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421.
422.
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
423.
424.
Strain softening and microstructural evolution of anorthite aggregates and quartz-anorthite layered composites deformed in torsion 总被引:1,自引:0,他引:1
Shaocheng Ji Zhenting Jiang Richard Wirth Bin Xia 《Earth and Planetary Science Letters》2004,222(2):377-390
Torsion experiments of anorthite (An) aggregates and layered composites with equal volume fractions of quartz (Qtz) and An were performed in a gas-medium apparatus at a confining pressure of 400 MPa, temperatures from 1373 to 1473 K, and twist rates from 1.0×10−4 to 3.0×10−4 rad/s. Dense specimens were fabricated from An glass and Qtz crystalline powder using hot isostatic pressing (HIP) techniques. Both An aggregates and Qtz-An layered composites show a continuous strain weakening from a peak stress at γ=0.2-0.3 to γ=3.2, and steady-state flow has not reached under the experimental conditions. The weakening is even more pronounced in the layered composites than the monolithic aggregates, suggesting channeling or localization of flow into the weak material between strong layers. The sheared An specimens developed pervasively C-S-C′ structures which are similar to those observed in natural ductile shear zones. TEM and electron backscattering diffraction (EBSD) fabric analyses suggest that grain boundary migration recrystallization-accommodated dislocation creep with (010)[100] as the dominant slip system was operating in the An. The strain softening may be due to the development of crystallographic preferred orientation (CPO), the operation of dynamic recrystallization and the formation of extremely fine-grained recrystallized material in the narrow C′ shear bands. 相似文献
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通过对“CM桩复合地基”(以下简称CM地基 )承载力试验结果的分析 ,获得了一些有益的结论 ,对其在徐州地区的推广和应用提供参考。 相似文献
427.
LI Guowu YANG Guangming MA Zhengsheng SHI Nicheng XIONG Ming FAN Haifu SHENG Ganfu China University of Geosciences 《《地质学报》英文版》2005,79(3):325-331
1 Introduction Chevkinite groups can be assigned to the chevkinite-(Ce) subgroup and perrierite-(Ce) subgroup in accord with the angle β : β ≈ 100o for the chevkinite subgroup and β ≈ 113o for the perrierite subgroup. Chevkinite-(Ce), polykovite-(Ce) and Maoniupingite (new mineral No. 017 of 2003) belong to the former subgroup, while renjeite and matsubaraite belong to the latter group. As strontio-chevkinite is a Sr-analogue of perrierite, usually the natural chevkinite-(Ce) group min… 相似文献
428.
David Besson Olivier Parize Jean-Loup Rubino Jean-Pierre Aguilar Marie-Pierre Aubry Bernard Beaudoin William A. Berggren Georges Clauzon Philippe Crumeyrolle Yann Dexcoté Nicolas Fiet Silvia Iaccarino Gonzalo Jiménez-Moreno Cécile Laporte-Galaa Jacques Michaux Katharina von Salis Jean-Pierre Suc Jean-Yves Reynaud Roland Wernli 《Comptes Rendus Geoscience》2005,337(12):1045-1054
An integrated study combining facies analysis, multiple group biostratigraphy, identification of depositional sequences and mapping has been conducted on the Miocene Molasse Basin of the external Alps (southeastern France). The filling of the basin is described as resulting from a succession of fluvial incisions subsequently filled during marine transgressions. The major incision is dated as Latest Burdigalian and the major transgression as Langhian. This revised interpretation of the Miocene physiographic evolution of the Molasse Basin implies a re-examination of previous stratigraphic correlations within the basin. To cite this article: D. Besson et al., C. R. Geoscience 337 (2005). 相似文献
429.
Former geophysical surveys performed in the region of the volcanic centre of the České Stř edohoří Mts. in North Bohemia (the
Ohře Rift zone) showed that anomalous volcanic bodies and features can be effectively identified within sedimentary environment.
For this reason we carried out new geophysical measurements in the area of the main mafic intrusion of essexitic character.
The target was the exact location and geometry of the intrusion and its relation to other components of the volcanic centre.
We used gravity, magnetic, shallow seismic and electromagnetic techniques. The new gravity and magnetic data were tied to
the old databases so that we could investigate the area as a whole complex. Electromagnetic measurements were applied in the
area of the expected extent of the intrusion, and the seismic measurements in the central part of the intrusion.
Based on all the data, mainly on gravity modelling, we delineated not only the surface and subsurface extent of the intrusion,
but we also defined the hidden relief of the intrusion. It was found that the intrusion is formed by a single body that has
a few protrusions, and not by a set of separate individual intrusions, as indicated by surface outcrops. However, the body
of the intrusion is affected by a major fault that caused lithological differences on both sides (essexite/monzodiorite).
In detail we show the depth of the debris cover and the thickness of the weathered zone in the central part of the essexite
body. We also derived indications of tectonic elements in the area of the intrusion in the main structural/tectonic direction
in the region. The results will be utilized to establish a 3D geological model of the whole volcanic centre.
This investigation may serve as an example of non-seismic geophysical exploration applied to the study of volcanic centres
surrounded by sedimentary rocks. 相似文献
430.
碎石桩复合地基设计方法的探讨 总被引:3,自引:0,他引:3
通过对碎石桩复合地基承载力和抗震液化设计的对比和分析,提出了以承载力和抗震液化相互综合考虑的设计方法。 相似文献