Analysis On The Vertical Load-bearing Characteristics By Pile Position Change In Steep-slope Area Of Qinba Mountain Region

In mountain area, the conditions of terrain, landforms, engineering geology and hydrogeology is very complicated. In order to meet the alignment and protect the natural environment, the bridges are often used to across steep-slopes areas in the highway construction of mountain region. Thus cause some bridge pile foundation will set in a steep slope area, even extremely steep slope. The Shiyan to tianshui expressway Shaanxi section across Qin-ba mountains area in the south of Shaanxi province. Along with the expressway the terrain changes greatly. Rock mass structure surface development to thin layer structure, thin layer fracturing structure and fracture structures. Therefore, the slope was easy weathering,crushing, caving, flaking by geological, rainfall erosion, weathering and human activity effect. All above adverse factors make a decision of pile under restrictions. Due to the particularity of the pile on steep slope with the pile location, location, location and the steep slope of the pile of position, piles and steep slope toe of the relationship between local loss, the influence of bearing capacity of pile foundation construction is the concern.Based on the summary and analysis of the investigation data of pile foundation in steep-slope area of the Shiyan to Tianshui expressway, firstly, this paper carry out calculation on the slope pile foundation's load transfer mechanism and vertical load-bearing capacity with different slope, pile length, pile diameter, obtain the changes of the bearing capacity of pile foundation in steep-slope area by using finite element analysis software. Then,the paper research on the other factors of vertical load-bearing characteristics,it include the lateral distance between pile top and slope, the relative position of pile-end with the steep-slope toe, especially the shape-change at slope toe.At last the paper proposed project proposals of pile location based on the all above research. Thesis results provide a basis for the slope of the bridge foundation design and construction technology.