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31.
32.
油气地表化探数据的失真(特别是数据中的高值失真点)直接影响到化探异常圈定。本文根据油气地表化探数据的分布特点,利用概率统计原理,提出一种适合油气化探资料前期处理的失真数据的概率判定方法和处理手段,在对实际资料的应用中,取得了良好的效果。  相似文献   
33.
Steel box columns are widely used in steel building structures in Taiwan due to their dual strong axes. To transfer the beam-end moment to the column, diaphragm plates of the same thickness and elevations as the beam flanges are usually welded inside the box column. The electro-slag welding (ESW) process is widely used to connect the diaphragms to the column flanges in Taiwan because of its convenience and efficiency. However, ESW may increase the hardness of the welds and heat-affected zones (HAZs), while reducing the Charpy-V notch strength in the HAZ. This situation can cause premature fracture of the diaphragm-to-column flange welds before a large plastic rotation is developed in the beam-to-box column joints. To quantify the critical eccentricity and the effectiveness of fracture prediction, this study uses fracture prediction models and finite element model (FEM) analysis to correlate the test results. In this study, two beam-to-box column connection subassembly tests are conducted with different loading protocols and ESW chamber shapes. To implement a fracture prediction model, the material parameters are established from circumferential notched tensile tests and FEM analysis. Test results indicate that the fracture instances can be predicted on the basis of the cumulative plastic deformation in the HAZs. Analytical results indicate that fracture instances and locations are sensitive to the relative locations of the ESW joints and beam flange. Tests also confirm that the possible fracture of the diaphragm-to-column flange joints can be mitigated by enlarging the chamber of the ESW joint.  相似文献   
34.
徐清扬  王浩  吴静 《工程地质学报》2016,24(s1):855-860
通过研究土的崩解特性进而指导工程施工,按《岩土工程勘察规范》对土的分类标准,对不同粒级分配的土样即砂土、黏粉、粉黏各选取两个代表性样品进行崩解特性试验,研究得出两点结论:(1)崩解过程开始时崩解速度较快,土样表面细小分散颗粒落入水中,此现象砂粉尤为明显,大量土体脱落,崩解速度极为快速。砂粉粒度程度较大,土的孔隙性和透水性较大,因此崩解速度较快,本次两个试样在近1h内完全崩解。黏粉试样含砂粉和粉黏,崩解速度处于砂粉及粉黏之间。而粉黏试样崩解时间较长,崩解过程较为缓慢,甚至几天都无法崩解;(2)崩解过程并不是一个规律的过程,跟土体的物理特性也有关系,且崩解过程中崩解方式不同,开始主要以粉末状和小碎块状为主,浸水时间较长后开始出现裂隙,随着裂隙的增大,期间伴随粉末状崩落,土体呈块状裂开,过程中不断有气泡逸出,水质浑浊。  相似文献   
35.
浆固碎石桩成桩注浆影响范围现场试验研究   总被引:5,自引:0,他引:5  
左威龙  刘汉龙  陈永辉 《岩土力学》2008,29(12):3329-3332
浆固碎石桩作为一种新型桩基技术,不仅具有一般刚性桩的桩体置换作用,而且能改善桩周土的力学性质,从而可有效地提高复合地基的承载力及减小沉降变形。通过现场进行成桩前后的桩周土性质研究,验证了注浆对桩周土性质的改善作用,得出成桩时注浆影响范围及分布规律。针对黏性土中浆固碎石桩浆液挤密作用,按平面轴对称问题分析了塑性区边界条件及内部单元体的平衡条件,提出浆固碎石桩浆液影响范围的计算公式。理论公式计算结果与原位测试结果较为符合,从而验证了计算方法的合理性,这对浆固碎石桩的注浆加固具有一定的指导意义。  相似文献   
36.
盐岩蠕变相似模型及相似材料研究   总被引:2,自引:0,他引:2  
任松  郭松涛  姜德义  杨春和 《岩土力学》2011,32(Z1):106-110
相似材料模型试验是研究岩土工程的重要手段之一。基于相似理论,应用量纲分析法,推导考虑盐岩蠕变特性的相似模型,得到相关参数的相似判据,并以不同粒径的工业盐、精铁粉为骨料,环氧树脂、乙二胺为黏合剂构成相似材料,经过大量的材料配比力学试验,得到了一种基本满足金坛盐岩蠕变相似模型要求的材料配比,为开展盐岩地下油气储库建造及运营期的变形、破坏相似材料模型试验打下了坚实的基础  相似文献   
37.
Abstract

Results of a study on change detection in hydrological time series of annual maximum river flow are presented. Out of more than a thousand long time series made available by the Global Runoff Data Centre (GRDC) in Koblenz, Germany, a worldwide data set consisting of 195 long series of daily mean flow records was selected, based on such criteria as length of series, currency, lack of gaps and missing values, adequate geographical distribution, and priority to smaller catchments. The analysis of annual maximum flows does not support the hypothesis of ubiquitous growth of high flows. Although 27 cases of strong, statistically significant increase were identified by the Mann-Kendall test, there are 31 decreases as well, and most (137) time series do not show any significant changes (at the 10% level). Caution is advised in interpreting these results as flooding is a complex phenomenon, caused by a number of factors that can be associated with local, regional, and hemispheric climatic processes. Moreover, river flow has strong natural variability and exhibits long-term persistence which can confound the results of trend and significance tests.  相似文献   
38.
This paper presents results from a full scale decay test made with a tanker in a relatively protected area in the Brazilian coast. In at least two tests the environmental loads (wind, waves and current) were very small and the time history of the surge motion was well behaved, making it possible to check some proposed models for the damping in the hull and mooring lines. Field data seem to confirm that the damping is indeed of the fluid viscosity type and the theoretical models are able to recover roughly 75% of the observed damping, the energy dissipation in the mooring lines being, by far, the major contribution. The remaining 25% are likely due to non modeled effects, such as the environment influence, which although small and not measured certainly exists, and to the friction between the mooring lines and the seabed.  相似文献   
39.
To investigate the behavior of dredged-sea-sand fill compacted inside tide embankments with a damaged geosynthetic mat, centrifugal model tests and numerical simulation were conducted, both considering variations in sea level. The results from the three centrifugal model tests demonstrate that the subsidence of the dredged-sea-sand fill inside tide embankments with a damaged geosynthetic mat was strongly affected by the loss of dredged-sea-sand into the filter layers with large particles and a decrease in the bearing capacity of the filter layers with small particles. In addition, a comparison of the test and simulation results confirms that the loss of sand into the filter layer and the subsidence of the dredged-sea-sand fill were well reproduced by the numerical simulation.  相似文献   
40.
根据曹娥江大闸的环境特点,对不同厂家的喷涂金属涂层和富锌涂料进行了浪溅区、潮差区和大气区的室外近2年的暴露试验以及室内近10 500 h的盐雾试验、盐水周期性浸泡试验和盐水浸泡试验.研究结果表明,喷涂金属层耐腐蚀性能普遍优于富锌涂料层;在试验采用的富锌涂料中,高锌粉含量的富锌涂料防腐蚀性能优于低锌粉含量的富锌涂料;从长效防腐蚀角度考虑,建议采用喷涂金属防腐蚀措施.  相似文献   
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