海南滨海粉细砂的工程特性与地基压实方法研究

Research on Engineering Characteristics and Foundation Compaction Methods of Hainan Coastal Fine Sand

滨海砂地基的工程特性与常规陆源砂地基有很大差异,如处理不当,易发生地基沉降变形、振动液化等工程问题。因此,基于海南地区的滨海粉细砂,考虑滨海砂地基的性质和环境地质条件,首先对其工程特性进行了试验分析,而后采用冲击压路机+振动压路机、振动压路机2种机械碾压方式进行了滨海砂地基现场碾压试验研究,并对其单遍压实度、单遍压实沉降差以及总的压实度与压实沉降差进行了对比分析。其结果表明:滨海砂地基宜在基底设置碎石土垫层,厚度宜为30 cm左右;单一采用振动压路机进行滨海砂垫层碾压对滨海砂地基压实度的影响有限,宜在垫层上采用冲击碾压和振动碾压相结合的施工工艺,其碾压参数宜为冲击碾压15遍+振动碾压4遍;压实沉降差控制标准为最后2遍的压实沉降差平均值以不超过2 mm为宜。

The engineering characteristics of coastal sand foundation are significantly different from those of conventional land-based sand foundation.Improper treatment can cause engineering problems of settlement deformation and vibration liquefaction.Based on Hainan coastal fine sand,the performance and environmental geological conditions of coastal sand foundation was thought over.Firstly,the engineering characteristic was analyzed;Then,onsite compaction test research on coastal sand foundation were studied by two compaction methods of impact roller+vibration roller and vibration roller.The single pass compact,single settlement difference,the total compact and the settlement difference are compared and analyzed.The results indicate that it is advisable to set up a gravel soil cushion layer at the base of coastal sand with 30 cm thichness;The impact of using a single vibrating roller to compact the coastal sand cushion layer on the compaction degree of the coastal sand foundation is limited.It is advisable to apply a combination of impact compaction and vibration compaction on the cushion layer,with rolling parameters of15 times of impact rolling and 4 times of vibrating rolling;The control standard for compaction settlement difference is that the average compaction settlement difference of the last two times should not exceed 2 mm.