碎裂岩中土工布复合锚杆与传统锚杆对比试验

土工布复合锚杆是一种应用于碎裂岩加固的新型锚锭结构。以某滑坡治理工程为平台,进行全长黏结型和预应力型两种形式锚杆的张拉试验,验证土工布复合锚杆加固碎裂岩的可行性。现场试验结果表明,土工布复合锚杆可以很好地解决碎裂岩中锚固注浆漏浆的问题。通过试验数据拟合分析,土工布的加筋鼓胀作用调整了锚固体与碎裂岩接触界面的应力分布,延长了线性变形阶段,提高了锚固体系的抗拔力。     

土工布在公路建设中的应用

介绍了道路结构用土工布的特点及特性,并重点阐述了其在各种路面工程中的应用情况。分析了土工布的优点,指出土工布在交通建设工程中具有广阔的前景。     

拉力型土工布加筋复合锚杆锚固界面应力传递试验分析

土工布复合锚杆是一种可应用于松散地层锚固工程的新型锚锭结构。以某滑坡治理工程为平台,开展了拉力型土工布加筋复合锚杆锚固体与破碎岩土体界面间应力传递规律的实测研究。现场试验结果表明,土工布的加筋鼓胀作用调整了锚固体与破碎岩土体接触界面的应力分布,土工布加筋复合锚杆锚固段近端存在稍长的应力协调缓冲段,随着荷载增大,黏结应力峰值向锚固段深部转移的现象不明显;实测破碎岩土体中拉力型土工布加筋复合锚杆主要抗力区域分布在3.0~13.0 m之间,即有效锚固体长度以不超过15 m为宜,过长的锚固长度对提高锚杆抗拔力意义不大;在松散破碎岩土体中应用土工布加筋复合锚杆技术能起到提高锚固力与节约成本的双重作用。     

沥青路面加铺结构中土工布夹层黏结性能

采用直剪试验并以剪切破坏能为评价指标,分析了黏层油类型、洒布量、土工布铺设工艺和路面使用环境等因素对沥青路面加铺结构中土工布夹层黏结性能的影响,同时通过带切缝复合梁弯曲疲劳试验验证了土工布夹层黏结性能与其抗反射裂缝效应的相关性.结果表明:采用乳化沥青、基质沥青和SBS改性沥青作为土工布夹层黏层油时,其优选洒布量分别为1.2,0.9,0.8kg/m2,其中SBS改性沥青黏层油的黏结效果最好,可达到常规加铺结构层间黏结水平;SBS改性沥青黏层油作1次洒布时,上层混合料摊铺温度较低将对土工布夹层黏结性能产生不利影响,SBS改性沥青黏层油作2次洒布时,上层混合料摊铺温度对其黏结性能无显著影响;随着服役温度升高或浸水时间延长,土工布夹层黏结性能将显著降低,而且相比于常规加铺结构层间黏结性能,其受温度影响较小,受浸水作用影响较大;土工布夹层的黏层性能与其抗反射裂缝效应具有良好的正相关性.     

隧洞土工布铺布机的应用

针对人工铺设土工布存在的缺陷,以实现土工布铺设机械化为目的,研发了一种隧洞土工布铺布机.它主要由底座、导轨、铺布小车三部分组成,在实际工程使用中,可以根据隧洞的大小对铺布机结构尺寸进行调整设计.铺布机采用定位、喷胶、小车回位、上布及端头压紧、铺布以及小车回位的施工工序,详细介绍了各工作原理及各工序要点.铺布机的使用降低了工人的劳动量,提高了施工质量.     

土工布加固软土地基的机理试验研究

土工布与土体的界面摩擦力是衡量其对土体加固效果的关键因素,本文首先根据土工布与土体拉拔摩擦试验的机理,设计并制作了界面剪切测试仪,该试验测试仪具有试验精度高、应用广泛和操作步骤简单的特征,然后采用此测试仪对土工布与砂土的界面摩擦力进行了试验研究,试验参数包括不同的竖向压力、土工布层数和砂土含水率。试验结果表明:增加竖向压力能够显著提高土工布与土体的界面摩擦力;相同竖向压力作用下,土工布层数超过2层时,对其界面摩擦力提高并不显著;相同条件下,当砂土含水率超过5%时,提高砂土含水率能够显著降低土工布与土体界面摩擦力。这些研究结果可为土工布加固土体的设计和施工提供依据。     

土工布防治裂缝技术在路面养护工程中的应用

介绍了土工布的发展过程,研究了土工布在沥青路面养护罩面工程中的作用机理及施工注意要点,通过土工布在沥青路面养护罩面工程中的应用实例分析,证实了土工布防治裂缝技术在路面养护工程中的可行性与实用性。     

丙纶土工布的生产现状与应用

土工布以高分子聚合物为原料制成，主要原料为聚酯纤维和聚丙烯纤维。介绍丙纶机织土工布、非织造土工布、土工膜、复合土工布和土工格栅的生产现状及其在公路、铁路、水利工程中的应用。     

土工膜在路堤防渗中的应用

通过拉拔试验进行了土工膜与粘土、砂、无纺土工布的界面摩擦特性和通过抗渗试验进行了完整土工膜、有破损土工膜的抗渗特性研究。试验结果表明 :无纺土工布对对土工膜与土体界面抗滑性的发挥没有更好的作用 ,土工膜与无纺土工布之间也不会产生软弱滑动面 ;完整的土工膜有较高的抗渗特性 ,无纺土工布对防止破损土工膜抗渗条件的恶化有较好的保护作用 ,对土工膜在工程中应用提出了一些建议     

土工布在旧水泥混凝土路面修复施工中的应用

通过具体工程案例,阐述了土工布在旧水泥混凝土路面修复施工技术上的应用及具体施工工艺和技术要求.实践证明,土工布可以防止旧水泥混凝土沥青加铺层结构中的裂缝反射,具有推广使用的价值.     

土工织物加筋土的土压力减轻作用试验研究

通过在研制改进的固结试验仪上 ,进行一系列考虑土工织物埋置在土中不同位置时加筋土的单轴固结试验及三轴K0 固结试验和不排水剪切试验 ,从静止土压力系数的变化 ,探讨了土中埋置有土工织物的加筋土层的土压力减轻作用及剪切强度的增加作用。得出了土工织物的数量、放置形式和超固结比的不同对土压力变化的影响规律 ,为加筋土边坡稳定分析提供了有意义的参考依据     

土工合成材料加筋土挡墙的工程应用

介绍土工合成材料加筋土挡墙的设计方法及土工格栅加筋土挡墙工程实例 ,对推动土工合成材料加筋土技术的工程应用具有一定意义。     

海军某工程水下土工布铺设工艺

土工布铺设为海军某工程堤身首道工序，该工程位于开敞、无遮掩海域，施工难度较大。本工程采用小锚牵引土工布边铺设边压载的施工工艺，对以后类似无掩护水域土工布铺设施工有一定的参考价值。     

Analysis of geotextile filter behaviour after 21 years in Valcros dam

In 1970, nonwoven geotextiles were used for the first time in an earth dam. The geotextile acted as a filter for the toe drain and on the upstream slope below the rip-rap. In 1992, samples were taken from both locations and performance tests were conducted in the laboratory. This paper presents the main results of the hydraulic behaviour of the geotextile filter in association with the soil of the dam. Also microscopic analyses are presented and, as the filter is considered to be performing well, selected filter criteria are checked.     

Effects of chemical precipitation on the permeability of geotextile envelopes for subsurface drainage systems in arid areas

This paper focuses on the effects of chemical precipitation on the permeability of geotextile envelopes for a subsurface drainage system in arid areas by conducting precipitation experiments of the geotextile in static or flowing solution. The results show that the precipitation process is not significantly promoted or inhibited by the network structure of geotextile. The precipitates in the form of rhombus wrap around the fiber surface. The number of geotextile pores with the smaller diameters decreases significantly after precipitation experiments. As the increase of the area density of precipitates (ΔR), the variation of the pore area (ΔS) and the variation of permeability coefficient (ΔK) of the geotextile decrease rapidly at first and then slowly. The ΔK and ΔS VS ΔR data were best fitted with logarithmic trend line. This study provides a preliminary reference for quantifying the chemical clogging process of geotextile envelopes in arid areas.     

土工织物加筋路堤筋-土界面摩擦力分布形式分析

编制了有限元程序,对大量工程实例进行了计算分析,提出了改进的筋-土界面摩擦力分布形式。     

整体式桥台桥梁台后土压力的季节性变化研究

建立了整体式桥台与土共同作用的有限元模型 ,计算分析了季节性温度变化下台后土压力的分布曲线。以三跨连续混凝土板桥为工程实例 ,提出并验证台后设置EPS压缩层和置换轻填土两种方案 ,同时配合台后土体加筋 ,为整体式桥台设计提供理论依据     

A Laboratory Investigation on the Behaviour of Reinforced Sand Samples Under Plane Strain and Triaxial Conditions

An experimental study on the behaviour of reconstituted samples of sand reinforced with geotextile layers is presented using standard triaxial and plane strain tests. After describing the main features of the plane strain device and of the data acquisition system, details are provided on the procedure developed for preparing plane strain samples containing inclined reinforcements with respect to the principal stress directions. Comments are also made on the influence of the preparation procedure on the overall behaviour observed during loading. Finally, the results of the experimental investigation are described with reference to standard triaxial tests with horizontal reinforcements, and to plane strain tests with horizontal and inclined reinforcements. The study complements data already available in the literature, for the development of constitutive laws applicable to the numerical analysis of reinforced earth structures.     

Use of geotextiles in earth structures for oil—gas pipelines under west siberia conditions

One of the methods of protection of the earth bed of a backfill for a pipeline as well as of embankments for the purpose of increasing their resisting capacity under complex engineering-geologic conditions (scouring, heaving, collapsibility, etc.) consists in the use of geotextile synthetic materials. Five new constructional schemes have been developed which possess high resisting (ballasting) capacity. Experimental investigations have been carried out to determine the mechanism of operation of the soil in combination with geotextile layers, using a special laboratory installation.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 21–23, May–June, 1992.     

The effects of permeable formworks with sucker liners on the physical properties of concrete surfaces

In this study, the effects of formwork, with drainage holes that are attached with different liners, on the physical properties of concrete surfaces are investigated. Nine formworks, three of them normal (reference) and six of them with drainage holes, were prepared. The three formworks, which had drainage holes, were attached with type I geotextile+hessian and the remaining three were attached with type II geotextile. Blow hole ratio, surface hardness by using the rebound hammer test, pull-off strength, carbonation, chloride penetration, sorptivity and abrasion resistance tests were measured on concrete blocks which were cast with the three types of formwork. It was observed that the concrete that was made with formwork attached with type II geotextile had better surface properties than that made with the reference formwork and formwork attached with type I geotextile+hessian.