A review of research on seismic behaviour of irregular building structures since 2002

The paper presents an overview of the progress in research regarding seismic response of plan and vertically irregular building structures. Three areas of research are surveyed. The first is the study of the effects of plan-irregularity by means of single-storey and multi-storey building models. The second area encompasses passive control as a strategy to mitigate torsional effects, by means of base isolation and other types of devices. Lastly, the third area concerns vertically irregular structures and setback buildings. Although fewer papers have been published in this last area with respect to the former ones, this state-of-the-art reports extensively on research efforts and progress into the seismic behaviour of irregular buildings in elevation to show the growing interest among specialists in the field.     

苏北盆地东部凹陷上白垩统泰州组沉积相*

苏北盆地是在晚白垩世发育起来的箕状断陷盆地。上白垩统泰州组（K₂t）为东部凹陷发育初期形成的一套碎屑岩沉积地层,自下而上总体构成由粗到细的沉积旋回。通过对区内52口探井的录井、测井和岩心资料综合分析,认为泰州组主要发育辫状河三角洲、曲流河三角洲及湖泊相3种沉积相类型,在此基础上又进一步识别出7种亚相和12种微相。泰州组分为两段,泰州组一段沉积早、中期为辫状河三角洲沉积,晚期转变为(曲流河)三角洲沉积;泰州组二段早期为深湖—半深湖沉积,中晚期为浅湖亚相。伴随湖平面的反复升降,表现出明显的多旋回性。研究区泰州组一段表现为典型的退积型三角洲沉积。通过进一步研究泰州组一段各沉积时期沉积相的平面分布及演变特征,指出在梁垛—安丰—李堡一带沉积砂体发育,是油气储集层发育的有利地区。     

塔北西部英买力地区英买2 工区古生界盐构造样式研究

盐构造研究对于油气勘探和理论研究均有着重要的意义。塔北隆起是塔里木盆地的重要勘探区块。根据地震及钻井资料,研究了塔北隆起西部英买力地区英买2 工区古生界盐构造样式、形成机制及其对区域构造的影响。塔北隆起西部古生界发育了与中寒武统膏盐岩有关的盐构造样式,包括盐丘、盐上逆断层、盐上正断层。通过相干图分析可见盐丘从底到顶展示出有规律的变化,盐底变形强的地区在顶部变形弱,而盐底变形弱的地区在顶部变形强;变形强弱的不同在相干图上表现为与周围不协调的椭圆,从盐丘底部到顶部,椭圆的长轴方向逆时针旋转了30°,反映了变形时有走滑运动的分量存在。通过演化剖面恢复,认为古生界盐构造在古生代末基本形成了现在的形态,在三叠纪断裂重新活动,伴随着生长地层发育。膏盐层的分隔作用造成了构造层次之间构造样式的不协调及其分层性特征,盐构造形成的构造裂隙控制了后期火成岩的发育部位。     

Petrogenesis and tectonic setting of bimodal volcanism in the Sakoli Mobile Belt, Central Indian shield

The Sakoli Mobile Belt comprises bimodal volcanic rocks that include metabasalt, rhyolite, tuffs, and epiclastic rocks with metapelites, quartzite, arkose, conglomerate, and banded iron formation (BIF). Mafic volcanic rocks are tholeiitic to quartz‐tholeiitic with normative quartz and hypersthene. SiO₂ shows a large compositional gap between the basic and acidic volcanics, depicting their bimodal nature. Both the volcanics have distinct geochemical trends but display some similarity in terms of enriched light rare earth element–large ion lithophile element characteristics with positive anomalies for U, Pb, and Th and distinct negative anomalies for Nb, P, and Ti. These characteristics are typical of continental rift volcanism. Both the volcanic rocks show strong negative Sr and Eu anomalies indicating fractionation of plagioclases and K‐feldspars, respectively. The high Fe/Mg ratios for the basic rocks indicate their evolved nature. Whole rock Sm–Nd isochrons for the acidic volcanic rocks indicate an age of crystallization for these volcanic rocks at about 1675 ± 180 Ma (initial ¹⁴³Nd/¹⁴⁴Nd = 0.51017 ± 0.00017, mean square weighted deviate [MSWD] = 1.6). The εNd_t (t = 2000 Ma) varies between ?0.19 and +2.22 for the basic volcanic rock and between ?2.85 and ?4.29 for the acidic volcanic rocks. Depleted mantle model ages vary from 2000 to 2275 Ma for the basic and from 2426 to 2777 Ma for the acidic volcanic rocks, respectively. These model ages indicate that protoliths for the acidic volcanic rocks probably had a much longer crustal residence time. Predominantly basaltic magma erupted during the deposition of the Dhabetekri Formation and part of it pooled at crustal or shallower subcrustal levels that probably triggered partial melting to generate the acidic magma. The influence of basic magma on the genesis of acidic magma is indicated by the higher Ni and Cr abundance at the observed silica levels of the acidic magma. A subsequent pulse of basic magma, which became crustally contaminated, erupted as minor component along with the dominantly acidic volcanics during the deposition of the Bhiwapur Formation.     

Heat transfer between a thermochemical plume channel and the surrounding mantle in the presence of horizontal mantle flow

Heat and mass transfer processes in the conduit of a thermochemical plume located beneath an oceanic plate far from a mid-ocean ridge (MOR) proceed under conditions of horizontal convective flows penetrating the plume conduit. In the region of a mantle flow approaching the plume conduit (in the frontal part of the conduit), the mantle material heats and melts. The melt moves through the plume conduit at the average velocity of flow v and is crystallized on the opposite side of the conduit (in the frontal part of the conduit). The heat and the chemical dope transferred by the conduit to the mantle flow are carried away by crystallized mantle material at the velocity v.The local coefficients of heat transfer at the boundary of the plume conduit are theoretically determined and the balance of heat fluxes through the side of the plume conduit per linear meter of the conduit height. The total heat generation rate, transmitted by the Hawaiian plume into the upper and lower mantle, is evaluated. With the use of regular patterns of heat transfer in the lower mantle, which is modeled on the horizontal layer, heated from below and cooled from above, the diameter of the plume source, the kinematic viscosity of the melt in the plume conduit, and the velocity of horizontal lower-mantle flows are evaluated and the dependences of the temperature drop, viscosity and Rayleigh number for the lower mantle on the diameter of the plume source are presented.     

Design of controlled elastic and inelastic structures

One of the founders of structural control theory and its application in civil engineering,Professor Emeritus Tsu T.Soong,envisioned the development of the integral design of structures protected by active control devices.Most of his disciples and colleagues continuously attempted to develop procedures to achieve such integral control.In his recent papers published jointly with some of the authors of this paper,Professor Soong developed design procedures for the entire structure using a design-redesign proce...     

中国东部上地幔岩石相转变及其意义

中国东部新生代玄武岩和大别-苏鲁超高压变质带中的含石榴石相橄榄岩, 带来了发生在上地幔的尖晶石→石榴石相转变和铝辉石→贫铝辉石+石榴石的重要信息, 为中国东部上地幔岩石结构分层奠定了重要基础.通过岩石学与实验岩石学的研究, 推导出发生相转变的P-T条件, 为建立中国东部大陆上地幔岩石分层结构提供了重要约束.尖晶石二辉橄榄岩向石榴石二辉橄榄岩相转变发生在55~70km, 随着深度增加, 石榴石二辉橄榄岩从富铝石榴石二辉橄榄岩(70~120km) 转变为贫铝石榴石二辉橄榄岩(> 120~150km).      

准噶尔盆地西北缘冲断构造新解

摘要：准噶尔盆地西北缘最重要的构造特征是发育一组冲断构造。对这组冲断构造的冲断时限和冲断性质的认识不同,导致对准噶尔盆地的属性存在断陷盆地与前陆盆地之争。西北缘花岗岩及其中发育的岩墙群的精确年龄限定了研究区在314～255 Ma中处于伸展状态。西北缘侏罗系沉积范围较三叠系广,早侏罗世发育碱性玄武岩,这些都表明准噶尔盆地在侏罗纪处于伸展阶段,盆地范围不断扩大。西北缘晚三叠世地层不整合覆盖于花岗岩之上,这种现象将本区冲断构造发生的时间限定为晚二叠世至早三叠世,最晚不超过晚三叠世。在地震资料解释的西北缘剖面上,冲断构造的前缘二叠纪地层平缓且厚度稳定。西北缘二叠系发育火山岩,沉积层序具从下到上粒度由粗变细的正旋回沉积特征,沉积速率稳定,沉降曲线由陡变缓,且古地温梯度和大地热流值均较高。西北缘的圈闭类型以岩性地层等非构造圈闭为主,以构造 岩性圈闭为辅。笔者认为西北缘冲断构造的性质是在314～255 Ma伸展阶段与侏罗纪伸展阶段之间发育的一次短期反转构造,发育基底卷入的高角度冲断带,并非大规模与造山作用相关的前陆冲断带。     

长江上游全新世特大洪水对西南 季风变化的响应

利用24次全新世特大洪水序列与川渝地区近两千年的洪灾史料,对长江上游特大洪水事件和气候变化的响应机制进行了分析。从长江上游特大洪水序列与阿拉伯海记录的西南季风气候变化对比分析来看,特大洪水事件与西南季风变化具有很好的响应关系,特大洪水事件多发生于西南季风较弱的阶段,这些阶段以西南季风气候快速变化为特征,是气候剧烈波动期或气候的转型期。与北大西洋、贵州董歌洞石笋所记录的气候变化比较,特大洪水有的与全新世气候突变一致,有的则不一致,可能特大洪水事件更多表现为地方事件。与文献记载的历史洪灾事件相比,长江上游低频高量级的特大洪水事件对西南季风的变化具有更好的响应关系,而高频低量级的洪灾事件具有更高的随机性,由于历史文献记载的洪水量级差异较大,如果将他们笼统地放在一起分析,可能会掩盖洪水事件对气候变化响应机制。     

辽西晚古生代长茂河子辉绿岩墙群的地球化学特征

根据全岩K-Ar年龄(287.5~243.6Ma), 辽西朝阳长茂河子辉绿岩墙群形成于晚古生代.这些辉绿岩分为低铁钛辉绿岩和高铁钛辉绿岩2种, 以低铁钛辉绿岩为主.低铁钛辉绿岩以低TiO₂(< 2%)、FeO_t(12.39%~15.33%)、V(227~335μg/g)、Sc(24~36μg/g) 含量和高的SiO₂ (45.61%~47.72%)、Al₂O₃(12.51%~16.71%)、MgO(6.66%~9.31%)、K₂O(0.57%~2.39%)、Cr(107~177μg/g)和Ni(96~235μg/g) 含量, 以及低Ti/Y(327~496)和Ti/Zr (69~114) 比值为特征, 类似于大陆拉斑玄武质岩石; 高铁钛辉绿岩以高的TiO₂ (5%~6%)、FeO_t(22.13%~22.16%)、V(850~859μg/g)、Sc(51~52μg/g) 含量和低的SiO₂ (42.88%~44.90%)、Al₂O₃(11.53%~11.57%)、MgO (5.15%~5.29%, Mg#=0.32)、K₂O (0.48%~0.51%)、Cr(< 2μg/g)和Ni(< 30μg/g) 含量及高的Ti/Y(1046~1106)、Ti/Zr(250~263) 比值为特征, 类似于Skaergaard侵入体.这些辉绿岩相对富集Rb、Th、U、Pb、Ti和轻稀土元素, 而相对亏损Ba、Sr、P和Nb、Ta.ε_Nd(t) (-6.43~-4.12)、ε_Sr(t) (42.94~64.19) 显示Sr-Nd同位素组成较为均匀, 并反映它们源于富集岩石圈地幔.认为长茂河子辉绿岩形成于富集岩石圈地幔的部分熔融, 经历了岩浆结晶分异与地壳混染作用.高铁钛辉绿岩和低高铁钛辉绿岩形成环境不同, 前者形成于相对低氧逸度或相对封闭的结晶环境中.