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级配碎石压实特性的研究 总被引:1,自引:0,他引:1
级配碎石的研究和应用,主要在于通过取得高质量的碎石,获得高密度的良好级配以及良好的施工压实手段来提高级配碎石的强度和稳定性。分析了级配碎石物理性能指标和影响级配碎石性能的因素,从材料选择、级配设计、不同机械组合及碾压方式方面入手,研究了级配碎石施工的压实特性和提高压实强度的方法,并通过具体试验路段进行了验证,总结了级配碎石的压实特性。 相似文献
275.
文章针对客车前挡风玻璃上的雨刷器各部件由于安装精度不够,造成雨刷器的执行机构失效,表现形式为烧保险、烧继电器、烧电机、烧电线等现象,造成车辆在下雨天不能正常使用,或根本不能使用,直接导致汽车客车晚点、停运、甚至引发交通事故,给运输企业、承包单位、乘客、社会带来较大的经济损失和社会问题,进行了分析与研究,并从汽车生产过程... 相似文献
276.
In oil and gas transportation, the compliant vertical access riser (CVAR) system conducts economic and operational advantages due to its special configuration. In this paper, the static performance of the CVAR is studied by an efficient numerical method. According to the unique configuration of the CVAR, the mathematical model is established based on minimum total potential energy principle. The equilibrium equations are discretized by finite difference method and then solved by Newton-Raphson technique. The accuracy of the numerical method is verified by OrcaFlex software. Detailed parametric analysis is carried out based on practical engineering requirements. The effects of buoyancy section's configuration including buoyancy factor, buoyancy section's length and buoyancy section's location, and external environmental factors including wellhead offset distance, water depth and current velocity on installation shape and mechanical properties of the CVAR are analyzed. The research shows that the presented numerical method has good applicability and flexibility for the early installation configuration design of marine risers which have no touchdown section but only one touchdown point and are equipped with multiple buoyancy blocks subjected to forces of different directions and magnitudes, such as CVARs. 相似文献
277.
This study is concerned with the thermal and mechanical instability behaviors of composite novel liners encased in deteriorated pipelines. A liner may contain many connected segments, and two adjacent segments may become disconnected after long years of service. In such a case, the single disconnected segment may reduce to a ring. An innovative polyhedral configuration is introduced to improve the bending stiffness of the composite ring that is confined by the pipeline. The radius and bending rigidity of the ring are simplified analytically to facilitate the derivation of the critical buckling load. By employing the classical shell criteria, and defining an admissible displacement function, the expression of the potential energy function is obtained with only two unknown parameters. Taking the first derivative of the energy function to the two unknowns respectively generates two equilibrium equations. By solving the two equations, the analytical buckling load is obtained for a composite polyhedral ring in a thermal variational field. Then, two comparisons are taken between the present analytical predictions and results from elsewhere, and good agreements are obtained. An amplification coefficient is defined as the ratio between the buckling load of the polyhedral and circular rings. Finally, parametric evaluations indicate the amplification coefficient reduces with the increase of thickness-to-radius ratio, the increase of the number of sides, and the increase of the temperature variation, respectively. Therefore, a polyhedral ring with a low thickness-to-radius ratio is recommended in engineering applications. 相似文献