In order to study the mechanical properties of stainless steel anchor channel components under tension,first,tensile static load tests were conducted on the anchor rod centerline and the mid span position of S-CAG-53/34 and S-CBG-52/34 stainless steel anchor channels.The experimental results showed that the stainless steel anchor channels mainly experienced buckling failure of the channel edge curling.Then,the finite element analysis software ABAQUS was used to establish the finite element models of two kinds of stainless steel anchor channel components.The numerical simulation results were compared with the experimental results to verify the accuracy and applicability of the finite element model.Finally,the finite element model of 50 full-scale specimens was established to study the influence of channel edge thickness,channel side wall thickness,bolt size,bolt spacing and adjacent load on the tensile performance of stainless steel anchor channel components.The analysis results show that increasing the thickness of the channel edge,the thickness of the side wall of the channel and reducing the spacing of the bolts can effectively improve the tensile bearing capacity of the stainless steel anchor channel components.Increasing the thickness of the channel edge and the side wall will increase the stiffness of the channel section,thereby improving the tensile bearing capacity of the middle part of the channel.Reducing the anchor spacing increases the flexural bearing capacity of the channel,thereby improving the tensile bearing capacity of the mid-span of the channel.Changing the length of the anchor rod has little effect on the tensile bearing capacity of the mid-span position of anchor channel,and applying multiple loads simultaneously within a certain spacing results in some anchor rods bearing higher loads,thereby affecting the bearing capacity of the channel.The analysis results show that this effect gradually decreases as the spacing between anchor rods decreases.
为了能够准确地描述岩石应力应变关系和损伤演化规律,假定微元的统计强度概率服从幂函数分布,推导了单轴应力条件下岩石的损伤本构方程;考虑围压条件下岩石峰后的残余强度,推导了三轴应力下岩石修正的损伤本构方程,并分别采用砂岩试样进行了实验验证.研究结果表明:(1)单轴载荷下岩石的损伤本构方程能够较好的表述全应力-应变曲线的弹性阶段、屈服阶段、应变软化阶段以及峰值应变和峰值强度特征;(2)单轴应力下岩石的损伤演化和加载过程中岩石裂隙的演化有良好的相关性;(3)修正的损伤本构方程可较好地反映三轴应力状态下岩石峰前非线性、应变软化以及峰后残余强度特征;(4)随着围压的增大,损伤-应变曲线逐渐变缓,岩石抵抗损伤的能力将逐步加强.以上研究成果可为工程岩体损伤失效性分析提供重要理论指导.
基于生产滤池中滤速变化特征,采用模型滤柱研究了滤速波动对滤后水浊度和滤层截留絮体分布的影响;通过生产实测,分析讨论了实际运行的Ⅴ型滤池中滤速变化特征及其对滤后水浊度的影响.实验研究结果表明:滤速波动的振幅和频率影响滤后水浊度和截留絮体分布,在一定范围内振幅越大、频率越高,滤后水浊度变化幅度越大、絮体在滤层的分布越均匀.生产实测表明:滤速增加对滤后水浊度的影响在过滤后期较初期明显,在滤速增幅和增长率基本一致的条件下,过滤后期滤速增加会引起滤后水浊度升高;小于2.0(m/h)/h的滤速增长率,无论是在过滤初期还是过滤后期都未引起显著的滤后水浊度增加;成组布设的滤池组(格数≥10)中,由其他滤池反冲洗引起的单格滤池强制滤速特征并不明显.
国家考古遗址公园经十余年发展已进入规范化发展新阶段,基于规划学科发展及未来国家考古遗址公园高质量发展的需求,通过对考古遗址公园规划属性及内容的总结反思,以汉长安城未央宫国家考古遗址公园为例,从"效力+效用"的评估视角,从实施导向、责任导向和权益导向出发,尝试构建包含空间落实、资源维护、公众满意度三个层次、五个步骤在内的考古遗址公园规划实施效果评估方法体系并实践应用,进而分析总结提出完善动态规划编制体系及开展规划实施机制和规划实施影响评估等方面的结论与建议,以期推动考古遗址公园可持续发展.
为了研究不锈钢筋与超高性能混凝土(ultra-high performance concrete,UHPC)的粘结性能,制作了 12 组 36 个试样进行中心拉拔试验,研究了保护层厚度、锚固长度、配箍率、钢筋直径及钢筋品种对不锈钢筋与UHPC的粘结锚固性能的影响.研究不锈钢与UHPC在锚固段的粘结应力分布,分析导致试件劈裂破坏的原因.通过统计回归对钢筋混凝土粘结强度表达式进行了修正,得到了更加适用于不锈钢筋UHPC粘结强度计算公式.结果表明,修正的粘结强度表达式可较为准确地求出不锈钢筋与UHPC的粘结强度.
