Engineering practice of surface grouting treatment through soft surrounding rock stratum by TBM
Xiaochen WangGuo YanxvWeiwei HanYanan LiuHonglu YangKexian LiGuangxuan ZhuJian Ping ChenYishan WeiBaozhi Li
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Abstract:
When the TBM passes through the weak and broken strata, it is easy to get stuck and be buried. Through the advance pre grouting engineering practice of TBM crossing fault zone in Qingdao area, the pre grouting reinforcement measures for preventing the occurrence of TBM card machine are explored, including grouting pressure, grouting drilling design, grouting material and other key parameters. The research results show that the surface pre grouting method is an effective grouting measure to prevent the occurrence of TBM stuck and buried accidents. Single cement slurry and C-S double slurry are used as grouting materials. The cement slurry is used to fill the void in soft broken stratum and C-S double slurry is used to improve the controllability of slurry diffusion. In the process of advanced pre-grouting construction on the ground surface, the application of progressive segmental grouting technology and membrane bag sealing grouting technology can effectively guarantee the strengthening range of soft ground and improve the effect of grouting reinforcement.Keywords:
Stratum
Grout
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This paper documents the findings from a research study that investigated the effects of grout mix design and grout placement method on the integrity of soil nails. The experimental plan included two separate series of tests. The first test series involved installation of fifteen soil nails, each 6.1m (20ft) in length, under simulated conditions. In these tests, steel tendons were placed inside six inch diameter PVC tubes that were split along the length, inside surface roughened and reassembled. The PVC tubes were then grouted using different grout placement methods and grout mixtures with varying consistency. The second test series involved thirty two actual soil nails that were installed on a 2.0m (6.5ft) tall vertical cut at approximate spacing of 1.2m (4 ft). The actual condition of the soil nails were observed at the conclusion of the study by exhuming the soil nails. The findings from this research found that proper installation of grout material can only be achieved when the grout is placed using a grout tube that extends the full length of the soil nail. Additionally, this study showed that grout consistency is an important variable that require careful control.
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