泉州市某仓储中心地基强夯处理与承载力检测

Dynamic compaction treatment and bearing capacity test of a warehouse foundation in Quanzhou

以泉州市某仓储中心地基强夯处理项目为例,建筑物主要持力层为淤泥和粉质黏土,设计要求地基承载力150 kPa,揭露持力层承载力为40~60 kPa,不满足设计要求,需要进行地基处理。根据地基地层特性,选择强夯加固对地基进行处理,地基处理后形成5~6 m厚硬壳层且地基承载力≥150 kPa,可满足设计要求。通过分析比较Menard计算公式与Billam方法,Menard计算公式只考虑锤重与落距,Billam计算法包含了锤重、落距、锤底面直径和折减系数多个因素,适用性较好,且计算精度相对高。选择Billam方法确定采用2000 kN·m夯击能,强夯采用布点为5.0 m×5.0 m,推测其加固影响深度约为5~6 m。并采用静载荷试验对施工质量进行了检测,试验总沉降较小,确定该工程参与统计的地基承载力特征值为150 kPa,地基承载力特征值满足设计要求,表明地基处理方案可行有效。

An example of foundation treatment of a warehouse foundation in Quanzhou is reported.The main bearing layers of the warehouse are mud and silt clay.The design requires a foundation bearing capacity of 150 kPa,while the bearing capacity of the soil is 40-60 kPa,which does not meet the design requirement.So the foundation treatment is required.According to the characteristics of ground condition,dynamic compaction method is selected to imporve the ground.A 5-6 m-thick stiff layer was formed after compaction and the bearing capacity was found to be greater than 150 kPa,which can meet the design requirements.Two methods,namely,Menard formula and Billam’s method,are used to evaluate the improvement effect.The Menard’s formula only considers hammer’s weight and hammer’s height,but the Billam’s method’s can consider hammer’s weight,hammer’s height,hammer’s diameter and reduced coefficient.It is found that the Billam’s method’s works well and has high calculation accuracy.The billam method is selected to determine the compaction energy of 2000 kN∙m.The distribution point of dynamic compaction is 5.0 m×5.0 m,and the reinforcement influence depth is about 5-6 m.Test results show the total settlement is small,and the characteristic value of bearing capacity is 150 kPa.So the characteristic value of the foundation bearing capacity meets the requirements,and the ground improvement technique is effective.