Finite-element modeling of a complex deep excavation in Shanghai   总被引：2，自引：0，他引：2  

Y. M. Hou  J. H. Wang  L. L. Zhang 《Acta Geotechnica》2009,4(1):7-16

The excavation of the north square underground shopping center of Shanghai South Railway Station is a complex deep excavation using the top-down construction method. The excavation has a considerable size and is close to the operating Metro Lines. In order to predict the performance of the excavation more accurately, 3D finite-element analyses are conducted to simulate the construction of this complex excavation. The effects of the anisotropic soil stiffness, the adjacent excavation, and zone excavation on the wall deformation are investigated. It is shown that the numerical simulation with anisotropic soil stiffness yields a more reasonable prediction of the wall deflection than the case with isotropic soil stiffness. The deformation of the shared diaphragm wall between two excavations is influenced by the construction sequence of the two excavations. The zoned excavation can greatly reduce the diaphragm wall deformation. However, only the zoned excavation at the first excavation stage affects the deformation of the walls significantly. When the depth of the excavation increases, the zoned excavation has minor effect on the deformation of diaphragm walls.  相似文献   

2008年汶川地震同震滑移特征、最大滑移量及构造意义   总被引：16，自引：10，他引：6       下载免费PDF全文

李海兵  司家亮  付小方  邱祝礼  李宁  J.Van der Woerd  裴军令  王宗秀  侯立玮  吴富崓 《第四纪研究》2009,29(3):387-402

2008年汶川地震（M_s8.0）形成了迄今为止空间上分布最为复杂、长度最大的逆冲型同震地表破裂带。沿约275km长的地表破裂带的同震滑移及其最大滑移量的确定,对认识和理解汶川地震地表破裂过程及其变形机制具有重要意义。我们沿地表破裂带进行了详细的滑移特征考察及其同震位移测量,发现沿映秀-北川破裂带分布南北两个滑移峰值区段,南段以深溪沟-虹口破裂段为中心,以逆冲为主伴随右旋走滑运动为特征,最大垂直位移量为6.0～6.7m,北段以北川破裂段为中心,以右旋走滑为主伴随逆冲运动为特征,最大垂直位移量为11～12m,南北两滑移峰值区段所代表的两次地表破裂事件与地震波数据反演结果一致。通过对北川段破裂带的精细地形剖面测量,以及地震前后对比,在北川县曲山镇沙坝村一组获得该破裂段的最大右旋水平位移为12～15m,最大垂直位移为11～12m,这是目前世界上一次地震产生的最大同震垂直位移,最大斜向滑移量为14～17m,为整个汶川地震地表破裂最大滑移量,是汶川地震的宏观震中。北川破裂段高角度的地震断裂、逆冲断裂面的倒转作用以及具最大滑移量的强烈变形作用是北川县城遭受到最强的地表破坏和地质灾害的主要原因。具有走滑量和逆冲量近一致（走滑水平位移/逆冲垂直位移比值为1）的斜向逆冲作用可能是山脉快速隆升的重要机制。  相似文献   

Effects of excitation frequency on detection accuracy of orthogonal wavelet decomposition for structural health monitoring     

RaulJ.Alonso MohammadNoorit SoheilSaadatt ArataMasuda ZhikunHou 《地震工程与工程振动(英文版)》2004,3(1):101-106

Accurate estimation of stiffness loss is a challenging problem in structural health monitoring. In this study orthogonal wavelet decomposition is used for identifying the stiffness loss in a single degree of freedom spring-mass-damper system. The effects of excitation frequency on accuracy of damage detection is investigated. Results show that pseudo-alias effects caused by the orthogonal wavelet decomposition (OWD), affect damage detectability. It is demonstrated that theproposed approach is sunable for damage detection when the excitation frequency is relatively low. This study shows how a priori knowledge about the signal and ability to control the sampling frequency can enhance damage detectability.  相似文献   

重复绝对重力测量观测的滇西地区和拉萨点的重力变化及其意义   总被引：22，自引：1，他引：21       下载免费PDF全文

王勇  张为民  詹金刚  郝兴华  王虎彪  许厚泽 《地球物理学报》2004,47(1):95-100

根据近年来在滇西地区和西藏拉萨绝对重力点上的一些新的绝对重力重复观测结果 ,对1990年以来在这些点上绝对重力重复观测结果进行了分析. 滇西地区的5个绝对重力观测 点的近10年的重复观测结果表明,大部分观测时段没有出现与地球动力学事件有关的重力变 化,只有丽江和洱源2个绝对重力观测点的观测结果显示丽江地震前后有变化. 为了研究该 重力变化的原因,本文正演模拟了出现重力变化期间丽江地震同震位错引起的重力变化,模 拟结果与实际观测结果有较好的一致性. 西藏拉萨近10年以来的重复观测结果给出了拉萨点 的绝对重力值以-1.82±0.9×10-8m·s-2·a-1速率下降,这从重力学 的角度反映出青藏高原的隆升. 对拉萨点的重力变化机制进行了探讨,根据印度板块与欧亚 大陆俯冲模型计算的拉萨点重力变化速率与观测到的重力变化速率较一致,表明现今拉萨地 区重力变化是由于印度板块与欧亚大陆俯冲所引起. 根据印度板块向欧亚大陆俯冲的位错模 型计算的拉萨点的重力变化与地表垂直位移的关系,将重力变化转换为拉萨点的隆升速率为 8.7mm/a.   相似文献   

Distributed TLDs in RC floors and their vibration reduction efficiency     

叶列平  陆新征  曲哲  侯建群 《地震工程与工程振动(英文版)》2008,7(1):107-112

A novel distributed tuned liquid damper （DTLD） for reducing vibration in structures is proposed in this paper. The basic working principle of the DTLDs is to fill the empty space inside the pipes or boxes of cast-in-situ hollow reinforced concrete （RC） floor slabs with water or other liquid. The pipes or boxes then work as a series of small TLDs inside the structure, to increase the damping ratio of the entire structural system. Numerical simulation that accounts for the fluid- structure conpling effect is carried out to evaluate the vibration-reduction efficiency of the DTLDs. The results show that the DTLDs are able to considerably increase the damping of the structure and thus reduce its vibration. An additional benefit is that the DTLDs do not require architectural space to be added to the structure.  相似文献   

康滇地轴中段西缘二叠纪火山岩岩石地球化学特征   总被引：2，自引：0，他引：2  

陈玉禄  侯浩  杨更 《四川地质学报》1999,(1)

沿扬子地台西缘与松潘甘孜造山带东缘结合部中段两侧分布的二叠纪火山岩,分别代表攀西裂谷时期海相和陆相环境中的火山喷发产物。西部为海相高钾钙碱性—碱性拉斑玄武岩系列,东部为陆相低钾钙碱性拉斑玄武岩系列;两者的来源深度不一,前者较后者相对较深。  相似文献   

西昆仑山加里东期花岗岩类构造的类型及其大地构造意义   总被引：27，自引：7，他引：20  

姜耀辉  芮行健  贺菊瑞  郭坤一  杨万志 《岩石学报》1999,15(1):88

The Caledonian granite belt in the West Kunlun Mts.is distributed on the south-side of Kudi tectonic belt in northwest Tibet Plateau.It consists of about 10 representative massifs in studied area.They were systematically studied,especially on west-side of Datong and Wuyitake massifs that were in lower degree of study before our work. Four tectonic genesis types——ocean ridge granites, volcanic arc granites, post-collision uplift granites and late-orogenic granites have been discriminated according to their features of occurrences,rock assemblage,facieology and petrogeochemistry.The results indicate that the West Kunlun Mts.is a Caledonian collision-orogenic belt and it has important significance for understanding the geological evolution of Tibet Plateau in early Paleozoic era.  相似文献   

地球物理综合信息平台软件设计   总被引：2，自引：2，他引：0  

侯遵泽 《物探化探计算技术》1999,21(1):45-48

本文在面向对象的可视化程序设计思想的指导下,设计了地球物理综合信息处理平台的基本框架,利用它可以设计、编制高度集成化的地球物理综合信息处理方法应用程序,这对信息的综合利用将十分有益  相似文献   

乌达矿区主采煤层煤相特征与煤的可选性   总被引：4，自引：0，他引：4  

代世峰  艾天杰  侯惠敏  毛鹤龄  马风学  李宝春  杨宝瑞  曹玉洵 《煤田地质与勘探》1999,27(1):10-12

对内蒙古乌达矿区主采煤层9煤层的煤岩学特征和煤相进行了分析,用煤样密度组成的煤岩学方法讨论不同煤相煤的可选性。研究表明,相同煤相不同煤的可选性相似,聚煤环境决定了煤中矿物的含量和赋存状态,同时也决定了煤的可选性。高位泥炭沼泽形成的煤可选性好,而低位泥炭沼泽形成的煤可选性差。   相似文献   

河网非恒定流汊点分组解法   总被引：9，自引：0，他引：9       下载免费PDF全文

侯玉  卓建民  郑国权 《水科学进展》1999,10(1):48-52

在分析汊点分组解法的基础上,提出了汊点分组解法的一般理论和算法。新方法的特点是可将河网汊点分片编码处理,而且汊点分组后可通过适用于一般分级解法的原汊点水位关系得到新的汊点方程组,新方法的通用性较好,值得推广应用。  相似文献