土压平衡盾构渣土改良泡沫发生性能试验  

Foam Generation Performance of Earth Pressure Balance Shield Soil Conditioning

作　　者：王斌 王树英[1,2,3] 郑响凑[1,2] WANG Bin;WANG Shu-ying;ZHENG Xiang-cou(School of Civil Engineering,Central South University,Changsha 410075,Hunan,China;Tunnel and Underground Engineering Research Center,Central South University,Changsha 410075,Hunan,China;Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structures,Central South University,Changsha 410075,Hunan,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学隧地工程研究中心,湖南长沙410075 [3]中南大学轨道交通工程结构防灾减灾湖南省重点实验室,湖南长沙410075

出　　处：《中国公路学报》2024年第1期154-164,共11页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52022112);中央高校基本科研业务费专项资金项目(2023ZZTS0370)。

摘　　要：泡沫性能对于土压平衡盾构渣土改良效果有重要影响。采用实验室自制的泡沫发生设备进行了一系列泡沫性能测试,主要研究了气体流量、液体流量以及发泡液浓度对泡沫流量、发泡倍率、半衰期以及泡沫细观形态的影响,并分析了泡沫宏观性能与细观粒径之间的相关性。研究结果表明:气液比相同时,随着气体流量的增加,泡沫流量先增大后减小,发泡倍率逐渐减小,泡沫半衰期先增大而后减小。气体流量一定时,随着液体流量的增加,泡沫流量近似线性增长,发泡倍率略有下降并趋于稳定,泡沫半衰期先增大后减小。发泡液浓度在2%以下时,泡沫流量、发泡倍率以及半衰期随着发泡液浓度的增大迅速增长,发泡液浓度大于3%时,泡沫性能受发泡液浓度的影响较小。气体流量为21 L·min^(-1)、液体流量为0.3~0.5 L·min^(-1)、发泡液浓度为3%条件下,该泡沫发生系统的发泡性能最佳。相对于液体流量和发泡液浓度,气体流量对泡沫气泡初始粒径分布的影响最为显著,随着气体流量的增大,泡沫变得更细更均匀。发泡倍率与泡沫粒径之间存在明显的相关性,泡沫越细,发泡倍率越低;泡沫半衰期与粒径之间的关系不如发泡倍率明显。在实际盾构渣土改良中,应该重视泡沫粒径与渣土颗粒孔隙的适配关系,泡沫改良更加适用于级配较好的渣土;相同地层条件下,不同级配的泡沫入渗时需要不同的注入压力。The performance of foam plays a pivotal role in the soil conditioning effectiveness of earth pressure balance(EPB)shield tunneling.This study presents a comprehensive set of foam performance tests conducted using a laboratory-designed foam generation system.The study primarily investigated the effects of gas flow rate,liquid flow rate,and foaming agent concentration on the flow rate,foaming expansion ratio,half-life,and mesoscale morphology of foam.Moreover,the correlation between macroscopic foam performance and mesoscale particle size was analyzed.The study results show that,under a constant gas-liquid ratio,the foam flow rate initially increases and subsequently decreases as the gas flow rate increases.Simultaneously,the foaming expansion ratio gradually decreases with increasing gas flow rate,and the foam half-life initially increases and subsequently decreases with the increase of gas flow rate.When the gas flow rate is constant,the foam flow rate increases approximately linearly with the increase in liquid flow rate.The foaming expansion ratio slightly decreases and tends to stabilize with the increase in liquid flow rate,while the foam half-life initially increases and then decreases with increasing liquid flow rate.When the foaming agent concentration is below 2%,the foam flow rate,foaming expansion ratio,and half-life increase rapidly with increasing foaming agent concentration.However,when the foaming agent concentration exceeds 3%,the foam performance is less affected by changes in foaming agent concentration.The foam generation system performs optimally under the following conditions:gas flow rate of 21 L·min^(-1),liquid flow rate of 0.3-0.5 L·min^(-1),and foaming agent concentration of 3%.The initial particle size distribution of foam bubbles is most affected by the gas flow rate compared to the liquid flow rate and foaming agent concentration.As the gas flow rate increases,the foam becomes finer and more uniform.A significant correlation is observed between foaming expansion ratio and the foam bub

关 键 词：隧道工程 渣土改良 泡沫发生器 发泡倍率 泡沫半衰期 泡沫粒径分布 

分 类 号：U455[建筑科学—桥梁与隧道工程]