超长空桩段密集旋挖桩群在软弱土层成孔施工技术

Construction Technology of Dense Spiral Excavation Pile Group in Super Long Empty Pile Section in Weak Soil Layer

旋挖灌注桩具有成孔速度快,安全性能好和对环境影响较小等优点而被广泛应用,但也具有成孔过程孔壁稳定性较差的缺点。在淤质、粉砂等软弱土层,且桩群设计较密集,桩距过近的情况下,即使采用泥浆护壁,旋挖桩在成孔过程也极易出现塌孔现象。通过南宁市水街中央城一期项目在超长空桩段密集旋挖钻孔灌注桩群在软弱土层成孔施工中,通过采用增强护壁,降低土体侧压力及施工过程的外部荷载、振动等措施,有效解决旋挖桩成孔难题。

Rotary drilling pile has many advantages, such as fast hole forming speed,good safety performance and little environmental impact, but it also has the disadvantage of poor stability of hole wall in hole forming process. In silt, silty sand and other soft soil layers, and pile group design is more intensive and pile spacing is too close, even if slurry protection is used, the collapse phenomenon of the rotary digging pile in the process of hole formation is very easy. The bored pile group in soft soil hole construction in long period of intensive rotary hollow pile by Nanning City Water Street Central City project, strengthening measures of wall, reducing the external load and vibration of soil lateral pressure and the construction process by using, effectively solve the problem of rotary drilling pile.