泥水盾构泥饼分散崩解试验与应用研究

Test and Application Study on Dispersion and Disintegration of Mud Cake on Slurry Shield

为了更好地进行盾构分散剂泥饼处治,针对黏性地层中不同盾构分散剂的对比评价和选型问题,依托济南济泺路穿黄隧道工程,对比纯水和分散剂作用下的泥饼崩解规律,以及不同分散剂和分散剂质量分数对粉质黏土的崩解效果影响,并将优选的分散剂应用于实际工程。试验得知:1)相比于纯水,分散剂能快速增大粉质黏土的崩解速率,使崩解速率随时间呈2阶段变化,即崩解速率快速达到最大,之后随着崩解的进行,分散剂与土体的作用面积减小使崩解速率降低;2)总崩解时间随分散剂质量分数增大而减少,当分散剂质量分数达到一定程度时,分散剂的作用效果达到最大;3)对比选出了效果更好、成本较低的B分散剂,优选的B分散剂应用于实际工程明显提高了盾构掘进速度,掘进参数更加稳定,掘进效率提高,验证了试验的可行性。

In this study,comparative evaluation and selection are conducted on various dispersants used in shield tunneling in a clayed stratum.The muck cake disintegration rules under pure water and dispersant are comparatively analyzed,and the disintegration effect of various dispersions and dispersion concentrations on silty clay are investigated.Furthermore,an optimal dispersion is applied to the Yellow river-crossing tunnel on Jiluo road in Jinan,China.The results indicate the following:(1)Compared with pure water,the dispersants quickly increase the disintegration rate of silty clay,resulting in two variation stages of disintegration rate with time,i.e.,rapidly reaches the peak and subsequently reduces due to the reduction of contact face area between the dispersant and water.(2)The total disintegration time decreases with an increase in the dispersant concentration.The disintegration effect of the dispersant is maximum only when the dispersant concentration reaches a certain value.(3)An optimal dispersant B with the best disintegration effect and low cost is chosen and applied to a project.The applicable results show that the shield tunnel speed is improved,and the tunnel parameters become more stable,verifying the rationality of the test data.