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| Engineering technology of framed anti-slide retaining structure crossing ancient landslide |
| CHEN Weizhi1，2，LI Anhong1，HU Huixing1，LIU Kaiwen2 |
| (1. China Railway Eryuan Engineering Group Co.，Ltd.，Chengdu，Sichuan 610031，China；2. School of Civil Engineering，
Southwest Jiaotong University，Chengdu，Sichuan 610031，China) |
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Abstract It becomes extremely easy to revitalize ancient landslides and increases the risks of engineering when excavation engineering crosses the ancient landslides. To meet the technical requirements for stability control of railway cuttings crossing huge ancient landslides，taking the framed anti-slide retaining structures(FARSs) as study object，the internal force calculation method of FARS was derived based on several calculation assumptions. Combined with the construction of an excavation engineering crossing the huge ancient landslide of Lindai—Zhijin railway，theoretical calculations，numerical simulation，construction method and filed test were carried out to reveal the internal force and displacement response characteristics of FARSs，the design method and construction technology of FARS were also proposed. The results：(1) The theoretical calculation results of the internal force of FARS were close to the results obtained from numerical simulation and filed test. The extreme values of bending moment and shear force were mainly located at the junction between piles and beams. These junctions were the key nodes for local strengthening of FARS. (2) It suggests that the front pile, the back pile and beam should be strengthened with the shear design when FARSs were applied to double–track railway，but secondary beam should be strengthened with the bending design. The internal forces of the front pile，back pile and beam were less affected by the operation speed，and the internal forces of the secondary beam increased slightly with the increase of operation speed. (3) The beams and secondary beams played a coordinated role in the deformation of front pile and back pile. The maximum lateral displacement of the front pile and back pile was less than 6.0mm under the landslide thrust，and FARS had good seismic performance in earthquake areas of nine degrees magnitudes and below(where the peak acceleration varying from 0.05 g to 0.4 g). (4) To build FARSs in an ancient landslide，the construction process should be from front to back，from top to bottom，alternate between piles，the construction technology should be sequential construction of front pile and back pile，partial cuts are reserved for connecting steel bars for beams，secondary beams and piles，back piles and beams are integrally poured. The results can be used a technical support to guide the subgrade construction and geological disaster prevention of Sichuan–Tibet railway，which is the representative railway in the complex and dangerous mountain areas.
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2021, Vol. 40 
