挤密碎石桩施工工艺与检测

南水北调中线穿黄工程北岸渠道位于黄河滩地,基础为粉土和砂土,由于地下水位较浅,地基承载力较低且在地震烈度为7度时存在深度为12 m的液化现象,设计单位设计采用了挤密砂桩加固地基、消除液化.但在施工过程中由于用于挤密砂桩施工的原材料生产强度不能满足强度要求,遂决定改进挤密砂桩的施工工艺,将原材料细度模数大于2.8的中粗砂改为粒径为5～20 mm的级配碎石.经过现场检测,经过挤密碎石桩处理后的砂层的各项指标均满足设计要求且优于挤密砂桩处理的效果;且提高了施工功效高,降低了原材料的成本,从而解决了挤密桩原材料供应强度的问题,加快了施工进度,节省了工程投资.

Construction and Testing Technology of Compacted Gravel Pile

The main trunk canal of MRP crossed Yellow River in the northern beach and the foundation is silt and sand. Due to shallow groundwater,the foundation bearing capacity is low and the seismic intensity of 7 degrees liquefaction phenomenon exists at the depth of 12 rn. Compacted sand pile was designed in order to reinforce the foundation to eliminate liquefaction. But in the course of construction, as the raw material for production of compacted sand pile strength cannot meet the requirements, it is decided to use the compacted sand pile technology to improve the construction process. The raw material fineness modulus are adjusted from 2. 8-sand to the size of 5-20 mm graded gravel. Following the on-the-spot inspection,all of the indexes meet with the design requirements better than the results of compacted sand pile,and it also improved the effectiveness of the construction, lowered the cost of the raw materials, thus solved the problem of supplying raw materials compaction pile, speed up the construction schedule,and saved the project investment.