Laboratory investigation of the performance of two-component grout behind the segment in sandy soils below the water table level
DOI:
https://doi.org/10.17794/rgn.2025.4.12Keywords:
mechanized excavation, washout, brush, two-component grout, injection pressureAbstract
The increasing use of TBMs in urban areas has heightened the significance of grouting behind tunnel segments. A key aspect of mechanized tunnelling is the application of grout for injection behind the tunnel segments (support system) to prevent ground settlement. This study aims to investigate the extent of two-component grout washout behind the segments and also simulates the presence of water flow in laboratory tests, which distinguishes it from other studies. Issues such as groundwater seepage and grout washout behind the segments—particularly when there are failures in the brush (caused by factors like reduced tail thickness from friction with the segment ring, misalignment in the shield from improper assembly, or damage to articulation jacks)—can lead to incomplete filling of the space and cause surface settlements. As a result, selecting an appropriate grout mixing design under these conditions is critical. A study was conducted to assess the injection of two-component grout with varying amounts of bentonite and sodium silicate. Different injection pressures and water conditions were simulated to evaluate grout penetration in coarse-grained soils. The grout injection tests at pressures of 1 and 2 bars showed that increasing the bentonite and sodium silicate in the grout mix not only reduces penetration into the soil but also helps prevent washout due to water flow. It is important to note that sodium silicate has a greater effect on this process than bentonite.
Downloads
Published
Issue
Section
License
Copyright (c) 2025 Samaneh Khodaei, Erfan Khoshzaher, Hamid Chakeri, Shahla Miri Darmarani
This work is licensed under a Creative Commons Attribution 4.0 International License.
Creative Commons-BY
Authors who publish with this journal agree to the following terms:
In agreeing this form, you certify that:
- You read the ethical codex of the RGN zbornik available at journal web.
- You submitted work is your original work, and has not previously been published and does not include any form of plagiarism.
- You own copyright in the submitted work, and are therefore permitted to assign the licence to publish to RGN zbornik.
- Your submitted work contains no violation of any existing copyright or other third party right or any material of an obscene, libellous or otherwise unlawful nature.
- You have obtained permission for and acknowledged the source of any illustrations, diagrams or other material included in the work of which you are not the copyright owner.
- You have taken due care to ensure the accuracy of the work, and that, to the best of your knowledge, there are no false statements made within it.
- All co-authors of this submitted work are aware of, and in agreement with, the terms of this licence and that the submitted manuscript has been approved by these authors.
Publication licence
You retain copyright in your submitted work, according to journal license policy (CC-BY). By signing this form you agree that RGN zbornik may publish it under the publication licence. In summary the licence allows the following:
Anyone is free:
- To copy, distribute, display, and perform the work.
- To make derivative works.
Under the following conditions:
- The original author must always be given credit.
- The work may not be used for commercial purposes.
- If the work is altered, transformed, or built upon, the resulting work may only be distributed under a licence identical to this one.
Exceptions to the licence
In addition to publishing the work printed under the above licence, RGN zbornik will also enable the work to be visible online.
The journal editorial can change the licence rules anytime but it cannot retroactively restrict author(s) rights.
