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Study on Grout Test for Wall Grouting of the Shield Built of Waste Silty Soil and Sand with High Silt Content
(1. China Design Group Co., Ltd., Nanjing 210014; 2. Transportation Industry R&D Center for Underwater Tunnel Intelligent Design,Construction and Maintenance Technologies and Equipment, Nanjing 210014; 3. School of Civil Engineering and Transportation, Hohai University, Nanjing 210024; 4. College of Mechanics and Materials, Hohai University, Nanjing 211100)
Abstract During slurry shield construction, a large quantity of waste mud and sand will be generated inevitably, and improper disposal of such material will impose negative impacts on the environment and also cause a waste of resources. In the Jiangyin Jingjiang Yangtze River Tunnel Project, waste silty soil and sand are used to replace commercial mortar in various proportions to prepare the grout used for wall grouting, so as to investigate how replacement ratios will affect the grout performance, and the phase composition and microstructure are analyzed in order to analyze how waste silty soil and sand will affect the grout performance. As the results suggest, addition of waste silty soil and sand will shorten the setting time of grout and enhance the stability of grout, but will cause the fluidity and early age strength of grout to decrease by a small extent. However, the grout performance can still meet the engineering requirements; when the replacement ratio is 40%, the grout fluidity is 26.8 cm, the setting time 11.5 h and bleeding rate 3.4%, which meet the grouting requirements, so this replacement ratio is the optimum value; after addition of waste silty soil and sand, the fly ash in the grout that does not completely participate in the reaction increases, the content of the reticular C-S-H (hydrated calcium silicate) gel decreases, and the extent of hydration reaction decreases.
Abstract：
During slurry shield construction, a large quantity of waste mud and sand will be generated inevitably, and improper disposal of such material will impose negative impacts on the environment and also cause a waste of resources. In the Jiangyin Jingjiang Yangtze River Tunnel Project, waste silty soil and sand are used to replace commercial mortar in various proportions to prepare the grout used for wall grouting, so as to investigate how replacement ratios will affect the grout performance, and the phase composition and microstructure are analyzed in order to analyze how waste silty soil and sand will affect the grout performance. As the results suggest, addition of waste silty soil and sand will shorten the setting time of grout and enhance the stability of grout, but will cause the fluidity and early age strength of grout to decrease by a small extent. However, the grout performance can still meet the engineering requirements; when the replacement ratio is 40%, the grout fluidity is 26.8 cm, the setting time 11.5 h and bleeding rate 3.4%, which meet the grouting requirements, so this replacement ratio is the optimum value; after addition of waste silty soil and sand, the fly ash in the grout that does not completely participate in the reaction increases, the content of the reticular C-S-H (hydrated calcium silicate) gel decreases, and the extent of hydration reaction decreases.
FANG Zhongqiang1,
2 YUAN Rui3 SUN Tongli1,
2 WANG Dengfeng3 JIANG Suyu4
.Study on Grout Test for Wall Grouting of the Shield Built of Waste Silty Soil and Sand with High Silt Content[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(3): 182-188
2023, Vol. 60 