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951.
造山岩套中镁铁质和长英质岩浆的相互作用研究进展 总被引:7,自引:0,他引:7
结合2002年9月14—21日在意大利中部召开的“欧洲花岗岩网络”年会的会议讨论和野外考察内容,评述了镁铁质和长英质岩浆的相互作用关系以及镁铁质熔体在巨量花岗岩浆形成中的作用。在花岗岩岩基内,不仅出露有狭义的花岗岩,还可见到更富镁铁质的岩石,例如辉长岩和闪长岩。一般,这些镁铁质岩石,既可能是慢源母岩浆结晶的产物,或是岩浆混合和分异一同化作用中的端员组分,也可能代表了下地壳源区的物质,或者是导致大陆壳部分熔融的热源物质记录。对镁铁质和长英质岩浆相互作用关系的研究,有助于限定造山作用过程中地壳物质再循环和新的地慢物质加入的相对贡献。 相似文献
952.
953.
D. Bala Subrahamanyam Radhika Ramachandran K. Sen Gupta Tuhin K. Mandal 《Boundary-Layer Meteorology》2003,107(3):683-695
The upper air data collected from the balloon-borne GLASS Sondes launched from the Oceanic Research Vessel (ORV) Sagar Kanya during the Intensive Field Phase of the Indian Ocean experiment (INDOEX, IFP-99;SK-141 Cruise) are utilized forstudying the variability in the mixed-layer heights observed over the western tropical Indian Ocean and central Arabian Sea. During the entire cruise, typical daytime convective mixed-layer heights (roughly corresponding to 1400 LT) obtained from V and q profiles, were observed to be in the range 200–900 m. Shallowmixed -layer heights are observed, in general, over the Inter-Tropical Convergence Zone (ITCZ). Over the central Arabian Sea, vertical profiles of V and q demonstrate a double mixed-layer structure of the marine atmospheric boundary layer (MABL), which gradually disappears close to the Indian coastline. 相似文献
954.
One of the significant effects of considering soil-structure interaction in the analysis of structures is the increase in
the fundamental natural period compared to the fundamental natural period of a similar structure, fixed at the base. Applied
Technology Council (ATC) originally set forth some provisions to calculate the fundamental natural period of flexible based
structures using the period of a similar structure, fixed at the base, and lateral and rocking stiffness coefficients of the
foundation. These provisions became the basis of current soil-structure interaction recommendations in several building codes.
The fundamental natural periods of structures founded on different types of foundations computed using recommendations of
the ATC are compared with those computed using a simplified model to perform soil-structure interaction of shear-type structures.
Results show that the provisions given in ATC may be used for structures supported on shallow footings but may not be applicable
for structures supported on pile foundations or foundations having the ratio of lateral to rotational stiffness coefficients
different from those of shallow foundations. An equation, similar to the equation recommended by ATC, is presented to estimate
the fundamental natural period of structures supported on pile foundations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
955.
沉降控制复合桩基的试验研究及适用范围探讨 总被引:1,自引:1,他引:1
沉降控制复合桩基在上海软土地区得到了广泛的应用,但某住宅小区由于其地质条件的特殊性,不能满足上海市< 地基基础设计规范>(DGJ08-11-1999)中沉降控制复合桩基对桩端持力层的特定要求,超出了其适用范围,通过多组原位试验研究,探讨了沉降控制复合桩基在这种特殊地质条件下桩土共同作用的工作机理,分析了在这种地质条件下应用沉降控制复合桩基的可行性. 相似文献
956.
桩筏基础相互作用分析 总被引:1,自引:0,他引:1
提出了考虑土-桩-筏相互作用的迭代分析方法,可获得筏板的内力和桩身轴力等.考虑了桩筏基础下群桩效应作用的群桩桩顶反力分布、群桩桩端力分布及桩与桩相互作用等问题,使得计算的群桩单桩刚度较合理.同时,具有能考虑土的非线性、成层地基及利用单桩静载试验成果反演分析所得参数运用于群桩分析等特点.采用的8节点等参板单元可适用于分析平面不规则形状及变厚度的薄筏板和厚筏板.用笔者提出的方法对桩筏基础实例进行了分析,研究了桩长对该桩筏基础相互作用的影响,并与实测成果及其他学者研究成果进行了对比,表明了该方法能较合理地分析桩筏基础相互作用. 相似文献
957.
塔里木东北地区盆山耦合及其对油气成藏的控制 总被引:6,自引:0,他引:6
震旦纪一寒武纪库鲁克塔格、英吉苏地区为陆内裂谷盆地。加里东末期与早海西运动造成塔东地区的普遍抬升剥蚀,孔雀河斜坡、罗布庄凸起开始形成,早二叠世,塔里木板块与中天山地块、哈萨克斯坦一准噶尔板块最终碰撞拼贴,古天山造山带相继形成。燕山晚期,受中特提斯洋关闭影响。塔里木盆地基底随造山带的构造抬升而部分抬升,喜马拉雅期开始,在南北向挤压力作用下,收缩、隆升的山体侧向扩张,向沉积盆地逆冲形成型逆冲推覆构造。造山带和盆地的共同演化不仅形成了多套烃源岩,而且控制了古生界和中新生界两套不同的油气成藏系统。元古界地层由北向南推覆,可能预示着在库鲁克塔格南缘西段山前前寒武纪地层下部保存有古生代和中新生代烃源岩建造,如果配有有利的油气储盖组合和圈闭,有望在山前获得突破。 相似文献
958.
The theory of physical interaction field by a differential geometrical approach combines the deformation field with the physical field (e.g., electromagnetic field), and derives a new tensorial relation between the deformation and the dielectric anisotropy of the crustal rocks. This relation can be applied to dielectric anisotropies of deformed natural rocks such as mylonites or gneisses. The dielectric anisotropies of mylonites are observed to increase as plastic strains of mylonites increase. Moreover, the derived tensorial relation can be linked to the electromagnetic potential field (deformational anomalies) in a deformed crust. A physico-geometrical consideration on this theory of physical interaction field is mathematically similar to ones on the theory of field in the Finsler space or on the concept of a unified gauge field. 相似文献
959.
A technique for modeling transient wave propagation in unbounded media is extended and applied to seismic soil–structure interaction analysis in the time domain. The technique, based on the discontinuous Galerkin method, requires lower computational cost and less storage than the boundary element method, and the time‐stepping scheme resulting from Newmark's method in conjunction with the technique is unconditionally stable, allowing for efficient and robust time‐domain computations. To extend the technique to cases characterized by seismic excitation, the free‐field motion is used to compute effective forces, which are introduced on the boundary of the computational domain containing the structure and the soil in the vicinity of the structure. A numerical example on a dam–foundation system subjected to seismic excitation demonstrates the performance of the method. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
960.
Michail A. Strunin Tetsuya Hiyama Jun Asanuma Tetsuo Ohata 《Boundary-Layer Meteorology》2004,111(3):491-522
This study investigates the convective boundary layer (CBL) that develops over anon-homogeneous surface under different thermal and dynamic conditions. Analysesare based on data obtained from a Russian research aircraft equipped with turbulentsensors during the GAME-Siberia experiment over Yakutsk in Siberia, from April to June 2000.Mesoscale thermal internal boundary layers (MTIBLs) that radically modified CBLdevelopment were observed under unstable atmospheric conditions. It was found thatMTIBLs strongly influenced the vertical and horizontal structures of virtual potentialtemperature, specific humidity and, most notably, the vertical sensible and latent heatfluxes. MTIBLs in the vicinity of the Lena River lowlands were confirmed by clouddistributions in satellite pictures.MTIBLs spread through the entire CBL and radically modify its structure if the CBL isunstable, and strong thermal features on the underlying surface have horizontal scalesexceeding 10 km. MTIBL detection is facilitated through the use of special parameterslinking shear stress and convective motion.The turbulent structure of the CBL with and without MTIBLs was scaled usingthe mosaic or flux aggregate approach. A non-dimensional parameterLRau/Lhetero (where LRau is Raupach's length and Lhetero is the horizontal scale of the surface heterogeneity)estimates the application limit of similarity and local similarity scaling models forthe mosaic parts over the surface. Normalized vertical profiles of wind speed, airtemperature, turbulent sensible and latent heat fluxes for the mosaic parts withLRauLhetero < 1 could be estimated by typical scalingcurves for the homogeneous CBL. Traditional similarity scaling models for the CBLcould not be applied for the mosaic parts with LRau/Lhetero > 1.For some horizontally non-homogeneous CBLs, horizontal sensible heat fluxes werecomparable with the vertical fluxes. The largest horizontal sensible heat fluxes occurred at the top of the surface layer and below the top of the CBL.Formerly affiliated to the Frontier Observational Research System for Global ChangeFormerly affiliated to the Frontier Observational Research System for Global Change 相似文献