| Since the implementation of west development strategy, many large-scale infrastructureprojects are under construction, and the large and super-large loess landslide increasing dayby day. Due to this kind of landslide are complex, serious and expensive to treat, the study onthe optimization of design is not enough a lot. So it is not only necessary but also urgent tocarry out the study of optimization of large and super-large landslide treatment design. Thepaper takes Dalu Ditch super-large loess landslide for example, on the basis of the analysis oflandslide engineering geological condition, deformation and failure characteristics,influencing factors, formation mechanism, the treatment scheme selection and structuredesign optimization are carried out, also provides a complete method of the optimization oflandslide treatment design. The main research contents and achievements of this thesis are asfollows:1. By collecting the historical and existing geological engineering data, and combining avariety of survey techniques with the engineering geologic analogy method, based onqualitative analysis, that the landslide is the new landslide revival of an old one, that aretensile crack-type creep formation mechanism which shows up as the pushing deformation inthe bottom, beding sliding in the middle and tensile crack occurred in the top.2. Based on the results of laboratory and in-situ shear test, the parameters needed in thelandslide stability calculation are determined, with the help of Slope/W module in GeoStudio,using the SPENCER method, the paper calculates the stability coefficient of five sections inthree conditions, which the F_s∈[0.927,1.111] and F∈[744.8,2603.5]kN/m, and indicates thatthe landslide has a poor stability and a large thrust.3. Taking Dalu Ditch landslide for example, in view of the characteristics of large and super-large loess landslide, the paper proposes the basic treatment principles and commontreatment measures, and puts forward three kinds of treatment schemes, using FAHP methodin the respects of stability, feasibility and economy, decides the optimal scheme, finally thepaper gives an order of the schemes base on the principle of maximum degree of membership,backfilling+A-type anti-slide piles+B-type anti-slide piles+drainage+slope protection isoptimal.4. Using the cantilever piles method to calculate the A, B piles’ internal force of theoptimal scheme. With the help of software, using finite element method, the distribution oflandslide thrust and size behind the piles are verified, and after combining the results of pilebending moment, shear force distribution calculated by cantilever piles method with the finiteelement method, we found that the differences are little. So the thesis argues that the finiteelement method can play a positive role of supplement and verification in the progress ofscheme details optimal design.5. The stress and strain distribution regularity of before and after setting piles arecompared by the finite element method, we found that the piles can effectively reduce thelandslide displacement and plastic strain, and change the stress distribution of stress in theslope, stabilize the landslide efficiently, on this basis, we complete the optimization of DaluDitch landslide treatment design after the reinforcement of A, B piles are calculated.6. The thesis offers a whole idea of landslide treatment optimization; including themacroscopic schemes quantitative optimization, and the microscopic schemes detailoptimization. In addition, the paper also demonstrates the feasible of FEM using in theanti-slide piles calculation, the simulation results can validate and renew the results of beamson elastic foundations theory.The results have a certain reference value for the treatment of large and super-large loesslandslide in the western region. |
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