强夯联合素混凝土桩在软基处理中的应用

Application of dynamic compaction combined with non-reinforced concrete piles in soft foundation treatment

填土地基土层结构松散,工程性质较差,往往难以直接用于工程建造。强夯工法具有造价低、施工速度快以及处理后场地整体均匀性好的优点,素混凝土桩具有单桩承载力高和沉降变形小的特点。本文以某工业园区的回填土场地基础工程为实例,表层为1~6m的新近回填土,从考虑技术、工期、造价等方面进行不同方案比选,最终采取了强夯和素混凝土桩复合地基方案。根据填土层的厚度不同分区进行地基处理,0~4 m厚度区域采取2 000 kN·m强夯能级,4 m以上区域采取4 000 kN·m强夯能级,柱下独立基础下采取素混凝土复合地基。最终检测结果表明,强夯联合素混凝土桩复合地基加固效果较好,可消除地基大部分工后沉降,地基承载力不小于100 kPa,独立基础下复合桩基的承载力不小于350 kPa,满足设计要求,为类似场地基础方案的优化提供参考。

The filling foundation is often difficult to be directly used for engineering construction because of its loose soil structure and poor engineering properties.The dynamic compaction method has the advantages of low cost,fast construction and uniform reinforcement.The plain concrete pile has the characteristics of high bearing capacity and small settlement.Taking the foundation project of a recently backfilled soil site with a surface layer of 1-6 m in an industrial park as an example,different treatment methods were compared and selected in terms of technology,construction period,and cost.The composite foundation scheme of dynamic compaction and plain concrete piles was finally adopted.According to the thickness of the filling layer,the foundation treatment is carried out in different partitions.The O-4 m thickness area adopts 2000 kN-m energy level dynamic compaction,and 4000 kNm energy level is adopted for the area above 4 m thickness.The individual foundation under column adopts plain concrete composite foundation.The load test results show that the reinforcement effect of the composite foundation piles is better.This treatment method can eliminate most of the post-construction settlement of the foundation,and the bearing capacity of the foundation is not less than 100 kPa.The bearing capacity of the composite pile foundation under the individual foundation is not less than 350 kPa,which meets the design requirements.The results of this work provide a reference for the optimization of similar site foundation schemes.