Experimental study of the improvement of surrounding soils due to the grouting with a geotextile

In an anchor support system, once the soil strength is improved by grouting with a geotextile, the pull-out force of anchors increases. To investigate the improvement of surrounding soils due to the grouting with a geotextile, a series of filtration and penetration tests under various parameters such as different initial degrees of compaction, water content and soil types were conducted via a self-developed device. In addition, microscopic tests were then carried out to obtain the soil's structure before and after grouting. The main conclusions are as follows: (1) The strength of surrounding soils is improved by grouting with a geotextile through the compaction effect and the slurry infiltration, while its strengthening effect gradually declines with the increase in the initial degree of compaction. (2) As the initial water content increases, the strengthening effect derived from the compaction effect and the cohesive substances infiltration decreases, while this improved efficiency of the soil strength declines due to the water infiltration during grouting. (3) Although the effect of grouting with a geotextile on different soils is obviously different due to the different efficiency of slurry (i.e., water and cohesive substances) infiltration, it can improve the soil strength regardless of soil type, especially for sandy soils. (4) Under the filtration of geotextile, a hardened layer is formed at the grout-soil interface due to the accumulation of cohesive substances, which is beneficial to the performance improvement in applications such as the capsule-type anchor.

Automated summary

By grouting with a geotextile in an anchor support system, the strength of surrounding soils can be improved, leading to an increase in pull-out force of anchors. A series of filtration and penetration tests were conducted to investigate the improvement of surrounding soils, and microscopic tests were carried out to observe the soil structure before and after grouting. The main conclusions are: (1) The strength of surrounding soils is improved through compaction and slurry infiltration, but the improvement decreases with increased initial degree of compaction. (2) Increasing initial water content reduces the improvement in soil strength due to decreased compaction effect and cohesive substances infiltration, and the infiltrated water during grouting also negatively affects the soil strength improvement. (3) Grouting with a geotextile can improve soil strength regardless of soil type, especially for sandy soils, although the efficiency of slurry infiltration varies. (4) The filtration of geotextile forms a hardened layer at the grout-soil interface, which is beneficial for applications such as capsule-type anchors.