某松散堆积体的地震稳定性模拟分析

某水电站左岸的大型松散堆积体在汶川地震中出现了局部变形破坏,但未产生整体破坏现象。应用FLAC3D软件对该松散堆积体的地震响应进行数值模拟分析,对其在强震作用下的稳定性及变形破坏特点进行分析,表明该堆积体在地震作用下的稳定性良好,只会在局部出现变形破坏,整体失稳的可能性不大,并且模拟结果与地震后该松散堆积体的实际稳定状态一致。     

内藏桁架的混凝土组合低剪力墙试验

提出了内藏桁架(包括钢桁架、钢筋桁架及钢钢筋组合桁架)混凝土组合剪力墙,该新型组合剪力墙包含2种组合:不同受力体系,桁架与剪力墙的组合;不同材料,型钢与混凝土的组合,形成了双重组合剪力墙.进行了6个1/3缩尺的剪力墙的抗震性能试验研究,包括普通混凝土剪力墙、内藏钢框架混凝土剪力墙、内藏钢筋桁架混凝土剪力墙、内藏钢框架钢筋桁架混凝土剪力墙、内藏钢桁架混凝土剪力墙及内藏钢钢筋组合桁架混凝土剪力墙.在试验研究基础上,对比分析了各剪力墙的刚度及其衰减过程、承载力、延性、滞回特性、能耗及破坏特征.试验表明,内藏钢框架及内藏不同材料桁架混凝土剪力墙的抗震性能比普通混凝土剪力墙明显提高.建立了内藏桁架混凝土剪力墙的承载力计算模型,计算结果与实测结果符合较好.提出了该新型剪力墙抗震设计的建议.     

车排子地区北部春风油田沙湾组速度分析

地震波速度是地球物理勘探和开发中最重要的一个参数。因此,结合地震与测井等实际资料,对车排子地区沙湾组纵向、横向上的速度变化规律做以研究,并分析了其纵向、横向上速度变化的原因。结果表明,不同地层的岩性、孔隙度、沉积相等因素是导致车排子地区沙湾组速度变化的主要原因。     

不同分子筛前驱体对γ-氧化铝改性的影响

用炭黑扩孔的方法制备出孔径较大的γ-Al2O3载体,然后用不同的ZSM-5分子筛前驱体对其进行表面改性。考察晶化时间、硅硼比等对ZSM-5分子筛前驱体的影响;采用XRD、IR、Py-IR和BET等手段对改性前后载体的酸性、孔结构等表面性质进行表征。结果表明:经过扩孔和ZSM-5分子筛前驱体改性后的γ-Al2O3载体的平均孔径由扩孔前的6.9 nm增加到9.0 nm左右,孔径分布中大于10 nm的孔有所增加;ZSM-5前驱体改性后不会导致γ-Al2O3载体的堵孔;载体的酸性增强并出现一定的B酸位。     

Shearlet域深度残差CNN用于沙漠地震信号去噪

由于沙漠地震信号中含有较强的随机噪声,从而给沙漠地震数据的处理和解释带来了很大的困难。针对上述问题,提出了一种基于Shearlet 变换的深度残差卷积神经网络( ST-CNN: Deep Ｒesidual Convolutional NeuralNetwork for Shearlet Transform) 模型,实现沙漠地震信号的随机噪声压制。在训练阶段,将沙漠地震信号经Shearlet 分解后的系数作为输入,将随机噪声经Shearlet 分解后的系数作为标签,通过卷积神经网络( CNN: Convolutional Neural Network) 学习输入和标签之间的映射关系; 在测试阶段,利用此映射关系即可从沙漠地震信号系数中预测出噪声系数,并间接地获得有效信号系数,最后通过Shearlet 反变换获得有效信号。通过与传统的Shearlet 硬阈值去噪算法对比,发现该算法可把沙漠地震信号的信噪比从－ 4． 48 dB 提高到14． 15 dB,具有更好的去噪效果。     

三维基础隔震结构多维地震反应的非线性分析

提出了一种铅芯橡胶碟簧三维隔震支座(3DB),它由铅芯叠层橡胶支座LRB和加有阻尼材料的碟形弹簧支座DSB串联组成,3DB能有效解决三维隔震支座竖向阻尼的难题,并可以有效地抑制摇摆,建立了3DB三维隔震框架结构多维地震反应的非线性分析模型及其运动方程,并以一栋平面为L形的五层3DB三维基础隔震框架结构为例,对其多维地震反应进行了计算机仿真分析,结果表明,本系统的三维隔震效果十分明显,地震反应降低了50％以上。     

Seismic tomography showing subduction and slab breakoff of the Yangtze block beneath the Dabie-Sulu orogenic belt

Seismic tomography reveals that a subducted ancient block has been preserved beneath the Moho of the Dabie-Sulu orogenic belt. Taking into account of geological and geochronological data, we inferred from the tomographic images that the Yangtze block was subducted northward beneath the Sino-Korean block and broken off at the depth <200 km during 200—190 Ma. The slab breakoff of the Yangtze block is the most important dynamic mechanism to control the exhumation of UHP rocks.     

双层钢板组合剪力墙抗震性能试验研究

以盐城广播电视塔实际工程中剪力墙的构造形式为基础,通过九个缩尺试件,研究不同构造形式的双层钢板内填混凝土组合剪力墙在常轴力和反复水平荷载作用下的刚度变化特征、破坏机理与破坏模式、抗震性能和极限承载能力.分析了墙板的高宽比、轴压比、钢板厚度、混凝土强度等级等对双层钢板内填混凝土组合剪力墙受力性能的影响.结果表明:双层钢板内填混凝土组合剪力墙能够充分发挥钢板与混凝土材料各自的优点,是一种良好的抗侧力构件.     

Fine three-dimensional P-wave velocity structure beneath the capital region and deep environment for the nucleation of strong earthquakes

A detailed 3-D P-wave velocity model of the crust and uppermost mantle under the capitol region is determined with a spatial resolution of 25 km in the horizontal direction and 4-17 km in depth. We used 48750 precise P-wave arrival time data from 2973 events of local crustal earthquakes, controlled seismic explosions and quarry blasts. These events were recorded by 123 seismic stations. The data are analyzed by using a 3-D seismic tomography method. Our tomographic model provides new information on the geological structure and complex seismotectonics of this region. Different patterns of velocity structures show up in the North China Basin, the Taihangshan and the Yanshan Mountainous areas. The velocity images of the upper crust reflect well the surface geological, topographic and lithological features. In the North China Basin, the depression and uplift areas are imaged as slow and fast velocity belts, respectively, which are oriented in NE-SW direction. The trend of velocity anomalies is the same as that of major structure and tectonics. Paleozoic strata and Pre-Cambrian basement rocks outcrop widely in the Taihangshan and Yanshan uplift areas, which exhibit strong and broad high-velocity anomalies in our tomographic images, while the Quaternary intermountain basins show up as small low-velocity anomalies. Most of large earthquakes, such as the 1976 Tangshan earthquake (M 7.8) and the 1679 Sanhe earthquake (M 8.0), generally occurred in high-velocity areas in the upper to middle crust. However, in the lower crust to the uppermost mantle under the source zones of the large earthquakes, low-velocity and high-conductivity anomalies exist, which are considered to be associated with fluids, just like the 1995 Kobe earthquake (M 7.2) and the 2001 Indian Bhuj earthquake (M 7.8). The fluids in the lower crust may cause the weakening of the seismogenic layer in the upper and middle crust and thus contribute to the initiation of the large crustal earthquakes.     

世构体系框架中节点抗震性能试验研究

通过对3个不同键槽长度的世构体系(预制预应力混凝土装配整体式框架结构)梁柱节点的低周反复荷载试验,研究世构体系框架节点的破坏形态、滞回性能、节点延性、耗能能力和刚度强度退化等抗震性能指标,对世构体系的抗震性能得出一个大致的评价.试验结果表明:世构体系的滞回曲线丰满,具有良好的耗能能力:世构体系的配筋设计可以参照现行的混凝土结构设计规范进行:经过良好的设计施工,世构体系的抗震性能完全能够满足预期的要求:目前采用的键槽长度能够满足抗震的需要.