (SE INDIA)

A 2-year set of profile data from Ovari to Kanyakumari Beach,SE India has been analysed by using empirical orthogonal function(EOF) techniques to identify characteristic patterns of temporal and spatial variation in the sediment volume of the beaches.The results show that variation in the sediment volume of the beach is determined by interaction between the biennial and seasonal exchanges.EOF analysis the pattern of alongshore sediment exchange along the study area.The method facilitated separation of onshore-offshore and alongshore modes of sediment transfer and identification of the patterns of alongshore sediment exchange.The eigenfunction modes confirm the dominance of biennial,annual,and biannual sediment transfers occurring on study area.The sediment movement along the shoreline of study area is mainly governed by the forces associated with the incoming waves and the availability of sediments within the area.The present investigation has been made as an attempt to appreciate the sediment movement in relation to wave activity along the coast.The longshore sediment transport is intensive in the northerly direction as compared to southerly direction.The normal condition is for and to be moved annually or more frequently in the shallows and on the beach.Waves and wave-driven currents cause longshore drift of sand along the beach and offshore.     

Tectonic and climatic controls on late Quaternary bajada sedimentation along Narmada-Son Fault(NSF),Gujarat,Western India

An alluvial bajada has been recognized along a part of the active Narmada-Son Fault(NSF) and confined by the Karjan River on the eastern side and by the Madhumati River on western side.The bajada sequence exposed along the incised cliffs of various north flowing parallel streams has been studied in their proximal,medial and distal part. The sediments are characterized on the basis of grain size,fabric,sedimentary structures,bed geometry and sorting, and lithologs prepared from the mapped cliff sections.Detailed study of sedimentary characteristics,lithofacies analysis and facies associations indicate that sediments are mainly of three types-sediments that were deposited by debris flows and sediment gravity flows,and as extensive bar deposits.Three major aggredational sequences are recognized.Each sequence is composed of coarsening-upward sequence of proximal facies overlain by fining-upward sequence of distal facies.Coarsening upward sequence record periods of tectonic activity related to uplift along the NSF and fan progradation,whereas fining-upward sequence results from tectonic quiescence periods.The presence of rhizocretions,calcium carbonate nodules and calcite sheets within the basal debris flow and sediment gravity flow indicate semi-arid climate,whereas the formation of pedoginized paleosol indicate relatively wetter climate prevailing in the study area.Tectonic activity along the NSF has played dominant role by controlling the geometry and volume of bajada sediments.Climate is found to be responsible for compositional and temporal distribution of bajada sediments.OSL dating suggests that the bajada sediments were deposited during the later part of late Pleistocene.The incision of the sediments is attributed to uplift due to inversion of the lower Narmada basin during the early Holocene.     

2011年5月11日西班牙东南洛尔卡Mw5．1地震诱发的大范围滑坡

2011年5月11日,一个中等震级地震（Mw5．1）袭击了西班牙东南部洛尔卡城和邻近地区,造成了显著的破坏和人员伤亡。通过地震影响区的野外考察对250多处主要是碎裂型（岩／土崩塌、碎裂的土质滑坡和岩崩）诱发滑坡进行了定点和特征描述。与以前该区域相似震级（Mw4．7～5．0）的地震事件,以及以前预测地震期间斜坡表现的模型结果相比,本次地震诱发滑坡的数量相当大。提出了几个原因来解释这种差异：（1）地震序列中相对高震级（Mw4．5）的前震可能弱化了区域内的斜坡强度;（2）这些事件产生了高的地震动峰值;（3）发生了地形场地效应。本研究的结果指出了在改进区域斜坡特征研究模型时考虑这些影响的重要性。