浅基础底面形状对沉降量影响之研究

基础底面形状是影响基础沉降的重要因素之一，关于基础的底面形状对其沉降量的影响规律尚缺乏研究。针对任意底面形状的浅基础，分析了其底面形状对基础沉降的影响原因，提出了标准图形的概念，并依此定义了基础沉降函数，对多种常见的底面形状的基础进行了沉降规律分析和总结。     

空洞的存在对浅基础承载力与沉降的影响分析

空洞的位置、形状、大小以及地基土的类型等诸因素都会对浅基础的承载力和沉降产生影响。利用一系列的二维弹塑性有限元方法分析一个空洞存在时其位置对浅基础承载力与沉降的影响，并对其发生机制进行研究。研究结果表明：空洞对浅基础承载力与沉降的影响存在一个极限范围。只有当空洞存在于这个影响极限范围之内时，空洞的存在才会显著地影响基础的承载力和沉降。另外，基于有限元量化分析结果，还提出一个简单实用的浅基础承载力的空洞影响效果计算方法。     

天然地基上浅基础底面尺寸的确定

本文通过分析天然地基上浅基础设计的一般方法,找出不完善的地方,即在设计过程中只考虑了地基承载力的影响,而忽略了地基不均匀沉降、基础倾斜的问题,笔者在此提出一种方法,即从规范入手,按允许沉降差和允许倾斜角确定基础的底面尺寸。     

矩形浅基础作用下地基的沉降分析

本文用有限元和无限元相耦合的数值方法来分析地基在承受矩形浅基础传来的坚向荷载作用下的沉降变形。分析中对矩形浅基础采用弹性本构模型，地基土体采用非线性及弹塑性本构模型。运用相应的程序对重庆红粘土地基进行计算，分析了矩形浅基础荷载作用下的地基沉降随载荷增加而变化的规律。     

砌体结构在实际工程中的应用及发展

本文通过分析天然地基上浅基础设计的一般方法,找出不完善的地方,即在设计过程中只考虑了地基承载力的影响,而忽略了地基不均匀沉降、基础倾斜的问题,笔者在此提出一种方法,即从规范入手,按允许沉降差和允许倾斜角确定基础的底面尺寸。     

浅基础承载力离心模型试验研究

笔者利用容量为10gt的离心机对砂基上的浅基础进行了较为系统的试验,用以研究基础的尺寸、形状、埋深和砂土相对密度对浅基础承载力、承载力因数（Nr,Nq）、形状因数（ζr,ζq）及破坏型式的影响。笔者提出一种利用浅基础离心模拟试验资料确定浅基础的承载力因数和形状因数的方法。利用此方法确定的44T-4砂的承载力因数,形状因数与已有的各种理论解和试验解进行了对比。研究工作得出了一些有意义的结论。     

以计算沉降为控制条件的群基础底面积优化设计

本文抓住建筑物后期使用中可能出现的不均匀沉降及过大沉降的潜在威胁为主线，提出对于群基础以计算沉降为控制条件先期基础设计优化，并介绍了具体思想和计算机处理过程；对于任何复杂成层地基和采用不同的沉降计算方法，经上机均可得到满意的计算结果，使其成为浅基础优化设计及基础CAD系统的重要环节。     

邻近浅埋基础建筑深基坑变形控制

浅埋基础建筑由于自身基础受力特点,对地面沉降特别是不均匀沉降的影响比较敏感,因此邻近浅埋基础建筑深基坑施工需更加关注基坑工程质量,严格控制基坑变形,尽量减小地面沉降及建筑沉降,确保建筑安全。对邻近浅埋基础深基坑施工变形控制的施工技术措施进行分析、总结,供类似工程借鉴。     

高层住宅基础优化设计实例

通过对浅层强风化炭质页(灰)岩进行深入的勘察检测和分析,将原设计的冲(钻)孔灌注桩优化为筏形基础,介绍了浅层地基土承载力取值、筏形基础浅埋稳定性分析、基础沉降预测等关键问题和沉降实测数据反演结果,对软硬不均地基上的筏形基础提出采用统计方法预测沉降的思路.     

高速公路小型桥涵条形浅基础地基承载力特征值数值模拟

依托实际工程，对具体的条形浅基础地基承载力特征值进行分析，得到了不同基础宽度条件下的地基土荷载沉降曲线；将《建筑地基基础设计规范》申的地基承载力确定方法引入作为数值模拟结果的判定准则，可以精确和合理的计算出浅基础的地基承栽力特征值。     

Use of power plant bottom ash as fine and coarse aggregates in high-strength concrete

In this study, experiments have been carried out to evaluate the utilization of bottom ash (by-product of power plant) as fine and coarse aggregates in high-strength concrete with compressive strength of 60–80 MPa. Firstly, the chemical and physical characteristics of bottom ash particles, such as chemical compositions, specific gravity and SEM images, were investigated. Further experiments were conducted by replacing fine and coarse bottom ash with normal sand and gravel varying in percentages (25%, 50%, 75%, and 100%). The effect of fine and coarse bottom ash on the flow characteristics and density of concrete mixture was investigated in the aspect of particle shapes and paste absorption of bottom ash. Mechanical properties, such as compressive strengths and modulus of elasticity and flexural strength of high-strength concrete with bottom ash were evaluated. It was found that the slump flow of fresh concrete was slightly decreased from 530 mm to 420 mm when coarse bottom ash was replaced 100% of normal coarse aggregates, while fine bottom ash did not affect the slump flow. Moreover, it also showed that both of fine and coarse bottom ash aggregates had more influence on the flexural strength than compressive strength.     

大底盘非对称塔楼结构的地震反应分析计算

大底盘非对称塔楼是一种复杂的结构体系,结构的上下刚度变化很大。采用PKPM软件中SATWE模块对一组上下刚度比值不同的非对称塔楼结构建模分析,计算得到结构的固有周期和模态振型,认为底盘与塔楼刚度比值β变化对结构各振型的振动模式影响不大,当β值取为3时,结构的周期和整体位移均达最小值。     

孔洞形状对大理岩渐进破坏力学特性影响研究

为研究孔洞形状对岩石破坏特性的影响,对含不同形状孔洞大理岩进行单轴压缩实验,利用高速摄像仪记录孔洞周边裂纹的萌生、扩展和贯通直至试样破坏的过程,分析孔洞形状对大理岩力学特性、破坏模式、裂纹扩展特性的影响规律,以及试样所储存的能量与岩石变形破坏的关系。研究发现,孔洞形状对大理岩的力学特性有明显影响,且不同边界类型的孔洞有不同的裂纹扩展特性。另外,试样的宏观破坏是由远场裂纹迅速扩展的结果,而初始裂纹对材料破坏没起到关键作用。从能量的角度提出一个可判别岩石脆性破坏的能量跌落系数,还发现岩块弹射烈度与单位体积吸收能量的大小有关。通过FLAC^3D对不同孔洞形状大理岩进行数值模拟,得到不同孔洞形状大理岩的应力分布和应力集中系数特征,其应力分布特征较好地反映了室内试验的破坏特征。     

Buckling analysis of stepped plates using modified buckling mode shapes

A new approximate procedure for buckling analysis of simply supported rectangular stepped or perforated plates subjected to uniform edge stresses is formulated. The procedure uses energy method based on modified buckling mode shapes. The change of thickness within a plate is characterized by introducing a stepping index. It is shown that the buckling (vibrational) mode shapes of stepped plates can be predicted by linear combination of various mode shapes of the equivalent flat plates. These buckling mode shapes, in turn, are incorporated to evaluate buckling loads of stepped plates. Some case studies are carried out to demonstrate the accuracy and the versatility of the proposed method by comparing them to the results presented by other researchers.     

Three-dimensional behavior of geosynthetic tubes

Geosynthetic tubes filled with pressurized slurry are used for various purposes (e.g., as dikes or breakwaters). The three-dimensional behavior of such structures is investigated. The tubes are assumed to be comprised of two rectangular sheets connected at their edges, and to rest on a tensionless elastic foundation. As the slurry is pumped in, the top surface rises and the outer portion of the bottom surface lifts off the foundation. For tubes with aspect ratios of 2:1 and 5:1, the deflected shapes, mid-surface stresses, and contact regions with the foundation are determined with the use of the finite element method and thin shell elements. Wrinkling occurs close to the long edges of the tubes.     

Experimental study on steel built‐up column moment connections with top and bottom trapezoidal side plates

Built‐up and box columns are used extensively in steel structures. A kind of built‐up column is composed of two I rolled shapes separated by calculated interval and welded between two cover plates. The uncertainties due to these columns are the flexibility of the column cover plates under the transferred beam flange plate forces and the brittle behavior of the groove weld between the beam flange plate and the column cover plate. The top and bottom trapezoidal side plates are proposed to improve the behavior of these column moment connections. Using this approach, the total beam flange forces transfer to the lateral sides of the column, parallel to the beam web, by means of top and bottom side plates. An experimental test is developed to study the behavior of the proposed connection under cyclic loading. The results indicate that the proposed connection has sufficient strength and ductility to apply in special moment frames. Also, the rehabilitated connection eliminates the vulnerabilities of deformation of the column cover plate and brittle fracture of groove welds in conventional connections. Copyright © 2016 John Wiley & Sons, Ltd.     

张拉式环形内挑顶蓬结构的动力特性分析

采用有限元法求解顶蓬结构的自振频率与振型,考虑顶蓬结构的覆盖材料质量及部分活荷质量,将其作为集中质量分布在结构各个结点上,保证结构自振特性分析的正确性.对顶蓬结构进行模态分析,弄清结构的各阶频率及对应的振型,了解结构各向刚度分布情况以及顶蓬结构的基本自振特性.从顶蓬结构的索截面面积、索中的预应力、荷载强度以及矢跨比等4...     

劲性混凝土柱施工技术

国家大剧院工程中，歌剧院、戏剧院及音乐厅内分别有8根、10根、18根矩形劲性混凝土柱，根据工程特点，从柱内型钢材料加工，柱内型钢安装，劲性柱的钢筋工程，模板工程和混凝土工程等方面制订施工方案，解决了一系列施工难题，劲性柱满足设计和规范的要求。     

上覆高位岩浆岩下离层空间的演化规律及其预测

针对工作面上覆高位硬厚岩浆岩条件,采用相似材料模拟试验研究了主关键层下离层空间的演化过程与形态特征,分析了离层空间的层位演化与横向扩展规律、覆岩与主关键层的运移规律;通过理论分析揭示了离层空间形成的机理与条件,提出了离层空间演化特征的确定方法,建立了主关键层底部最大离层空间的分析模型与预测方法。研究表明:岩层组合失稳运移形成"月牙"形离层空间,以间歇式跳跃上升至岩浆岩底部,岩浆岩底部存在较大的离层空间,并由"月牙"形逐渐转变为"一字"形,岩浆岩破裂运移导致离层闭合。离层空间在亚关键层及主关键层底部自下而上动态发育与闭合,层位高度及发育范围与推进距离呈正相关性,可采用"多梯形"方法确定其演化过程。覆岩运移经历下位关键层沉降、运移向主关键层底部发展、底部盆地沉降、岩浆岩运移及整体稳定等5个状态,覆岩下沉形态先后呈"V"型、"√"型及"U"型。岩浆岩运移过程分为下部支撑、底部离层扩展、破裂随动、失稳运移及离层闭合稳定等5个阶段。建立了最大离层空间的覆岩结构及弹性基础梁模型,得到其断面积和体积的预测计算式,为高位岩浆岩下安全开采提供了理论依据。