天津市典型老旧民居抗震能力分析     

姚新强  陈宇坤  杨绪连  高武平 《震灾防御技术》2014,9(2):280-288

本文对天津市典型老旧民居进行了抗震能力分析,介绍了它们的结构形式,抗震性能。并根据相应的规范和标准,对其中一幢民居楼进行了抗震能力分析和鉴定。研究表明,在遭受Ⅶ度小震时,顶层中等破坏;Ⅷ度中震时,顶层严重破坏;Ⅸ度大震时,顶层倒塌。建议尽快进行抗震加固。本文指出了抗震薄弱环节,并给出了抗震加固措施。本文可为天津市典型老旧民居的抗震加固提供科学依据和技术支持。  相似文献   

山东济南和新泰馒头组中浊积岩和滑塌堆积的基本特征及其大地构造意义   总被引：7，自引：3，他引：4  

闫臻  杨长春  李继亮  肖文交  王真理  徐兴旺 《地质科学》2005,40(4):579-584

馒头组是华北地台盖层的重要组成之一,以陆源细碎屑岩为主夹碳酸盐岩。前人研究认为馒头组是滨海沼泽相、潮坪—泻湖相和沿岸滩坝相沉积组合。我们首次在济南和新泰地区馒头组中发现浊积岩和滑塌堆积组合,表明华北地台早寒武世沉积组合形成于深海半深海浅海中,曾存在古斜坡和构造隆升作用。详细研究浊积岩和滑塌堆积的基本地质特征,不仅对于进一步认识华北地台古生代古地貌特征以及古潜山的形成和演化具有重要意义,而且可为渤海湾盆地中古潜山成因以及潜山油气资源勘探提供借鉴。  相似文献   

Origin and significance of soft-sediment deformation in the Old Red Sandstone of central South Wales,UK     

《Proceedings of the Geologists' Association. Geologists' Association》2017,128(3):422-430

Vertically oriented water-escape cusps are the most common type of soft-sediment deformation structure in sandstone-rich intervals of the fluvial Brownstones and Senni Formations (Cosheston Subgroup, Daugleddau Group) of the Lower Old Red Sandstone in the central Brecon Beacons and eastern Black Mountains, South Wales. The structures are widely distributed and occur at several stratigraphical levels. They can be divided into two styles. (1) Small-scale (height less than a single bed), isolated water-escape cusps formed when loosely packed sediment deposited rapidly in flood events liquefied in advance of subsequent flood events or pulses, causing localised fluidization due to the escape of excess pore water. Inclined cusps higher in some beds confirm the relationship of this deformation style to active flood events. (2) Horizons of larger-scale (occupying the entire bed thickness), laterally continuous water-escape cusps and fold trains can be traced for hundreds of metres to kilometres and result from widespread liquefaction in response to earthquakes. A lack of overturning indicates that their formation did not coincide with active flow conditions. Further detailed mapping is needed to clarify the continuity and extent of such structures and their relationship to faults that may have been active during sedimentation. The occurrence of triggers capable of causing liquefaction in granular materials provides a greater control on the occurrence of soft-sediment deformation than do lithological controls such as grain size or interbedding of sandstone and mudstone. The findings are broadly consistent with interpretations of soft-sediment deformation in the Cosheston Subgroup in Pembrokeshire, SW Wales.  相似文献   

The Old Red Sandstone of Britain and Ireland — a review     

《Proceedings of the Geologists' Association. Geologists' Association》2017,128(3):409-421

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福建海坛岛青峰老红砂旋回沉积的粒度特征及其古环境意义   总被引：1，自引：0，他引：1  

申健玲  李志忠  靳建辉  邓涛  姜锋  苑秀全  于晓莉  赖海成 《中国沙漠》2016,36(4):972-982

福建海坛岛青峰老红砂剖面以棕红色砂层和黄橙色砂层的交替旋回变化为显著特征。通过野外考察、采样和测定分析,对青峰老红砂剖面的粒度特征及其古气候意义进行深入研究。结果表明：（1）青峰剖面棕红色砂层以细砂为主,黄橙色砂层以中砂为主,细砂-中砂在剖面上呈现明显的交替旋回变化;（2）棕红色砂层和黄橙色砂层的粒度频率曲线均以单峰加一细尾为主,含有一定量的粉砂、黏土;概率累积曲线以滚-跳-悬三段式为主,但两种砂层在组分含量、斜率等方面存在差异;（3）粒度参数呈现明显的波动旋回变化,可能指示沉积时期区域风力、搬运动力、化学风化强度方面发生了周期性变化,即棕红色砂层显示了暖湿气候条件下的红壤化过程,黄橙色砂层则显示凉干气候条件下的黄壤化过程。因此,青峰老红砂旋回沉积表明第四纪晚期以来,福建东部沿海的古气候古土壤可能经历了南亚热带（赤红壤）和暖温带（黄壤）的交替变迁。  相似文献   

Physical model experiments for sediment supply to the old Rhine through induced bank erosion     

Andres DIE MORAN  Kamal EL KADI ABDERREZZAK  Erik MOSSELMAN  Helmut HABERSACK  Franck LEBERT  Denis AELBRECHT  Eric LAPERROUSAZ 《国际泥沙研究》2013,28(4):431-447

A mobile-bed, undistorted physical model （1：40） has been used to investigate different sediment supply strategies to the Old Rhine through bank protection removal and modifications of groyne dimensions and configuration, which cause bank erosion. This trained channel was previously the main bed of the upper Rhine downstream of Basel （Switzerland）, but it has an artificially low flow regime since the construction of the Grand Canal d＇Alsace, a navigation canal, and a flow control dam at Kembs （France）. Training works and subsequent channel incision have also greatly reduced sediment transport rates and created a heavily armoured bed. The modelled pilot site has a groyne field on the left bank. Results show that the currently existing groynes at the site are not effective in creating high bank-side velocities conducive to bank erosion, even for flow rates significantly higher than the mean annual flow rate. The river bank has also proved to be more resistant than previously thought, allowing long stretches of bank protection to be safely removed. The physical model testing process has produced a new configuration for the groyne field, where two higher, larger island groynes are placed further apart than the three existing attached groynes. This innovative approach has proved effective, causing bank erosion for flow rates below the mean annual flow rate, with consistent erosion being observed. It has also been found that such a configuration does not pose a hazard for the Grand Canal d＇Alsace, which is situated next to the Old Rhine, through excessive bank erosion during high flow events.  相似文献   

Multistage Deformation in the Northeastern Segment of the Jiangshao Fault (Suture) Belt: Constraints for the Relationship between the Yangtze Plate and the Cathaysia Old Land     

ZHANG Jin  LI Jinyi  XIAO Wenxi  FENG Qianwen  MA Zongjin 《《地质学报》英文版》2013,87(4):948-978

Multistage deformation events have occurred in the northeastern Jiangshao Fault (Suture) Belt. The earliest two are ductile deformation events. The first is the ca. 820 Ma top-to-the-northwest ductile thrusting, which directly resulted from the collision between the Cathaysia Old Land and the Chencai Arc (?) during the Late Neoproterozoic, and the Jiangnan Orogenic Belt that formed as the ocean closed between the Yangtze Plate and the jointed Cathaysia Old Land and the Chencai Arc due to continuous compression. The second is the ductile left-lateral strike-slipping that occurred in the latest Early Paleozoic. Since the Jinning period, all deformation events represent the reactivation or inversion of intraplate structures due to the collisions between the North China and Yangtze plates during the Triassic and between the Philippine Sea and Eurasian plates during the Cenozoic. In the Triassic, brittle right-lateral strike-slipping and subsequent top-to-the south thrusting occurred along the whole northeastern Jiangshao Fault Zone because of the collision between the North China and Yangtze plates. In the Late Mesozoic, regional extension took place across southeastern China. In the Cenozoic, the collision between the Philippine Sea and Eurasian plates resulted in brittle thrusts along the whole Jiangnan Old land in the Miocene. The Jiangshao Fault Belt is a weak zone in the crust with long history, and its reactivation is one of important characteristics of the deformation in South China; however, late-stage deformation events did not occur beyond the Jiangnan Old Land and most of them are parallel to the strike of the Old Land, which is similar to the Cenozoic deformation in Central Asia. In addition, the Jiangnan old Land is not a collisional boundary between the Yangtze Plate and Cathaysia Old Land in the Triassic.  相似文献   

A palaeomagnetic study of Devonian sandstone from Central Spitsbergen     

M. Jele&#;ska  M. Lewandowski 《Geophysical Journal International》1986,87(2):617-632

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棋子山运动的发现及其意义     

陶书华 《地质论评》2008,54(3):335-342

棋子山运动是一次强烈的地质构造运动。它使老黄土下部及其同期异相的湖积层发生了一系列的构造变动——断层、褶曲（向斜、背斜）等;使我国北方的地貌条件有了很大的改变,许多大的湖泊如泥河湾古湖、三门古湖等都在此时灭亡;桑干河、汾河、渭河、黄河等都在此时形成。棋子山运动发生在老黄土下部堆积之后,老黄土上部堆积之初;在地磁柱上属安比拉亚时,其绝对年龄为距今049～050 Ma。由于棋子山运动的发生,在河谷地带和山前平原生成了非常良好的蓄水构造,成为许多大、中城市的供水水源地和矿产生成地;同时也由于棋子山运动的发生,使断裂的复活、地震的发生、边坡的坍塌,给许多工程带来了不利因素和造成了严重后果。  相似文献   

Tracking hydrological responses of a thermokarst lake in the Old Crow Flats (Yukon Territory,Canada) to recent climate variability using aerial photographs and paleolimnological methods     

Lauren A. MacDonald  Kevin W. Turner  Ann M. Balasubramaniam  Brent B. Wolfe  Roland I. Hall  Jon N. Sweetman 《水文研究》2012,26(1):117-129

Recent studies using remote sensing analysis of lake‐rich thermokarst landscapes have documented evidence of declining lake surface area in response to recent warming. However, images alone cannot identify whether these declines are due to increasing frequency of lake drainage events associated with accelerated thermokarst activity or to increasing evaporation in response to longer ice‐free season duration. Here, we explore the potential of combining aerial photograph time series with paleolimnological analyses to track changes in hydrological conditions of a thermokarst lake in the Old Crow Flats (OCF), Canada, and to identify their causes. Images show that the water level in lake OCF 48 declined markedly sometime between 1972 and 2001. In a sediment core from OCF 48, complacent stratigraphic profiles of several physical, geochemical, and biological parameters from ～1874–1967 indicate hydro‐limnological conditions were relatively stable. From ～1967–1989, declines in organic matter content, organic carbon isotope values, and pigment concentrations are interpreted to reflect an increase in supply of minerogenic sediment, and subsequent decline in aquatic productivity, caused by increased thermo‐erosion of shoreline soils. Lake expansion was likely caused by increased summer rainfall, as recorded by increased cellulose‐inferred lake‐water oxygen isotope compositions. Stratigraphic trends defining the lake expansion phase terminated at ～1989, which likely marks the year when the lake drained. Above‐average precipitation during the previous year probably raised the lake level and promoted further thermo‐erosion of the shoreline soils that caused the lake to drain. These are meteorological conditions that have led to other recent lake‐drainage events in the OCF. Thus, the decline in lake level, evident in the aerial photograph from 2001, is unlikely to have been caused by evaporation, but rather is a remnant of a drainage event that took place more than a decade earlier. After drainage, the lake began to refill, and most paleolimnological parameters approach levels that are similar to those during the stable phase. These findings indicate that combined use of aerial images and paleolimnological methods offers much promise for identifying the hydrological consequences of recent climatic variations on thermokarst lakes. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献