Internal Force And Deformation Characteristics Of Double Row Anti-slide Pile And Anchor Frame Structure In Expansive Soil Slope

The Hunan-Guangxi railway Liuzhou to Nanning period of expansion and reconstruction project of a section of expansive soil cutting slope as the engineering background. Understanded engineering characteristics of the expansive soil through the indoor test.Understanded the structure internal force change rule by monitoring the slope of expansive soil.Finally, through the classical theory computation and numerical calculation method further, analysis of slope stability and its retaining structure stress and deformation distribution law. The main work and conclusions are as follows:(1) Through the indoor test of expansive soil, obtained the expansive soil mechanics index, expansion ratio and mechanical parameters for theoretical and numerical calculation.(2) Monitored the anti-slide piles in the expansive soil cutting slope.For the front row piles, the front earth pressure can be approximated as trapezoid and the back can be approximated as triangular distribution; For the back row piles,earth pressure back the pile is approximately triangular distribution, the front soil pressure is approximately triangular distribution;Row of piles does not exist synergistic effect due to the larger distance.(3) Found in the monitored of the anchor frame structure, in the lower non expansive slope, the impact of rainfall on the bolt axial force is small, and the impact of rainfall on the bolt axial force is great in the expansive slope.In the bottom of the frame,the maximum measured soil pressure not exceeding24kPa.(4) Using the classical design theory, the anti-slide pile and anchor frame beam internal force was analyzed and calculated.The results showed that:"m" and "K" method for calculating internal force cantilever segment income difference is not big, but the obvious difference between the anchoring section, with the "K" method for calculating internal force of anti-slide pile is more close to the measured values; strong rainfall condition, bolt axial force may be much larger than the design value; by using the elastic foundation beam method to calculate the bending moment of frame beam, elastic half-space foundation model and Winkler model the calculated frame beam bending moment distribution almost entirely coincidence; longitudinal beam, two foundation model under bending moment distribution form, using Winkler model to get the theoretical value than the measured value.(5) Using ADINA finite element software for monitoring section numerical simulation. With the increase of the distance between the two row of piles, pile interaction is more and more small, space reaches a certain value, the two row pile no synergistic effect of row piles, thrust force and displacement of rainfall on slope stability; the anchor frame structure of the internal force influence, to the lower slope affected by rainfall; anchor frame beam internal force influence, and the internal force of anti-slide pile under the effect of rainfall is much smaller, and the actual monitoring results coincide.(6) By means of the finite element calculation and measured results of comparative analysis, finite element method can simulate well the anti-slide pile deformation; but finite element calculate earth pressure is the slope reaches the final balance value, therefore the calculation results than the measured value of earth pressure is much greater. The double-row anti-slide pile design process by using finite element numerical analysis methods such as qualitative analysis of two row pile interaction and scope, so as to determine the design method and pile spacing, size and other parameters.