The Effect Of Mountain Torrent On The Function Of Pile Foundation In Steep-slope Area And Its Safety Evaluation

For the especial environment, when the mountain flood happened, the pile foundation insteep-slope always encountering the effect of scour and rock-fall which will have a threat onits normal function and safety. Therefore, in order to make sure the pile foundation can workas normal, and the bridge could in its safety state, the change of capacity of the pilefoundation and its safety should be researched when its encountered mountain flood.Based on the researches of the scholars at home and abroad, through established analysismodel, using theoretical calculation and numerical simulation, the effect of mountain floodworked on the pile foundation was researched. And depending on Fu Yong highway, throughfield investigation, by establishing safety evaluation system, the safety of the pile foundationin steep-slope which encountered mountain flood was evaluated. The main research contentsare as follows:1. Based on the researches at home and abroad, the characteristics of mountain flood andthe impact type of the pile foundation when encountered mountain flood was summarized.2. Under the effect of mountain flood, the scour depth of slope was analyzed. Throughtheoretical analysis, the formula to calculate the vertical-bearing capacity of the pile aftermountain flood happened was derived. Based on numerical simulation, when the pileencountered mountain flood, the vertical load–bearing characteristics of the pile in differentworking conditions was analyzed.3. The trajectory, the speed and the force when it compacted on pile of the rock-fall wasanalyzed. Through theoretical analysis, the formulas to calculate the internal force andhorizontal displacement of the pile were derived, which based on different analysis model ofthe rock-fall. The method to calculate the critical impact force for the pile in steep-slope wasput forward.4. Using fuzzy comprehensive evaluation method, based on the research about theimpact of pile in steep-slope when it encountered mountain flood, the evaluation system forthe pile foundation in steep-slope was established. Depending on Fu Yong Highway, thesafety of the pile foundation in steep-slope was evaluated. The methods to defense the impactwhich mountain flood worked on the pile foundation in steep-slope were put forward.