排序方式： 共有45条查询结果，搜索用时 15 毫秒
11.
A new approach for simulating the excavation and construction of subsequent panels is proposed to investigate the effects from the installation of diaphragm walls on the surrounding and adjacent buildings. The method has been combined with a 3-D nonlinear analysis and a constitutive law providing bulk and shear modulus variation, depending on the stress path (loading, unloading, reloading). From the application of the method in a normally to slightly over-consolidated clayey soil it was found that the panel length is the most affecting factor of ground movements and lateral stress reduction during panel installation. Moreover, from the evaluation of horizontal stress reduction and the variation of horizontal displacements arises that the effects from the construction of a panel are mainly limited to a zone within a distance of the order of the panel length. The effects on an adjacent building have also been investigated by applying a full soil–structure interaction including the whole building. Settlement profiles and settlements are given at specific points as increasing with subsequent installation of panels, providing the ability of specific monitoring guidelines for the upcoming construction of the diaphragm wall in front of the building. Contrary to lateral movements, which mostly take place at the panel under construction, it was found that the effect of settlements covers a larger area leading to a progressive settlement increase. The effect highly depends on the distance from the panel under construction. 相似文献
12.
13.
利用2017年8月9日精河6.6级地震后获取的高分辨率无人机影像，对叶里斯南也肯村153栋房屋进行结构分类和震害解译，获取研究区内土木结构、砖木结构、砖混结构、框架结构4种类型房屋数量及震害特征，并依据解译结果计算每种结构房屋平均震害指数。由于研究区内砖木结构、砖混结构、框架结构房屋数量偏少，房屋内部的震害难以用无人机影像识别，这3类房屋的震害解译结果与现场调查结果相比差别较大，而土木结构房屋平均震害指数及所对应的地震烈度结果与现场调查结果基本一致，表明无人机影像可为房屋震害定量评估提供重要参考。 相似文献
14.
工程爆破施工过程中如何控制其对周围建筑物、正在施工项目和处于养护龄期内的混凝土结构的影响一直是爆破施工中的实际问题,直接关系爆破施工的单响药量和施工进度。隧道爆破掘进施工中为了追求施工进度,往往在爆破方案中使用较大的单响装药量,从而忽略了大药量爆破产生的冲击波效应对隧道岩壁、已有结构的破坏,本文简单介绍了施工前或施工中,进行质点振动速度监测的实际应用。 相似文献
15.
《Geoforum》2017
Steel is a critical material for modern-day societies, and more than half of the world’s steel is used in buildings. As the extraction of iron ore and the production and transport of manufactured steel have significant environmental costs, the fate of steel is important for socio-technical transitions towards more sustainable materials use. Using steel in buildings as a case study socio-technical transition, this paper develops a novel application of the multi-level perspective (MLP) that adopts an explicitly material lens. We focus on the circulation of steel between three key life stages for buildings which are treated as socio-technical regimes as described in the MLP. Drawing on concepts from assemblage theory, we consider the role played by the material and expressive qualities of steel within each of these regimes. Our material focus also requires attention to the spatial dimensions of these three regimes and their implications for socio-technical transitions. We describe the nexus of material affordances and inter-scalar relations that influences the use of steel in buildings and consider the potential for change. The main contribution of this paper is to extend the MLP to incorporate a focus on materiality and, in a related way, spatiality. Based on the analysis presented we consider how steel use in Australian buildings may be rendered more sustainable. 相似文献
16.
17.
村镇房屋是历次震害中最薄弱的建筑,提高其抗震性能刻不容缓。本文依据《中国地震动参数区划图》（GB18306-2015）的地震动峰值加速度、反应谱特征周期和地震烈度的取值,以陕南6县18镇54个自然村的1161栋村镇房屋为抽样样本,完成样本的结构类型、结构类型的破坏比及破坏损失比、场地条件、抗震概念设计、村民的抗震知识和抗震防灾意识等现状的统计分析。结果表明:陕南村镇房屋的结构类型有生土结构、木结构、砖木结构、砖混结构和框架结构,其中砖混结构是其主要的抗震结构类型;砖木结构、砖混结构和框架结构在不同地震烈度影响下的破坏比有差异,而破坏损失比相同;陕南村镇房屋的场地条件变化复杂,抗震概念设计存在缺陷且村民的抗震知识和抗震防灾意识淡薄,亟待提高。 相似文献
18.
This paper proposes a new framework for ground extraction and building detection in LiDAR data. The proposed approach constructs the connectivity of a grid over the LiDAR point-cloud in order to perform multi-scale data decomposition. This is realised by forming a top-hat scale-space using differential morphological profiles (DMPs) on points’ residuals from the approximated surface. The geometric attributes of the contained features are estimated by mapping characteristic values from DMPs. Ground definition is achieved by using features’ geometry, whilst their surface and regional attributes are additionally considered for building detection. A new algorithm for local fitting surfaces (LoFS) is proposed for extracting planar points. Finally, transitions between planar ground and non-ground regions are observed in order to separate regions of similar geometrical and surface properties but different contexts (i.e. bridges and buildings). The methods were evaluated using ISPRS benchmark datasets and show superior results in comparison to the current state-of-the-art. 相似文献
19.
Although multiresolution segmentation (MRS) is a powerful technique for dealing with very high resolution imagery, some of the image objects that it generates do not match the geometries of the target objects, which reduces the classification accuracy. MRS can, however, be guided to produce results that approach the desired object geometry using either supervised or unsupervised approaches. Although some studies have suggested that a supervised approach is preferable, there has been no comparative evaluation of these two approaches. Therefore, in this study, we have compared supervised and unsupervised approaches to MRS. One supervised and two unsupervised segmentation methods were tested on three areas using QuickBird and WorldView-2 satellite imagery. The results were assessed using both segmentation evaluation methods and an accuracy assessment of the resulting building classifications. Thus, differences in the geometries of the image objects and in the potential to achieve satisfactory thematic accuracies were evaluated. The two approaches yielded remarkably similar classification results, with overall accuracies ranging from 82% to 86%. The performance of one of the unsupervised methods was unexpectedly similar to that of the supervised method; they identified almost identical scale parameters as being optimal for segmenting buildings, resulting in very similar geometries for the resulting image objects. The second unsupervised method produced very different image objects from the supervised method, but their classification accuracies were still very similar. The latter result was unexpected because, contrary to previously published findings, it suggests a high degree of independence between the segmentation results and classification accuracy. The results of this study have two important implications. The first is that object-based image analysis can be automated without sacrificing classification accuracy, and the second is that the previously accepted idea that classification is dependent on segmentation is challenged by our unexpected results, casting doubt on the value of pursuing ‘optimal segmentation’. Our results rather suggest that as long as under-segmentation remains at acceptable levels, imperfections in segmentation can be ruled out, so that a high level of classification accuracy can still be achieved. 相似文献
20.
邓敏贞 《资源与生态学报(英文版)》2012,3(2):183-191
建筑是能源消耗大户,也是导致环境污染与气候变化的原因之一.推动绿色建筑的发展,是实现低碳经济与可持续发展的重要路径.当前,中国已经颁布了一些法律法规以及通过信息工具——绿色建筑认证等制度措施来推动绿色建筑的发展,但是实践中存在一些问题,相关制度设计也不够成熟.美国以及欧盟在绿色建筑方面的立法与实践经验相对比较丰富.中国可以借鉴这些国家的一些成功经验,采取一些措施促进绿色建筑的发展,如提高人们对绿色建筑的认识,设计出更多样化的激励工具等等. 相似文献