上海轨道交通旁通道自然解冻融沉注浆加固技术与效果分析

上海市某隧道旁通道是第一个参照《旁通道冻结法融沉注浆加固建设指导意见》完成自然解冻融沉注浆的旁通道。事实证明,其所有测点的沉降量均在控制范围内,《旁通道冻结法融沉注浆加固建设指导意见》是科学的。介绍了该旁通道的注浆加固施工工艺及加固效果。根据加固效果分析提出进行有效融沉注浆的建议:在开始融沉注浆的第一个月内应增加注浆频率和注浆量,可有效控制最终的沉降量;对距离旁通道轴线较近的隧道区域应进行强化注浆,可有效减小隧道的最终沉降量。     

通信设备用阀控式密封铅酸蓄电池的维护和管理

从维护和管理的角度出发,对影响蓄电池寿命的因素进行了分析,对如何提高电池的使用寿命进行了探讨,并根据日常的一些维护经验,对蓄电池的维护提出了建议。     

富水蚀变岩大断面高速铁路隧道开挖大变形控制技术

以富水花岗岩侵入蚀变带区域高速铁路隧道建设为背景,对隧道开挖围岩变形控制技术进行研究。运用隧道工程理论、数值模拟和现场监测等技术与方法,提出了从全断面开挖法、台阶法、CD法到CRD法的安全度逐渐增加的隧道开挖方法,确定了避免富水花岗蚀变岩进一步应变软化和力学参数弱化的隧道开挖支护结构形式及其参数,得出了适当加大预留变形量结合衬砌紧跟的施工工艺。实践表明,按研究出的开挖方法和支护方案进行施工,可以有效控制隧道围岩大变形而使变形快速收敛,能够减少侵限处理工作量,并确保富水花岗蚀变岩隧道开挖时围岩稳定和地下工程结构安全。     

深圳地铁“建设-移交”(BT)模式创新和适应性分析

基于深圳地铁建设资金状况、质量特点、工期要求、国内潜在BT(建设-移交)承办方资金实力和施工能力、监理和设计单位的履约能力等因素,深圳地铁在传统BT模式上创新,在回购时间点、承办人角色、BT与非BT工程划分、监理与设计管理等方面进行有益的尝试,开创"投融资+设计施工总承包+回报"的深圳地铁BT模式,并取得实践上的成功。     

地铁出入口大跨度接口梁数值分析

建立空间计算模型对地铁出入口大跨度接口梁的内力等进行数值分析,提出接口梁空间计算模型及其内力计算结果,对比传统平面简化计算模型的内力结果,得知空间计算模型结果更接近接口梁的真实受力状态,接口梁的扭矩不是受力的控制性因素,而接口梁的弯矩接近弹性支座梁的弯矩。     

宁波南站上跨深基坑铁路便桥静态监测技术

宁波南站上跨深基坑铁路便桥结构形式为国内首创,在便桥下深基坑开挖的同时,须保证沿海铁路列车绝对安全平稳的通行,安全监测至关重要。本文根据该工程的现场实际和结构的特点,拟定了桥梁静态监测的具体实施方案、数据分析与处理模式,研究了该桥梁变形的规律,及时提供监测分析意见,为深基坑安全和信息化施工提供指导,为铁路便桥安全运营提供保障。这对今后类似的桥梁施工监测有一定的指导和借鉴意义。     

A simple formulation for predicting the ultimate strength of ships

The aim of this study is to derive a simple analytical formula for predicting the ultimate collapse strength of a single- and double-hull ship under a vertical bending moment, and also to characterize the accuracy and applicability for earlier approximate formulations. It is known that a ship hull will reach the overall collapse state if both collapse of the compression flange and yielding of the tension flange occur. Side shells in the vicinity of the compression and the tension flanges will often fail also, but the material around the final neutral axis will remain in the elastic state. Based on this observation, a credible distribution of longitudinal stresses around the hull section at the overall collapse state is assumed, and an explicit analytical equation for calculating the hull ultimate strength is obtained. A comparison between the derived formula and existing expressions is made for largescale box girder models, a one-third-scale frigate hull model, and full-scale ship hulls.List of symbols A _B total sectional area of outer bottom - A _B total sectional area of inner bottom - A _D total sectional area of deck - A _S half-sectional area of all sides (including longitudinal bulkheads and inner sides) - a _s sectional area of a longitudinal stiffener with effective plating - b breadth of plate between longitudinal stiffeners - D hull depth - D _B height of double bottom - E Young's modulus - g neutral axis position above the base line in the sagging condition or below the deck in the hogging condition - H depth of hull section in linear elastic state - I _s moment of inertia of a longitudinal stiffener with effective plating - l length of a longitudinal stiffener between transverse beams - M _E elastic bending moment - M _p fully plastic bending moment of hull section - M _u ultimate bending moment capacity of hull section - M _uh ,M _us ultimate bending moment in hogging or sagging conditions - r radius of gyration of a longitudinal stiffener with effective plating [=(I _s /a _s )^1/2] - t plate thickness - Z elastic section modulus at the compression flange - Z _B ,Z _D elastic section modulus at bottom or deck - slenderness ratio of plate between stiffeners [= (b/t)(_y/E)^1/2] - slenderness ratio of a longitudinal stiffener with effective plating [=(l/r)(_y/E)^1/2] - _y yield strength of the material - _yB , _yB , _yD yield strength of outer bottom, inner bottom - _yS deck, or side - _u ultimate buckling strength of the compression flange - _uB , _uB , _uD ultimate buckling strength of outer bottom - _uS inner bottom, deck, or side     

Surf-riding and oscillations of a ship in quartering waves

The behavior of a ship encountering large regular waves from astern at low frequency is the object of investigation, with a parallel study of surf-riding and periodic motion paterns. First, the theoretical analysis of surf-riding is extended from purely following to quartering seas. Steady-state continuation is used to identify all possible surf-riding states for one wavelength. Examination of stability indicates the existence of stable and unstable states and predicts a new type of oscillatory surf-riding. Global analysis is also applied to determine the areas of state space which lead to surf-riding for a given ship and wave conditions. In the case of overtaking waves, the large rudder-yaw-surge oscillations of the vessel are examined, showing the mechanism and conditions responsible for loss of controllability at certain vessel headings.List of symbols c wave celerity (m/s) - C(p) roll damping moment (Ntm) - g acceleration of gravity (m/s²) - GM metacentric height (m) - H wave height (m) - I _x ,I _z roll and yaw ship moments of inertia (kg m²) - k wave number (m^–1) - K _H ,K _W ,K _R hull reaction, wave, rudder, and propeller - K _p forces in the roll direction (Ntm) - m ship mass (kg) - n propeller rate of rotation (rpm) - N _H ,N _W ,N _R hull reaction, wave, rudder, and propeller - N _P moments in the yaw direction (Ntm) - p roll angular velocity (rad/s) - r rate-of-turn (rad/s) - R(,x) restoring moment (Ntm) - Res(u) ship resistance (Nt) - t time (s) - u surge velocity (m/s) - U vessel speed (m/s) - v sway velocity (m/s) - W ship weight (Nt) - x longitudinal position of the ship measured from the wave system (m) - x _G ,z _G longitudinal and vertical center of gravity (m) - x _S longitudinal position of a ship section (S), in the ship-fixed system (m) - X _H ,X _W ,X _R hull reaction, wave, rudder, and propeller - X _P forces in the surge direction (Nt) - y transverse position of the ship, measured from the wave system (m) - Y _H ,Y _W ,Y _R hull reaction, wave, rudder, and propeller - Y _p forces in the sway direction (Nt) - z _Y vertical position of the point of action of the lateral reaction force during turn (m) - z _W vertical position of the point of action of the lateral wave force (m) Greek symbols angle of drift (rad) - rudder angle (rad) - wavelength (m) - position of the ship in the earth-fixed system (m) - water density (kg/m³) - angle of heel (rad) - heading angle (rad) - _e frequency of encounter (rad/s) Hydrodynamic coefficients K roll added mass - N _v ,N _r yaw acceleration coefficients - N _v N _r N _rr N _rrv ,N _vvr yaw velocity coefficients K. Spyrou: Ship behavior in quartering waves - X _u surge acceleration coefficient - X _u X _vr surge velocity coefficients - Y _v ,Y _r sway acceleration coefficients - Y _v ,Y _r ,Y _vv ,Y _rr ,Y _vr sway velocity coefficients European Union-nominated Fellow of the Science and Technology Agency of Japan, Visiting Researcher, National Research Institute of Fisheries Engineering of Japan     

轿车车身静态刚度计算及静态竖直弯曲刚度优化分析

采用UG软件建立了某国产轿车白车身静态分析有限元模型，计算并验证了其主要工况下的静态扭转特性，并进行了轿车车身静态弯曲挠度关于板单元厚度的灵敏度计算分析。针对分析结果进行了具体加强刚度的优化设计。     

遗传算法在五连杆悬架优化中的应用

针对五连杆悬架的特点，运用多体系统动力学的理论建立了悬架的运动学分析模型，基于遗传算法开发了优化器的核心单元，并解决了它们之间的通讯和协调问题以实现在车轮上下跳动过程中车轮外倾角的运动学特性变化量与目标值之间的偏差最小作为优化设计的目标，说明了遗传算法在五连杆悬架优化中的应用。应用这种优化体系对某型轿车五连杆悬架进行了实例优化分析。