兰州大学机构库 >土木工程与力学学院
南竹加筋复合锚杆锚固机理研究
Alternative TitleStudy on the Anchorage Mechanism of the Bamboo-Steel Composite Rockbolt
任非凡
Thesis Advisor韩文峰 ; 谌文武
2009-11-27
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword南竹加筋复合锚杆 锚固工艺 锚固机理 理论模型 拉拔试验 数值模拟 边坡稳定
Abstract目前,国家加大了文物保护力度,特别是保存在我国西北丝绸之路上的土遗址,由于遭受严重的风蚀和雨水冲刷、构造裂隙的破坏,大批的土遗址濒临破坏,范围急剧收缩,已经成为广大专家学者最为关注的问题之一。锚固作为提高岩土体稳定性和解决复杂岩土工程问题最经济、有效的方法之一,它可以提高土体的强度及其自稳能力,易于施工,正被广大的文物保护单位所采用。 南竹加筋复合锚杆作为一种新型锚杆以其自身的优越性虽已被应用于一些土遗址保护加固工程中,但其加固技术尚属首创,其施工工艺和流程、锚固机理、锚固效果尚未得到科学合理的阐释,结构的多界面性以及界面各介质的交互作用为系统地研究复合锚杆带了很大的挑战。因此,对其进行系统的研究不但可填补南竹加筋复合锚杆锚固机理研究的空白,为复合锚杆自身优化提供依据,而且也可为干旱半干旱地区土遗址高陡边坡复合锚杆加固技术的推广应用提供科学依据,并对其他类型工程锚杆的锚固机理研究具有一定的借鉴意义。 论文阐释了交河故城遗址的工程地质环境和崖体边坡的破坏模式,对现有的复合锚杆锚固工艺进行优化。应用弹塑性力学、断裂力学、数学、变形监测、数值分析等理论、技术手段,从理论、试验、数值模拟三个方面,对南竹加筋复合锚杆的锚固机理及变形破坏进行系统的研究。并以交河故城崖体边坡41-5亚区为例,用强度折减有限元法,对其锚固前、后的边坡稳定性进行分析对比。主要研究成果如下: (1)研究区地处吐鲁番盆地中央隆起构造带上,构造运动强烈,崖体坡度大,构造裂隙、卸荷裂隙发育且相互交错,河流侵蚀切割现象严重,加之特殊气候下形成的携砂风对崖面软弱地层的掏蚀所形成的临空面,极大地破坏了交河故城崖体的稳定性。 (2)结合交河故城锚固工程,对现有复合锚杆施工工艺进行现场调查、统计、对比,针对复合锚杆自身特性及土遗址加固的特殊性,分别从布孔定位、临时支护、钻孔、清孔、上锚杆、插入锚杆、注浆、安设锚具、锚孔封堵、表面作旧、锚杆养护等多方面进行优化研究。 (3)基于三线型剪切-滑移理论模型,对南竹加筋复合锚杆的锚固机理进行了分析,将整个受力阶段分为四个阶段,即弹性阶段、弹性-软化阶段、弹性-软化-解耦阶段以及软化-解耦阶段,并获得了锚杆界面各个受力阶段所对应的荷载-位移关系、剪应力分布、轴向应力分布的闭合解。通过对试验所获取的荷载-位移曲线进行分析,获取三个特征点,继而对剪切-滑移模型进行参数标定,预测锚杆的荷载-位移曲线、各个受力阶段的剪应力分布以及轴向应力分布。经过对比锚杆拉拔试验与理论分析结果,两者符合较好。对锚固理论进行的参数分析结果表明:①随着锚杆长度的增加,最大承载力也随之增大,但当锚杆长度大于有效锚固长度后,最大承载力增幅不大;②随着锚杆轴向刚度的增大,锚杆的最大承载力呈近似线性的增长;③随着残余强度因子k值的增加,最大承载力不断增加。 (4)通过在钢绞线、南竹管材内、外表面粘贴电阻应变计,利用静态应变仪、锚杆拉力计,对南竹加筋复合锚杆进行拉拔试验,总结分析出了以下规律: a) 复合锚杆的主要破坏形式为钢绞...
Other AbstractAt present, China has paid more attention to protection of cultural relics, because a large number of earthen sites, especially those in the Silk Road of China, have being destroyed due to severe wind and rain erosion, structural fissures. And it has become one of the most issues that many experts focus on. As an effective and economical measure, rock-soil anchoring technique can increase the strength of soil and its self-stability. Therefore, it has been widely used by the departments of cultural relic protection. As a new type of rockbolt, Bamboo-steel composite rockbolts have been successfully applied in some soil relic projects. However, its anchorage mechanism and construction technology have not been studied systematically yet, and it will be much difficult to research the composite rockbolt because of its complicate structure and multi-interfacial feature. Therefore, a systematic study on this new rockbolts will not only fill the blank of the anchorage mechanism and technology, but also it can provide a scientific basis for applying this composite rockbolts in the steep slopes of the arid and semi-arid region, meanwhile, it has a reference meaning for learning other types of rockbolts. First of all, basing on collecting literature and field investigation, this paper demonstrates the geological environment of the study area, and anchorage techniques are optimized through investigating and comparing the present techniques. Then, combining with the theoretical and technological methods, such as the elastic-plastic mechanics, fracture mechanics, mathematics, deformation monitoring and numerical analysis and so on, the anchorage mechanism of the composite rockbolt is systematically studied by the theoretical, experimental and numerical means respectively. Finally, taking the 41-5 sub-region of Jiaohe ancient city as an example, the slope stability analysis before and after anchoring with composite rockbolts is respectively studied using the strength-reduction finite element method. The main results of the paper are listed as below: (1)The study area is located in the central uplift structure belt of the Turpan Basin, which is influenced by strong tectonic movement. The cliff is very steep with many tectonic fissures and unloading fissures, and its base has been eroded severely by the river. The weak strata at the cliff have also been eroded by the sand-carrying wind, which is formed in the special climate. As a result, many free faces have been for...
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Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226068
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
任非凡. 南竹加筋复合锚杆锚固机理研究[D]. 兰州. 兰州大学,2009.
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