软弱夹层中型剪力试验最大法向压力的确定

原位大型剪力试验是获取软弱夹层抗剪强度参数的标准方法,但常常受投资、周期、场地等因素制约而难以充分开展。通过对软弱夹层中型剪力试验的长期研究,成功解决了制样难题,最大限度保护了试样的原始状态,剪切面积达400 cm^2,并提出确定法向压力的合理方法,确保了试验成果的准确性与适用性。经工程实践验证,软弱夹层中型剪力试验是原位大型剪力试验的首选补充替代方法。

钻孔剪力试验原理及其应用

论述了钻孔剪力试验的基本原理,试验过程中参数的选择,资料分析处理方法及其应用。

CAI在三轴剪力试验教学中的运用

通过对模拟实验型CAI教学模式在土力学试验教学中的应用研究和具体方案设计,主要解决了实验室设备不足、贵重仪器损耗大和学生动手机会少的矛盾。它将是现代教育技术在教学中推广应用的重要形式。

钻孔剪力试验原理及其应用

论述了孔剪力试验的基本原理，试验过程中参数的选择，资料分析处理方法及其应用。

钢筋焊接网焊点抗剪力试验工装的设计与比较分析

为了使万能材料试验机能够满足钢筋焊接网焊点抗剪力试验的要求,设计了拉力型和压力型2种试验工装。并根据实际使用情况,对以上2种试验工装进行了对比分析,并指出了其各自的优缺点。

预制装配式型钢混凝土剪力墙试验与模拟受力分析

文中以预制装配式型钢混凝土剪力墙为研究对象,制作试件开展低周往复加载试验,分析结构承载能力等性能。根据结构受力情况,采用有限元软件模拟剪力墙受力,最终获得了与试验结果相吻合的分析数值,验证了数值模拟方法在预制剪力墙结构受力分析上的有效性。

基于MFBFE剪力墙单元研究及低周反复试验数值分析

基于力插值纤维单元是目前钢筋混凝土结构非线性分析最常用的单元,它忽略单元的截面剪切变形,采用平截面假定,但对于剪力墙构件,其截面高度比较大,仍采用平截面假定忽略截面剪切变形将会造成较大的误差。基于这一背景,文中提出考虑截面剪切变形的修正基于力插值纤维单元(MFBFE),其截面不再是平截面,而是曲面,用以模拟剪力墙的地震反应非线性分析。基于OpenSees进行MFBFE单元开发,并对一组9个剪力墙试件进行水平低周往复模拟。实例分析结果显示较好地预测了构件的初始刚度、屈服力、极限力、卸载刚度、残余位移、延性和能量耗散,表明MFBFE单元模拟剪力墙地震反应非线性分析有较高的精度。并且对MFBFE单元在不同轴压比、不同高宽比、不同混凝土强度、不同纵向配筋率、不同约束区长度、不同配箍率下进行趋势分析。数据显示,文中提出的分析模型的适用范围很广,对于上述不同的计算和构造条件下都满足精度要求。

三轴试验单试样多级加荷的适用性分析

抗剪强度是地基设计参数计算中的重要指标,本文通过对重塑土和原状土三轴试验的单样多级加荷与多样四级加荷试验方法的对比,阐述了单样多级加荷方法所提供抗剪强度值在实践中的可行性。

土石粗粒料的弹塑性本构模型研究

通过粗粒料三轴剪力试验和强度试验资料 ,进行回归得到了粗粒料的强度准则τ =Aσb,并以此为屈服准则 ,结合弹塑性理论建立了粗粒料的弹塑性本构模型 ,该模型连续、不存在奇点 ,模型参数少。推导出粗粒料的弹塑性矩阵Dep,试验结果与模型计算结果吻合较好。

五联式自动剪力仪简介

一、概况:五联式自动剪力仪由液压加荷、剪切和主机及自动记录三部分组成(见照片1),是在南京水电仪表厂生产的应变式直接剪力仪的基础上改进的。我们采用了液压传动,原百分表人工读数改用光线示波器自动记录,用一千瓦电动机带动齿轮油泵,使柱塞油缸和剪切油缸动作。柱塞油缸顶升砝码,用作加卸垂直荷重,用剪切油缸推动齿条轴进行剪切。垂直荷重控制高度及最大剪切位移和启闭自动记录分别用三只限位开关和三只电磁阀控制,达到简单的程序控制,实现了加荷、剪切、记录自动化。二、仪器操作:整台仪器一人操作便可,把土样装入剪力盒仍需人工,其余皆自动操作。(一)工作程序:揿'开机'钮,电动机启动,油泵开始工作,输出压力油,使剪切盒推头快进到位,随即打开剪切试验开关。

南京长江第四大桥预制节段拼装箱梁的技术特色

南京长江第四大桥的引桥主要为预制节段拼装箱梁桥,该文介绍了其中的技术特色,包括标准化的制梁、运梁和架梁工艺,注重耐久性的结构体系与设计施工措施,运用拉压杆模型方法进行锚固区细部构造设计,采用特制的专用架桥机满足多种架梁作业需求。此外,还通过足尺模型试验和键齿剪力键试验,检验了节段预制、拼装质量,研究了桥梁的结构行为。

利用砼／基岩剪力试件进行岩体变形试验探讨

利用砼／基岩剪力试件进行岩体变形试验，可以节约经费和时间，但如何进行试验准备和计算弹性模量还存在一些问题，本文作者通过实践和理论推导，及参照这两种试验的规程提出一套利用砼／基岩剪力试件进行岩体变形试验和计算的方法。

Post-fire cyclic behavior of reinforced concrete shear walls

The effects of fire exposure,reinforcement ratio and the presence of axial load under fire on the seismic behavior of reinforced concrete(RC) shear walls were investigated.Five RC shear walls were tested under low cyclic loading.Prior to the cyclic test,three specimens were exposed to fire and two of them were also subjected to a constant axial load.Test results indicate that the ultimate load of the specimen with lower reinforcement ratio is reduced by 15.8%after exposure to elevated temperatures.While the reductions in the energy dissipation and initial stiffness are 59.2%and 51.8%,respectively,which are much higher than those in the ultimate load.However,this deterioration can be slowed down by properly increasing reinforcement due to the strength and stiffness recovery of steel bars after cooling.In addition,the combined action of elevated temperatures and axial load results in more energy dissipation than the action of fire exposure alone.

Particle breakage and the mobilized drained shear strengths of sand

This paper presents particle breakage and the mobilized drained shear strengths of sand with the purpose of clarifying the influence of particle breakage on the mobilized shear strengths of sand. Several drained triaxial tests were carried out on Silica sand No.5 under 3 MPa confining pressure to produce the pre-crushed sands in simulating the high- pressure shear process on soil to result in particle breakage, and then the pre-crushed sands were re- sheared in series of drained triaxial tests to investigate the mobilized strengths of the pre-crushed sands in detecting the influence of particle breakage. It was found that, by deteriorating strain-stress behavior, particle breakage resulted in change of stress-dilataney behavior in translation and rotation of the relation of the dilatancy factor and the effective principal stress ratio. For a given initial void ratio, particle breakage resulted in impairment of dilatancy behavior of soil to be more contractive in deterioration of the mobilized friction angle and the mobilized dilatancy angle and reduction of void ratio. However, particle breakage resulted in increase of the mobilized basic friction angle especially before failure. In addition, the influence of particle breakage on the mobilized strengths was revealed to be influenced by the shear stress-strain state.

Shear creep parameters of simulative soil for deep-sea sediment

Based on mineral component and in-situ vane shear strength of deep-sea sediment, four kinds of simulative soils were prepared by mixing different bentonites with water in order to find the best simulative soil for the deep-sea sediment collected from the Pacific C-C area. Shear creep characteristics of the simulative soil were studied by shear creep test and shear creep parameters were determined by Burgers creep model. Research results show that the shear creep curves of the simulative soil can be divided into transient creep, unstable creep and stable creep, where the unstable creep stage is very short due to its high water content. The shear creep parameters increase with compressive stress and change slightly or fluctuate to approach a constant value with shear stress, and thus average creep parameters under the same compressive stress are used as the creep parameters of the simulative soil. Traction of the deep-sea mining machine walking at a constant velocity can be calculated by the shear creep constitutive equation of the deep-sea simulative soil, which provides a theoretical basis for safe operation and optimal design of the deep-sea mining machine.

Shear-resistant behavior of light composite shear wall

Shear test results for a composite wall panel in a light composite structure system are compared with test results for shear walls in Japan.The analysis results show that this kind of composite wall panel works very well,and can be regarded as a solid panel.The composite wall panel with a hidden frame is essential for bringing its effect on shear resistance into full play.Comprehensive analysis of the shear-resistant behavior of the composite wall panel suggests that the shear of the composite shear wall panel can be controlled by the cracking strength of the web shearing diagonal crack.

Experimental study on remodeling strength of granular materials under different loads and lengths of time

Remodeled clay and sand rock specimens were prepared by designing lateral confinement and water drainage experiments based on the stress exerted on granular materials in a waste dump.An in situ test was conducted in an internal waste dump;the physical and mechanical parameters of the remodeled rock mass dumped at different time and depths were measured.Based on statistics,regression analysis was performed with regard to the shearing stress parameters acquired from the two tests.Other factors,such as remodeling pressure(burial depth),remodeling time(amount of time since waste was dumped),and the corresponding functional relationship,were determined.Analysis indicates that the cohesion of the remodeled clay and its remodeling pressure are correlated by a quadratic function but are not correlated with remodeling time length.In situ experimental results indicate that the shear strength of reshaped granular materials in the internal dump is positively correlated with burial depth but poorly correlated with time length.Cohesion Cand burial depth H follow a quadratic function,specifically for a short time since waste has been dumped.As revealed by both in situ and laboratory experiments,the remodeling strength of granular materials varies in a certain pattern.The consistency of such materials verifies the reliability of the remodeling experimental program.

Nonlinear elastic-perfect plastic constitutive model of soil-structure interface under high stress

Briefly introduced the simple shear apparatus under high stress that was developed from RMT. A series simple shear tests under high stress show that the relationcurve between shear stress and tangential displacement under high normal stress is different from the hyperbolic curve in direct shear tests, and the complete deformation process of interface under high stress can be described as nonlinear elastic-perfect plastic(NEPP). According to some characteristics of the fitting curve, the deficiency of theNEPP was pointed out. The mathematic 'half value index' was used to illustrate thatWeibull distribution with three parameters (WNEPP) can overcome the mathematical deficiencies of the NEPP. The advantage of the WNEPP is that the fitting curve of WNEPPmore accurately coincided with the testing data was testified by further comparison.

Stress-strain analysis of loess triaxial shear test by PFC^(3D)

In order to compensate for limitations of microscopic study on loess triaxial tests, taking the loess in Longxi area as an example, the authors established the loess triaxial test model by using PFC3D software and simulating tfiaxial shear test under the different confining pressures in 0 kPa, 50 kPa and 300 kPa. Compared with laboratory triaxial shear test, the numerical simulation test has a guiding role in loess mechanical strength analysis.

ABAQUS混凝土损伤塑性模型参数验证

为了统一ABAQUS混凝土损伤塑性模型与规范提供的混凝土本构模型,在规范提供的混凝土本构关系的基础上引入损伤因子的概念,对混凝土损伤塑性模型本构关系参数的确定方法进行了研究。用各等级混凝土本构关系参数模拟结果与规范曲线的对比,验证CDP模型参数的正确性;用一混凝土剪力墙试验的模拟分析,验证本构关系参数用于结构分析情况下的可靠性。两种验证结果证明,给出的CDP模型参数确定方法是正确的,用该方法确定的参数进行结构模拟分析所得结果是可靠的,并指出了CDP模型的不足。