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| Eexperimental study of the bearing capacity of existing pile foundation in silty clay stratum promoted by pile side grouting |
| ZHOU Yong1, LI Zhaofeng2, ZUO Zhiwu1, WANG Chuan1,2, WANG Yuxin2, LIN Chunjin2, ZHANG Xin3, ZHANG Qianqing2, YAO Wang3, WANG Kai3
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1. Shandong High Speed Group Co., Ltd., Jinan 250101, Shandong, China;
2. Geotechnical and Structural Engineering Research Center, Shandong University, Jinan 250061, Shandong, China;
3. Shangdong Hi-speed Company Limited, Jinan 250014, Shandong, China
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Abstract Aiming at the problem of insufficient bearing capacity of existing pile foundation in silty clay stratum, the effect of improving bearing capacity of existing pile foundation by side grouting was studied systematically through grouting simulation experiment. The reinforcement mechanism was mainly through the compaction effect of grouting material on the soil around the pile, increasing the friction resistance of the pile-soil interface, restricting the settlement of the pile body, and improving the bearing capacity of the pile foundation. The results showed that the grouting water cement ratio, grouting pressure, grouting hole layout position and grouting amount were the four main controlling factors for the reinforcement effect of pile foundation. The combined action of slurry water-cement ratio and grouting pressure directly affected the compaction effect of slurry on silty clay stratum by controlling the shape of slurry veins. According to the different compaction effects, the combination of different water cement ratio and grouting pressure was divided into three reinforcement design areas: strong, medium and weak. Among them, the compacted soil with a slurry water-cement ratio of 0.8 and a grouting pressure of 2 MPa improved the physical and mechanical strength to the greatest extent. The increase of the bearing capacity of pile foundation was positively correlated with the amount of grouting, and inversely proportional to the distance between the formation position of grouting vein and the pile body. According to the different distance between the formation position of grouting vein and the pile body, the soil reinforced by grouting was divided into the strong action area and the weak action area. In addition, the improvement of lateral friction resistance of pile side grouting was mainly generated in the middle and lower section of pile body. In practical engineering, the reinforcement of this section reduced the consumption of manpower and material resources.
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Received: 10 February 2022
Published: 20 March 2022
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