摘要
研究目的:盾构隧道近接既有结构穿越工程中逐渐引进克泥效工法进行辅助施工,克泥效浆液在地层中的扩散性能对中盾壁后注浆效果有重要影响。基于自主研制的克泥效浆液恒压注浆扩散试验系统,开展A液水粉比、净注浆压力、地层渗透系数对浆液在地层中扩散性能(终浆量、终浆时间、扩散距离)影响试验。结合宾汉姆流体砂土扩散模型,对比浆液扩散距离的理论值和试验值,验证模型试验系统和试验结果的可靠性。研究结论:(1)克泥效浆液的屈服应力和塑性黏度随着A液水粉比的增加先增后减,且在A液水粉比3.0时出现极大值;(2)克泥效浆液在土体中的扩散行为表现出填充扩散和渗透扩散的明显差异,填充扩散阶段主要出现在注入的前30 s内,可达到终浆量的70%~80%;渗透扩散阶段浆液注入缓慢,与注浆终浆时间密切相关;(3)随着A液水粉比增加,注浆终浆量、终浆时间先减后增;随着净注浆压力增加,注浆终浆量、终浆时间均增加;克泥效浆液扩散距离与浆液黏度负相关,与净注浆压力正相关;(4)各因素对浆液扩散距离的影响强弱为:地层渗透系数>A液水粉比>净注浆压力;(5)本研究成果可为克泥效工法的工程运用和施工参数选取提供参考和借鉴。
Research purposes:Clay shock method has gradually been introduced for auxiliary construction in the engineering of shield tunneling adjacent to existing structures.The diffusion performance of clay shock slurry in the stratum has a significant impact on the grouting effect behind the middle shield shell.Based on the self-developed grouting diffusion test system with constant-pressure for clay shock slurry,experiments were conducted to investigate the effects of water powder ratio of liquid A,net grouting pressure,and permeability coefficient of stratum on the diffusion performance of slurry in the stratum,including final slurry amount,grouting end time,and diffusion distance.Combining the Bingham fluid diffusion model in sand,the theory and experimental diffusion distances of slurry were compared,and the reliability of the model test system and test results were verified.Research conclusions:(1)The yield stress and plastic viscosity of the clay shock slurry first increase and then decrease with the increase of the water-powder ratio of liquid A,and reach a local maximum value at the water-powder ratio of 3.0.(2)The diffusion behavior of clay shock slurry in soil shows a significant difference between filling diffusion and penetration diffusion.The filling diffusion stage mainly occurs in the first 30 seconds of injection,and can reach 70%-80%of the final slurry amount.The injection of slurry during penetration diffusion stage is slow,which closely related to the grouting end time.(3)As the water-powder ratio of liquid A increases,the final slurry amount and grouting end time first decrease and then increase,and as the net grouting pressure increases,the final slurry amount and grouting end time both increase.The diffusion distance of clay shock slurry is negatively correlated with slurry viscosity and positively correlated with net grouting pressure.(4)The influence of the diffusion distance is as follows:permeability coefficient of stratum>water-powder ratio of liquid A>net grouting pressure.(5)The results of this study can provide references for the engineering application and construction parameter selection of the clay shock method.
作者
张志强
张康健
陈豪
ZHANG Zhiqiang;ZHANG Kangjian;CHEN Hao(State Key Laboratory of Intelligent Geotechnics and Tunnelling,Southwest Jiaotong University,Chengdu,Sichuan 610031,China)
出处
《铁道工程学报》
EI
CSCD
北大核心
2024年第9期60-66,共7页
Journal of Railway Engineering Society
基金
国家自然科学基金(52378414)
陕西省自然科学基础研究计划(2019JLP-23)。
关键词
盾构施工
克泥效
扩散性能
注浆试验
宾汉姆流体
shield construction
clay shock
diffusion performance
grouting experiment
Bingham fluid
作者简介
张志强,1968年出生,男,教授,博士生导师。
