中国木结构古建筑抗震性能的研究   总被引：4，自引：1，他引：3       下载免费PDF全文

苏军  高大峰 《地震工程学报》2008,30(3):239-244

以殿堂式木结构为研究对象,通过理论分析和数值模拟推导出了榫卯节点和铺作层之间的半刚性单元的刚度矩阵,即采用组合式弹簧单元模拟柱脚与础石、榫卯节点和铺作层之间的连接单元,给出了动力方程,并通过对<营造法式>中的殿堂和厅堂模型结构的分析,求解出了结构各个层面的地震动力放大系数,为木结构古建筑的保护、维修和加固提供理论依据和技术参考,对现代建筑结构抗震研究也具有借鉴意义.  相似文献   

钢筋混凝土框架角节点抗剪强度试验研究   总被引：3，自引：1，他引：2  

崔建宇  孙建刚  宋玉普 《地震工程与工程振动》2008,28(5)

通过对6个钢筋混凝土框架梁柱角节点在低周反复荷载作用下的试验,调查了高强度节点箍筋、双向加载等对节点强度的影响。试验结果证明,节点强度试验值为规范设计值的85%左右,设计式应导入强度降低系数。高强度箍筋对节点强度提高影响很小,在节点强度设计时可忽略不计。双向加载的节点强度只有单向加载时的80%,节点抗震设计时角节点应作为所有边节点中最不利情况考虑。楼板虽然可以提高梁的强度及刚度,但对角节点强度及最大荷载后的节点延性有不利影响。  相似文献   

论赤平极射投影在山口岩水利工程中的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

陈炳贵  方宏伟 《地球物理学进展》2008,23(2):631-635

本论文首先简单介绍了水利工程中分析岩质边坡稳定性常用的一种图解法——赤平极射投影法,然后介绍了这种方法在山口岩水利工程稳定性分析中的具体应用,因其在该水利工程的坝基和岩质边坡稳定性分析中发挥了一定的作用,满足了工程实践的要求,故希望对其它水利工程坝基抗滑和岩质边坡的稳定性分析具有指导意义.  相似文献   

The effect of surface irregularities on a falling rock motion     

Ivan Gratchev  Somayeh Saeidi 《Geomechanics and Geoengineering》2019,14(1):52-58

This laboratory study seeks to investigate the effect of surface irregularities on the motion characteristics of a falling rock. The irregularly-shaped surfaces of greywacke with a range of joint roughness coefficient (JRC) from 2 to 18 were used in an experimental setup where a falling rock was dropped from a height of 110 cm. A high-speed camera was utilised to capture the trajectory of the falling rock upon its impact with the rock surface. The data from 287 tests were statistically analysed to determine the dominant type of motion and to establish relationships between JRC and the coefficient of restitution (CoR). The effect of surface roughness was seen in different modes of motion of the falling rock with more irregular surfaces often produced ‘sliding’ or ‘rolling’ instead of ‘bouncing’. The obtained data indicated that the rock surface roughness did not seem to have a significant effect on CoR; however, it affected the rebound angle of the falling rock.  相似文献   

钢框架带悬臂梁拼接节点的抗水平地表变形试验研究   总被引：1，自引：0，他引：1  

夏军武  周勇利  陈婷  熊军辉 《地震学刊》2011,(6):671-674

以单层单跨带悬臂梁段拼接钢框架为研究对象,通过地表变形的物理相似模拟试验,研究了钢框架带悬臂梁段拼接节点在地表水平变形作用下的附加应力和变形规律。主要研究在水平拉伸和水平压缩作用下,拼接节点处腹板拼接板和上下翼缘拼接板内产生的附加内力及变形曲线,分析了上下翼缘拼接板和腹板拼接板中间位置点的变形值随着试验加载值的增加而变化的原因。研究结果表明：地表水平拉伸作用最为不利;拼接节点虽会产生附加变形,但在很大程度上仍处于弹性阶段,卸栽后可以恢复,表现出良好的抗变形性能。最后给出建议：在地表变形地区新建或加固改造钢结构建构筑物时,采用钢框架带悬臂梁段高强螺栓拼接连接,可以很好地吸收变形能。  相似文献   

Insights on the kinematics of deep-seated gravitational slope deformations along the 1915 Avezzano earthquake fault (Central Italy), from time-series DInSAR     

M. Moro  M. Saroli  C. Tolomei  S. Salvi 《Geomorphology》2009,112(3-4):261-276

Small meandering channels of about 1 m wide on an intertidal mudflat in the Westerschelde estuary the Netherlands) were studied with the aim to improve understanding of the effect of highly cohesive bed and bank sediment on channel inception and meander geometry and dynamics. The study is supported by experiments and modelling. The estuarine meandering channels are less dynamical than alluvial meandering rivers, and the dynamics are more localised. Moreover, the high thresholds for bed sediment erosion and for bank failure lead to two processes, uncommon in larger rivers, that cause most of the morphological change. First, the beds of the channels are eroded by backward migrating steps under hydraulic jumps, while the remainder of the bed surface along the channel is hardly eroded. Second, channel banks erode i) where eroding steps locally cause undercutting of otherwise stable channel banks and ii) in very sharp bends where the flow separates from the inner-bend channel boundary and impinges directly on the bank on the opposite side of the channel. Further morphological change is probably induced by rainfall splash erosion and by storm waves that weaken the mud, and by large mud fluxes from the estuary. The steps were successfully reproduced in laboratory flume experiments. An existing model for step migration predicted celerities consistent with field and laboratory observations and demonstrated a strong dependence on the threshold for erosion. Bank stability models confirm that banks and steps only fail when undercut and weakened by waves, rain or excess pore pressure in agreement with observations. The effects of a high threshold for bank erosion was implemented in an existing meander simulation model that reproduced the observed locations of bank erosion somewhat better than without the threshold, but flow separation and its effect on meander bends remains poorly understood.  相似文献   

预应力混凝土空间框架节点二维拟静力试验研究   总被引：1，自引：0，他引：1  

李旭红  房贞政  陈浩德 《地震工程与工程振动》2009,29(1)

采用拟静力试验方法对预应力混凝土和普通钢筋混凝土空间框架内节点进行了不同轴压比下单、双向循环加载的试验研究,得到不同加载方式下试件的滞回曲线。分析了各个试件的破坏形式、承载力、刚度、延性及耗能能力,通过比较和对滞回曲线的分析得出：双向水平荷载作用对构件耦合作用明显,构件存在扭转效应,构件的强度退化和刚度退化比单向荷载作用严重,节点的耗能能力降低。  相似文献   

海试引发深水油气综合地球物理采集的几点思考   总被引：1，自引：1，他引：0       下载免费PDF全文

陈洁  温宁  罗文造  关晓春  王立明  王功祥 《地球物理学进展》2009,24(1):102-112

深水地球物理采集技术随着国际海洋油气勘探的不断升温,技术水平不断提高.本文结合我国的地球物理海试实践,提出深水油气综合地球物理采集的几点思考,地震采集参数的选择,重磁震采集过程的实时监控,总结海试过程深水地球物理采集的两方面进展,一是精确定位的长缆二维地震采集技术,二是高精度的重磁震联合质量监控的综合地球物理测量技术,为深水油气勘探提供采集技术保障.  相似文献   

偏压连拱隧道施工的动态模拟及最优化分析   总被引：2，自引：0，他引：2  

庄宁  朱苦竹  李军伟 《岩土力学》2009,30(9):2875-2880

建立了偏压连拱隧道的3D有限元模型,对不同施工工况进行了数值模拟,并与现场监测资料进行比较,通过分析拱顶沉降、中隔墙的位移和应力、围岩的塑性区分布、初衬和二衬应力的变化规律,对偏压连拱隧道施工进行最优化设计,以此得出了最优施工步距、开挖顺序、断面开挖形式、左右两洞开挖面的最佳施工间距,对类似连拱偏压隧道的施工有重要的理论和实际指导意义。  相似文献   

考虑横缝键槽咬合的拱坝地震响应分析     

江守燕  杜成斌  陈灯红 《地震学刊》2010,(2):177-184

基于非线性指数型动接触本构模型,对实际键槽模型进行简化处理。采用的本构模型可以考虑缝面的开合非线性以及横缝键槽的咬合作用。采用点-面接触模型模拟横缝的非线性动接触行为,精细研究了缝面开度、径向位移的变化及其对坝体应力状态的影响,并与平缝结果进行了比较。以一座拟建的混凝土重力拱坝,探讨了横缝及其诱导缝对大坝工作性态的影响,并对横缝键槽的影响进行了综合分析。研究表明,横缝的径向滑移量要远大于开度,当考虑诱导缝时,由于大坝整体性受到削弱,横缝开度变大;考虑键槽效应后,径向滑移效应大幅减小,而法向开度增大,坝踵处的主拉应力以及拱冠梁顶处的拱向拉应力的最大值均变大。  相似文献