石质文物三维信息留存与应用

对石质文物三维信息留存的几种主要方法:基于传统测量方式,基于近景摄影测量方式,基于三维激光扫描方式进行了系统论述,并对其原理、处理流程、优缺点进行了对比,结合实际工程实例给出石质文物三维信息留存的主要应用,并对未来发展趋势进行了展望.     

应力空间岩土本构模型的三维图像

本构模型的三维图像对于全面掌握本构理论具有十分重要的意义,然而现有文献提供的三维模型图像要么粗糙要么不成系统,且目前还没有学者系统地进行过本构模型三维图示化的工作。因此,在简要总结现有本构理论的基础上,对常用的大多数岩土材料本构模型进行了三维图示化,它们对于进一步完善本构理论具有积极的指导作用。     

库区滑坡稳定性二维、三维分析与应用

库区滑坡的地形、滑床及其地下水位面等几何形状复杂,具有典型的三维特征,为了更合理地分析评价其稳定性,在同等条件下选取二维剩余推力法和三维极限平衡法同时进行计算对比分析。以某库区滑坡作为实例,分别运用二维、三维方法反演确定其强度参数,计算各典型库水位下的滑坡稳定系数,并对滑坡稳定系数在水库水位变化(包括上升和下降变化)的情况下进行了敏感性对比分析。结果表明,三维方法的计算分析结果更为客观、合理;而且综合二维、三维计算结果进行分析,可得到符合实际的结论,为分析评价库区滑坡稳定性提供了一条好的途径。     

桥梁模型的三维激光扫描变形分析及精度评定

对三维激光扫描的误差来源进行了阐述,并以桥梁模型为载体设计了变形监测实验。三维激光扫描仪和高精度全站仪同时观测,对两类数据进行处理,分析了桥梁的变形情况,最后对扫描数据的精度可靠性进行了评定。     

煤矿采区三维地震勘探概况与应用

结合煤矿采区三维地震勘探技术的特点,分析了三维地震勘探技术对高产高效矿井建设的作用,并对该技术在煤矿采区中的应用情况进行了阐述,指出三维地震勘探技术在煤矿采区地质勘探中占有重要的地位。     

三维激光扫描技术在高铁特大桥梁形位检测中的应用

许多已投入运营的高速铁路桥梁受施工质量、地质灾害、周围超挖超采等因素影响,其桥墩位置和垂直度已偏离设计位置,在没有监测措施或监测错过最大变形期的情况下如何准确测量桥墩位置和垂直度,为桥梁病害整治提供精准数据依据,实施难度较犬.本文根据实际案例,详细阐述了三维激光扫描技术在高速铁路特大桥形位检测中应用的技术方案、点云数据...     

Levee damage and bridge scour by 2019 typhoon Hagibis in Kanto Region,Japan

Typhoon Hagibis made landfall in Japan at 19:00 JST on 12th October 2019. The heavy rainfall caused by the typhoon was mostly concentrated within a 24-hour period; it brought devastating damage to eastern Japan. This report focuses on the flood-induced levee damage and bridge scour generated by the typhoon in the Kanto region. The levee breaches occurred mainly in the northern part of the region. They were concentrated along the Kuji and Naka Rivers and tributaries of the Tone and Arakawa Rivers. In most breached locations, the cause of the damage was the landward overtopping of the river water. Surface erosion on the slope of the protected side and/or slope failure on the protected side due to seepage-induced instability were the main causes of the levee breaches. Apart from the flooding induced by the inundation of the river water, inland flooding was also found. Damage to a river bridge due to local scour revealed the importance of considering the movement of sandbars in river channels, i.e., changes in the river flow conditions, when assessing the risks of bridge scour.     

3D analytical prediction of building damage due to ground subsidence produced by tunneling

Tunnel construction entails the generation of ground settlements, which can endanger the adjacent buildings. The prediction of damages in buildings is usually based on the classical Gaussian profiles for the approximation of the subsidence trough and the equivalent beam method for modeling the response of building walls. Current available expressions refer to walls aligned transversally with respect to the tunnel axis, which usually represents the worst-case scenario. However, approximations must be done for other building alignments, since no analytical expressions are available for these cases. We propose a novel equation for the determination of the horizontal ground strain, which departs from the equations of the classical Gaussian settlement profiles. The novel formulation allows the application of the equivalent beam method in 3D and the modeling of the tunnel advance. The results show significant variations of the estimated damage depending on the wall position with respect to the tunnel axis. The paper reviews also certain relevant aspects of building damage predictions, such as the influence area of settlements and the possible contribution of ground horizontal strain to damage reduction. A parametric analysis is further performed to create a non-linear regression model that allows direct estimation of the maximum tensile strain in a building wall according to input values of geological conditions and wall and tunnel geometries.     

Impacts of small scale rainfall variability in urban areas: a case study with 1D and 1D/2D hydrological models in a multifractal framework

In this paper the sensitivity to small scale unmeasured rainfall variability (i.e. at scales smaller than 1 km by 1 km by 5 min in time, which are usually available with C-band radars) of a 1D/2D model with a 10 m resolution and a semi-distributed 1D model of the same 1.47 km² urban area is analyzed. The 1D/2D model is the open source numerical platform Multi-Hydro, which couples (open source) distributed models of involved hydrological/hydraulic processes. The methodology implemented to evaluate the uncertainties consists of generating an ensemble of realistic rainfall fields downscaled to a resolution of 12.3 m in space and 18.75 s in time with the help of a stochastic universal multifractal model. The corresponding ensemble of hydrographs is then simulated. It appears that the uncertainty is significant and that Multi-Hydro unveils much more uncertainty than the simpler 1D model. This points out a need to develop high resolution distributed modelling in urban areas.     

系统集成和面向对象编程技术在桥梁CAD中的应用

系统集成是当前设计单位提高竞争力的必然之路.钢结构桥梁构件有一种较好的构件统一性.利用系统集成开发CAD系统成为一种可能.在本文中,首先阐述了面向对象编程和泛型编程思想,接着根据系统集成思想和作者在开发日本ASDF桥梁设计系统过程中的经验,提出了新一代集成化的钢结构桥梁输入方式.     

山东省城乡一体化规划的探索与实践

城乡一体化规划是一种新的规划类型和当前的规划热点。本文总结了山东省城乡一体化规划的探索与实践,对该类规划在规划体系中的地位和作用、不同空间尺度的城乡一体化规划的编制方法、内容和深度进行了探讨。认为城乡一体化规划是市县域范围内最大的规划,在"三规合一"中应代替城市总体规划,与国民经济和社会发展规划、土地利用总体规划相协调。     

高速公路桥梁主要病害成因及其对策探讨

通过对廊涿高速沿线桥的普查,系统的归纳了公路桥梁的主要病害及其成因,并给出合理的维修及养护建议,以此来保证高速公路桥梁的使用寿命。     

城市桥梁噪声分析及降噪措施设置

通过对城市桥梁噪声产生的原因及特性进行分析,提出在桥梁建设阶段,在桥面铺装、伸缩缝、声屏障、桥梁结构优化等方面可采取的降噪措施,从而对城市桥梁噪声的噪声源和传声途径进行控制,以保证人民群众正常生活的声环境质量。     

中小型农村旧桥的养护加固及维修管理

中小型农村旧桥已难以适应快速发展的交通需求,因此对于此类桥梁的维修养护成为目前亟待解决的热点问题。通过分析农村旧桥的使用现状提出一系列旧桥养护、加固及维修管理的思路,期望对促进农村路网维护建设发挥重要作用。     

三维激光扫描技术在桥梁钢管桩群桩姿态测量中的应用

随着桥梁施工技术的发展,桥梁工程中采用钢吊箱围堰技术施作水中主墩承台的工法被广泛应用.钢吊箱围堰技术需根据现场每一根钢管桩的桩中心坐标和倾斜姿态,预制与钢管桩群桩几何关系相匹配的巨型钢吊箱,经拖运、现场吊装下放、混凝土封底处理后,进行承台施工.本文以上海闵浦三桥为例,介绍在制作钢吊箱前基于三维激光扫描技术对现场钢管桩平...     

桥梁损伤辨识中数据融合与遗传算法的应用

介绍了基本遗传算法和改进遗传算法,并在位移与频率振型基础上进行桥梁损伤识别,基于模式逻辑实现数据融合,从实例分析中,看出通过改进的遗传算法对桥梁结构进行损伤识别,比传统遗传算法有更好的识别性能,识别结果更加准确,有必要在实际桥梁损伤识别中加大利用和推广。     

Seismic energy dissipation and local concentration of damage in bridge bents

Seismic damage on bridge systems is basically concentrated on the piers. Hence, it is necessary to develop comprehensive studies oriented to improve our understanding of the bridge bents seismic response. Accordingly, the seismic behaviour and local concentration of damage within a typical bridge bent were analysed, considering different rotational restrictions of the foundation-soil system and different steel ratio arrangements. The contributions to structural damage of both, maximum deformation and cumulative damage, were assessed for records with different characteristics. The results showed that the amount of damage dissipated by the bent and the distribution of damage were strongly affected by the flexural strength variation along the columns. In models with non-uniform strength distribution, the inelastic demands were concentrated on few plastic hinges and bent degradation and failure were reached before the energy dissipation capacity of all potential hinges occurred. The analyses results also showed that the rotational restriction imposed by the foundation had a notable influence on the energy dissipation capacity and location of damage. Finally, the determination of damage indices in plastic hinge regions showed that most of the damage is produced by the cumulative effect of plastic energy dissipation, independently of the ground motion characteristics.     

Loading to failure and 3D nonlinear FE modelling of a strengthened RC bridge

A reinforced concrete railway trough bridge in Örnsköldsvik, Sweden, was strengthened in bending with rods of carbon-fibre-reinforced polymer and loaded to failure. The aim was to test and calibrate methods developed in the European Research Project ‘Sustainable Bridges’ regarding assessment and strengthening of existing bridges. A steel beam was placed in the middle of one of the two spans and was pulled downwards. Failure was reached at an applied load of 11.7 MN. It was initiated by a bond failure caused by a combined action of shear, torsion as well as bending after yielding in the longitudinal steel reinforcement and the stirrups. The bond failure led to a redistribution of the internal forces from the tensile reinforcement to the stirrups, causing the final failure. The computer models developed to simulate the loading process were improved step by step from linear shell models to more detailed models. The most developed model, a three-dimensional nonlinear finite element model with discrete reinforcement, gave accurate accounts of the response of the bridge.     

Applications of mesh parameterization and deformation for unwrapping 3D images of rock tunnels

This paper presents analysis on two 3D mesh to 2D map strategies applied to unwrap images of rock tunnels and facilitate visualization of large datasets. First, we examined mesh parameterization algorithms which are used in computer graphics to convert a 3D mesh model to a 2D representation.We found that while these methods were automatic and could provide 2D maps with minimal metric distortion (ie: conservation of lengths in 3D when mapped to 2D), they exhibited twisted shapes and were not intuitive to interpret. Second, we proposed two novel approaches, combining mesh deformation algorithms, which are used in computer animation to reshape a 3D mesh to resemble a 3D plane, and projection onto a 2D plane. We found that while these methods required user interaction and introduced a greater amount of metric distortion, their outputs were fairly intuitive to interpret. To compare the relative merits of mesh parameterization and mesh deformation and projection, the different strategies are applied to a 8.2 m wide by 41 m long by 6.7 m high subsection of a mining tunnel. The metric distortion produced was calculated and their respective output 2D maps are presented and discussed.     

路桥施工中沥青路面早期破坏分析

路桥施工中广泛采用沥青路面,而出现早期破坏的现象比较普遍。针对我国路桥施工的实际情况,分析了目前沥青路面产生早期破坏的主要原因,提出了防止路面早期破坏的方法和建议。