线性加载下塑料排水板地基固结理论探讨  

CONSOLIDATION THEORY FOR PREFABRICATED VERTICAL DRAIN WITH LINEAR PRELOADING

作　　者：黄朝煊 方咏来 

机构地区：[1]浙江省水利水电勘测设计院,杭州310002

出　　处：《工程地质学报》2017年第3期678-685,共8页Journal of Engineering Geology

基　　金：浙江省水利水电勘测设计院科标业项目(B1608;B1609);水利部公益性行业科研专项项目(201401010)资助

摘　　要：针对目前国内外塑料排水地基固结计算均近似采用砂井等效模型的不足,本文将塑料排水板等效为形状极为接近的扁椭圆柱体,根据同焦椭圆柱理论及等应变假设,推导了线性加载下塑料排水板地基的固结解析解;根据ADINA有限元计算及现有学者数值计算成果对比验证了本文理论的正确性。通过与目前不同砂井等效模型对比分析,认为在理想竖井的二维平面固结理论下,本文理论与Long&Covo等效法"dw=0.5b+0.7δ"较为接近,说明扁矩形截面的排水"形状效应"比等面积圆形截面更优;对于考虑井阻影响时,我国《海堤工程设计规范》(GB/T 51015-2014)以及《真空预压加固软土地基技术规程》(JTS147-2-2009)中建议的等效法均具有一定误差,建议采用本文理论计算。此外,地基荷载线性加载时间越长,地基前期固结速率越慢,与骤加恒载情况差异越显著。Consolidation calculations for prefabricated vertical drains（ PVds） are approximately equivalent to sand well model at home and abroad. PVds are equivalent to the flat oval cylinder in this paper. Consolidation solution for PVD foundation is derived with linear load according to equal strain assumption with confocal elliptical coordinate.The correctness of present theory is verified by ADINA finite element calculation and the existing results. The present theory is closer to Long Covo model ＂dw= 0. 5b ＋ 0. 7δ＂in two-dimensional consolidation theory. The＂shape effect＂of flat rectangular cross is better than circular cross-section. Equivalent model for PVds in＂Code for design of sea dike project（ GB/T 51015-2014） ＂and ＂Technical Specification for Vacuum preloading Technique to Improve Soft Soils（ JTS147-2-2009） ＂overestimates the capacity of PVds while considering well resistance. In addition,the longer of linear loading time,the slower rate of consolidation rate,and significant difference with the plummeted loading conditions.

关 键 词：固结理论 塑料排水板 同焦椭圆柱坐标系 线性加载 井阻 

分 类 号：P642[天文地球—工程地质学]