Effect Evaluation Method And Optimization Design Of Anti-slide Piles In Slope Engneering

The anti-slide pile, which has been widely used in slope engineering, is one of the major engineering measures in the treatment of landslide. However, the design of piles still exist many problems, and the result of the design still has some uncertainties, especially the design of double row piles is more immature. In view of these problems, by means of a series of research methods, like site geologic survry, in-site monitoring and numerical analysis, studied the mechanism of anti-slide piles, and Put forward a method of quantitative evaluation of the effectiveness of anti-slide pile, and studied the reasonable value of the cross-section size and distance of anti-slide piles. In addition, studied the influence of the piles top connection way and the piles row distance to internal forces distribution of the double-row piles, and put forward some suggestions on selecting the reasonable piles top connection way and piles rowdistance. The main research contents are as follows:(1) The existence condition and action sphere of soil arching effect were analyzed. The development rules of soil arching effect between the rectangular section piles were systematically studied. The influencing factors of soil arching effects were summarized. It revealed the rules of pile-soil interaction around piles.(2) Put forward the evaluating methods of the safety of anti-slide Piles.The conception of safety degree and operating state was put forward. The internal forces and landslide thrust were estimated by bank analysis based on the monitoring data.(3) Based on the soil arching theory. the calculation formulas of the cross-section size and distance of anti-slide piles were deduced from the mechanical equilibrium equation and the strength condition of soil arching. The reasonable values of cross-section size and distance of piles were discussed.(4) The types of piles top connection ways were summarized in the design of double-row piles at present. Analyzed the effect of piles top connection way on the internal forces and lateral displacement of the fore-and-aft row piles.The optimal piles top connection way was found.(5) The piles row distance of double-row piles was systematically studied. The influence of the piles row distance and the connecting beam to the internal forces of the double-row piles was studied. The distribution of the landslide thrust on double-row piles was discussed.And the the dissertation's main innovative results are as follows:(1) Given two methods to calculate the distribution of internal forces of anti-slide piles. The one is by the monitoring data of the lateral displacement and reinforced stress to deduce the internal forces distribution, the other is directly by the monitoring data of the lateral displacement. As to the last one, based on the inclinometer data, the function of pile lateral displacement could be deduced from least-squares curve fitting by orthogonal polynomials, and then according to Euler-Bernoulli beam theory internal force distribution the internal forces distribution of anti-slide piles could be calculated from the displacement function.(2) Put forward the quantitative evaluation method of anti sliding property of anti-slide piles. The safety degree and operating state were used to evaluate anti sliding property of anti-slide piles. The operating state can be deduced from in-site monitoring data.(3) The calculation model of the cross-section size and distance of anti-slide piles was established.A method of comprehensively determining the cross-section sizeand distance was put forward.(4) The effect of piles top connection way on the internal forces and lateral displacement of the fore-and-aft row piles was systematically studied. It reveals that the front-and-bank rows connection is most reasonable.(5) The influence of the piles row distance to the internal forces of the double pile was systematically studied. The calculation method of the distribution of landslide thrust on the fore-and-aft row piles was established.The reasonable value of piles row distance was put forward.