压力分散型锚索锚固段的设计方法

Design method of fixed anchor unit for compression dispersion-type anchor

边坡加固技术是工程界一直关注的重要课题,边坡开挖后坡体内应力调整和位移变化的复杂性,对加固技术有了新的要求,而在此方面国内起步较晚,且多数采用拉力(分散)型锚索对岩体实施预加力。经过大量试验结果表明,在破碎岩体中,当锚索长度大于8～10 m后,拉力(分散)型锚索的承载力无法获取较高的锚固力,而压力分散型锚索的受力性能不仅合理,而且在这种地层中可以实现较大的承载力,本文结合二康公路现场实践,采用Winkler假设,基于锚索粘结应力分布的特点,通过锚索锚固段受力状态分析和应力分布规律,利用理论与试验结果相对比,提出一种新的设计方法,及基于峰值粘结应力的计算方法,并通过具体工程实例验证,这种计算方法是符合压力分散型锚索在破碎岩体边坡加固中的受力模式,与现场试验是完全吻合的,具有一定的参考价值,供工程界参考。

Slope reinforcement was a very important engineering technique. As the complexity of stress adjusting and displacement variation in cut slope, it was not satisfied to use the tension dispersion-type anchor. Many test results showed that the tension dispersion-type anchor could not give enough anchor forces when the length of anchor exceeded 8～10 meters in broken rock mass. The compression dispersion-type anchor was provided not only with reasonable mechanical behavior, but also with enough anchor forces as well. The mechanism of compression dispersion-type anchor was studied, and a new design method of the compression dispersion-type anchor for broken rock mass slope was proposed. Compared the calculated results with those of in-situ, the new design method was proved to be reasonable and could be applied to the slope reinforcement project.