液化地层震动沉管桩施工对策

南京某综合办公楼桩基工程采用震动沉管桩，由于该区地层的粉砂层存在不同端阻力分界面，因上层长时间的震动，下层粉砂层发生液化，导致桩尖与沉管脱离，桩管内出现水泥浆：为此在施工中采用活瓣桩尖，并用0．5m^3的砼封底，有效地解决了桩管冒浆问题。

Countermeasures on Driven Cast-in-Place Pile Vibration Caused Strata Liquidation

Vibration driven cast-in-place piling is used in pile foundation of a Nanjing office building, owing to different end resistance boundary is existed in silt layer of strata, because of long term vibration on upper part, silt layer in lower part has liquidized, caused the pipe stopper disengaging from pipe and resulted in cement slurry went into the pipe. Therefore valve stopper is used in construction, and 0.5m^3 concrete bottom closed, thus the problem of slurry burst out from pipe has been effectively solved.