软岩填筑体多层多孔微生物灌浆室内模型试验研究

MODEL TEST OF MULTI-LAYER POROUS MICROBIAL GROUTING IN SOFT ROCK FILLINGS

目前利用无损检测技术来评价微生物矿化反应加固效果的研究较少。在试验确定微生物灌浆周期、灌浆速率以及最优灌浆间距的基础上,结合填筑体内部进行管路灌浆的思想自主设计了用于填筑体加固的多层多孔灌浆管道系统,利用该系统开展泥质页岩残积土的微生物灌浆室内模型试验。利用超声波检测技术,针对循环灌浆得到的残积土胶结体开展详细的加固效果分析,结果表明:(1)利用多层多孔灌浆管道系统对填筑体进行微生物诱导方解石沉淀(MICP)技术处理后,残积土填筑模型的超声波速增大明显,表明采用该灌浆方法可有效提高填筑体密实度,证明了应用自主设计的多孔灌浆系统进行填筑体加固的可行性;(2)利用超声波检测技术测定不同灌浆阶段填筑体的正、侧面波速,发现其波速与增量呈左右对称分布,且随着微生物注浆加固次数的增加,模型加固区域逐步向上部土体扩散,其中中部土体加固效果较强;探究了填筑体内部的加固规律以及超声波速技术用于评价加固效果的可行性;(3)利用超声波检测技术,采用"正面提供权重,侧面提供波速"的方法对各测点的波速进行推算,得到填筑体的波速值云图,进一步揭示了填筑体内部密实度的变化规律。研究结论可为微生物加固填筑体的效果分析提供借鉴与依据。

There are few studies about using non-destructive testing technology to evaluate the reinforcement effect of microbial cementation presently.This paper is based on the determination of best microbial grouting period and grouting rate,and uses a self-design multi-layer porous microbial grouting pipeline system to carry out indoor model test of microbial grouting in shale residual soil.Effectiveness of reinforcement is evaluated with ultrasonic testing technology.The results show that:(1)The ultrasonic velocity of residual soil fillings increases obviously after microbial grouting with multi-layer porous grouting pipeline system,which proves that multi-layer porous grouting pipeline system performs well during the grouting.(2)The wave velocities and wave velocities increments of the cements are symmetrical.The reinforcement effect of the soil in the middle of the fillings is remarkable,which provides preliminary law about the process of microbial grouting with multi-layer porous grouting pipeline system in shale residual.(3)The strategy that“the side wave velocity value determines the total value while the front wave velocity value determines the proportion of each measuring point”is taken to calculate the velocity of each measuring point,which further reveals the process of reinforcement insides the fillings through cloud chart of wave velocity value of fillings.The research conclusions can provide reference and basis for the effect analysis of microbial reinforcement.