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51.
高液限土主要分布于我国南方地区,是公路修筑中常见的特殊土之一,我国有关规范规定其不得直接用于路基的填筑。本文对广东某高速公路的高液限土进行了详细的室内稳定剂改良试验,得出了不同处治方法的改良效果。铺筑了采用康耐稳定剂改良的高液限土试验路,并进行了相应的观测,初步明确了康耐稳定剂改良高液限土路基的稳定效果。 相似文献
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Container shipping has been expanding dramatically during the last decade. Due to their special structural characteristics, such as the wide breadth and large hatch openings, horizontal bending and torsion play an important role to the fatigue safety of containerships. In this study the fatigue contributions from vertical bending, horizontal bending and torsion are investigated using full-scale measurements of strain records on two containerships. Further, these contributions are compared to results from direct calculations where a nonlinear 3D panel method is used to compute wave loads in time domain. It is concluded that both bending and torsion have significant impacts on the fatigue assessment of containerships. The stresses caused by these loads could be correctly computed by full-ship finite element analysis. However, this requires large computational effort, since for fatigue assessment purposes the FE analysis needs to be carried out for all encountered sea states and operational conditions with sufficient time steps for each condition. In this paper, a new procedure is proposed to run the structure finite element analysis under only one sea condition for only a few time steps. Then, these results are used to obtain a relationship between wave loads and structural stresses through a linear regression analysis. This relation can be further used to compute stresses for arbitrary sea states and operational conditions using the computed wave loads (bending and torsion moments) as input. Based on this proposed method for structure stress analysis, an efficient procedure is formulated and found to be in very good agreement with the full-ship finite element analysis. In addition it is several orders of magnitude more time efficient for fatigue assessment of containership structures. 相似文献
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A novel multiclass macroscopic model is proposed in this article. In order to enhance first-in, first-out property (FIFO) and transmission function in the multiclass traffic modeling, a new multiclass cell transmission model with FIFO property (herein called FM-CTM) is extended from its prior multiclass cell transmission model (M-CTM). Also, to enhance its analytical compactness and resultant computational convenience, FM-CTM is formulated in this paper as a set of closed-form matrix equations. The objective is to improve the accuracy of traffic state estimation by enforcing FIFO property when a fast vehicle cannot overtake a slow vehicle due to a limitation of a single-lane road. Moreover, the proposed model takes into account a different priority for vehicles of each class to move forward through congested road conditions, and that makes the flow calculation independent from their free-flow speeds. Some hypothetical and real-world freeway networks with a constant or varying number of lanes are selected to verify FM-CTM by comparing with M-CTM and the conventional CTM. Observed densities of VISSIM and real-world dataset of I-80 are selected to compare with the simulated densities from the three CTMs. The numerical results show that FM-CTM outperforms the other two models by 15% of accuracy measures in most cases. Therefore, the proposed model is expected to be well applicable to the road network with a mixed traffic and varying number of lanes. 相似文献
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注浆是土木、水利和矿山等工程建设中重要的防渗和加固技术。文章基于国内外注浆技术研究文献,总结了水泥等颗粒性浆液的“渗滤效应”及“黏度时空变异性”等理论研究成果,论述了非水反应高聚物、CW环氧树脂和微生物菌液等注浆新材料的应用现状及发展前景,介绍了细观力学数值模拟研究的突破性进展,可为地下工程注浆技术发展提供借鉴和启发作用。 相似文献
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为剖析家庭属性差异对大学生出行方式选择行为的影响,基于非集计理论,构建家庭属性差异的大学生出行选择多元Logit 模型. 根据四川省2 571 份大学生出行行为调查问卷,运用SPSS 软件标定模型参数,获取影响大学生出行选择的主要家庭属性因素,并进行敏感性分析. 结果表明:家庭平均年收入、经济净流对大学生出行方式选择有显著的影响;以航空运输为参考,家庭平均年收入、经济净流对公路运输方式选择的影响大于铁路运输;“祖辈替孙辈购买机票”的折扣票务形式可提高大学生选择航空出行的概率. 相似文献
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During the last years, many governments have set targets for increasing the share of biofuels in the transportation sector. Understanding consumer behavior is essential in designing policies that efficiently increase the uptake of cleaner technologies. In this paper we analyze adopters and non-adopters of alternative fuel vehicles (AFVs). We use diffusion of innovation theory and the established notion that the social system and interpersonal influence play important roles in adoption. Based on a nationwide database of car owners we analyze interpersonal influence on adoption from three social domains: neighbors, family and coworkers. The results point primarily at a neighbor effect in that AFV adoption is more likely if neighbors also have adopted. The results also point at significant effects of interpersonal influence from coworkers and family members but these effects weaken or disappear when income, education level, marriage, age, gender and green party votes are controlled for. The results extend the diffusion of innovation and AFV literature with empirical support for interpersonal influence based on objective data where response bias is not a factor. Implications for further research, environmental and transport policy, and practitioners are discussed. 相似文献
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城市公交票价是公交系统健康发展的重要因素,票价制定需兼顾公交企业的市场性和公益性双重属性,在保证服务质量的同时,考虑运营成本和最大限度吸引公交需求,实现经济效益和社会效益的双赢.在本文中,根据用户均衡理论,构建了城市多方式交通出行的需求分析模型,采用灵敏度分析方法给出了城市公交价格-需求弹性的计算方法.在此基础上,充分考虑了各种方式的交通特征、公交需求弹性、公交运营成本及政府限价等因素,提出了城市公交票价优化的数学规划模型,并给出了求解算法.最后,以国内某城市居民出行调查及公交运营数据为基础,分析了不同条件下公交客运需求的变化规律及城市公交票价的优化策略. 相似文献