承压水对抗拔桩施工的影响及对策

Influence of confined water on uplift pile construction and countermeasures

针对某具体工程实例,通过磁测检测、取芯检测、开挖检测、静载试验试桩检测,分析了抗拔桩抗拔承载力不足的原因及承压水对抗拔桩带来的危害,指出承压水及抗拔桩施工工艺引起的桩侧摩阻力的降低是导致抗拔桩抗拔承载力不足的原因。提出了具有承压水水文地质条件下抗拔桩施工工艺与质量控制措施即试桩、降止水、提高泥浆质量、采用后压浆工艺及增加上覆土,以期对类似工程地质及水文地质条件下抗拔桩的施工提供参考。

In view of a specific engineering example,the reasons for the insufficient uplift bearing capacity of uplift piles and the harm caused by confined water to uplift piles were analyzed through magnetic testing,core testing,excavation testing,and static load test pile testing.It is pointed out that the reduction of pile side friction resistance caused by confined water and the construction technology of uplift piles is the reason for the insufficient uplift bearing capacity of uplift piles.The construction technology and quality control measures of uplift piles under hydrogeological conditions of confined water were put forward,namely test pile,dewatering and water sealing,improving mud quality,adopting post grouting technology and increasing overlying soil in order to provide reference for the construction of uplift piles under similar engineering geology and hydrogeological conditions.