Study on novel alkali-activated cementitious grout for scour control of offshore foundation

IF 3.3 2区工程技术 Q3 ENERGY & FUELS Geomechanics for Energy and the Environment Pub Date : 2025-03-11 DOI:10.1016/j.gete.2025.100663

Fei Sha , Yulong Dong , Shijiu Gu , Xiaochen Fan , Wenwen Xiao

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Abstract

To address scour hazards surrounding offshore foundations, a new method employing novel alkali-activated cementitious grout (AACG) has been proposed for improvement of seabed soil. Ground granulated blast-furnace slag (GGBFS) was replaced by fly ash (FA), steel slag (SS) or FA + SS to prepare precursors, the replacement amounts were 10 %, 20 %, 30 % and 40 %. Fresh-state and mechanical properties, minerals and microstructures were investigated. A novel scour simulation test device was developed to simulate engineering conditions of scour and remediation. Flow-soil coupled scour resistance tests were conducted, shear tests and SEM measurements of solidified soil were carried out. The results showed that the optimal ratio of GGBFS:FA:SS was 6:2:2 for AACG. The optimized AACG has better fluidity and lower brittleness, and its 28 d unconfined compressive strength (UCS) achieves 13.5 MPa. For AACG solidified soil, the maximum scour depth was reduced by 33.3 % and the maximum sediment transport amount was decreased by 53.2 %, which were compared to those of cement - sodium silicate (C-S) double slurry. Moreover, the increase degrees of internal friction angle, cohesion and critical shear stress were 700 %, 7.9 % and 786 %, respectively. The scour resistance of AACG solidified soil was superior. The inherent relationship between UCS and critical shear stress was discussed. UCS can be used to rapidly assess the scour resistance of consolidated soil. This study introduced an eco-friendly AACG as an innovative stabilizer for soil reinforcement around offshore structural foundations, offering significant application and environmental values for scour control.

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为解决近海地基周围的冲刷危险，有人提出了一种采用新型碱活性水泥基灌浆料（AACG）的新方法来改良海底土壤。用粉煤灰（FA）、钢渣（SS）或 FA + SS 取代磨细高炉矿渣（GGBFS）来制备前驱体，取代量分别为 10%、20%、30% 和 40%。对新鲜状态和机械性能、矿物和微观结构进行了研究。开发了一种新型冲刷模拟试验装置，用于模拟冲刷和修复的工程条件。进行了流动-土壤耦合抗冲刷试验，并对固化土壤进行了剪切试验和扫描电镜测量。结果表明，对于 AACG 而言，GGBFS:FA:SS 的最佳比例为 6:2:2。优化后的 AACG 具有更好的流动性和更低的脆性，其 28 d 的无侧限抗压强度（UCS）达到 13.5 MPa。与水泥-硅酸钠（C-S）双水泥浆相比，AACG 固化土的最大冲刷深度减少了 33.3%，最大泥沙输移量减少了 53.2%。此外，内摩擦角、内聚力和临界剪应力分别增加了 700%、7.9% 和 786%。AACG 固化土的抗冲刷性更优越。讨论了 UCS 与临界剪应力之间的内在关系。UCS 可用于快速评估固结土的抗冲刷性。这项研究介绍了一种生态友好型 AACG，作为一种创新的稳定剂用于近海结构地基周围的土壤加固，在冲刷控制方面具有重要的应用价值和环境价值。

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来源期刊

Geomechanics for Energy and the Environment Earth and Planetary Sciences-Geotechnical Engineering and Engineering Geology

CiteScore

5.90

自引率

11.80%

发文量

期刊介绍： The aim of the Journal is to publish research results of the highest quality and of lasting importance on the subject of geomechanics, with the focus on applications to geological energy production and storage, and the interaction of soils and rocks with the natural and engineered environment. Special attention is given to concepts and developments of new energy geotechnologies that comprise intrinsic mechanisms protecting the environment against a potential engineering induced damage, hence warranting sustainable usage of energy resources. The scope of the journal is broad, including fundamental concepts in geomechanics and mechanics of porous media, the experiments and analysis of novel phenomena and applications. Of special interest are issues resulting from coupling of particular physics, chemistry and biology of external forcings, as well as of pore fluid/gas and minerals to the solid mechanics of the medium skeleton and pore fluid mechanics. The multi-scale and inter-scale interactions between the phenomena and the behavior representations are also of particular interest. Contributions to general theoretical approach to these issues, but of potential reference to geomechanics in its context of energy and the environment are also most welcome.