新型环保均质塑性(EHP)桩的桩身完整性研究

Study on the integrity of new environment homogeneous plastic(EHP)piles

水泥土搅拌桩在软土地基加固工程中应用广泛,但成桩过程中易受原位土体性质及地基成层性的影响,经常出现桩身完整性较差、强度不均匀的问题。在传统水泥土搅拌桩的基础上,提出了一种加固软土地基的新型环保均质塑性桩——EHP桩。采用提钻出土技术,利用水泥作为固化剂及土体在原位地基外强制搅拌,然后回填至钻孔内的施工方式,具有施工效率高,桩身完整性好,污染小等优点。通过低应变反射法分析成桩后的EHP桩桩身完整性与桩身缺陷,并与传统水泥土搅拌桩的桩身结构进行对比,验证了EHP桩处理软土地基的施工适用性和优越性。结果表明:EHP桩的桩身完整性等级基本接近Ⅰ级,桩身强度和完整性均优于传统水泥土搅拌桩。

The cement-soil mixing pile is widely used in the soft soil foundation reinforcement engineering,but it is easy to be affected by the in-situ soil properties and the stratification of the foundation during the pile forming process,which often leads to the problems of poor integrity and uneven strength of the pile body.Based on the traditional cement soil mixing pile,a new environment homogeneous plastic pile(EHP pile)was proposed to strengthen the soft soil foundation.It adopted the technology of drilling and excavation,using cement series curing agent and soil to force mixing outside the in-situ foundation,and then backfilling to the borehole,with the advantages of high construction efficiency,good integrity of pile body,small pollution and so on.Through the low strain reflection method,the integrity and defects of EHP pile after pile forming were analyzed,and compared with the pile structure of traditional cement soil mixing pile,the applicability and superiority of EHP pile in soft soil foundation treatment were verified.The results showed that the integrity grade of EHP pile was close to grade I,and the strength and integrity of EHP pile were better than that of traditional cement soil mixing piles.