| The natural environment and geological condition in southwest China is complex, somespecial engineering problems often appear in infrastructure construction, such as the treatmentof high fill slope (landslide) in mountain area. The failure mechanism of high fill slope(landslide) is much more complex than ordinary slope (landslide); the disaster has thecharacteristics of huge volume, sudden, serious consequence and so on. These factors lead tothe result that the most unfavorable condition of slope and combined retaining structure in theprocess of treatment is not exactly the same with the original design, so this paper takes thetreatment engineering of high fill slope of an southwest airport after sliding failure as basis,through field investigation and analysis, week links of construction management that havegreat influence on the stability of slope and force bearing of retaining structure are acquired:namely prestress stretching of anti-slide pile with anchor cable, replacement of the soilbetween piles, compaction degree of reinforced high fill body, and stability of slope and forcebearing of retaining structure are studied from these three aspects, and the results of numericalsimulation are compared and verified with the monitoring data.Research contents and achievements are as follows:(1) Through field investigation, exploration and geological analysis, factors thatinfluence the formation of landslide are obtained, which include the strata, water, geologicalstructure, filling body and so on. Through the analysis of field monitoring data, it is obtainedthat the treatment of this landslide has characteristic of shallow sliding and the combinedretaining structure can ensure the stability of shallow sliding.(2) Through the numerical simulation of the finite element software MIDAS/GTS, it isconcluded that small tension of the pre-stressed anchor cable provides relative small negativemoment for anti-slide pile, which cannot effectively resist the lateral pressure of soil behindthe pile, the pile body directly bears the soil thrust, and with the increase of soil layers,positive moment of anti-slide pile becomes larger, as well as the lateral pressure of filling soil,the bending condition of pile is not reasonable. At the same time, when the tension is small,displacement of front high cantilever pile becomes bigger, and stability of slope becomeslower.(3) Through the numerical simulation analysis, it is obtained that the excavation andreplacement of soil between piles only have a slight influence on the displacement and forcebearing of anti-slide pile, which doesn’t have an obvious contribution to the treatment ofslope engineering, stability safety coefficient of the slope almost has no change and maintainsaround1.308. (4) Through the numerical simulation analysis, it can be obtained that the stability safetycoefficient of anti-slide piles under low degree of compaction is obviously smaller than thatunder reasonable degree compaction, when K equals0.95, safety coefficient Fsequals1.3082,when K equals0.90,safety coefficient Fsequals1.2125, and when K equals0.85, safetycoefficient Fsequals1.0934, with the decrease of degree of compaction, the slope tends to beunstable, so the factor that has serious influence on the treatment effects of the whole slope isthe degree of compaction of filling body with reinforced soil at the top of pile.(5) Through the results of numerical simulation, it is obtained that when using retainingstructure to reinforce slope, peak value of the internal force of retaining structure occurs nearthe strata where physical parameters abruptly change, and this phenomenon is most obvious atthe interface between poor soil and bedrock, so the strength of materials of related part of thestructure should be improved first in actual construction.(6) Through the comparison of displacement of pile top and slope which respectivelyobtained from field monitoring and numerical simulation, the correctness of numericalsimulation is acquired. |
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