The Key Technology And Application Of Collapsible Loess Sand Layer Using Rotary Excavation Method Into A Pile

This study is based on the analysis and research in the past rotary excavation method into pile construction case and relevant experts on the basis of research achievements.In xi ’an area of collapsible loess sand layer of the special geological conditions,through the two aspects of construction technology and construction organization,improvement and optimization to realize rotary excavation method into a pile with a good combination of sand layer geological conditions.During the study,first of all to study found that the traditional rotary excavat ion method construction technique of slurry mixing proportion is relatively fixed,not targeted for special soil conditions,at the same time spin dig a bit drilling hole formation process will produce bad influence on the stability of hole wall,secondly,the study of construction organization,construction site personnel management more difficult to achieve rapid construction,the construction of no stacks up relations between the rational utilization of each construction step, affect the efficiency of construction.It is in view of the problems above,this study through a combination of theoretical analysis and field experiment,to improve the traditional method.In construction technology,in view of the collapsible loess sand layer geological,first of all,mud mixture ratio adjustment and experimental verification,get a set of role has a good solid wall mud mixture ratio as a result,in addition to spin dig a bit increase process, improve the ability of expansion of the bit wall.In terms of construction organization,by changing the team management pattern,increase the cohesion between the construction steps,greatly improving the construction efficiency.Finally combined with the research results,proposed the concrete proposal for a pile foundation engineering,and applied to the project.