基坑吊脚墙支护中锁脚锚索的设计方法探讨

Discussion on Design Method of Feet-Lock Anchor in Foundation Pit Hanging Foot Wall Support

吊脚式支护结构在上土下岩地层的深基坑支护中被广泛采用,但是吊脚式支护结构的设计计算理论却相对缺乏。锁脚锚索作为吊脚式支护结构的固脚构件,是极其重要的受力构件,其受力的安全可靠性直接关系吊脚式支护结构的安全性。针对目前吊脚式支护中锁脚锚索拉力设计方法缺少有效计算方法的问题,从支护结构实际受力的变化过程,采用增量法计算支护结构的受力和变形,并采用力的转移思想,将坑底以下基坑内侧土反力合力等效为锁脚锚索的水平拉力之和。这样计算基坑支护的受力和变形更符合工程实际,是一种较可靠的计算方法,可供类似工程设计参考。

Suspended foot support structure is widely used in deep foundation pit support in the upper soil and lower rock,but the design theory of suspended foot support structure is relatively lacking.As the foot-fixing component of the hanging-foot supporting structure,the feet-lock anchor is an extremely important force-bearing component.The safety and reliability of its load ability is directly related to the safety of the hanging-foot supporting structure.Aiming at the current lack of effective calculation method for the design of the feet-lock anchor tension in hanging foot support,this article starts from the change process of the actual force of the supporting structure,uses the incremental method to calculate the force and deformation of the supporting structure,and adopts the idea of force transfer.The earth reaction force on the inner side of the foundation pit below the bottom of the pit is equivalent to the sum of the horizontal tension of the feet-lock anchor.The result is that the force and deformation of the foundation pit support calculated in this way are more in line with engineering reality.Therefore,it is a relatively reliable calculation method that can be used as a reference for similar engineering design.