地铁洞内咬合桩富水粉细砂层塌孔原因分析及应对措施

CAUSE ANALYSIS AND RESPONSE MEASURES FOR HOLE COLLAPSE IN WATER-RICH SILTY FINE SAND STRATUM FOR SECANT PILES IN SUBWAY TUNNEL

咬合桩作为一种新型的基坑支护结构,已被广泛应用于基坑支护实践中。通过机场线西延工程,阐述了咬合桩首次在地铁PBA暗挖区间密贴下穿既有车站应用中出现的荤桩成孔过程中多次塌孔现象,现场采取的应对措施,成功解决了PBA咬合桩在富水粉细砂地层中成孔的问题。

Secant pile,as a kind of new foundation pit support structure,has been widely used for foundation pit support.This paper describes the circumstances of repeated hole collapses during reinforced concrete pile boring when the secant pile is firstly used to pass underneath the existing station closely in PBA tunneling section by extending the airport line westwards as well as the response measures taken on site,to solve the boring problems of PBA secant pile in water-rich silty fine sand stratum successfully.