等应变条件下增压式真空预压固结解析解  

Analytical solution of consolidation by air-boosted vacuum preloading under equal strain condition

作　　者：刘景锦[1,2] 罗学思 雷华阳[1,2] 郑刚[1,2] 罗昊鹏 LIU Jing-jin;LUO Xue-si;LEI Hua-yang;ZHENG Gang;LUO Hao-peng(School of Civil Engineering,Tianjin University,Tianjin 300350,China;Key Laboratory of Coast Civil Structure Safety of Ministry of Education,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学建筑工程学院,天津300350 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300350

出　　处：《岩土力学》2024年第3期809-821,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金青年项目(No.51908406)。

摘　　要：从注气增压对土体作用效果的角度出发,建立增压式真空预压固结解析理论模型。提出基于注气增压压力等效的受力简化模型;引入新参数——径向渗透系数增大系数η,反映注气过程对土体渗透性质的改变。根据Barron等应变假定和达西定律,考虑排水板涂抹效应与井阻作用、土体径-竖向渗流以及上部堆载,推导增压式真空预压固结控制方程及其解析解,并利用弹性力学方法推导等效注气增压压力p(t)的计算公式。针对瞬时增压和线性增压两种特例给出具体解析解公式,并通过与工程案例对比分析,验证了解析解及等效力计算方法的合理性。通过对固结性状的分析得出如下结论:注气增压方法可增大土体负孔隙水压力值,加速土体排水固结;“参数η”对固结速率的影响较大,分析模型中考虑注气过程对径向渗透系数的改变会更加合理;井阻作用会导致土体固结速率减慢,径-竖向渗流时孔压能够消散完成,而只有径向渗流时孔压无法消散完成。This paper presents an analytical theoretical model for air-boosted vacuum preloading,focusing on the influence of air injection on soil consolidation.A simplified force model based on the equivalence of air-boosted pressure is proposed,and a new parameter called the“horizontal permeability coefficient increase parameterh”is introduced to account for changes in soil permeability due to gas injection.Based on Barron equal vertical strain assumption and linear Darcy’s law,the governing equation and consolidation analytical solution for air-boosted vacuum preloading are derived,considering factors such as radial and vertical seepage,prefabricated vertical drain smear effect,well resistance,and surcharge.Additionally,the theoretical formula for the equivalent air-boosted pressure p(t)is derived using elastic mechanics methods.Specific analytical solutions are provided for two cases:instantaneous air-boosted and linear air-boosted.An engineering case study is used to verify the rationality of the analytical solution and the mechanical equivalence method.Through the analysis of consolidation behavior,the following conclusions are drawn:the air injection boosting method increases the negative pore water pressure in the soil,facilitating faster drainage and consolidation;the“η”parameter significantly affects the consolidation rate,and considering changes in the horizontal permeability coefficient during gas injection improves the accuracy of the analysis model;well resistance slows down the consolidation rate,and while pore pressure can dissipate completely during radial and vertical seepage,it may not dissipate completely during radial seepage alone.

关 键 词：增压式真空预压 等应变条件 固结理论 解析解 

分 类 号：TU433[建筑科学—岩土工程]