塑料排水板处理地基固结特性研究

摘要

目前塑料排水板（Prefabricated Vertical Drains，PVD）处理地基的固结计算均采用传统的砂井等效法，其等效直径可通过较多计算式得到，如周长等效法、周长折减0．75倍等效法（《海堤工程设计规范》（GB／T 51015—2014））等，但目前还没有形成统一的认识。基于等应变假设，类比于砂井地基固结理论，重新推导了排水板地基固结解析解，并通过ADINA 有限元软件验证其合理性。然后采用有限元法对排水板地基固结的二维（2D）模型（即排水板渗透系数kw→＋∞时）进行研究，认为在2D 固结模型下Long 和Covo（1994）的砂井等效法与有限元计算成果较接近，但仍存在一定偏差。最后，给出了2D 固结模型下精度更高的等效直径计算式。该研究对排水板处理地基固结有参考作用。%At present,traditional sand well consolidation theory is adopted to calculate the consolidation characteris-tics of foundation treated by prefabricated vertical drains.The equivalent diameter of prefabricated vertical drain can be obtained by formulas including Hansbo’s perimeter equivalence and the equivalent reduction 0.75 times the per-imeter in Code for Design ofSea Dike Project.But there is no unified understanding on it.In view of this,an analyt-ical solution for the consolidation of foundation treated by prefabricated vertical drains is presented based on equal strain assumption.The rationality of this solution is validated by using ADINA.Furthermore,finite element method is adopted to build a 2D model of foundation treated by prefabricated vertical drains.The coefficient of permeability of drain tends to infinity in the model.It is found that the consolidation characteristics in the 2D model by Long &Covo (1994)are close to those by finite element method,yet with some deviations.Finally,the formula for calcu-lating the equivalent diameter of 2D consolidation model of higher accuracy is given.