考虑通水量影响的塑料排水板加固深度的理论研究

Theoretical study of reinforced depth of plastic vertical drain considering the water flux

针对新近吹填土淤泥地基处理中加固深度小，土体强度增强有限等问题，提出理论分析加固深度的新思路，即以传统的负压下砂井固结方程的解析解为基础，通过迭代法计算出土体中任意一点的固结度，换算出土体的加固深度，从而分析研究塑料排水板的通水量变化对加固深度的影响，得出加固深度的变化规律。结果表明：在真空预压处理新近吹填土淤泥地基时，排水板的通水量对地基的加固深度有显著的影响；在一定的固结时间（90d）内，排水板之间的土体会形成5～10m的硬壳层，通过延长加固时间可以增加硬壳层的厚度；当通水量减小超过60％时，延长固结时间对改善加固深度作用不大。因此，设计和施工中应充分考虑排水板的通水量影响。

Its soil strength increases only a little and its effective depth is very small in the newly hydraulic reclamation silt foundation treatment. A new idea about analysis of reinforcement depth was proposed. The consolidation degree of soil at any point was calculated by iterative method base on the conventional consolidation equation for sand-drained ground under negative pressure, and the reinforced depth was deduced through the consolidation degree. The variation of reinforced depth was analyzed. The results show that： fill in the vacuum preloading of the newly hydraulic reclamation silt foundation, the water flux of plastic vertical drain（PVD） have a significant influence on the effective reinforced depth. Within a certain period of consolidation（90 days）, the hard soil layer between the PVDs will form 5- 10 m. The thickness of hard soil will increase by extending consolidation time. When the water flux dropped 60%, the reinforced depth will little change with increasing consolidation time. Therefore, influence of PVD＇s water flux is considered in design and construction.