长板短桩复合地基排水系统简化分析

长板-短桩组合型复合地基由塑料排水板、水泥土搅拌桩和地基土三部分构成，其平面布置形式多呈正三角形。由于桩与排水板在平面上分布的非对称性，很难获取其固结解析分析模型。为了从解析分析的角度探讨该组合型复合地基固结特性，必须建立其典型分析模型。本文首先根据长板-短桩复合地基的特点建立了简化的分析模型，获得了模型排水系统的解析解；其次由塑料排水板与砂井排水等效的原理得到了长板-短桩复合地基中地基土的等效渗透系数；最后利用有限元法和工程实例验证了长板-短桩复合地基排水系统简化分析的合理性和可行性。本文的研究成果为长板-短桩组合型复合地基固结理论的发展和固结特性的解析分析奠定了理论基础。

Simplified Analysis for Drainage System of Composite Foundation Improved by Cement-mixing Columns and Vertical Drains

The composite foundation composed by long prefabricated vertical drains and short soil-cement columns is referred to as D-M composite foundation. The distribution of equilateral triangle is commonly used in construction. Due to the unsymmetrical distribution of piles and vertical drains in plane, it is not easy to obtain a model for analyzing its consolidation characteristic. To develop the consolidation analysis of D-M composite foundation, it is necessary to build a typical analysis model for its consolidation analysis. At first the simplified analysis model was established so as to get its analytical solution in this paper; And then the conversion function of soil permeability was conducted on the basis of equivalent drainage relationship between its drainage and sand well. At last, the analysis results were verified to be reasonable and feasible by finite element method and actual project application. The results got in this paper are benefit to the deep theoretical analysis of the consolidation characteristics of D-M composite foundation.