预成孔置换强夯法在软土地基中的试验研究

Experimental Investigation on Treatment of Soft Soil Foundation by Prebored Dynamic Replacement

强夯置换法是一种软土地基处理方法,存在置换墩不着底、工后沉降大、施工效率低等缺点。针对强夯置换法的上述缺点,提出了一种新型软土地基处理方法——预成孔置换强夯法。该方法通过将高能级强夯法与预先成孔填料相结合,达到提高地基承载力、减小工后沉降的目的。通过开展试验区(24 m×24 m)试验,在夯后进行平板载荷试验、重型动力触探试验及充水预压试验,验证了该方法的可行性,并最终将该技术成功应用于整个软土地基场地。试验结果表明:夯后动力触探击数提高了260%以上,复合地基承载力达到280 kPa,储罐基础沉降最大值、相邻测点沉降差均远小于规范要求。该方法的成功应用对于今后类似地基的处理具有一定的参考意义。

Dynamic replacement,as a treatment method for soft soil foundation,has some shortcomings such as the gap between the replacement columns and the basement,large post-construction settlement,and low construction efficiency.In view of this,a dynamic replacement method with prebored filling is proposed to enhance the bearing capacity of foundation and reduce the post-construction settlement by tamping the prebored columns filled with materials under high energy level.The method is verified feasible through plate loading test,heavy dynamic penetration test and water filling and preloading test after tamping,and finally successfully applied to the whole soft soil foundation site.The number of dynamic sounding blows after tamping increased by over 260%,the bearing capacity of composite foundation reached 280 kPa,and the maximum settlement of tank foundation and the settlement difference of adjacent measuring points are far less than the requirements of specification.The successful application of this method serves as reference for the treatment of similar foundation.