基于增量法的预应力锚杆复合土钉支护体系的设计计算

摘要

From working mechanism,soil-nailed retaining structure is different from pre-stressed anchor supporting structure and reinforced earth structure:pre-stressed anchor supporting structure is an-chorage mechanism,reinforced earth structure is reinforcement mechanism.However,soil-nailed retai-ning structure is a combination of reinforcement and anchorage.Based on the anchorage theory in slope stability,soil nailing and soil are regarded as reinforced soil,which parameters including cohesion and internal friction angle will be changed.In this way,soil nail - pre-stressed anchor composite retaining system is simplified as pre-stressed anchor flexible retaining structure which acts on the special reinforced soil.When calculated,load increments which arise form digging and pre-stressing will be distributed be-tween the anchors and the reinforced soil based incremental method,then the reinforced soil is analyzed individually.Therefore,the rule of development and change of axial force of soil nail can be solved.Last,the calculation model is verified with a project example,which presents that increment method can be used in design calculation of composite soil-nailed retaining structure.%从作用机理上分析，土钉支护体系与锚杆支挡体系及加筋土结构有所不同：锚杆支挡体系为锚固机制；加筋土结构为加固机制；而土钉支护体系为加固基础上的锚固机制。从边坡锚固稳定的思路出发，将土钉与土体视为 c，φ有所改变的增强体，预应力锚杆复合土钉支护体系简化为作用于特殊增强体的预应力锚杆柔性支护，结合增量法分析每步开挖及预应力施加产生的荷载增量并进行合理分配，较好地解决了开挖支护过程中土钉受力的发展变化规律。最后通过工程实例对所建模型的计算结果进行验证，表明增量法用于复合土钉支护体系的设计计算具有一定的合理性。