城市街道广场尺度对视听环境的影响机制研究

As about 90% information received by human brain is from the audiovisual senses, the change of urban audiovisual environment has a great impact on human life. With the development of urban economic, the urbanization of rural population, the increase number of private cars and the implementation of the block system lead to the expansion of roads and parking space, which can subsequently change environmental sound pressure levels, acoustic comfort, human perceptions, etc. This project aims to study the influence mechanism of scales of urban streets and squares on the audiovisual environment. Sound pressure level, sound comfort and characteristic variables that have great impact on human perception will be investigated through an audiovisual field survey in urban streets and squares. Then, based on 3D GIS modeling, the noise map can be generated by calculation with Cadna/A, and the space accessibility and "street eye" range can be derived using AXIAL MAP and VGA method, respectively. Finally, three-dimensional scale characteristics of the street and square that contribute to a suitable audiovisual environment, including approachable scale, safe pedestrian walkway, sound pressure level conforming with the standard and acoustic comfort, will be revealed after systematic evaluation of the above variables on the map, and the influence mechanism of scales of the urban streets and squares on the audiovisual environment can be understood. This project will set up a database with regard to the impact of scales on the audiovisual environment, and as such this research will be beneficial to the architect to improve design by selecting the correct scale values according to the audiovisual database during project planning. The accomplishment of this project can help prevent the improper control of scales in the incremental planning under the development pressure of urban economic, transportation and population.

人的信息获取约90%来自视听感官。随着经济发展，农村人口城市化、私家车增多和街区制推广导致道路及停车空间尺度急剧扩张严重影响了街道广场的视听环境（人的尺度感、空间安全性、声压级和声舒适度）。针对上述问题，本项目旨在揭示尺度对街道广场视听环境的影响机制。首先，对不同尺度街道广场进行视听野外调查，记录人的尺度感知变量，测量声压级和声功率，评估声舒适度和声源属性。然后，基于3DGIS 建模，通过AXIAL MAP和VGA法得出空间可达性数值和“街道眼”范围，利用Cadna/A计算噪声地图。进而，通过分析上述视听评测值的三维尺度分布，定位“近人尺度、步行安全、声压级达标、声舒适”的街道广场三维尺度特征，揭示尺度对街道广场视听环境的影响规律，建立视听环境影响数据库。项目完成有助于建筑师在方案阶段参照不同尺度环境视听数据变化进行改进设计，避免靠城市经济发展速度、交通和人口发展规划等压力带来的尺度失控。

我们主要研究了在城市地区街道尺度在视觉、声音和视听舒适度评价方面的影响(尺度指的是街道宽度W、建筑高度H、和Street-width-to-building-height街道宽度和建筑高度比率W/H,称为高宽比)。此外，我们还检验了除视觉舒适度外，声音水平与上述主观舒适度评价之间的关系。研究方法包括调查地点的选择、三维模拟、问卷调查，并对所得数据进行分析。测量时利用三维摄像机对街道尺度和街道视觉信息进行记录，生成街道的虚拟三维模型。同时，采集街道双通道无损声信号。随后，以164名受试者为研究对象，测试采用具有相应声音的三维虚拟现实街道。分析结果表明，视听的主观舒适度与街道尺度直接相关：一、正相关关系：(1)视觉舒适度和W/H之间存在较强的正相关关系；(2)视听舒适度和W/H存在较强的正相关关系；(3) 视听舒适度W和SL都存在较强的正相关关系。二、负相关关系：(1)声舒适与W之间观察到显著的负相关；(2)视觉舒适与H之间观察到显著的负相关；(3)听觉舒适与H之间观察到显著的负相关；(4)视听舒适度与H之间观察到显著的负相关；(5)听觉舒适度与SL之间观察到显著的负相关；(6)视听舒适度和SL之间观察到显著的负相关。我们的调查研究表明，高质量的视觉、听觉和视听舒适度可以通过增加W/H，减少W和H，减少SL实现。总体而言，当街道宽高比大于1，街道宽度小于20米、街道建筑高度小于26米、声级小于58dBA时，受访者认为视听水平最舒适。希望这些研究结果能够帮助设计者通过控制街道尺度和建筑高度，预测城市街道理想的视听环境质量。