考虑土-结构相互作用下不规则建筑振动控制分析

当建筑物建造于比较软的地基之上,土-结构相互作用会导致土-结构相互作用体系的动力特性发生改变,以至于影响建筑振动的控制效果.因此,在分析建筑振动的控制时要考虑土-结构相互作用.本文主要是从土-结构相互作用下不规则建筑振动的被动控制、主动控制和半主动控制三个方面进行分析,综合论述了土-结构相互作用下不规则建筑振动的控制问题.     

非对称沟埋式涵洞涵-土作用机理(英文)

现行公路桥涵设计通用规范中的线性土压力理论不能准确反映非对称沟埋式涵洞结构的实际受力特性.结合现场试验和数值模拟研究了沟谷非对称设涵时,涵-土体系的受力状态和变形特性以及涵顶填土内部的土拱效应.讨论了偏栽效应对涵-土体系受力和变形的影响.研究结果表明,涵顶填土达到一定高度后填土内部产生土拱效应,该土拱效应能够缓解涵顶的应力集中,但其具有不稳定性.现场试验和数值模拟得到的涵顶土压力均大于现行公路桥涵设计通用规范的计算结果.而且偏载效应对涵-土体系的受力状态和变形特性的影响也不容忽视.     

非线性土-结动力相互作用的时域子结构分析

采用子结构方法分析了二维平面应变有限元土-结动力相互作用.为研究土-结相互作用的影响,进行了土-结相互作用问题的完整分析,即考虑线性和非线性土-结相互作用及不考虑土-结相互作用进行了分析计算.土-结相互作用的时域分析计算量很大,为减小计算量,提出了计算褶积分的有效方法.算法基于单位脉冲反应矩阵在某个时间步后的线性时间关系进行近似求解,即采用递归算法.对长模拟时间,这种时间近似求解能显著减小计算量.     

基于Rayleigh-Love杆理论的非均质土中大直径桩纵向振动（英文）

目的:研究大直径桩横向惯性效应对其动力响应的影响以及与土体径向非均质性的关系。创新点:1.采用Rayleigh-Love杆模型模拟大直径桩,考虑其横向惯性效应;2.所建立的桩土相互作用模型能同时考虑土体的竖向成层性和径向非均质性。方法:1.采用Rayleigh-Love杆模型模拟大直径桩,建立桩土体系纵向振动控制方程(公式(1)和(4));2.通过求解方程,得到桩顶纵向振动频域响应解析解(公式(15))和时域响应半解析解(公式(16));3.通过参数分析的方法,研究横向惯性效应对桩顶响应的影响以及与桩身参数和桩周土径向非均质性的关系(图2~9);4.通过与工程实例的对比,证明本文解的合理性(图11)。结论:1.考虑横向惯性效应时,桩底反射信号后移,导致桩的计算长度大于其实际值;2.横向惯性效应的影响程度随着桩身半径、泊松比、桩周土软化范围和软化程度的增大而增强,随着桩身混凝土强度等级、桩周土硬化范围和硬化程度的增大而减弱;3.考虑横向惯性效应时的计算曲线与实测曲线更为吻合。     

二聚体C_2H_4-nFn-BrF(n=0,2)的结构和π溴键性质的研究

本文计算使用了高精度的CP(counterpoise)校正方法,在MP2/aug-cc-pVDZ水平,得到了C2H4-BrF、trans-C2H2F2-BrF和cis-C2H2F2-BrF的结构。与C2H4-BrF对比,发现在F取代效应的影响下,C2H4-nFn-BrF(n=2)的π-Br键(Br…C=C)变长和倾斜了。F取代效应降低了π-Br键的相互作用能,电子相关效应增加了π-Br键的相互作用能。在C2H4-nFn-BrF(n=2)体系中发现了新的二级相互作用。     

二聚体C2H4-nFn-BrF(n=O,2)的结构和π溴键性质的研究

本文计算使用了高精度的CP(counterpoise)校正方法,在MP2/aug-cc-pVDZ水平,得到了C2H4-BrF、trans-C2H2F2-BrF和cis-C2H2F2-BrF的结构.与C2H4-BrF对比,发现在F取代效应的影响下,C2H4-nFn-BrF(n=2)的π-Br键(Br··C=C)变长和倾斜了.F取代效应降低了π-Br键的相互作用能,电子相关效应增加了π-Br键的相互作用能.在C2H4-nFn-BrF(n=2)体系中发现了新的二级相互作用.     

磁场中氦原子内电子的自旋效应研究

本文利用求解能量本征方程方法,研究外磁场对氦原子中两电子体系能量的影响,进而研究自旋效应.理论结果表明,若自旋状态在磁场方向的投影为零,则自旋磁矩与外磁场的相互作用能量为零,自旋对体系无影响;反之,若自旋状态在磁场方向的投影不为零,则自旋磁矩与外磁场的相互作用能量不为零,自旋对体系有影响.所以,氦原子处于基态时,自旋对体系无影响;处于激发态时,自旋的影响随自旋状态的不同而不同.     

二聚体C2H4-nFn-BrF（n=0，2）的结构和π溴键性质的研究

本文计算使用了高精度的CP(counterpoise)校正方法，在MP2／aug-cc-pVDZ水平，得到了C2H4-BrF、trans-C2H2F2-BrF和cis-C2H2F2-BrF的结构。与C2H4-BrF对比，发现在F取代效应的影响下，C2H4-nFn-BrF(n=2)的π-Br键(Br…C=C)变长和倾斜了。F取代效应降低了π-Br键的相互作用能，电子相关效应增加了π-Br键的相互作用能。在C2H4-nFn-BrF（n=2)体系中发现了新的二级相互作用。     

有限棱柱法对单桩与土相互作用系统的弹塑性分析

用有限棱柱单元法对采用长桩的单桩与土相互作用系统进行了三维弹塑性分析，并开发出一种可模拟半无限空间地基土边界条件的无限棱柱元．计算中考虑了承台对地基土的约束作用及桩土之间的竖向相对位移，地基土的本构模型采用修正剑桥模型．分析了集中荷载作用下摩擦长桩与土相互作用系统，得到了合理的荷载－沉降曲线及桩侧摩阻力的分布曲线，为长桩的研究与设计提供了一种有效的计算方法     

甘氨酸和水（1：1）氢键相互作用的理论研究

用5种DFT方法、MP2和HF方法,对甘氨酸和一个水分予之间的相互作用进行了研究,找到了4种稳定结构,均为环状双氢键结构;计算了4种结构的最优化几何参数和结合能,并对结合能进行了基组叠加误差（BSSE）校正．报道了红外光谱、红外强度和振动频率位移．用自洽反应场模型在6—311＋＋g（d,p）基组水平上研究了溶剂效应的影响,结果表明溶剂的极性对络合物的结构以及相对稳定性都有很大影响．     

Influence of structure plane size on seismic response of soil-structure interaction

The influence of the change of structure plane size on seismic response was studied for a soil-structure interaction system. Based on the finite element method, a soil-structure interaction calculation model was established to analyze the seismic response by changing the structure plane size and choosing different earthquake waves for different soil fields. The results show that when the natural periods of vibration for different structure plane sizes are close, under the same earthquake wave, the total displacement on the top layer of the structure and the foundation rotation displacement decrease with the increase of structure plane size, and the proportion of superstructure elastic selfdeformation displacement to the total displacement increases with the increase of structure plane size. While for different types of sites and seismic waves, under the horizontal and vertical seismic waves, the seismic responses of different plane sizes have a similar change rule.     

Damage assessment for buried structures against internal blast load

The soil-structure interaction (SSI) decoupling is applied to simplify buried structure against internal blast load as spring effect. Shear failure, bending failure and combined failure modes are considered based on five transverse velocity profiles for the rigid-plastic structural element. The critical equations for shear and bending failure are derived respectively. Pressureimpulse diagrams are accordingly developed to assess damage of the buried structures against internal blast load. Comparison is done to show influences of soil-structure interaction and shear-to-bending strength ratio of a structural element. A case study is conducted to show the application of damage assessment to a reinforced concrete beam element of buried structure.     

具有弹性支承的振动系统刚度系数的简化计算

利用振动模型简化了带有弹性支座的线弹性梁和刚架振动的刚度系数的计算 ,从而为此类线弹性振动的刚度系数的计算提供了简捷的方法     

计算悬空管线固有频率的新方法

长输管线在石油工程中大量使用 .穿河段管线由于河水的冲刷变得悬空 ,如果管线附近的涡泻频率接近管线的固有频率 ,将引起悬空管线的共振 ,并且导致管线的破坏 .本文将悬空管线视为弹性基础上的半无限长梁 ,建立了悬空段管线和埋入土中管线的偏微分振动方程 ,提出了计算管线固有频率的迭代计算方法 ,实例计算结果同现场测试结果基本一致 .     

Simplified damage assessment of slab against external blast load

Recently, the mode approximation method (MAM) has been adopted to analyze beam elements against blast load. However, in real cases, the main structural element of an underground structure is slab and side wall since they not only support the structure itself but also may sustain external loads from blast, earthquake, and other kinds of impact. In the present study, the MAM is extended from beam to plate elements and the soil-structure interaction is considered and simplified when calculating structural response under blast load. Pressure-impulse diagrams are generated accordingly for further quick damage assessment.     

公路隧道洞口段地震动力分析

根据以往的受震破坏经验,在公路隧道的高烈度地震带,地下工程可能会遭受严重震害,尤其洞口段为抗震薄弱区,本文采用FLAC3D软件,从土—结构相互作用模型出发,运用数值分析方法对隧道洞口段进行了三维弹性和弹塑性分析,得出了相应结论,并对结果进行分析,指出隧道抗减震设计中应注意的事项,并提出相应解决措施。     

Experimental Study of Structure Shock Vibration in Soft Caused by Explosion of Conventional Weapons

When hitting underground structures directly or exploding in rock-soil media near underground structures, the conventional weapons with large charge weight will make underground structures be subjected to strong shock vibration and cause personal casualty and damage of precision electronic equipments, The shock vibration has become one of the cardinal killing means of weapons. However, the existing methods of predicting structure shock vibration are limited evidently. In this paper the coupling coefficient of acceleration in clayey soil is obtained firstly. Subsequently based on repeated experiments of chemical explosion, after dimension analysis and by using method of multivariate stepwise regression, the calculation formulae of shock vibration acceleration for the underground structure are obtained finally. The formulae consider top and side explosion respectively, taking into account the effects of penetration depth, charge weight, distance to explosion center, rock-soil media, size of structure and buried depth. They are easy to use with high practicability and degree of confidence, and can provide credible evidence for prediction of shock vibration and vibration isolating design of underground structure.     

Experimental Study of Structure Shock Vibration in Soil Caused by Explosion of Conventional Weapons

When hitting underground structures directly or exploding in rock-soil media near underground structures, the conventional weapons with large charge weight will make underground structures be subjected to strong shock vibration and cause personal casualty and damage of precision electronic equipments. The shock vibration has become one of the cardinal killing means of weapons. However, the existing methods of predicting structure shock vibration are limited evidently. In this paper the coupling coefficient of acceleration in clayey soil is obtained firstly. Subsequently based on repeated experiments of chemical explosion, after dimension analysis and by using method of multivariate stepwise regression, the calculation formulae of shock vibration acceleration for the underground structure are obtained finally. The formulae consider top and side explosion respectively, taking into account the effects of penetration depth, charge weight, distance to explosion center, rock-soil media, size of structure and buried depth. They are easy to use with high practicability and degree of confidence, and can provide credible evidence for prediction of shock vibration and vibration isolating design of underground structure.     

固定辙叉区轮轨静态接触几何关系计算

针对固定辙叉特殊的轨线布置及复杂的轮轨接触关系,建立固定辙叉区轮轨接触几何关系算法,分析固定辙叉区沿辙叉走行方向主要接触参数的变化规律以及各关键断面轮轨接触点变化情况。结果表明:在辙叉轮载过渡段轮轨接触参数变化规律复杂,结构不平顺变化幅值最大且波长较短;轮对横移量增加,轮轨接触几何参数增大,轮轨动力作用增强;辙叉咽喉区和轮载过渡段辙叉侧轮轨接触点变化存在突变。提出应合理设计辙叉区轮载过渡段结构参数,优化轮轨接触几何关系,进而改善列车通过时辙叉的受力性能。     

火炉子沟大桥动力特性分析

用有限元计算桥梁结构的前几阶固有频率和振型等模态参数,在此基础上进行现场动态测试,将动测信号进行频谱分析,可识别出桥梁结构的固有频率等参数.综合分析表明,该桥梁结构动力特性的计算值与动测识别值两者是一致的,因此,该大桥动力特性达到了设计要求.这种计算和现场测试相结合的方法,能可靠得到桥梁结构的动力特性,借此,可检验大桥的施工质量和确定大桥的实际承载能力.