沉箱内砂土振冲施工密实度检测方法及振冲参数优化

针对重力式码头沉箱内仓格空间狭小、排水困难、内部填料密实加固困难、沉箱侧壁及底部完整性难以保证等问题,对比分析4个采用了不同振冲参数的沉箱仓格的砂土的静力触探试验结果。对影响加固效果的3个振冲参数(振冲点数、密实电流、留振时间)进行优化,最终确定单点振冲、密实电流80 A、留振时间20 s的工况最佳,该工况能在保证填料密实度要求的同时,将振冲对沉箱的影响降低,并节约了施工成本。同时发现沉箱内振冲密实电流与对应位置平均锥尖阻力存在二次曲线相关关系。

Test method of compactness for vibroflotation sand in caisson and vibrofloation parameter optimization

In view of such problems as narrow space inside the caisson cell of gravity wharf,difficulty in drainage,difficulty in strengthening the internal packing compactness,and difficulty in ensuring the integrity of the side wall and bottom of the caisson,the static contact test results of four caisson compartments with different vibroflotation parameters were compared and analyzed.The three vibroflot parameters(vibroflot number,compacted current and retained vibration time)affecting the reinforcement effect were optimized,and the optimal working conditions of single point vibroflot,compacted current 80 A and retained vibration time 20 s were finally determined.This working condition can reduce the influence of vibroflot on the caisson and save the construction cost while ensuring the compactness of the packing.It is also found that there is a conic curve correlation between the vibro-compaction current in the caisson and the average cone resistance at the corresponding position.