基于蠕变试验基础上的再生沥青混合料力学模型分析

结合沈阳至山海关高速公路路面维修工程,在旧料和原材料性能分析基础上,运用小梁弯曲蠕变试验采集数据,通过拟和方法确定试验参数,研究再生沥青混合料的力学模型.结果表明,广义Maxwell模型能够很好地表征再生沥青混合料的粘弹性力学行为.     

农村公路建设与管养问题探讨

农村公路建设与管理的特点决定了它有别高速公路、国省道等级干线公路的建设原则和方针,要求其既要遵守公路建设的一般要求,更要切合实现,凸显便利地服务农村农民兄弟的特点。文章对农村公路建设与管养中存在的问题进行分析,并对其解决办法提出建议。     

后压浆灌注桩的改良特性研究

通过对后压浆灌注桩与普通灌注桩的试验数据对比分析,发现后压浆能极大地改善桩端与桩周土体的物理力学性质,使桩的承载力明显提高,沉降明显减小,具有良好的工程应用前景。     

非饱和路基渗流与变形有限元分析

对路基进行渗流与变形的有限元分析,结果表明由于路基水温状况不良而导致产生薄弱环节是造成翻浆破坏的主要原因,并讨论了防治公路翻浆冒泥应采取的措施.     

辽宁省东部山区公路边坡生态防护研究

根据抚顺市境内彰桓线、下李线、台上线、永尖线、阿平线等公路边坡生态防护建设实际,对公路边坡常见的植物防护形式做简单介绍,并对生态防护的意义、经济效益和社会效益以及当前存在的问题进行具体分析和阐述。     

公路施工企业信用评价与招投标挂钩奖励问题探讨

交通运输部制定的《公路工程标准施工招标资格预审文件》和《公路工程标准施工招标文件》中提出,企业的市场信用评价结果与招投标挂钩,并在多方面对信用评级高的企业给予奖励。该措施存在一些不足之处,应从上下位法规统一、平稳过渡等方面进行改进和完善。     

Stability Analysis of a Force-Aided Lever Actuation System for Dry Clutches with Negative Stiffness Element

A force-aided lever with a preload spring is not only force-saving but also energy-saving. Therefore, it has great potential to be applied to dry clutch actuations. However, the negative stiffness of the clutch diaphragm spring introduces unstable dynamics which becomes more intensive due to the preload spring. In order to explore the intensified unstability, this paper builds dynamic models for the rotating lever coupling a negative stiffness diaphragm spring and a preload spring. The stability analysis using the Routh-Huiwitz criterion shows that the open-loop system can never be stable due to the negative stiffness. Even if the diaphragm spring stiffness is positive, the system is still unstable when the preload of the spring exceeds an upper limit. A proportionalintegral- derivative (PID) closed-loop scheme addressing this problem is designed to stabilize the system. The stability analysis for the closed-loop system shows that stable region emerges in spite of the negative stiffness; the more the negative stiffness is, the less the allowed preload is. Further, the influences of the dimensions and PID parameters on the stability condition are investigated. Finally, the transient dynamic responses of the system subjected to disturbance are compared between the unstable open-loop and stabilized closed-loop systems.