山区高速公路设计与交通安全问题研究

从交通安全的角度,通过剖析山区高速公路设计的线形问题、视觉问题和气候问题,阐明了山区高速公路设计中平面线形、纵断面线形、平纵线形组合在设计中的重要性,说明了视觉及气候环境对交通安全的影响,并进行了具体的分析。     

高速公路设计中的平面线形设计

本文针对高速公路平面线形设计两个问题,重点分析了现今高速公路平面线形设计采用的直线形设计方法和曲线形设计方法与应用,从而为设计人员在进行高速公路平面线形设计时如何采用合适的设计方法提供了选择依据。     

高速公路限速方案研究

文中重点是对国内外高速公路限速现状、限速流程进行研究，通过对高速公路的技术指标核查、交通特征、交通事故以及运行速度协调性等的进行分析，阐述了限速对高速公路的重要性，提出了限速解决方案。     

龙泉关服务型互通方案选择的探讨

在既有山区高速公路上增设互通式立体交叉,不仅要受到地形、地物、地质等自然条件的制约,还要受到既有高速的平纵指标,既有构造物的限制,结合工程实例,对在既有高速上增设的互通式立体交叉进行仔细研究和探讨,提出了既有山区高速公路上增设互通式立体交叉的思路和建议,供同类工程参考。     

公路线形安全性评价系统开发与应用

讨论基于《公路项目安全性评价指南（JTG/T B05-2004）》理论与评价方法,利用Visual Studio.NET 2002和Object ARX二次开发技术对公路线形安全评价系统进行了设计与实现,通过本系统在具体工程项目设计中的应用,验证了本系统的实用性和可靠性。     

基于模糊评判的高速公路线形安全性评价

本文采用层次分析法、改进的德尔菲法及模糊评判法相结合,在复杂的系统中较准确的反映了高速公路线形安全性系统的状况,通过实例证明此方法可行,评价的结果较公正、客观、合理。     

山区高速公路桥梁施工安全管理与控制

文中针对山区高速公路桥梁施工安全管理与控制存在的问题进行研究,分析施工参与的各方之间管理的协调性、有效性,研究如何确保这个管理系统的环境适应性,以提升山区高速公路建设安全管理新理念,解决山区高速公路建设安全控制的关键问题。     

高速公路岩堆边坡仿真分析与评价研究

在分析宜巴高速公路三里花岩堆边坡基本特征及破坏机理的基础上,基于FLAC3D理论,建立了山区高速公路岩堆边坡三维仿真分析模型,在此基础上,考虑岩堆天然自重、降雨、地震和人类活动等荷载组合作用,模拟分析了岩堆边坡在不同工况条件下的变形破坏机理和稳定性,并对岩堆边坡的稳定状态进行了评价。     

山区公路提档升级线形设计的思考

针对山区提档升级公路的线形设计,提出三种设计思路,分别是改扩建困难路段灵活运用线形指标、最大化地利用老路、局部线形组合差路段进行改线或优化线形。并结合十堰市S281郧阳区南化至白浪段改扩建工程,从线形优化、降低工程造价及减少生态环境破坏等方面分析了设计思路的可行性和优越性。     

基于实测数据的高速公路车速特征分析

为了补全目前车速特征的研究漏洞,找到对高速公路交通安全影响较为突出的车速特征。以实测数据为基础,采用多特征分析法分别分析了高速公路车速的离散性、协调性和线性一致性及其对高速公路交通安全的影响。分析结果表明,对高速公路交通安全起到关键性作用的车速特征是离散性和线性一致性,控制好高速公路车速的离散性和线性一致性,可将恶性交通事故遏制在萌芽状态,提升高速公路的交通安全等级。     

基于响应面法的潜载导弹垂直发射装置多目标优化

针对某型潜载垂直发射装置的冲击降载问题,利用响应面法与优化技术相结合的设计方法,进行了发射装置结构优化设计.首先利用拉丁超立方试验方法采样,通过Ansys workbench平台进行发射装置抗冲击性能分析,构建发射装置受冲击结构载荷和总质量的响应面,研究结构参数对发射装置综合性能的灵敏度;再运用多目标驱动算法对发射装置进行多目标优化,得到其最优解集,最终实现其抗冲击性能提高14.9％,发射装置整体质量降低2.1％.结果表明,该方法具有较高的精度和实用性,对相关理论研究和工程应用具有一定的价值.     

超大型浮体柔性连接器动响应研究

为了降低VLFS(超大型浮体)模块连接的巨大载荷,通常选择柔性连接器.本文以某横向浮筒式的浅吃水超大型浮体为研究对象,采用RMFC模型(刚性模块柔性连接器)分析连接器载荷和模块运动响应,并与三模块模型试验进行比较验证.通过较高和较低横向刚度的系列纵向和垂向刚度组合的连接器载荷计算,给出连接器载荷随刚度变化的关系,分析连接器载荷峰值出现的原因.针对连接器载荷峰值对应的刚度组合,计算模块运动响应,分析模块相对运动模式.研究结果表明,对于较高和较低的横向刚度,均存在一定的纵向和垂向刚度组合,导致连接器载荷出现较大的峰值;连接器载荷峰值对应浪向角85°左右的海况,模块相对运动主要表现为艏摇.     

水面舰船波浪弯矩计算方法研究

我国现行《舰船通用规范》适用于设计水线长不超过160m的水面舰船,当设计水线长在160～200m时,规范规定参照执行。随着舰船的尺度逐渐加大,波浪载荷的计算问题更加复杂。比较了4种规范的波浪载荷计算公式,并应用线性切片理论,采用短期和长期预报的方法,计算大尺度舰船的垂向波浪诱导弯矩值。因此,对于一定范围内的大尺度水面舰船,采用"通用规范"所得波浪载荷值计算船体强度还有一定安全性,并可运用多种计算方法合理选取波浪弯矩值。     

削角直立堤断面稳定性及波浪力分析试验研究

通过模型试验观测波浪作用下削角直立堤断面的稳定性、堤顶越浪情况及削角直立堤受力情况,并与依据《海港水文规范》和《防波堤设计与施工规范》计算的波浪力理论值进行了对比分析,结果表明,上部结构采用削角型胸墙的直立堤具有减轻波浪水平压力,增加竖向压力,提高堤身稳定的优点。并通过实测波浪力的合成总力计算,得出了削角直立堤断面整体稳定。     

水力插板与抛石斜坡复合堤稳定机理

在海岸防护堤坝工程中,采用水力插板桩技术修筑直立墙,并在墙前水下形成抛石护坡,此种水力插板与抛石斜坡组成的的复合堤,已在工程实践中表现出良好的安全稳定性。对直立堤、抛石堤以及复合堤3种堤型开展不同波况下直立墙上和抛石护坡中波压力的试验研究,对复合堤的稳定性优于直立堤和抛石堤的机理进行分析。试验结果表明,抛石护坡明显降低了直立墙上的波压力,减轻了波浪冲击;直立墙阻止越浪带动抛石堤顶部块体向堤后运动,避免抛石护坡的过度破坏。两者结合使复合堤具有比直立堤和抛石堤更好的稳定性。     

Finite element modeling of suction anchors under combined loading

Suction anchors are subjected to inclined, quasi-horizontal or quasi-vertical loadings. The type of the structure and depth of water govern the inclination of the load. Under this load condition, suction anchor experiences a combination of horizontal and vertical translations, and rotation. Therefore the soil's reaction to this load condition can be idealized as horizontal and vertical loadings, together with a moment. The magnitude and combination of the reactions depend on the load inclination, soil property and the point at which the load is applied. The behavior of the suction anchor subjected to the combined V–H-M loading is elaborated in this paper. This is to observe the effects of soil properties on the failure mechanism and ultimate capacity of the foundation. This was achieved by applying the pure horizontal and vertical displacements, and rotation and their combinations to the foundation, on V–H, V-M and H-M spaces and the yield-locus created for each space. The general purpose finite element program DIANA was used for this study. Non-linear analysis was conducted using a simplified elastic-perfectly-plastic model with Von-Mises yield criterion for saturated and consolidated clay.     

舰载导弹垂直发射时适配器动态特性研究

为研究舰载导弹发射时的适配器动态特性,应用有限元软件Abaqus建立含有适配器的舰载导弹垂直发射非线性结构动力学模型,并采用中心差分法进行发射过程的瞬态动力学计算;计算结果揭示发射过程中适配器的应力变化、所受摩擦力变化规律及适配器厚度变化规律,为舰载导弹垂直发射箱中适配器的设计提供设计依据。     

斜支柱小水线面双体船初稳性特征研究

对斜支柱小水线面双体船初稳性进行研究分析.在直支柱小水线面双体船的原理基础上,结合支柱倾斜所产生的问题和特殊性,分析得出了斜支柱小水线面双体船初稳性的计算方法并编写Fortran程序简化计算.进行实例计算,计算结果表明斜支柱小水线面双体船初稳性好于直支柱.随着支柱与水线面夹角逐渐减小,初稳性高GM增大.     

Experimental study of slam-induced stresses in a containership

Experiments for the ship motions and sea loads were carried out on a segmented model of a container ship in ballast condition. Comparisons between the measurements and the theoretical results were carried out for the vertical motions and bending moments. For the evaluation of the primary stresses it is assumed that the total vertical bending moment induced by waves is divided into one component obtained by the linear theory and another one is due to the slamming loads. Several formulations for the determination of the slamming loads are compared with experimental results. The vibratory response of the model is calculated by modelling the hull with rotational springs and rigid links. Linear finite elements with a consistent mass formulation are adopted for the structural model and the response is obtained by modal superimposing and direct integration methods.     

Vibration-assisted decommissioning of a slip joint: Application to an offshore wind turbine

An alternative option to the traditional grouted joint for wind turbines is a direct steel-to-steel connection, also known as slip joint. In a recently published work, a proof of concept of a vibration-assisted installation and decommissioning technique of a slip joint was illustrated. Leveraging on the obtained results, the current study shows for the first time a decommissioning campaign carried out using a vibration-assisted technique applied on a prototype hydraulic wind turbine tower located in the North Sea, and connected to the monopile through a slip joint. The key aspect of the dismounting procedure is a priori knowledge of the resonance frequency clusters corresponding to the slip joint’s cross-sectional modes. Therefore, field hammer tests and experimental modal analysis were carried out inside the wind turbine tower. The identified frequencies and mode shapes were then compared with numerical ones estimated by a finite element model of the investigated structure. The comparison showed that a set of frequency clusters can be directly selected from a detailed numerical model. The preparatory work of the slip joint decommissioning was then executed by installing electric shaker devices, based on the dynamic identification results, and hydraulic jacks mounted inside the wind turbine tower. A first decommissioning trial was carried out in May 2019, while the final decommissioning was performed in August 2019. After analysing the measurements of the hydraulic pressures, displacements and excitation frequencies during the decommissioning campaigns, the results showed that it is possible to disconnect the slip joint if, in combination to a vertical static force, one of the identified cross-sectional mode shapes is excited. The vibration-assisted decommissioning proved to be a successful technique to dismount the connection in a controlled and straightforward manner.