【作者】 陈琛；

【导师】 夏元友；

【作者基本信息】 武汉理工大学 ， 岩土工程， 2010， 硕士

【摘要】 压力分散型锚索自研究开发成功以来,已经逐渐被应用于水利、交通等各个领域中,对软岩和承载力较低的土体的永久性加固起到了巨大的作用。但其理论研究还落后于工程实践,设计计算方法还不成熟,有许多问题需要进一步研究和探讨。因此深入研究其作用机理和合理的设计方法来指导锚索的合理化施工,对提高我国岩土工程的预应力锚固理论及实际应用技术具有十分重要的意义。本文依托二广高速公路(粤境)怀集至三水段边坡加固工程,以该公路工程中加固边坡的压力分散型锚索为研究对象,采用室内模型试验、理论分析与数值模拟分析相结合的方法对压力分散型锚索锚固机理展开研究,并基于数值分析研究了注浆体与围岩孔壁间剪应力的分布状态上,提出了压力分散型锚索锚固段设计新方法。首先,从试验、数值分析及理论研究三方面综述了预应力锚索,特别是压力分散型锚索的研究进展,详细介绍了压力分散型锚索的结构与受力特点、与普通拉力型锚索的区别、自身优点及使用范围。其次,结合室内模型试验及数值模拟,对压力分散型锚索锚固段作用机理进行了分析,结果表明：(1)在锚索预应力相同的情况下,随着围岩体强度的增大,注浆体与岩体孔壁间的剪应力峰值也随之增大,锚固段有效长度减小；注浆体轴应力峰值随着围岩体强度的增加而增大,且注浆体轴力有效长度也逐渐减小。(2)压力分散型锚索注浆体与围岩孔壁间剪应力在承压板处存在一个初始应力,最大值在距离承压板0.05m左右的地方；注浆体与围岩孔壁间剪应力曲线分布有两种形式。最后,在综合国内外关于预应力锚索设计方法的基础上,结合室内试验和数值模拟的成果,提出了在不同预应力、不同界面粘结力条件下,针对注浆体与围岩孔壁间剪应力分布的两种曲线形式,分别给出了压力分散型锚索单元锚固长有效长度与锚索极限承载力的设计公式。更多还原

【Abstract】 As pressure diffusion cable researching and developing successfully, it has been increasingly used in water conservancy, transportation and other fields, and it played a huge role on the soft rock and soil bearing capacity of the lower permanent reinforcement. But the theory fall behind the engineering practice and the design calculation method is not yet ripe, there are many issues need further study and discussion. It is great significance for improving geotechnical engineering prestressed anchorage theory and practical application if studying its mechanism of action and rational design methods as well as guiding the rationalization of construction of cable.Taking the part of Er-guang Expressway Project within Guangdong province (from Huaiji to Sanshui) as the research background. indoor model test, theory analysis and numerical analysis are used to research the mechanism of pressure diffusion cable. Distribution of shear stress between injecting cement paste and hole wall are gained by numerical analysis. The design method of pressure diffusion cable anchorage section is given by the results.First of all, stress mechanism, especially the progress of are reviewed through experimental, numerical analysis and theoretical. The paper introduce pressure diffusion cable including structure and mechanical characteristics, the difference between ordinary pull-type cable, the advantages as well as application range in details.Secondly, combining with model experiment and numerical simulation, the anchorage mechanism of pressure diffusion cable are analyzed. The results showed that:(1) If the pressure diffusion cable are received same prestress, with the rock strength Increases, shear stress between injecting cement paste and hole wall also increased and the effective length of anchorage section decreased. The same rule to the axial force of grouting. (2) shear stress between injecting cement paste and hole wall of pressure diffusion cable in the bearing plate there is an initial stress, the maximum pressure plate at a distance of about 0.05m place; the shear stress between injecting cement paste and hole wall of pressure diffusion cable distribution curve in two forms.Finally, combining with prestressed cable design method in home and abroad as well as the results of laboratory and numerical simulation, two curves form of shear stress between injecting cement paste and hole wall of pressure diffusion cable are proposed on the condition of different prestress and bond force. At the same time, basing on the two curves form, the formula of effective length and ultimate strength are given.更多还原