振冲法加固砂土地基工艺选择及施工参数控制

Construction technology selection and parameter control in sandy soil ground by vibroflotation

根据砂土的黏粒含量,振冲法可采用不加填料的振冲密实法或有填料的振冲置换法,选择合适的振冲施工工艺和确定合理的工艺参数,与地基加固效果和地基处理的工程投资密切相关。在振冲器的振动荷载作用下,由于饱和砂土的液化产生振密作用,根据孔隙水压力的增长模型,推导了饱和砂土的临界液化时间,并分析留振时间的影响因素。结合两个工程实例,探讨了振冲密实法和振冲置换法两种工艺的适应性及加固效果。根据砂土的类型和黏粒含量,将砂土地基分为3类,不同的砂土地基采用合适的振冲工艺,并得出施工参数的合理区间。

According to the clay proportion of sandy soil,the vibroflotation method can be used with vibro-compaction without backfill or vibro-replacement with backfill.For a ground treatment engineering,the appropriate construction technology and reasonable technological parameters are crucial for the reinforcement effect and the project investment.The effect of vibration density is produced by the liquefaction of saturated sand which is subjected dynamic loadings inside soil caused by vibrator.On the basis of the growth model of pore water pressure,we derive the critical liquefaction time of saturated sand,and analyze the influence factors and engineering significance of the vibration duration time.We also discuss the adaptability and reinforcement effect of the two vibroflotation technologies of vibro-compaction and vibro-replacement through the two engineering cases.Finally,according to the type of sandy soil and their clay proportion,we divide the sandy soil ground into three types,select the suited obtain construction technology for different ground types,and obtain the proper range of parameters.