Linear viscoelastic behaviours of bituminous mixtures and fiberglass geogrids interfaces

One major research topic is to characterize the mechanical behaviour of actual reinforced pavement structures from laboratory experimentation and take it into account for the design. This investigation aims to verify the effect of fiberglass geogrid presence on interface linear viscoelastic (LVE) behaviour separately and as a system along with the bituminous mixture layers. To conduct the research, two different fiberglass geogrids, with ultimate tensile strength (UTS) of 100 and 50 kN/m, and tack coat made of straight-run bitumen and modified by polymer were combined for the fabrication of three reinforced configurations. In addition, two unreinforced configurations were also fabricated. The first was a single layer slab and the second was a double-layered slab composed of two bituminous mixtures (same type) bonded layers by a tack coat. Complex modulus tests were carried out in specimens cored in two different directions, vertically (V) and horizontally (H) cored. The experimental data were fitted using the 2 Springs, 2 Parabolic Elements and 1 Dashpot (2S2P1D) model. The test results showed that all interfaces’ complex modulus obtained for V specimens were LVE. Moreover, complex viscous properties of the interfaces were obtained from the used binder. The interface containing polymer modification presented the highest stiffness.     

模块式加筋土挡墙墙面板与土工格栅之间的摩擦性质研究

根据模块式加筋土挡墙的墙面板和土工格栅之间摩擦的足尺试验结果,分析两者之间的摩擦力和摩擦因数,以及影响两者之间摩擦性质的因素。试验研究表明:摩擦力及摩擦因数与竖向压应力有良好的对数关系,筋带竖向间距的大小决定墙体的墙面板与筋带之间可以采用摩擦连接的范围。该结果具有工程应用价值。     

Oriented polymer grid reinforcement

Tensar high strength oriented polymer grids were developed in the UK in the late 1970s. Extensive research has been conducted in Europe and North America to investigate the various civil engineering applications for these materials. The availability of these high strength, durable reinforcing grids has led to many innovative and economical developments in geotechnical and highway engineering. This paper describes the major application areas: reinforced soil walls and slopes, reinstatement of slope failures; embankment foundations over soft soil; reinforcement of road bases for paved roads; and asphalt reinforcement.     

加筋散粒体材料力学性能的大型三轴试验研究

着重研究了风积砂、加筋风积砂、砂砾、加筋砂砾等几种散粒体材料的强度和变形性能,分析了加筋对材料强度和应力-应变关系的影响。研究表明：通过三轴试验可以获得散粒体材料的强度参数c和!;同时,可以拟定材料本构关系的各主要参数。     

西户高速公路土工格栅的施工技术

介绍了西户高速公路的工程概况。基于该段地表土天然含水量大，除了采取用垫层法外，还需铺设土工格栅以使底部形成板体结构。介绍了土工格栅的性能，施工要求和铺设方法。由于土工格栅性能优异，结构特殊合理、格栅纵模相连，能量大程度地减少基础沉降，增强整体性能，施工效果良好。     

桥头软基现浇筒桩处理现场试验分析

为研究现浇筒桩和土工格栅加筋碎石垫层组成的复合地基加固软弱路基的作用机理及效果,介绍了某高速公路桥头筒桩处理中进行的地表沉降、分层沉降、深层土体位移、孔隙水压力、桩土应力等项目的现场测试成果。结果发现:该处理方法具有经济合理,承载力高,沉降小等特点,为解决软土“桥头跳车”提供了一种经济、有效的手段;土工格栅可以很好地调节荷载分布,使荷载更多的向桩身集中;超静孔压不大,且有规律性,不影响沉降稳定性;地基侧向变形小,变形速率在时间和深度上都呈递减趋势。     

用土工合成材料防治半刚性路面反射裂缝技术

叙述了半刚性路面反射裂缝的产生原因及防治对策，并介绍了采用土工织物和玻纤地工格栅防治半刚性路面反射裂缝的长工工艺和施工技术要求，最后结合两个具体事例阐述了土工织物及玻纤土工格栅在防治公路半刚性路面反射裂缝中的应用。     

新型可视土工拉拔试验仪的研发与应用

研制了一台新型可视自动采集数据的土工拉拔试验装置,可用于多种土工材料和填料作用下的拉拔试验。该装置改进了加载系统和反力系统,实现了拉拔界面的可视与数据采集的自动化,并可量测土工材料不同嵌固长度处的位移,获取土工材料变形值,探索筋土作用过程中筋材受力机理及界面土体位移变化规律。使用新研制的试验装置开展了以砾类粗粒土为填料的格栅拉拔试验,结果表明:上覆荷载增大,土中格栅的应变变小,土体与格栅的界面摩擦和嵌固作用越显著;筋土界面处土体颗粒存在平移及转动两种运动模式,且界面处土体形成稳定的位移集中带。     

加筋土生态挡墙在农村公路中的应用

介绍了加筋土生态挡墙的施工工艺流程,从地基处理、土工格栅铺设、包裹体施工、泄水孔预埋、填料铺摊压实五方面阐述了其施工技术要点,并提出了质量控制措施,以促进该挡土墙在公路建设中的推广应用。     

长期荷载作用下土工格栅蠕变特性的试验研究

为探讨长期荷载作用下土工格栅的蠕变特性,在不同的外加荷载和环境温度的各种组合条件下,进行土工格栅的室内蠕变试验,以此获得格栅的蠕变关系曲线、载荷-应变等时曲线及拉伸模量的变化特征,并进行综合对比分析。根据试验与分析发现:荷载水平、环境温度和材料生产工艺是影响土工格栅长期蠕变特性的重要因素。进而,采用时温叠加原理,对于某一给定环境温度下确定土工格栅长期强度的经验估算模式和蠕变强度折减系数。试验结果与理论分析为土工格栅加筋结构长期工作性能的分析与评价提供参考依据。