共查询到19条相似文献，搜索用时 125 毫秒
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介绍了沥青砼路面裂缝的四种常见形式,分析形成裂缝的5种因素,提出有效治理龟裂、块状裂缝、横向裂缝、纵向裂缝的措施。 相似文献
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沥青路面表面纵向与横向疲劳裂缝扩展研究 总被引：1，自引：0，他引：1
基于自上而下的表面纵、横向疲劳裂缝严重影响沥青路面的使用品质,首先分析表面疲劳裂缝的形成机理,然后采用奇异等参元法及断裂力学理论,应用有限元软件ABAQUS,建立20结点等参立方体单元的有限元模型,数值计算路面表面纵、横向疲劳裂缝扩展,探讨表面纵、横向裂缝疲劳扩展的规律。计算表明:①表面纵、横向裂缝扩展只考虑偏载作用,随着裂缝向下扩展,其K2是增大到一个峰值后,再由此下降。裂缝扩展前期,纵、横向裂缝的K2差别不大,而在中后期,纵向裂缝的K2要大于横向裂缝。②各路面结构参数中面层厚度h1和模量E1及基层模量E2对表面纵、横向裂缝扩展影响较大,其它参数(土基模量E0、底基层厚度h3和模量E3、基层厚度h2)则影响很小。 相似文献
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本文时楼板裂缝产生的原因进行了分析,从裂缝原因、裂缝防治措施和处理等方面进行了论述,指出只要按规范进行设计与施工,即可使裂缝得到有效的控制. 相似文献
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着重对混凝土及原材料的抗裂性能、混凝土结构中构造缝的设计、现浇混凝土楼板裂缝防治、地基不均匀沉降裂缝防治、多层砌体房屋温度裂缝机理与防治措施、温度裂缝与外墙屋面保温等方面进行了研究。 相似文献
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混凝土内出现的裂缝按深度的不同,分为贯穿裂缝、深层裂缝及表面裂缝三种。为了保证出现最少的裂缝,就必须在混凝土施工时掌握它的基本性能,并根据实际应用情况采取有效措施,以确保施工质量。 相似文献
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现浇普通混凝土楼板裂缝是长期困扰设计、施工的一个难题.特别是住宅工程楼板的裂缝发生后,不仅影响美观还给用户以不安全的印象.虽然理论认为,现浇普通混凝土楼板裂缝是难以避免的现象,但通过设计、施工等一系列严格的技术管理措施,减少和避免裂缝的发展是完全可能的.影响楼板裂缝的因素是多种多样的,本文作者结合设计和工程实践,从裂缝产生的原因、发生部位、裂缝控制措施等方面,浅略谈谈自己的看法. 相似文献
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目前的土木建筑工程,以混凝土结构占主导地位,混凝土结构由于内外因素的作用不可避免地存在裂缝,而裂缝是混凝土结构物承载能力、耐久性及防水性降低的主要原因。本文介绍了混凝土裂缝的形式、产生原因以及混凝土裂缝的处理。 相似文献
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The paper deals with the experimental characterisation of damage evolution within the radial (R)–tangential (T) growth plane of softwood loaded in tension perpendicular to the grain. The reported investigations comprise in-situ monitoring of crack propagation by means of Confocal Laser Scanning Microscopy (CLSM) and evaluations of crack patterns of broken specimens. Three types of notched specimens, representing different crack propagation systems, were tested; for all configurations, both, loading and crack propagation direction were located within the RT plane of wood. The CLSM pictures of broken specimens show distinct differences among the regarded configurations with respect to crack paths. Two different damage mechanisms were identified being rupture of earlywood cell walls in the case of crack propagation in tangential direction and debonding of wood fibers, i.e. rupture of the interface zone between adjacent tracheids, in case of crack progression in radial direction. In the case of an intermediate crack system with an angle of 45° between initial notch direction and radial direction the crack evolution was monitored in-situ during the tension test, whereby the combined action of both basic fracture mechanisms was observed. 相似文献
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本文对现浇混凝土楼板产生裂缝的各种原因进行了分析,并论述了产生裂缝所带来的各种危害;同时提出了一些相应的控制措施,以防止现浇板产生裂缝,保证工程质量。 相似文献
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本文论述了砌体结构裂缝产生的性质和原因 ,并针对裂缝宽度的标准问题及如何防止墙体开裂构造措施提出几点建议。 相似文献
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谈对混凝土裂缝的处理 总被引：2，自引：0，他引：2
工程结构出现裂缝是比较普遍的现象;而结构裂缝大部分是能够通过设计阶段、施工措施来避免的,本文对构件裂缝的成因、预防及处理进行了详细探讨。 相似文献
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K. Frühmann E. K. Tschegg C. Dai S. E. Stanzl-Tschegg 《Wood Science and Technology》2002,36(4):319-334
Mode I and Mode III loading experiments were performed on side grooved CT specimens of two types of Laminated Veneer Lumber
(LVL). Steady state crack propagation was maintained in order to detect complete load displacement diagrams. Fracture behaviour
and influence of fiber orientation were studied and all important fracture mechanical values (stiffness/compliance, microstructural
damage, crack initiation energy, specific fracture energy etc) were determined. Much higher crack initiation energies and
specific fracture energies resulted in mode III loading than in mode I loading for both material types. Under external mode
III loading, crack initiation occurs in mode III and crack propagation however takes place under mode I owing to crack surface
interference. The influence of fiber orientation on fracture mechanical properties of LVL was discussed.
Received 15 September 1999 相似文献
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Successive temperature distribution images around the notch tips during fracture toughness testing of paper were obtained by means of an infrared thermography system. Analysis of the images gave the critical times when the temperature significantly rose at the notch tip and when the distance between two maximum temperature spots started to decrease during the testing. Other successive microscopic images around the notch tips showed the relation between crack opening and displacement and the transitional point of the relation. The onset of stable or unstable crack growth as indicated in these critical times and the point agree with each other. For the specimen with a small width, an unstable crack starts to grow at the maximum load point without the stable crack growth period. On the other hand, a stable crack grows before the maximum load point unless the specimen width is small.The period of the stable crack growth increases with an increase in width. Differing from the methods based on thermal images to determine the onset of crack growth, the microscopic method is applicable at a wide range of strain rates and is thus suitable for quasistatic fracture toughness testing.This work was presented in part at the 8th annual meeting of the Society of Packaging Science and Technology, Japan, Tokyo, June 1999 相似文献