A 3D finite element simulation model for TBM tunnelling in soft ground     

Thomas Kasper  Günther Meschke 《国际地质力学数值与分析法杂志》2004,28(14):1441-1460

  相似文献   

1999年8月11日日全食期间的重力吸引效应研究     

刘少明 《大地测量与地球动力学》2004,24(4):13-19

对1999年8月11日日全食阴影扫过欧洲期间,设在Annelles,Uccle,Walferdange和Bondy弹簧和超导重力仪的记录进行了分析.为了确定月亮对太阳万有引力可能的遮挡效应的极限,对超导和弹簧重力仪记录进行了比较.同时也对LCR和阿斯卡尼亚重力仪观测结果进行了讨论.结论是如果日食重力吸引效应存在,它应在超导重力仪±1 nm/s2(0.1×10-8ms-2)的观测精度范围之内.研究发现在以上情形下,弹簧和超导重力仪都在它们的精度范围内工作,并且日食引起的异常环境干扰可能使重力信号有重大的改变.  相似文献   

The crustal and upper-mantle structure of the interior Arabian platform   总被引：4，自引：0，他引：4  

Abdullah M. S. Al-Amri 《Geophysical Journal International》1999,136(2):421-430

  相似文献   

1.8 Ga Svecofennian post-collisional shoshonitic magmatism in the Fennoscandian shield   总被引：8，自引：0，他引：8  

O. Eklund  D. Konopelko  H. Rutanen  S. Fr  jd    A. D. Shebanov 《Lithos》1998,45(1-4):87-108

At least 14 small (1–11 km across) 1.8 Ga Svecofennian post-collisional bimodal intrusions occur in southern Finland and Russian Karelia in a 600-km-long belt from the Åland Islands to the NW Lake Ladoga region. The rocks range from ultramafic, calc-alkaline, apatite-rich potassium lamprophyres to peraluminous HiBaSr granites, and form a shoshonitic series with K₂O+Na₂O>5%, K₂O/Na₂O>0.5, Al₂O₃>9% over a wide spectrum of SiO₂ (32–78%). Although strongly enriched in all rocks, the LILE Ba and Sr and the LREE generally define a decreasing trend with increasing SiO₂. Depletion is noted for HFSE Ti, Nb and Ta. Available isotopic data show overlapping values for lamprophyres and granites within separate intrusions and a cogenetic origin is thus not precluded. Initial magmas (Mg#>65) in this shoshonitic association are considered to be generated in an enriched lithospheric mantle during post-collisional uplift some 30 Ma after the regional Svecofennian metamorphic peak. However, prior to the melting episode, the lithospheric mantle was affected by carbonatite metasomatism; more extensively in the east than in the west. The melts generated in the more carbonate-rich mantle are extremely enriched in P₂O₅4%, F12,000 ppm, LILE: Ba9000 ppm, Sr7000 ppm, LREE: La600 ppm and Ce1000 ppm. The parental magma underwent 55–60% fractionation of biotite+clinopyroxene+apatite+magnetite+sphene whereupon intermediate varieties were produced. After further fractionation, 60–80%, of K-feldspar+amphibole+plagioclase±(minor magnetite, sphene and apatite), leucosyenites and quartz-monzonites were formed. In the west, where the source was less affected by carbonatite metasomatism, calc-alkaline lamprophyres (vogesites, minettes and spessartites) and equivalent plutonic rocks (monzonites) were formed. Removal of about 50% of biotite, amphibole, plagioclase, magnetite, apatite and sphene produced peraluminous HiBaSr granites. The impact of crustal assimilation is considered to be low. At about 1.8 Ga, the post-collisional shoshonitic magmatism brought juvenile material, particularly enriched in alkalis, LILE, LREE and F, into the crust. Although areally restricted, the regional distribution of the post-collisional intrusions may indicate that larger volumes of 1.8 Ga juvenile material resides in unexposed parts of the crust.  相似文献   

大型越江盾构隧道施工安全与风险管理探讨          下载免费PDF全文

安政翃  季玉国 《探矿工程》2008,35(12):78-83

对大型泥水盾构隧道施工安全与施工风险进行详细全面的分析,指出了施工安全与施工风险对人身安全、工程结构和施工机械设备带来的危害。结合工程实例和实践经验,对大型越江盾构隧道施工安全与风险管理进行全面探讨。  相似文献   

盾构施工参数与沉降变形关系模型构建     

张建坤  陈昌彦  陈浩 《测绘科学》2016,41(8):156-160

针对盾构施工参数变化对施工引起的地表变形的重要影响,该文构建了盾构施工参数与地表沉降变形关系模型。以北京市某地铁盾构区间施工过程中的实测数据为基础,分析了不同盾构施工参数与地表沉降变形的关联度和相关性,得到不同参数对沉降变形贡献值的大小;之后,利用多元回归模型方法建立主要影响参数与地表变形的关系模型,并进行模型的合理性检验;最后,利用该模型得到的沉降量与实测数据进行对比分析,结果显示符合性较好。  相似文献   

Lithospheric thermal structure in the Baltic shield   总被引：1，自引：0，他引：1  

V. Pasquale  M. Verdoya  P. Chiozzi 《Geophysical Journal International》1991,106(3):611-620

  相似文献   

Frequency dependence of Q in the mantle underlying the shield areas of Eurasia, Part I: analyses of short and intermediate period data   总被引：1，自引：0，他引：1  

Zoltan A. Der  Alison C. Lees  Vernon F. Cormier  Lisa M. Anderson 《Geophysical Journal International》1986,87(3):1057-1084

  相似文献   

Frequency dependence of Q in the mantle underlying the shield areas of Eurasia, Part III: The Q model   总被引：2，自引：0，他引：2  

Zoltan A. Der  Alison C. Lees  Vernon F. Cormier 《Geophysical Journal International》1986,87(3):1103-1112

  相似文献   

某地铁区间盾构法施工监测分析     

曹占虎 《测绘工程》2014,23(9):70-73

地铁区间盾构法施工监测是确保地铁区间施工安全的重要保障。在分析盾构隧道施工地表建（构）筑物沉降监测、建（构）筑物倾斜监测、裂缝监测、隧道管片隆沉监测、隧道管片水平收敛监测等监测内容、监测方法、监测频率及控制标准的基础上,结合某地铁区间盾构法施工监测工程实践,分析所获得的横向地表沉降、隧道管片沉降或隆起、净空水平收敛监测的结果,得到相应横向地表沉降、纵向地表沉降和沉降过程的规律,以及隧道管片沉降或隆起、净空水平收敛监测变形规律。  相似文献