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| Research on the Reinforcement Effect of Cement-soil Mixing Pile on Collapsible Loess Foundation |
| JIA Jianqing1, ZHAO Yangyang2, JIA Chao3, XIN Chengping1, ZHANG Bangxin1 |
1. Lanzhou Jiaotong University, Lanzhou, Gansu 730000, China;
2. China Railway Third Bureau Group Sixth Engineering Co. Ltd, Jinzhong, Shanxi 030600, China;
3. Guangdong Shengxiang Traffic Engineering Testing Co. Ltd, Guangzhou, Guangdong 511400, China |
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Abstract Research purposes: To determine the reinforcement effect of cement-soil mixing pile on collapsible loess foundation, taking one section located at Taiyuan-Jiaozuo high speed railway engineering as an example, firstly, physical and mechanical properties of the loess were tested, the collapsibility indexes and grades were determined, and mechanical characteristics and change law were also analyzed. Then the reinforcement plans and the parameters of tested piles were designed, and the pile quality was tested by core pulling test. Thirdly, the characteristic value of bearing capacity of composite foundation reinforced by cement-soil mixing pile with different parameters were all studied using bearing capacity test of composite foundation as well as numerical simulation method. Finally, the test subgrade was paved on the foundation reinforced by cement-soil mixing pile, and the settlement laws were determined by means of field monitoring, theoretical calculation and numerical simulation.
Research conclusions: (1) The quality of the three kinds of water-cement ratio test piles was great and the unconfined extrusion strength was 1.6 MPa, 1.8 MPa and 2.0 MPa respectively which were larger than 1.0 MPa, and the water-cement ratio in this foundation construction is 0.5. (2) The characteristic value of bearing capacity of single pile composite foundation from field monitoring was 261~266 kPa, and they were 282.87 kPa and 209 kPa respectively obtained from theoretical calculation and numerical simulation. (3) The field monitoring subsidence, theoretical calculation subsidence and numerical simulation subsidence were 21.17 mm, 31.25 mm and 26.14 mm, respectively. All of these indicated that the strength of composite foundation could meet requirement of engineering design. (4) The research results can provide reference for the design of reinforcement scheme on soft foundation of high speed railway.
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Received: 20 August 2021
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2022, Vol. 39 
