【作者】 王毅；

【导师】 谷拴成；

【作者基本信息】 西安科技大学 ， 建筑与土木工程， 2009， 硕士

【摘要】 近年来,随着水利、能源、交通等基础设施与城市高层建筑的方兴未艾,岩土锚固工程获得了迅猛的发展。在保证岩土工程成功和安全的所有措施中,岩土锚固技术无疑是可供选择的最成熟和经济可靠的。锚杆锚固力的计算是岩土预应力锚固工程中的一个关键问题。锚固力是通过作用在灌浆体和岩土界面上的剪力传递到地层的,现行有关设计规范和技术标准虽都定性的认识到了锚固力沿锚杆轴线方向分布的不均匀性,但均采用均匀分布假设来计算锚杆的锚固力。事实上,内锚头在岩土界面上的剪力和杆体中各截面的轴力分别由锚杆口部向根部衰减,并非常量,目前的简化计算方法并不符合实际情况。已经有不少的技术人员已经认识到了这种现象,并对其进行了实验研究,也得出了不少的定性结论,但都是以实验室研究为依据,采用常规的土工试验数据来简单计算岩土中的锚固力,与工程的实际情况相差甚远。为更好的优化设计,降低工程造价,迫切要求人们弄清楚黄土层中锚杆的锚固力与土质特性之间的锚固机理,为设计计算提供更精确的理论。根据黄土地层锚索(杆)锚固理论发展的需求,以及本人在黄土地层中进行锚固工程设计、施工的实际情况,提出了“黄土预应力锚固机理的研究”的课题并开展了研究工作。本文借助资料查阅和现场拉拔试验,以理论分析、总结和数学推导为研究手段,以指导工程实践为基本目标,在结合前人研究成果的基础上,运用数学方法,推导出粘结面上剪应力的分布函数,给出锚索(杆)极限承载力的计算公式;最后结合现场拉拔试验,总结黄土层中粘结面上的传力机理、结构内力和变形特征规律,推求出相对简单、实用的极限承载力计算公式。通过现场实验,得出了锚索(杆)锚固段应力的分布曲线图,进一步验证了锚索(杆)锚固段粘结力呈不均匀分布的理论,并得出了黄土地层中的锚索(杆)最优锚固段长度为8～10m的结论,这些公式和结论对指导现场施工和生产具有一定的理论意义和现实意义。更多还原

【Abstract】 In recently years, with the enlarging of construction scale about the infrastructure of hydraulic、energy and traffic etc and high.rise building of city, Geotechnical Engineering develops very rapidly. In all measures to ensure the success and safety of Engineering, geotechnical anchorage is one of the technologies which is matured、economical and credibility. The calculation of anchorage ability of bolt is a key problem in geotechnical pre.stressed anchorage engineering. The anchorage ability is through the shear stress on the interface between grout and geotechnical transfer to the stratum, and the norm standard and technical criterion all adopt the uniform distribute assumption to calculate the anchorage ability of bolt as though they all noticed that the anchorage ability along bolt body is not uniform distributed. In fact, the shear stress on the geotechnical interface and axial force on body of bolt are attenuate from the tunnel wall to the root segment of bolt, not constant, current simplified calculation method not agree with the practical situation. There had many technical personnel noticed the phenomenon, and implement experiment study, abtained some qualitative conclusions, but all based on the experiment study, adopt routine soil mechanics data to simply calculate the anchorage ability is not agree with the practical situation.In order to optimize dedign, reduce the cost of project, that need people to study the anchorage mechanism between anchorage ability of bolt and soil property, supply more accurate theory for design calculation. According to the develop need of bolt (cables) anchorage theory and design、construction ete practical situation in loess Strata, present the subject that“study on the pre.stressed anchorage mechanism in loess Strata”. This paper based on the data investigation and in situ pull out test, use theoretical analysis、mathematic deduce, derived the distribution model of shear stress on the bonding interface, presented calculate formula about ultimate load.bearing capacity of bolt (cables); In the end, combine with the in situ pull out test, summarized the mechanism of tranfer load on the bonding interface、inner force of structure and regularity about deformation, presented a simple and practical calculate formula about ultimate load.bearing capacity. Through in situ test, abtained the figure of stress distribution on the bond section of bolt (cables), further verified the theory of bonding force on the bond section is not uniform, and abtained the conclusion that the optimum bonding length of bolt (cables) in the loess strata is 8～10 meter, these formula and conclusion used to direct the engineering practice have practical and theorical significance.更多还原