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- Title
水泥 / 粉煤灰碱改性对废弃粉质土砂配制 盾构壁后注浆性能的影响.
- Authors
梁玉强; 张雷; 李德; 江苏禹; 王登峰; 袁锐
- Abstract
The complex mineral composition and high mud content of abandoned silty soil sand in shields can easily lead to incomplete hydration and agglomeration, resulting in deterioration of the grouting performance. However, the use of abandoned silty soil sand to prepare back-filled grouting, the proportion of replacement commercial sand can only be around 30% ~ 40% to meet the site and general index requirements. Based on the actual engineering site, a wall grouting experiment was carried out by partially replacing commercial sand (60% ) with high content of abandoned silty soil sand, and the effect of cement and fly ash alkali modification strategies on the performance of post-wall injection grouting with high-mix abandoned silty soil sand was analysised. The results show that when the replacement proportion of modified cement does not exceed 50%, it has a positive effect on the back-filled grouting of abandoned silty soil sand, which can shorten the setting time and reduce the water secretion rate while still making the flow and compressive strength conform to the general index. Modified fly ash has a smaller effect on the grouting compared to modified cement, but it can still effectively shorten the setting time and water secretion rate. The reason for this is that the alkaline modification of the cement accelerates the hydration reaction of the cement, which in turn reduces the setting time of the grouting and has an effect on the water consumption, which in turn affects the flow and consistency of the grouting; whereas the fly ash modification destroys the originally ordered glass phase structure of mullite and quartz in the fly ash, although the later generation of C-A-S-H ( calcium silicate aluminate hydrate) has an effect on the mechanical properties. Although the C-A-S-H ( hydrated calcium silicate) produced at a later stage has a certain effect on the mechanical properties, it can still optimise the setting process and water consumption of the grouting due to the conversion of fly ash into zeolite-like material.
- Publication
Science Technology & Engineering, 2023, Vol 23, Issue 35, p15171
- ISSN
1671-1815
- Publication type
Article