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Abstract In allusion to the Wenzhou typical soft soil properties，combined with pedestrian subway channel engineering in Wenzhou No.2 subsidiary hospital，taking advantage of ordinary cement-sodium silicate double liquid，superfine cement-sodium silicate double liquid and specially made sulphoaluminate cement paste three kinds of soil improvement grouting materials，i. e. a series of indoor laboratory tests and field injectivity tests are carried out. The results show that compasion of superfine cement with the same quantity of the general cement，they have the same intensity，the superfine cement gelation time is long and it is vulnerable to be diluted by the ground water. Compared with the general cement，the superfine cement cost is about 3 times higher，so it is suggested that general cement instead of the superfine cement grouting materials to reinforce silty horizon. The in-situ experiment shows that the grout diffusion radius and compressive strength increases with the increase of grouting pressure under the same grouting time；grout diffusion radius increases with the increase of grouting speed under the same grouting pressure，but the growth trend slows down with the increase of injection rate，. Moreover，the key parameters of grouting have been ascertained and confirmed in practice，the grout diffusion radius is 1.0–3.0 m，the terminate pressure in grouting is 1.0–1.5 MPa，the reinforced depth of grouting is 4–5 m. After grouting，analysis method and sampling method after excavation are inducted to inspect the grouting effect，the results indicate that the grouting effect is in accord with the design construction requirements. The successful application of the grouting project has very good reference and broad application prospect for underground reinforcement engineering in Wenzhou region and Yangtze river delta with rich deep weak silty soil.
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Received: 23 April 2012
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2013, Vol. 32 
