Internal Force Calculation And Experimental Study Of The Bridge Double Piles Structure In High-steep Transverse Slope

With the rapid development of the expressway in the western mountainous areas of our country, Many elevated viaducts and halfway half bridge form are used to through the steep slope, in order to satify the road horizontal and vertical alignment and to protect the environments, leading to part of pile foundations built in the high steep bank slope. In this case, the bridge double piles structure has been widely used to protect the stability of the slope bridge plie foundation and the safety of adjacent environment, it is definitely a key problem for engineering design, that is how to accurately determine the internal force and displacement of such pile foundations. In this dissertationt those problem are detailed investigated and researched from theory and test fields, combined with the western traffic construction technology projects“study on the design and construction technology for pile column bridge built in the high-steep transverse slope”(No. 200831878531), and a series of design theories and computational methods are obtained for the bridge double piles structure in high-steep transverse slope.Firstly, the mechanical characteristics of normal vertical bearing pile、lateral bearing pile、combinative loading pile and slope pile are discussed, and the primary differences between high-steep transverse slope bridge piles and normal piles are listed. Based on that, the model of piles-slope interaction and inter-piles soil interaction is established profiting from the internal force calculation methods of passive pile under complex loading and the mature theories of double row retaining piles and anti-sliding piles: The back pile beared thrust is simplified as slope slide thrust and active earth pressure by critical sliding surface, lateral soil resistance for the double piles is calculated by elastic subgrade reaction method, And the inter-piles soil to front pile acting force is calculated considering pile spacing and landslide affected areas’impact. Then, reckoning in the influence of vertical and lateral loading joint action, the differential equations of pile sections with different characteristics are deduced, and the internal force and displacement calculation method of the bridge double piles structure are proposed based on finite difference solution, the calculation program is also obtained by using Matlab.In view of relevant model test data is deficient, this thesis designs different slope angles indoor model test for high-steep transverse slope bridge piles. According to the measured internal force distribution and rock resistance around the pile, the reliability of analysis method was confirmed based on the experimental results. Then, further analysis has been discussed to different loading condition piles’bearing mechanism and deformation characteristics. Finally, with the strong repeatability of the finite element method, the three-dimensional numerical model is established with advanced nonlinear finite element analysis software ADINA, mainly analysing the mechanical response of slope under different bridge loading and the impact of different combined loading on piles’force and displacement. Then, through changing pile stiffness、Horizontal tie beam stiffness and elastic modulus of slope materials, the sensitivity analysis results of the bridge double plies structure are also obtained.