JRC-JCS模型在抗剪强度参数取值中的应用

工程岩体的失稳几乎都是沿着结构面发生的。而岩体结构面的抗剪性质并不完全满足莫尔一库仑准则，因此在岩质边坡的稳定性分析中采用莫尔一库仑准则有可能会带来较大误差。本文简要的回顾了岩体结构面抗剪强度估算方法发展的历程，提出了基于JRC-Jcs模型计算等效抗剪强度参数的概念和方法，并通过简单计算实例阐明了这一方法在处理实际工程问题中的特点。     

讲授"圆轴扭转时剪应力公式推导"的一种新方法

建议采用解静不定问题的力学思想导出圆轴扭转剪应力公式，从而加强学科思想的教学。     

Critical cyclic stress ratio of undisturbed saturated soft clay in the yangtze estuary under complex stress conditions

There exists a critical cyclic stress ratio when sand or clay is subjected to cyclic loading. It is an index distinguishing stable state or failure state. The soil static and dynamic universal triaxial and torsional shear apparatus developed by Dalian University of Technology in China was employed to perform different types of tests on saturated soft marine clay in the Yangtze estuary. Undisturbed samples were subjected to undrained cyclic vertical and torsional coupling shear and cyclic torsional shear after three-directional anisotropic consolidation with different initial consolidation parameters. The effects of initial orientation angle of major principal stress, initial ratio of deviatoric stress, initial coefficient of intermediate principal stress and stress mode of cyclic shear on the critical cyclic stress ratio were investigated. It is found that the critical cyclic stress ratio decreases significantly with increasing initial orientation angle of major principal stress and initial ratio of deviatoric stress. Compared with the effects of the initial orientation angle of major principal stress and initial ratio of deviatoric stress, the effect of initial coefficient of intermediate principal stress is less evident. Under the same consolidation condition, the critical cyclic stress ratio from the cyclic coupling shear test is lower than that from the cyclic torsional shear test, indicating that the stress mode of cyclic shear has an obvious effect on the critical cyclic stress ratio. The main reason is that the continuous rotation in principal stress directions during cyclic coupling shear damages the original structure of soil more than the cyclic torsional shear does.     

Bilateral shear strength of rectangular frame column based on simplified space truss-arch model

To investigate the bilateral shear strength of rectangular frame column subjected to oblique horizontal load, we presented a simplified space truss-arch model developed from unilateral truss-arch model. Main parameters in the new model were the cross-sectional area, transverse reinforcement raito, axial load, and material strength of the column. The reduction coefficient of concrete sterength owing to the severe cracking of column was also introduced in the model. Finally, 14 specimens under oblique horizontal load were tested to verified the feasibility and applicability of the space truss-arch model.     

装载计算机操作中改善船体纵向受力状况的方法

介绍了在装载计算机操作中改善船舶纵向受力（切力和弯矩沿船长分布）状况的基本原理、操作步骤和操作实例。它为在装载计算机操作中如何选定合适的位置,采取调整货物（或集装箱）装载量或打、排压载水等措施来改善船舶切力和弯矩沿船长分布的状况提供了一种实用方法。     

框架梁端剪力值确定

文章对抗震设防区框架结构梁端剪力值如何结合斜截面受剪承载力来正确确定问题进行了探讨.     

细沟侵蚀可蚀性参数及土壤临界抗剪应力的有理(实验)求解方法

利用室内细沟侵蚀模拟试验结果,把细沟可蚀性参数和土壤临界抗剪应力的研究与侵蚀的过程结合起来,通过对土壤水蚀预报模型WEEP中控制土壤侵蚀的水动力学模型进行理论分析,导出了由实验直接计算得到细沟侵蚀可蚀性参数Kr 值及土壤临界抗剪切应力τc的方法.由推导得到的计算方法与计算公式,求得了不同工况下细沟侵蚀可蚀性参数及相应的临界抗剪切应力值.结果表明,对于同一种土壤,在不同的水动力学条件下,计算得到的细沟侵蚀可蚀性参数基本是一致的.对于实验所用的黄绵土,计算得到的细沟可蚀性参数Kr 均值为( 0 32 4± 0 0 0 3)kg·N-1·s-1.临界抗剪切应力τc 随坡度的增大有增大的趋势.不同水动力条件下回归系数值均大于 0 71.提出的计算细沟侵蚀可蚀性参数Kr 值及土壤临界抗剪切应力τc的方法,将有助于建立和完善土壤侵蚀预报过程模型.     

复杂应力条件下土与结构物相互作用接触面的力学特性

为研究外加荷载对接触面力学特性的影响,通过土与结构物相互作用的物理试验和数值模拟研究接触面最大剪应力的变化规律,运用PFC2D模拟土与结构物相互作用过程中颗粒位移和颗粒接触力的不同响应.结果表明:当法向应力一定时,最大剪应力随围压的增大而近似线性增大;当平均应力一定时,最大剪应力随法向应力的增大而近似线性增大;当法向应力一定、围压逐渐增加时,颗粒位移和颗粒接触力的分布与法向应力与围压的比值有关.     

基于Somachine的飞剪定长控制

飞剪的定长控制一直是控制领域里研究的一个重要的问题。施耐德实验室硬件平台是由电脑、施耐德的运动控制器LMC058F42、伺服驱动器Lexium32A、伺服电机BMH0701、触摸屏XBGT2200及施耐德实验室定制的飞剪系统模型组成。本文首先介绍了该系统的硬件模块,主要介绍了运动控制器、伺服驱动器及伺服电机。然后介绍了飞剪控制的具体过程及要实现的目标,简要阐述了飞剪运动方程式算法的推导过程,给出了通过Somachine来实现该算法的软件程序。在施耐德实验室中通过该硬件平台最终实现了对飞剪的控制,在控制精度上取得了令人满意的效果,使得每次切割的长度误差小于1mm,从而验证了飞剪运动方程式算法的正确性。     

干湿循环对改良膨胀土抗剪强度影响分析

通过对干湿循环后的掺石灰和砂混合料的改良膨胀土进行直接剪切试验,研究了干湿循环对于改良膨胀土抗剪强度影响。结果表明,龄期对于掺石灰和砂混合料的改良膨胀土抗剪强度影响较大,并且发现干湿循环五次后,随着干湿循环次数的增大,改良膨胀土的抗剪强度降低。