柱状节理坝基岩体三维各向异性数值分析

在分析柱状节理不连续性和各向异性的工程特性基础上,对某拱坝及坝基的柱状节理岩体进行三维数值模拟分析。考虑河谷初始地应力场和岩体各向异性力学性质,采用各向同性本构和各向异性弹塑性本构进行对比分析。计算表明,坝基柱状节理岩体各向异性特性对工程整体应力、变形的影响比较明显,采用各向异性弹塑性模型计算更能反映柱状节理的特殊性。其结果为该坝区岩体工程各向异性力学分析提供了示例。     

某异型钢管混凝土拱桥地震反应分析

本文以某异型钢管混凝土拱桥为研究对象,通过ANSYS建立了结构的空间有限元模型,计算和分析了该桥的动力特性。同时,通过MATLAB程序生成拟合规范反应谱的人工地震波,并运用时程分析法计算了该桥在一维和多维输入下的地震反应,分析了该桥的地震反应规律,为钢管混凝土拱桥的抗震性能分析提供了一定的依据。     

黄精复方治疗气阴两虚型2型糖尿病32例临床观察

目的：探讨黄精复方治疗气阴两虚型2型糖尿病的临床疗效。方法：将气阴两虚型2型糖尿病患者64 例随机分为治疗组和对照组,每组各32 例。所有患者均采取饮食、运动等生活方式干预,对照组口服二甲双胍片治疗,治疗组在对照组基础上加用黄精复方治疗,疗程均为12周。观察2组综合疗效及治疗前后中医证候积分、体质量指数（BMI）、空腹血糖（FBG）、餐后2 h血糖（2hPG）、糖化血红蛋白（HbA1c）、空腹胰岛素（FINS）、胰岛素抵抗指数（HOMA-IR）、总胆固醇（TC）、三酰甘油（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）的变化,记录2组不良反应。结果：总有效率治疗组为87.50%（28/32）,高于对照组的59.37%（19/32）,差异有统计学意义（P＜0.05）。2组中医证候积分、BMI、FBG、2hPG、HbA1c、FINS、HOMA-IR、TC、TG、LDL-C、HDL-C治疗前后组内比较及治疗后组间比较,差异均有统计学意义（均P＜0.05）。结论：黄精复方治疗气阴两虚型2型糖尿病可以缓解患者的中医证候,降低血糖、血脂,改善胰岛功能,从而提高临床疗效。     

钢管混凝土拱桥海上应用实例

近年来钢管混凝土拱桥建设在全国迅速发展,型式多样、各有千秋。本文就大跨度全钢系杆拱在大连新港50万吨级进口原油码头引桥上的成功应用做以下介绍。     

桩承式加筋路堤作用机理理论分析与数值模拟

软土地基上填筑高路堤常常面临地基承载力不足、沉降和不均匀沉降过大等问题。桩承式加筋路堤能够有效地解决这些难题。通过理论分析和有限元数值模拟,研究了路堤填土-加筋材料-桩体-桩间土之间的相互作用机理,讨论了路堤填土中的土拱效率、桩体效率、路堤底面差异沉降和筋材拉力的变化规律。研究结果表明,填土中的土拱效应和筋材张力膜效应能够有效地提高桩体效率,防止软土屈服;筋材内部拉力呈非线性分布,桩顶边缘处筋材拉力最大。     

Earthquake response of concrete arch dams: a plastic–damage approach

There are several alternatives to evaluate seismic damage‐cracking behavior of concrete arch dams, among which damage theory is the most popular. A more recent option introduced for this purpose is plastic–damage (PD) approach. In this study, a special finite element program coded in 3‐D space is developed on the basis of a well‐established PD model successfully applied to gravity dams in 2‐D plane stress state. The model originally proposed by Lee and Fenves in 1998 relies on isotropic damaged elasticity in combination with isotropic tensile and compressive plasticity to capture inelastic behaviors of concrete in cyclic or dynamic loadings. The present implementation is based on the rate‐dependent version of the model, including large crack opening/closing possibilities. Moreover, with utilizing the Hilber–Hughes–Taylor time integration scheme, an incremental–iterative solution strategy is detailed for the coupled dam–reservoir equations while the damage–dependent damping stress is included. The program is initially validated, and then, it is employed for the main analyses of the Koyna gravity dam in a 3‐D modeling as well as a typical concrete arch dam. The former is a major verification for the further examination on the arch dam. The application of the PD model to an arch dam is more challenging because the governing stress condition is multiaxial, causing shear damage to become more important than uniaxial states dominated in gravity dams. In fact, the softening and strength loss in compression for the damaged regions under multiaxial cyclic loadings affect its seismic safety. Copyright © 2013 John Wiley & Sons, Ltd.     

Integrating airborne and multi‐temporal long‐range terrestrial laser scanning with total station measurements for mapping and monitoring a compound slow moving rock slide

A slow moving compound rock slide located in the northern Apennines of Italy was mapped and monitored through the integration of Airborne Laser Scanning (ALS), multi‐temporal long‐range Terrestrial Laser Scanning (TLS), and Automated Total Station (ATS) measurements. Landslide features were mapped using a High Resolution Digital Terrain Model (HR‐DTM) obtained by merging ALS and TLS data in an Iterative Closest Point (ICP) procedure. Slope movements in the order of centimeters to a few decimeters were quantified with Differential TLS (D‐TLS) based on a Surface Matching approach and supported by ATS data to define stable reference surfaces. The integrated approach allowed mapping of the composite geomorphic features of the rock slide under examination, revealing its complex dynamic nature and further proving that laser scanning is a versatile and widely applicable tool for slope process analysis. Copyright © 2013 John Wiley & Sons, Ltd.     

Influence of Surfactants on Degradation of 1‐(2‐Chlorobenzoyl)‐3‐(4‐chlorophenyl) Urea by Nanoscale Zerovalent Iron

Nanoscale zerovalent iron (NZVI) has been proved to be effective in the degradation of environmental pollutants and exhibits advantages in the removal of 1‐(2‐chlorobenzoyl)‐3‐(4‐chlorophenyl) urea (CCU), an analog of diflubenzuron. This present study focused on the influence of surfactants in the degradation procedure with NZVI in order to provide a simple and rapid removal method for CCU. Triton X‐100, Tween 20, Tween 80, sodium dodecyl sulfonate (SDS), and cetyltrimethylammonium bromide (CTAB) were investigated under anaerobic conditions. The experimental results demonstrated that the degradation rate increased sharply with the presence of SD during the first 15 min, up to 99.97% with addition of 0.01 g L^?1 SDS, whereas the presence of Triton X‐100, Tween 80, and Tween 20 resulted in a slight enhancement of the degradation of CCU. The enhancement strength of them was in the order Tween 20, Triton X‐100, and Tween 80. However, addition of the cationic surfactant CTAB resulted in a significant inhibitive effect. In contrast, the mixed surfactants did not result in the expected performance, and the performance was lower than that using some certain single surfactant among the mixed surfactants.     

老挝Nam Ngum 5水电站重力拱坝裂缝处理实践

针对老挝Nam Ngum 5水电站重力拱坝裂缝进行的灌浆处理,采用化学灌浆和水泥灌浆相结合,取得了良好的治理效果。详细介绍了裂缝深度的检测方法和裂缝止裂措施,以及灌浆施工工艺。     

全反射X射线荧光光谱法同时测定复混肥料中钒铬锰铁镍铜锌铅

样品经硝酸微波消解,以镓为内标,采用全反射X射线荧光光谱法(TXRF)同时测定复混肥料中的钒、铬、锰、铁、镍、铜、锌、铅,方法检出限从铅的1.0μg/g到钒的7.0μg/g,精密度(RSD)铬为2.5%,铅为16%,除铅以外,其余元素的RSD均小于10%;方法回收率为80%～120%,Pb的回收率略低主要是由于化肥中As Kα谱线对Pb Lα谱线的干扰导致测定结果偏低。用TXRF和电感耦合等离子体发射光谱法(ICP-AES)测定不同复混肥料中各元素的含量,经统计检验,两种方法测定结果在95%置信区间内无显著性差异。对于金属元素含量较高的样品,TXRF法测定结果的相对标准偏差小于ICP-AES法。对于不同的复混肥料,在微量、痕量元素检测范围内,TXRF法具有较高的准确度和适用性,仪器使用和维护成本低,方法快速准确。