考虑窜孔效应的人工挖孔桩护壁设计方法研究

护壁对于人工挖孔桩成孔过程中防止土体塌落及滑动有着极为重要的作用,是施工中保障人员安全和工程质量的主要构件。针对人工挖孔桩的护壁设计问题,分灌注桩和空桩两种工况分别建立了力学分析模型,以护壁的抗拉强度和水平位移作为护壁失效的控制条件,结合桩间土受力模型,提出了预防窜孔问题的人工挖孔桩护壁设计方法。将本文提出的新的设计方法应用于实际工程,结果表明了本文方法的合理性,并根据实际应用结果提出了施工建议。研究成果对人工挖孔桩护壁的设计与施工安全有积极的指导和借鉴意义。

A design method for the protective wall of artificial-dug pile hole considering effect of hole connection

The protective wall of artificial-dug pile hole is very important for prevention of soil slumping and sliding in the process of hole digging. It is one of the main components in safeguarding personnel safety and project quality. For the design of such wall, mechanical analysis models are established according to two working conditions of pumping concrete and empty hole, respectively. Tensile strength and horizontal displacement are used as the controlling failure conditions for the wall. Combining the model of the soil stress between piles, a design method is proposed for the wall of hand-dug pile hole to prevent connection of holes. Application of this new design method to a real project shows its reasonability. Furthermore, suggestions on implementation based on the practical application effect are made. The study results would be of guidance significance to design and construction of protective walls of hand-dug pile holes.