湿陷性土地区工程建设质量问题综述     

朱沈阳 《岩土工程技术》2004,18(4):209-212

对湿陷性土地区勘察、设计、施工问题进行了论述 ,给出一些工程实例 ,对以后湿陷性土地区工程建设具一定的指导意义  相似文献   

Satellite gradiometry using a satellite pair   总被引：1，自引：1，他引：1  

W. Keller  M.A. Sharifi 《Journal of Geodesy》2005,78(9):544-557

The GRACE mission has substantiated the low–low satellite-to-satellite tracking (LL-SST) concept. The LL-SST configuration can be combined with the previously realized high–low SST concept in the CHAMP mission to provide a much higher accuracy. The line of sight (LOS) acceleration difference between the GRACE satellite pair, the simplest form of the combined observable, is mostly used for mapping the global gravity field of the Earth in terms of spherical harmonic coefficients. As an alternative observable, a linear combination of the gravitational gradient tensor components is proposed. Being a one-point function and having a direct relation with the field geometry (curvature of the field at the point) are two noteworthy achievements of the alternative formulation. In addition, using an observation quantity that is related to the second-instead of the first-order derivatives of the gravitational potential amplifies the high-frequency part of the signal. Since the transition from the first- to the second-order derivatives includes the application of a finite-differences scheme, the high-frequency part of the noise is also amplified. Nevertheless, due to the different spectral behaviour of signal and noise, in the end the second-order approach leads to improved gravitational field resolution. Mathematical formulae for the gradiometry approach, for both linear and higher-degree approximations, are derived. The proposed approach is implemented for recovery of the global gravitational field and the results are compared with those of LOS acceleration differences. Moreover, LOS acceleration difference residuals are calculated, which are at the level of a few tenths of mGal. Error analysis shows that the residuals of the estimated degree variances are less than 10^–3. Furthermore, the gravity anomaly residuals are less than 2 mGal for most points on the Earth.  相似文献   

Inversion of source parameters for moderate and small earthquakes in Beijing region     

兰从欣  刘杰  郑斯华  马士振  李菊珍 《地震学报(英文版)》2005,18(5):532-543

Introduction Beijing and the adjacent regions is a significant seismically active area and many geoscien- tists have studied to different extents the non-elastic attenuation and source parameters in the area. GAO et al (1986) and ZHUO et al (1990) studied the coda Q in the Beijing region by the method of dominant frequency and mechanical frequency division with the simulated data. With the con- tinuous construction of digital seismic station network, the digital data are more favorably used…  相似文献   

2003年西藏波密南Ms5.7地震现场考察     

何玉林  曹忠权  陈立春  陈亚明 《中国地震》2005,21(4):469-474

2003年8月18日在西藏林芝地区发生的MS5．7地震的宏观震中位于波密县城扎木镇南13km的高山无人区。极震区烈度达到Ⅶ度。Ⅶ和Ⅵ度区面积分别为3200和11000km^2。这次地震的发生与NW向的嘉黎断裂和NE向的扎木-马尼翁断裂的活动有关。震区建筑物遭到一定程度的破坏或影响，地面破坏现象较明显。  相似文献   

Experimental Research on Microscopic Indicators of Temperature's Returning-to-Zero in Deformation of Calcite and Discussions of Correlation Problem     

Yao Daquan 《中国地震研究》2005,19(1):35-42

1 RESEARCHINTOTHEACTIVITYTIMEOFFAULTSINBEDROCKAREASDatemeasurementoffaultactivityisessentialforrecognizingtheactivitybehaviorofafault,inversingseismologicalandgeologicaleventsandprobingintoearthquakerhythms .Itismoredifficulttodeterminetheactivitytimeoffa…  相似文献   

燕郊等测点迁移优化与地磁观测研究   总被引：1，自引：2，他引：1  

高金田  赵从利 《地震地磁观测与研究》1997,18(3):47-55

为优化地磁观测条件，开展了燕郊、夏垫等测点迁移工作；按照测眯迁移原则与实施技术方案，完整地收集并整理了地质构造与地球物理等方面的基本资料；进行了野外实地勘察，磁场梯度的测量，确定了新测点，在新老测点上进行了较长时间的地磁场对比观测；应用多种方法分析研究了地磁对比观测资料，结果表明，新老测点与有关测点的地磁变化具有良好的一致性，并得到了新老测点之间的地磁数据的按点差。  相似文献   

SEDIMENT MODEL EXPERIMENT IN JINGHONG HYDROPOWER PROJECT AREA     

TAN Guangming  Pro.  Doc. Wuhan University of Hydraulic  electric Engineering  Wuhan  China ZHANG Xiaofeng Pro.  Doc. Wuhan University of Hydraulic  electric Engineering  Wuhan  China DUAN Wenzhong Pro. Wuhan University of Hyd 《国际泥沙研究》1997,(3)

I.BRIEFINTRODUCTIONInthechainofhydroelectricpowerstationsalongthemiddleandlowerreachesofLancangiiangforer,Jinghongpowerstationisthe6thonewiththemultipleeconomicbenefitofelectricalgenerationandnavigation.Thepowerstationconsistsof3x300MWunitsandeachturbinehasamaximumintakingflowof390m'/s.Arrangedfromtherighttoleflbankofthedamisashipelex,ator.ti7hichisaccessibleto300tonboats,thespillwa}'damsectionandthepowerhouse.Ontheright,middleandleftsideofthepotverhouserespectively.therearethreebotto…  相似文献   

Site effects in Mexico City: Constraints from surface wave inversion of shallow refraction data   总被引：1，自引：0，他引：1  

J. Ramos-Martínez  F.J. Chávez-García  E. Romero-Jiménez  J.L. Rodríguez-Zúñiga  J.M. Gómez-González 《Journal of Applied Geophysics》1997,36(4):157-165

In order to understand and simulate site effects on strong ground motion records of recent earthquakes in Mexico City, it is fundamental to determine the in situ elastic and anelastic properties of the shallow stratigraphy of the basin. The main properties of interest are the shear wave velocities and Q-quality factors and their correlation with similar parameters in zones of the city. Despite population density and paved surfaces, it is feasible to gather shallow refraction data to obtain laterally homogeneous subsoil structures at some locations. We focused our analysis in the Texcoco Lake region of the northeastern Mexico City basin. This area consists of unconsolidated clay sediments, similar to those of the lake bed zone in Mexico City, where ground motion amplification and long duration disturbances are commonly observed. We recorded Rayleigh and Love waves using explosive and sledgehammer sources and 4.5 Hz vertical and horizontal geophones, respectively. Additionally, for the explosive source, we recorded three-component seismograms using 1 Hz seismometers. We obtained phase velocity dispersion curves from ray parameter-frequency domain analyses and inverted them for vertical distribution of S wave velocity. The initial model was obtained from a standard first-break refraction analysis. We also obtained an estimation of the Q_S shear wave quality factor for the uppermost stratigraphy. Results compare well with tilt and cone penetrometer resistance measurements at the same test site, emphasizing the importance of these studies for engineering purposes.  相似文献   

中国早期的地震科学考察     

齐书勤 《山西地震》1997,(4):43-47

叙述了翁文灏、谢家荣、王竹泉、李善帮等地震科学研究的开拓者对１９１３年云南峨山、１９１７年安徽霍山、１９２０年海原、１９３３年四川叠溪、１９３６年灵山、１９３７年山东菏泽等大地震进行的现场科学考察情况以及研究成果，指出这些成果和论著是中国近现代地震科学的奠基之作。认为，认真借鉴前人的研究成果，对地震科学的进步与发展，大有裨益。  相似文献   

敦煌辐射校正场方向反射特性测量与评价   总被引：1，自引：0，他引：1  

何积泰  陆亦怀 《遥感学报》1997,1(4):246-251

和为中国遥感卫星辐射校正场项目的前期准备工作，于１９９４年６月和１９９６年９月，利用自知研制的智能型野外双向反射特征性面测量系统－－ＶＦ９２１对敦煌辐射校正场地面方向反射特性（ＢＲＯＦ）进行了测量。通过对这两次测量数据的处理和分析，对场地地ＢＲＯＦ特性进行了分析和评价。同时，对于整个测量系统和数据获取与处理中还存在的问题进行了讨论。  相似文献