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991.
992.
已有的管道极限弯矩承载力解析方法忽略了截面的椭圆化变形,且假设管道截面达到全塑性抵抗力,这对于薄壁管道是不合理的。针对这些不足,在已有解析解的基础上,考虑管道截面塑性区的椭圆化变形以及管道轴向与环向材料的各向异性,推导了管道在内压、轴向力和弯矩联合荷载作用下的极限弯矩承载力解析解。并通过定义材料屈服后不同的广义模量,提出了管道极限弯矩承载力的上限解析解和下限解析解。在此基础上,研究了材料各向异性系数、径厚比以及初始荷载等参数对极限弯矩承载力上限和下限解析解的影响,并得到了一些有益的结论。 相似文献
993.
Dongxing Wang Nor Edine Abriak Rachid Zentar 《Marine Georesources & Geotechnology》2017,35(4):472-480
The dredged marine sediments are classified as waste and how to deal with such kind of abandoned materials is a great challenge. The main objective of this experimental work is to provide a novel way to reuse dredged sediment as filling materials in road section. The laboratory dewatering test is performed to model the in situ evaporation and dewatering process of untreated and treated sediment with chemical binder. The impact of binder amount and time is discussed on the change of water content influenced by evaporation. To valorize dredged sediments as roadbed materials, a hydraulic binder is incorporated to investigate its effect on the bearing capacity and strength performance. The suitability of stabilized sediment is assessed based on the obtained mechanical results followed by a detailed discussion on the in situ test roads. 相似文献
994.
995.
The purpose of this study is the evaluation of dynamic behavior induced by seismic activity on a silo system, containing bulk material, with a soil foundation. The interaction effects between the silo and bulk material, as well as the effects produced between the foundation of the silo and the soil, were taken into account. Proposed simplified approximation, as well as the finite model, were used for analysis. The results, from the presented approximation, were compared with a more rigorous obtainment method. Initially, the produced simplified approximation, with elastic material assumption for the grain, could determine the pressures on the dynamic material along with displacements along the height of the silo wall and base shear force, etc., with remarkable precision. Some comparisons, via a change of soil and/or foundation conditions, were also made regarding the seismic pressure of the dynamic material pressure, displacement and base shear forces for both squat and slender silos. Comparing the analytical predictions to results from the numerical simulations produced good results. It can be concluded that the model can be used effectively to perform a broad suite of parametric studies, not only at the design stage but also as a reliable tool for predicting system behavior under the limit state of the system. The results and comprehensive analysis show that displacement effects and base shear forces generally decreased when soil was softer; however, soil structure interaction (SSI) did not have any considerable effects on squat silos and therefore need not be taken into practice. 相似文献
996.
利用GFZ Release 05卫星重力GRACE观测数据,计算2010年2月27日智利MW8.8逆冲型地震的同震重力和重力梯度变化,分析其分布特征,可知:由GRACE探测到的同震重力变化在断层俯冲区域可达-9.5μGal,断层隆升区域可达+3.5μGal,结果与利用SNREI地球模型的位错理论计算的同震重力变化较一致,说明利用GFZ Release05 DDK5滤波数据,更能精确的反映同震重力场变化;GRACE检测的智利地震同震径向重力梯度变化Trr最大可达-600μE,位于发震断层东侧俯冲区域;通过对同震重力梯度分布特征分析,初步判断发生同震物质迁移的区域范围在断层俯冲区域为(67°—72°W,33°—38°S),在断层隆升区域为(73°—77°W,35°—39°S)。 相似文献
997.
Recognition of shear heating on a long‐lived major fault using Raman carbonaceous material thermometry: implications for strength and displacement history of the MTL,SW Japan 下载免费PDF全文
The extent to which movement on major faults causes long term shear heating is a contentious issue and an important aspect in the debate about the strength of major faults in the crust. Comparing the results of experimental work on the kinetics of crystallization of carbonaceous material with results of thermal modeling show that the Raman carbonaceous material (CM) geothermometer is well suited to studying shear heating on geological time scales in suitable lithologies exposed around exhumed major fault zones. The Median Tectonic Line (MTL), SW Japan, is the largest on‐land fault in Japan with a length of > 800 km. Application of Raman CM thermometry to pelitic schist adjacent to the fault reveals the presence of a rise in peak temperature of around 60 °C over a distance of around 150 m perpendicular to the MTL fault plane. The spatial association of this thermal anomaly with the fault implies it is due to shear heating. Thermal modeling shows the recorded thermal anomaly and steep temperature gradient is compatible with very high rates of displacement over time scales of a few thousand years. However, the implied displacement rates lie outside those generally observed. An alternative explanation is that an originally broader thermal anomaly that developed during strike slip faulting was shortened due to the effects of normal faulting. Constraints on displacement rate, width of the original anomaly, duration of heating and peak temperature imply a coefficient of friction, μ, greater than 0.4. 相似文献
998.
999.
黔西南金矿勘查已升级至国家战略层面,弄清其成因机制具有重要意义。综合运用区域重磁资料,对区内深部基底物质进行研究,通过对浅、深部隐伏岩体圈定及地质-重力模型异常拟合计算,结合区域地质、矿产及化探资料,提出金矿成矿物源,主要有两种供给方式,一种为前人的由表层沉积岩提供矿源层,一种为本研究提出的由深部以中生代花岗岩或变质基底(含基性-超基性岩浆岩类参与)提供矿源层。厘定了12处浅部隐伏岩体异常区,分离出4大深部岩浆岩块体。研究成果基本反映了区内的客观地质现象和地质作用结果,为研究区金矿勘探提供相关依据。 相似文献
1000.
鄂尔多斯盆地铀富集分布的影响因素分析 总被引:3,自引:1,他引:2
前人研究成果分析表明,鄂尔多斯盆地石油主要富集于三叠系延长组和侏罗系地层,天然气主要为下古生界气藏,煤主要赋存于石炭系至侏罗系诸多地层。收集到的地质、测井资料和岩芯分析资料表明铀赋存于盆地奥陶系、石炭二叠系、三叠系、侏罗系及白垩系地层,铀在盆地深部和浅部地层赋存特征不同,深部地层的高自然伽马异常与铀丰度相关性显著。断裂构造存在证据和分布特征研究表明,鄂尔多斯盆地断裂构造发育,且对铀元素分布具有重要作用。本研究表明,盆地历经的构造运动和沉积环境变迁决定了多种矿产的赋存特征,盆地中油、气、煤对铀富集分布具有积极的促进作用。盆地内有机质丰度与铀异常关系密切。 相似文献