共查询到20条相似文献,搜索用时 93 毫秒
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大型沟埋式管道侧向土压力的研究 总被引:1,自引:0,他引:1
本文利用现场实测资料,采用回归分析方法,在考虑了填土高度、密度,管道和槽壁间的胸腔大小,侧压力计算点距管底的高度,填土内部的摩擦力等影响管道侧向土压力的因素后,对沟埋式管道侧向土压力的计算提出了新的公式。 相似文献
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太沙基提出了顶面倾斜时的粘性回填土的侧向土压力的图解法。这一方法在解决实际挡土墙问题中显得冗长,因为在确定挡土墙的侧向土压力分布图时要画数个莫尔圆。本文提出此问题的解析法。文中以表格形式列出了不同ψ、β和c/γz取值的主动土压力系数Ka和被动土压力系数Kp。并举实例以说明其应用。 相似文献
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从超前桩复合土钉墙失稳形式出发,采用理论分析,建立了超前桩复合土钉墙稳定性分析模型,推导出了超前桩复合土钉墙稳定性计算式,并以工程实例进行了验证. 相似文献
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多级挡土墙墙背土压力分布规律试验研究 总被引:2,自引:1,他引:1
以十漫高速公路高边坡多级挡土墙为研究对象,在高达67m的填方路段进行墙背土压力试验研究,探索墙背土压力分布规律。在挡土墙墙背上按照一定间距安置了多个土压力测试仪,进行208d的定期测试。结果表明:随着填土高度的增长,墙背土压力经历快速增长、短期的平稳和缓慢增长阶段,两者最初近似成线性关系,之后表现为明显的非线性。 相似文献
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产品销售物流配送中心布局方法研究 总被引:7,自引:0,他引:7
论述了产品销售物流配送中心布局规划的重要性,分析了配送中心布局规划现有数学模型的不足,然后提出了基于经济规模理论的配送中心布局规划方法。在考虑配送中心经济规模的前提下,建立了确立配送中心布局方案的数学模型,模型以总费用最小为规划目标函数,并可利用遍历算法对该模型进行求解。经过实例验证,说明运用经济规模理论在确定配送中心个数的范围之后,该模型能在物流中心位置和路网条件已知的情况下对配送中心的个数、位置和规模进行定量确定,对生产企业在较大范围内规划其销售物流的配送系统有重要的理论价值和实用意义。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1695-1707
Vehicle safety is a major concerns for researchers, governments and vehicle manufacturers, and therefore a special attention is paid to it. Particularly, rollover is one of the types of accidents where researchers have focused due to the gravity of injuries and the social impact it generates. One of the parameters that define bus lateral behaviour is the acceleration threshold limit, which is defined as the lateral acceleration from which the rollover process begins to take place. This parameter can be obtained by means of a lateral rollover platform test or estimated by means of mathematical models. In this paper, the differences between these methods are deeply analysed, and a new mathematical model is proposed to estimate the acceleration threshold limit in the lateral rollover test. The proposed model simulates the lateral rollover test, and, for the first time, it includes the effect of a variable position of the centre of gravity. Finally, the maximum speed at which the bus can travel in a bend without rolling over is computed. 相似文献
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为解决带外伸横梁的钢箱梁桥横梁计算有效分布宽度问题,借助无限长板带对位荷载下的应力分布研究结果,导出了不同桥宽和不同宽度外伸横梁对应的有效分布宽度扩散角;然后分别采用板壳有限元模型和梁单元模型对实际工程中超宽桥梁外伸横梁受力进行对比分析,以验证导出的有效分布宽度扩散角的实用性和有效性。结果表明:采用导出的有效分布宽度扩散角的梁单元模型计算结果与板壳有限元模型计算结果非常接近,且能够包络板壳有限元模型的计算结果,是偏于安全的。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(3):338-359
This paper describes an analytical study of the lateral dynamics of multi-articulated vehicles with multiple axles. A linear planar model of vehicle dynamics is adopted for multiple-axle vehicle combinations with an optional number of trailers. Two tractor and double-trailer combinations are examined for their directional stability and response. Non-oscillatory stability and steering sensitivity in steady-state turning and lane changing are analysed using a stability factor of multiple-axle vehicle combinations. Off-tracking in the steady-state turning of multiple-axle vehicle combinations is also analysed. Numerical calculations for oscillatory stability, steering sensitivity, and off-tracking are presented for multiple-axle vehicle combinations. 相似文献
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为了进一步深入研究拱梁组合式连续梁桥的横向分布特性,以龙溪大桥为背景,采用空间有限元的分析方法,对拱梁组合式连续渠桥的横向分布特性及沿纵向的变化规律进行了研究,并与传统计算刚架拱桥的简化弹性支撑连续梁法进行对比。对比分析后认为,两种方法结果吻合很好,在实际设计拱梁组合式连续梁桥时,横向分布系数计算可以采用弹性支承连续梁简化方法。 相似文献
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悬臂式轻型挡土墙断面简单,施工方便,在公路建设中使用较为普遍。结合实践,提出设计中应注意的墙身外倾问题,分析其产生的原因,探讨预防措施。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(9):1247-1268
This paper presents a lateral driver model for vehicle–driver closed-loop simulation at the limits of handling. An appropriate driver model can be used to evaluate the performance of vehicle chassis control systems via computer simulations before vehicle tests which incurs expenses especially at the limits of handling. The driver model consists of two parts. The first part is an upper-level controller employing force-based approach to reduce the number of unknown vehicle parameters. The feedforward part of the upper controller has been designed by using the centre of percussion. The feedback part aims to minimise ‘tangential error’, defined as the sum of body slip angle and yaw error, to match vehicle direction and road heading angle. The part is designed to regenerate an appropriate skid motion similar to that of a professional driver at the limits. The second part is a lower-level controller which converts the desired front lateral force to steering wheel angle. The lower-level controller also consists of feedforward and feedback parts. A two-degree-of-freedom bicycle model-based feedforward part provides nominal steering wheel angle, and the feedback part aims to eliminate unmodelled error. The performance of the lateral driver model has been investigated via computer simulations. It has been shown that the steering behaviours of the proposed driver model are quite close to those of a professional driver at the limits. Compared with the previously developed lateral driver models, the proposed lateral driver model shows good tracking performance at the limits of handling. 相似文献