四川茂县维城乡后山古滑坡形成机制及稳定性评价

结合灾后应急勘察,通过大比例尺工程地质测绘及钻探等手段对维城乡后山堆积体结构进行了系统调查,认为后山堆积体为一古滑坡。滑坡形成前为一变质砂岩和千枚岩构成的顺向坡且顺坡面走向陡倾长大结构面发育,峡谷期河流的快速下蚀作用使斜坡前缘形成陡立临空面,重力作用下,坡体后缘顺层滑移拉裂并最终整体滑动形成古滑坡,运用理正软件搜索古滑坡潜在不稳定滑面．并对其稳定性进行计算和评价,认为其局部复活但整体处于稳定状态。     

汶川地震中西安高层建筑震害调查及分析

汶川大地震中,西安地区大部分高层建筑遭到程度不同的损坏,为了进一步分析高层建筑物的安全性能,以破坏比较明显的西安北郊赛高国际大厦为例进行分析。在震害调查的基础上,对该结构运用专用分析软件ETABS进行了地震作用下反应谱分析和弹性时程分析,对结构的安全性能和抗震能力进行了评估。结果表明,结构的各项指标均能符合规范要求,但其扭转效应较为明显,反映出结构剪力墙布置偏少且不均匀,部分非结构构件做法欠妥,应在构造措施上予以改善。赛高国际表现的问题具有普遍性,损坏主要集中在结构抗震缝、填充墙、外装饰层和装饰柱等非结构构件,主体结构抗震性能满足规范要求。     

汶川地震对江口电站进水口边坡稳定性影响分析

汶川地震发生后,江口电站进水口边坡监测结果显示边坡表面位移较小,深层位移较大,但测斜仪位移分布曲线较光滑,且震后边坡位移变化较小,说明进水口边坡基本稳定.测斜仪位移分布曲线是否出现Z形突变,以及位移一时间过程线有无明显增长,可作为边坡稳定的依据.     

State Estimation in Structural Systems with Model Uncertainties

This paper presents an observer designed under the assumption that differences between predicted and measured outputs arise from discrepancies between the real structural system and the nominal model used to represent it. The observer gain is independent of the assumed model error parametrization and proves to be the transpose of the state to output matrix of a state space formulation. The estimated state with the proposed observer is shown to be identical to that obtained by exciting the nominal model with the known input while adjusting the measured portion of the state to match the measurements at the start of every step. Numerical experiments suggest that the proposed observer can provide state estimates that are substantially more accurate than results predicted by projecting the measurements in a truncated modal space.     

“5·12汶川大地震”带给我们的反思

文章通过对“5.12汶川大地震”灾区的实地考察,从建筑规划选址、结构、材料与施工等环节分析了部分建筑遭受破坏的原因,并指出加强建筑设计、施工与管理,提升建筑质量,从而提高建筑的防灾能力。     

汶川地震灾区水电工程震损调查及抗震复核工作简介

汶川特大地震震级高、影响范围大,破坏性强,处于震中附近的水电工程,尤其是高坝枢纽,均经受住了超出设防标准的强烈地震的考验。汶川地震灾区4座高坝的震损情况,对大坝震损破坏特征和抗震性能进行了初步分析,归纳了水电工程防震抗震的五点基本认识。为进一步加强西南地区水电工程高坝抗震研究设计,提高水电工程抗震能力,提出开展西南地区高坝抗震安全研究课题的意见和建议。     

汶川地震对岷江上游水电工程的影响分析

2008年5月12日四川汶川发生8.0级地震,导致岷江上游河段山体垮塌,大中型水电站机组停运,交通中断,但挡水大坝无一溃决,整体稳定;其他主要建筑物的直接震损有限,部分建筑设施受地震滑坡影响突出。通过工程震损调查,在简述岷江水电工程基本特征以及流域地震地质环境的基础上,对紫坪铺和沙牌两座高坝电站的震损情况,以及各闸坝引水式电站的地震灾害作了重点分析;并根据震损情况,就工程防震抗震设计与建设,提出了的几点初步认识。     

Seismic base isolation using low-cost Scrap Tire Pads (STP)

This paper focuses on the experimental studies conducted on the development of no-cost seismic base isolation pads using scrap automobile tire pads (STP). The mechanical and dynamic properties of STP specimens made from different tire brands, with different number of layers, and orientations are evaluated experimentally. The tests are conducted using (a) axial compression tests, (b) lumped mass small displacement free vibration, and (c) large displacement (inclined plate and reverse-cyclic) static shear tests. The results of these STP tests are compared among themselves and against a commercially available laminated rubber bearing specimen. A general relationship has been proposed which formulates the stiffness differences between the two principal directions of rectangular pads. The paper includes three hypothetical design applications for the use of STPs. STPs are prepared by placing 18 cm × 20 cm cut tread sections layers of car tires on top each other. Larger size STPs can also be formed by placing longer strips of tread sections (integer multiples of tread width) side by side in alternating direction layers or using a woven structure. Test results have shown that the friction between tire layers is sufficient to keep layers intact. Although STP application cannot eliminate foundation-basement structural requirements, it presents advantages such as low-technology no-cost pad, weight reduction, ease of handling, simple shear stiffness adjustment by changing the number of layers, and environmental benefits by recycling scrap tires.     

导管架式海洋平台结构的磁流变阻尼隔震控制

首先针对渤海JZ20-2MUQ导管架式海洋平台结构,建立了应用磁流变阻尼器的智能隔震体系,并通过对导管架式海洋平台结构特点和磁流变阻尼器性能的分析,提出了磁流变限位型阻尼器被动控制、Passive off、Passive on和半主动四种控制方案。然后,分别在冰激振动和地震作用下,对平台隔震结构进行了数值仿真计算,分析比较了不同磁流变阻尼控制方案对平台隔震结构的控制效果以及对隔震层变形的限制作用。结果表明。磁流变阻尼隔震控制方案能有效控制导管架式平台结构的振动,平台结构位移和甲板加速度反应可降低30％以上,隔震层变形可控制在40mm左右的有限范围内。