Study On Design Method For Multi-Frame Foundation Beam With Anchor Bolts In Cut Slope Engineering In Red Beds Soft Rock

Frame foundation beam with anchor bolts has been widely used in engineering practice because of its many advantages, such as good protection effect, simple construction, low cost. Many favorable results have been achieved in slope protection and slope control. However, the present analysis theories are mostly based on the single-stage frame foundation beam with anchor bolts, while they neglect the interaction between frame foundation beams with anchor bolts, and there are hardly any theories about multi-frame foundation beam with anchor bolts. Therefore, in order to get the better severices in engineering practice, the whole method based on the influence between Frame foundation beam with anchor bolts during construction process and the distrition patterns of slope pressure should be proposed. So the main contents and research results are as follows:Firstly, on the basis of theoretical analysis and numerical simulation method, The reinforcement mechanism of multi-frame foundation beam with anchor bolts and the variation characteristics of structural internal force in the staged excavation are detailed in this article, at the same time, the variation characteristics of the relaxation region for cutting slope in the staged excavation are also determined and the control design phase in the process of excavation is put forward.Secondly, relying on the tyical high slope engineering of express highway in Suining-Ziyang-Meishan, based on the results of numerical simulation, combined with previous relevant experience, the thesis proposes a approximate method of the relaxation region for slope in the staged excavation of muti-slope in red beds soft rock.,which namely first determines the relaxation region for slope according to slope crest of0.5-0.6h and slope toe of0.2-0.3h(h is the height of this stage), then connects the inflextion point of upper and lower level as the whole boundaries of the relaxation region for slope after slope exvacation.Thirdly, on this basis, A design method for frame foundation beam with anchor bolts by the use of limit equilibrium theory is proposed. First, the anchor bolt can be analyzed to determine through the slope stability design, then, based on static balance and coordination between deformation, the internal forces of foundation beam and slope pressure can be ascertained by adopting Winkler foundation beam. This method is reasonable according to indoor model test and further validation, while access to the excavation in different conditions, the slope pressure under the overall framework of the beam at all levels is big in the middle and small at both ends.A theoretical reference for design method of multi-frame foundation beam with anchor bolts is provided in this paper. It can be extended to the similar projects and has specifically important theoretical ang practical significane.