浅谈土工格栅在公路工程中的应用

介绍了土工格栅的含义、功能及其加固土机理,对土工格栅的性能指标进行了归类,并按原材料及成型过程对土工格栅进行了分类,分析了土工格栅的性能指标并突出了格栅材料的泊松比,最后对土工格栅的一般施工工艺流程及其应用作了进一步的阐述。     

双级土工格栅加筋土挡墙的测试分析

通过对梅坎铁路双级土工格栅加筋土挡墙的墙面板水平土压力、垂直土压力及土工格栅变形的原位观测 ,分析了墙面板水平土压力的变化及分布规律、垂直土压力变化及土工格栅的变形随填高及时间的变化规律 ,并对挡土墙的破裂面进行了探讨     

土工格栅蠕变特性及其黏弹塑性损伤本构模型研究

首先通过土工格栅蠕变试验,比较分析了不同荷载水平下的土工格栅蠕变规律。对以往典型的土工格栅蠕变模型进行归纳分类,并将之与蠕变试验结果对比,评价它们的适用性与可靠性。在此基础上提出了一种土工格栅黏弹塑性损伤本构模型,并应用最优化方法求解模型参数,论证了其合理有效性。研究指出,以往研究所提三类典型的蠕变模型都只适合于描述低应力水平下的衰减模式蠕变,不适合描述高应力水平下的非衰减模式蠕变;土工格栅三参数黏弹性模型,能够较准确地反映土工格栅在低应力水平情况下的两阶段衰减蠕变特性;而考虑材料黏塑性变形以及损伤而建立的土工格栅黏弹塑性损伤模型,能够准确地反映其在高应力水平情况下的三阶段非衰减蠕变特性。     

土工格栅对大孔混凝土基本力学性能的影响

土工格栅抗拉强度高,而混凝土抗拉强度较低,把土工格栅加入混凝土中可以对混凝土进行增强处理,形成土工格栅混凝土,从而防止水土流失.本文通过用不同材料孔径的土工格栅加入到混凝土中,来提升混凝土的强度.结果表明土工格栅可以明显提升混凝土的强度,并且用1.5 cm的玻璃纤维土工格栅比3.5 cm的塑料土工格栅效果要好.     

浅谈土工格栅在公路工程中的应用

对塑料土工格栅、玻纤土工格栅和经编土工格栅的性能做了比较,对三种土工格栅的应用进行了总结,并对目前公路工程中的加筋选材问题提出了一些观点,以利于土工合成材料加筋技术在具体工程中的应用.     

土工格栅加筋陡边坡变形及稳定性分析

通过数值模拟的手段建立了采用土工格栅加筋土高陡路堤模型,分析了土工格栅加筋高陡路堤边坡的变形特性及稳定性,指出经土工格栅加筋后的高陡边坡稳定性得到极大地提高,可以满足路堤边坡稳定性的设计要求。     

土工格栅的力学特性及应用范围

通过对土工格栅加固土机理的分析 ,介绍了土工格栅的应用范围 ,并对土工格栅在各方面的应用作了简要论述 ,最后列举了部分工程应用实例     

土工格栅在砂砾路基中的应用技术

介绍了西（安）户（县）高速公路土工格栅在砂砾路基中处理软基工的应用技术。并通过西户高速公路土工格栅的应用，从施工角度对土工格栅在砂砾路基中的施工技术进行分析和总结，进一步提出了土工格栅在砂砾路基施工铺设中采用毛砂找平层、保护层的施工工艺，对土格栅进行保护，防止土工格栅褶皱和损坏。     

土工格栅的主要性能及其工程应用

本文介绍了土工格栅的分类及其主要性能,并简要概述了土工格栅在工程中的应用,特别是在道路工程上的应用,对土工格栅今后的发展提出了展望。     

土工格栅的力学特征及应用范围

通过对土工格栅和固土机理的分析,介绍了土工格栅的应用范围,并对土工格栅在各方面的应用作了简要论述,最后列举了部分工程应用实例。     

老路拼接中土工格栅治理路面结构阻裂作用分析

结合滨河路老路改造工程,应用数值仿真,引进了奇异单元模拟裂缝尖端的应力应变场,建立了土工格栅治理新老路路面拼接的计算模型,对行车荷载偏载作用下老路拼接工程中土工格栅的阻裂作用进行分析。结果表明:老路拼接裂缝为张拉型,应力强度因子KI远大于KII,拼接位置主要发生弯拉破坏;新老路不均匀沉降作用下,铺设土工格栅应力强度因子小于未铺设土工格栅应力强度因子,土工格栅阻止裂缝的扩展,对路面裂缝有阻裂作用;在新老路路面拼接处,半刚性基层开裂先于面层,土工格栅铺设位置越靠上,越有利于发挥土工格栅的抗拉效果,建议在路面基层顶面铺设土工格栅。     

奥林匹克水上公园填方工程的试验研究

奥运水上公园工程中,静水赛道开挖出大量的砂质粉土和粉细砂,而又必须将这些工程特性极差的土料用于动水赛道的填筑。本文通过室内试验研究了以不同掺量的水泥、粉煤灰作为加固剂,养护不同龄期后砂质粉土的物理力学特性;通过现场足尺试验研究了水泥加固土填方和加筋挡土墙的性能;通过试验选择了合理的施工方式,为大面积正式施工做准备。结果表明:水泥加固后,砂质粉土的强度明显提高,其中粘聚力提高尤为明显;搅拌机拌和的均匀性要高于圆盘耙拌和;正常工作状态下,挡土墙中土工格栅的拉力大小只相当于其极限抗拉强度的2.1~15.9%,采用土工格栅加筋挡土墙具有较高的安全系数。     

水泥土土工格栅地基处理应用分析

作为一种新的地基处理方法,水泥土土工格栅结构复合地基因工序简单、成本低廉、施工方便、效果理想而被广泛应用。许昌市某22层酒店工程中,采用水泥土土工格栅结构复合地基,减少了挖填土方量,工艺简单,可缩短工期50%,节省造价约30%。     

暴雨条件下自嵌式加筋挡土墙稳定性数值模拟分析

结合具体工程,对暴雨条件下自嵌式加筋挡土墙存在的变形、受力特征和稳定性进行了有限元数值模拟,并与一般气候条件下进行对比。结果表明:在暴雨条件下,墙体将产生较大的侧向变形;墙背土压力在加筋处明显增大;挡土墙内部筋材之间局部出现拉应力区,筋材断裂后拉应力区明显扩大,存在墙面倾覆的趋势。该结论在对特大暴雨后加筋挡土墙局部破坏事故的现场调查后得到了验证。     

高强土工格室在高速公路路基施工中的应用

介绍了高强土工格室的使用性能及加固原理,结合某路基填挖结合处应用高强土工格室施工的情况,对其施工工艺进行了总结,同时阐述了高强土工格室在特殊路基的应用领域,实践表明土工格室在路基施工中的应用是可行的。     

Tanque verde retaining wall structure: Revisited after 11 + years

Between December 1984 and September 1985, 46 concrete panel retaining walls were constructed using structural geogrids of polyethylene to create grade separations for a transportation intersection in Tucson, Arizona. During construction, select panel walls were instrumented to measure temperature, lateral and vertical soil pressures, and strains in the geogrid. The combination of elevated temperature and aggressive soil exposure and aging, while under stress, make this particular project a focal point of continued investigation.

Geogrid samples retrieved from this project in September 1993 and again in June 1996 were evaluated and compared to an archived sample from the same production run. Wall instrumentation, which has been monitored from 1985 to 1992, was most recently monitored in June 1996 to evaluate the mechanical stability of these walls. Instrumentation readings and results from evaluation of the physical and mechanical properties of the exhumed geogrid samples are presented in this paper.

It is concluded from testing of exhumed samples, after 11 + years of exposure, that the polyethylene geogrid has not experienced any measurable change in its physical or mechanical performance properties, nor has the wall been compromised in its stability or performance.     

Mechanical property and deformation behavior of geogrid reinforced calcareous sand

The strength and deformation properties of maritime geotechnical structures made primarily of calcareous sand are critical for project safety, and geogrid reinforcement is a promising new approach. A series of consolidated drained triaxial experiments were conducted to evaluate the mechanical property and deformation behaviors of geogrid reinforced calcareous sand (GRCS), taking into consideration the impacts of the geogrid layer, relative density, particle size, and confining pressure. In comparison to the unreinforced calcareous sand, the strength of the GRCS is greatly enhanced, and the deviatoric stress-strain curves are altered from slightly softening to hardening, as well as the suppressed shearing dilatancy. The geogrid, relative compactness, particle size, and confining pressure are all intimately related to the volume changes and shearing dilatancy of reinforced specimens, but particle crushing is mostly impacted by the confining pressure. The interactions of geogrid ribs and calcareous sand particles are summarized as two types of constraint and friction using scanning electron microscope tests to establish a simplified calculation method of horizontal and vertical equivalent additional stresses that could provide a reference for revealing the mechanical mechanism of GRCS.     

不同车速下高速公路X形桩网复合地基动力特性研究

基于大比例模型试验系统,开展高速公路车辆荷载作用下X形桩网复合地基动力模型试验研究;测试了不同车速作用下桩网复合路基的动力响应,包括路基内部动应力分布、动应力扩散、格栅动应变、格栅累积应变、桩土差异沉降等的变化规律。结果表明,高速和低速状态下,动应力均会在格栅处产生波动,并且高频车速对车辆附加荷载贡献较小;当车速达到高速状态时,格栅的动应变变化较小,路肩处的垫层应力传递系数要小于路基中心处;格栅动应变比与格栅应变增量比存在线性关系,并且格栅的累积变形主要是在低速状态下产生的;车速越快,X形桩身动应力幅值越大,其桩身轴力小于圆形桩。     

Evaluation of creep behavior of high density polyethylene and polyethylene-terephthalate geogrids

The tensile creep behavior of polyethylene-terephthalate (PET) and high density polyethylene (HDPE) geogrids was evaluated using five test methods: the short- and long-term stepped isothermal method (SIM), the short- and long-term time-temperature superposition (TTS), and the conventional method. SIM and TTS are acceleration tests using elevated temperatures. SIM uses a single specimen throughout all temperature steps in contrast to TTS in which a new specimen is employed for each temperature step. The test results indicate that at the same percentage of ultimate tensile strength, PET geogrid exhibited less creep deformation than the HDPE geogrid. The HDPE geogrid exhibited primary, secondary, and tertiary creep stages before rupture, whereas only primary creep and tertiary creep were detected in the PET geogrid. Furthermore, the strain rate of the primary creep stage was found to be independent of the applied loads for the PET geogrid, while it increased exponentially for the HDPE geogrid. The activation energies deduced from different accelerated creep tests were very similar for the PET geogrid. In contrast, the activation energies were higher from the short-term acceleration tests than from the long-term tests for the HDPE geogrid. The four-parameter Weibull model was able to predict the linear and non-linear creep behavior up to 100 years based on 10-h creep testing data. The creep reduction factor of 100 years design life was evaluated and higher values were resulted from the HDPE geogrid than from the PET geogrid.     

循环荷载下土工格栅加筋铁路道床累积#br# 沉降模型试验研究

散粒体道床层的循环累积变形是有砟轨道沉降的主要来源，文章采用有砟轨道路基模型试验来研究道砟层与底砟层间布置土工格栅加固道床控制有砟轨道沉降，开展了高速和重载等不同列车荷载下与不同类型土工格栅加固条件下的多组循环加载试验，加载过程中全程监测道砟层累积沉降、轨枕振动、道砟层底部土压力与土工格栅应变数据并进行分析，以研究土工格栅控制有砟轨道道床沉降的作用机理。研究结果表明：土工格栅对于控制道砟层累积沉降具有较显著的效果，但当土工格栅的刚度达到一定程度后刚度对土工格栅控制沉降效果的影响不大；土工格栅能够显著减小轨枕下方道砟层土压力峰值，从而降低道砟磨耗破碎程度及由此引起的道床沉降；道砟层累积沉降的发展意味着道砟颗粒的错动，而道砟颗粒的错动与位移将引起嵌锁于道砟层中的土工格栅发生张拉，从而土工格栅将反过来对道砟颗粒的进一步位移错动形成侧向约束，体现于宏观即表现为道砟层累积沉降得到控制。