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| Calculation of reinforcement effect of fracturing-compaction grouting in soft strata |
| ZHANG Lianzhen1，2，LIU Rentai2，ZHANG Qingsong2，LI Shucai2 |
(1. College of Pipeline and Civil Engineering，China University of Petroleum，Qingdao，Shandong 266580，China；
2. Research Center of Geotechnical and Structural Engineering，Shandong University，Jinan，Shandong 250061，China) |
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Abstract Quantitative calculation of grouting reinforcement effect is essential for grouting design. A new method to accurately compute grouting reinforcement effect was proposed for fracturing-compaction grouting in soft strata. The simplified model of grouting reinforcement effect was established based on the reinforcement mechanism of grouting. The characteristics of grouted body such as anisotropy and spatial distribution were studied. The effect of related factors on grouting reinforcement was also be analysed. Results show that the grouted body is markedly anisotropic. The grouted body in the direction parallel to grout vein has higher stiffness，higher permeability but lower shear strength than in the direction perpendicular to the grout vein. The cohesive strength and permeability coefficient of grouted body in the direction parallel to grout vein are two aspects of weakness of grouted body. In the grouted region，the modulus of compressibility and cohesive strength decrease linearly along the extension direction of grouted vein. The performance of grouted body is positively related with grouting pressure，and negatively related with the distance of separation between the injection holes. The more grout injected in a hole results in a better performance of grouted body around injection hole. The proposed calculation method was used in grouting design for reinforcing the sand layer in Qingdao metro line 2 and its effectiveness was confirmed.
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2018, Vol. 37 
