共查询到19条相似文献，搜索用时 187 毫秒
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基于拟静力法和水平层分析法的计算思路,以无粘性填土的刚性挡土墙为研究对象,考虑土拱效应引起的大主应力圆弧拱,推导给出了地震被动土压力的分布和合力作用点的计算表达式。通过参数分析表明:水平和竖向地震作用对被动土压力有减小作用,其中,水平地震作用的影响更为显著;填土内摩擦角对土压力强度影响显著,内摩擦角越大,被动土压力越大;引发土拱效应的墙土摩擦角的增大能降低被动土压力的合力作用点,这对挡土墙的抗倾覆稳定是不利的。 相似文献
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档土墙上的土压力是一个古老的课题,经典的库仑土压力理论和朗肯土压力理论,因其计算简单和力学概念明确,在土木工程中得到广泛应用.但长期以来挡土墙的研究对象-般是针对墙背为直线的挡土墙,而对于阶梯式的挡土墙,特剐是对于平面内非直线的阶梯状拱形挡土墙的土压力分布特征少有研究. 相似文献
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基于现有规范、理论和工程经验,对浅埋和深埋地下结构的界限确定方法进行了归纳分析,给出了深埋地下结构竖向土压力计算的2种理论,即普氏压力拱和泰沙基理论,并将该理论应用于深埋拱形地下结构之中,得到了非饱和土和饱和土中深埋圆形隧道周围的土压力计算方法。 相似文献
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文章介绍了运用FLAC模拟饱和土地层,完全不舍水地层及与非饱和土地层,拟采用直墙拱形隧道开挖施工方案,运用FLAC软件对3种地层开挖施工对地表的沉降量进行了模拟。得出采用非饱和土和饱和土时地表沉降都小于完全不含水地层的沉降量。 相似文献
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土钉墙是由天然土体通过土钉墙就地加固并与喷射砼面板相结合,形成重力挡墙以此来抵抗墙后的土压力,针对土钉墙的施工方法进行论述。 相似文献
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本文介绍了一种挡土墙地震土压力作用点的计算方法。以Kotter方程为基础,假定挡土墙破坏面为平面,求出了挡土墙在地震影响下的主动和被动土压力作用点。分析了被动状态下竖向地震加速度系数及墙体摩擦角对挡土墙土压力作用点的影响,并和以前的不同方法计算的l值以及试验得到的l值进行了比较,该法所得结果与前人试验结果最接近,表明该方法是可行的。 相似文献
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随着如今建筑工程技术的发展,地下工程的发展也相当的快速,作为地下工程基础深的深基坑的支护就彰显的尤为关键,而支护方式也越来越多,土钉墙就是其中一种。本设计便是用土钉墙支护技术来进行基坑围护。本设计里利用朗肯土压力理论进行相关土层的土压力计算,查看相关书籍及规范,计算了土钉的抗拔承载力,基坑整体稳定性验算也在设计考虑范围中,从而有数据计算得出安全可靠的设计内容去进行基坑的支护。 相似文献
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R. Ponalagusamy R. Tamil Selvi A.K. Banerjee 《Journal of The Franklin Institute》2012,349(5):1681-1698
The effects of rheological behavior of blood and pulsatility on flow through an artery with stenosis have been investigated. Blood has been represented by a non-Newtonian fluid obeying Herschel–Bulkley equation. Using the Reynolds number as the perturbation parameter, a perturbation technique is adopted to solve the resulting quasi-steady non-linear coupled implicit system of differential equations. Analytical expressions for velocity distribution, wall shear stress, volumetric flow rate and the mean flow resistance have been obtained. It is observed that the wall shear stress and flow resistance increase for increasing value of yield stress with other parameters held fixed. One of the remarkable results of the present analysis is not only to bring out the effect of the size of the stenosis but also to study the influence of the shape of the stenosis. The change in the shape of the stenosis brings out a significant change in the value of flow resistance but it has no effect on the variation of wall shear stress except shifting the point (where it attains its maximum value) towards downstream. It is pertinent to point out that pulsatile flow of Newtonian fluid, Bingham plastic fluid and Power-law fluid become particular cases of the present model. The present approach has general validity in comparison with many mathematical models developed by others and may be applied to any mathematical model by taking into account of any type of rheological property of blood. The obtained velocity profiles have been compared with the experimental data and it is observed that blood behaves like a Herschel–Bulkley fluid rather than Power-law and Bingham fluids. Finally, some biorheological applications of the present model have briefly been discussed. 相似文献
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Keith J. Barker Betzalel Avitzur Walter C. Hahn 《Journal of The Franklin Institute》1976,301(3):263-277
The effects of friction upon the intermediate and final distorted grids for wire drawing and/or extrusion were analytically studied for an assumed triangular velocity field. An upper-bound solution for the process was used. This solution predicted that the shape of the final and intermediate distorted grids were functions of the process geometry and of friction. Initially, combinations of reduction and semi-cone angle (α) were found for which the triangular velocity field was energetically preferred over an existing spherical velocity field. The analytical final distorted grids were then compared to experimentally obtained final distorted grids to determine the experimental friction. This was done by plotting calibration curves for distortion where friction served as the parameter and by comparing the actual distortion with the family of calibration curves. 相似文献
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E.E. Gdoutos 《Journal of The Franklin Institute》1981,312(5):361-371
An analysis of the plastic enclaves developed around the end points of rigid fiber inclusions embedded in an elastic plate is undertaken. The plate is subjected to a uniform uniaxial stress at any angle of inclination with the axis of the fiber. It is assumed that the material of the plate is elastic-perfectly plastic and that the deformations are small. A singular solution of the stress field in the vicinity of the end points of the fiber is used in conjunction with the Mises yield criterion to obtain the radius of the plastic zone under conditions of plane strain and generalized plane stress. The dependence of the size and shape of the plastic deformation on the orientation of the fiber, the Poisson's ratio of the plate and the state of stress (plane strain or generalized plane stress) is established. 相似文献
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刘轶伦 《科技成果管理与研究》2008,(6):69-70
本文以某混凝土刚架系杆拱桥为原型,借助ANSYS软件建立平面有限元模型,计算拱肋结构各控制截面在温度荷载作用下的内力与应力值,并通过改变矢跨比,将不同情况下的计算结果进行对比,并对结果进行分析。 相似文献
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In the present study, in the first part for a spherical vessel with known dimensions and working pressure, two methods of hoop and equivalent stress optimization across the wall thickness are employed to determine the best autofrettage pressure. In the next part for a predefined working pressure the minimum wall thickness of the vessel is calculated using two other design criteria i.e. (A) optimizing the hoop stress, and (B) assuming a suitable percent for the penetration of yielding within the wall thickness. Finally, the optimum thickness and the necessary strengthening pressure are extracted and different plots are introduced for different types of structural materials under different internal pressures. 相似文献
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通过对加筋土的筋-土间摩擦性能的力学试验，研究了在不同材料、不同压实度以及不同压力情况下的似摩擦系数的变化规律，特别是在两种板限状态下（即筋带重复使用和填料饱和水）似摩擦系数的变化规律．填补了国内的空白，为从事相关工作的人员在实际应用中提供一定的理论参考。 相似文献
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在核心企业较高的信用水平和较好的项目质量前提下,供应链融资业务的成功运作取决于融资企业努力程度。在信息对称条件下,作为主委托人的制造商通过设计固定的优惠激励,保证主委托人制造商和次委托人银行的收入效用最大化。在信息不对称情况下,如果次委托人适当降低代理人的努力投入标准,则主委托人的线性优惠激励使融资企业选择最优努力水平,并且使主委托人(制造商)和次委托人(银行)期望收益效用最大化。 相似文献
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Sam Tang 《Journal of The Franklin Institute》1973,295(5):357-372
Closed-form solutions are obtained for the stress and die pressure distributions, time and flow rates for drawing and extruding superplastic cylinders through a cone-shaped die with Coulomb friction. Numerical examples are presented graphically and the possible existence of a maximum limit for area reduction in the drawing process is pointed out and discussed. 相似文献