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锚固是岩体工程增稳的主要措施,对充分发挥岩体的自承潜力,调节和提高岩体自身强度和自稳能力有着十分重要的作用。由于锚固工程本身的复杂性和多样性,导致目前锚固机制、设计理论以及计算方法都不够完善。现有的锚固段荷载传递解析解存在两大难题,一是没有反映锚固段应力变化过程,随着荷载不断加大,接触面是逐渐被破坏,剪应力的峰值将由端口逐渐向内转移;二是在端口处是一个应力奇异点,难以很好地解决。通过对当前多种锚固段荷载传递解析解的适用性及局限性进行分析归纳,指出应将锚固段应力分布划分为弹性、塑性和破坏3个阶段,在不同的阶段应力分布形式不一样,不能一概而论。在此基础上,基于传递系数,针对沿锚固段剪应力呈非均匀性分布形式,提出了一种能反映这3个阶段变化规律的荷载传递解析公式,获得了锚固段剪应力和轴力的分布规律和影响因素。对各解析解方法求出的临界锚固长度进行了算例对比,证实所提算法是合理和有效的。该算法适用于预应力锚索锚固段工程设计。
Anchorage is the main measure to stabilize the rock mass engineering. It plays a very important role in giving full play to the self-supporting potential of the rock mass, adjusting and improving its own strength and self-stability. Due to the complexity and diversity of the anchoring engineering itself, the current anchoring mechanism, design theory and calculation methods are not perfect. The existing analytic solution of load transfer in anchorage section has two major problems: firstly, it does not reflect the process of stress variation in anchorage section; as the load increases, the contact surface is gradually destroyed and the peak value of shear stress will gradually shift inward from the port; Is a stress at the port singularity, it is difficult to solve well. By analyzing and summarizing the applicability and limitations of current analytical solutions of load transfer in anchorage sections, it is pointed out that the distribution of stress distribution in anchorage section should be divided into three stages of elasticity, plasticity and failure. The stress distribution forms in different stages are different, All in all. On this basis, based on the transfer coefficient, a load transfer analytical formula that reflects the variation of these three stages is proposed for the non-uniform distribution of shear stress along the anchorage section, and the shear stress and axial force of the anchorage section are obtained Distribution rules and influencing factors. The critical anchoring length obtained from each analytical solution is compared with examples to prove that the proposed algorithm is reasonable and effective. The algorithm is suitable for engineering design of prestressed anchor cable anchorage section.