岩土力学2024，Vol.45Issue(7)：2037-2049,13.DOI:10.16285/j.rsm.2023.1123
酶诱导碳酸钙沉淀技术加固TBM壁后吹填豆砾石最优配比试验及机制研究
Study on the mechanism and optimal proportioning test of pea gravel backfill behind TBM tunnel linings reinforced with enzyme-induced calcium carbonate precipitation(EICP)technology
摘要
Abstract
In tunnel boring machine(TBM)tunnels,the pea gravel as a filling layer between the tunnel lining segments and surrounding rock is of significant importance for the load-bearing capacity and impermeability of the segments.Due to the poor flowability of cement slurry,it fails to adequately fill the backfill layer,resulting in defects such as voids behind the walls and inadequate grouting.Enzyme-induced calcium carbonate precipitation technology(EICP)has emerged as an environmentally friendly and efficient reinforcement method.The grouting material is liquid,exhibiting excellent fluidity and diffusivity,making it a promising solution for grouting in pea gravel backfill layers.To optimize the effectiveness of EICP grouting in pea gravel,an attempt was made to use standard sand and pea gravel as backfill aggregates.In order to quantitatively analyze the optimal mixing ratio,experiments were conducted with different ratios of pea gravel to sand(0.5,0.75,1.0,1.25,1.5)and varying grouting frequencies(9,12,15 times)in sand column solidification tests.Through unconfined compressive strength tests,permeability tests,determination of calcium carbonate content,ultrasonic velocity measurements,and scanning electron microscopy(SEM)microscopic analysis,the impact of different ratios of pea gravel to sand on the solidification effectiveness of EICP was analyzed from both macro and micro perspectives.The results indicate that the optimal ratio for EICP reinforcement of mixed pea gravel and sand is 1∶1.5.After 15 grouting cycles,the uniaxial compressive strength of the specimens can reach up to 4.55 MPa,and the permeability coefficient is 1.72×10-5 m/s.Samples with a higher sand content exhibit a notable phenomenon where interparticle voids are readily filled and compacted by calcium carbonate crystals.This process results in a higher proportion of effective bonding among calcium carbonate crystals,consequently contributing to an elevated unconfined compressive strength of the stone body.The findings of this study can provide a theoretical basis for the engineering application of EICP technology in reinforcing TBM backfilled pea gravel.关键词
酶诱导碳酸钙沉淀技术(EICP)/隧道掘进机/豆砾石/无侧限抗压强度/渗透性/微观机制Key words
enzyme-induced calcium carbonate deposition(EICP)/tunnel boring machine/pea gravel/unconfined compressive strength/permeability/microscopic mechanism分类
交通工程引用本文复制引用
姜启武,黄明,崔明娟,靳贵晓,彭仪欣..酶诱导碳酸钙沉淀技术加固TBM壁后吹填豆砾石最优配比试验及机制研究[J].岩土力学,2024,45(7):2037-2049,13.基金项目
国家自然科学基金(No.41972276,No.52108307) （No.41972276,No.52108307）
福建省自然科学基金(No.2020J06013) （No.2020J06013）
福建省"雏鹰计划"青年拔尖人才项目(No.00387088) （No.00387088）
福州大学"旗山学者"项目(No.XRC-22015).This work was supported by the National Natural Science Foundation of China(41972276,52108307),the Natural Science Foundation of Fujian Province(2020J06013),the Foal Eagle Program"Youth Top-notch Talent Project of Fujian Province,China(00387088)and Qishan Scholar Project of Fuzhou University(XRC-22015). （No.XRC-22015）
