Bearing Capacity Of Cast-in-place Piles In The Karst Region Of Yichun, Jiangxi

The karst region is where the soluble bedrock, usually carbonate rock takes more than 30 percent of total rock masses. With the great deal of railroad construction in China, more and more engineering projects locate in the karst region. Due to the existing of the soluble rock mass, the bearing capacity problems of drilled piles installed in the karst region are definitely encounted. The invstigation of the behaviors of drilled piles installed in the karst region takes a important role in theoretical study and engineering practice and are greatly significant in technology and ecomnomy.The general methods in the paper include the review of nationally and internationally published literature and collection of project information on-site. Zhaojiali bridge on the new Hu-Kun railroad which locates in the section of Yichun in Jiangxi province is taken as a case study. Through the combination of ANSI simulation with the actual project, the effect of different types of materials filled in the cave formed due to the dissolution of soluble rock on the property of drilled pile is tested by a numerical method. Meanwhile, the deformation and stability of the rock layer between the pile foundation bottom and the top of the cave caused by dissolution of soluble rock mass have been analyzed. The influence of the deformation and stability of pile end rock on the load-settlement curve and bearing capacity of the pile are investigated. The affect of cave which located among pile group on the load-settlement curve and bearing capacity of piles is analyzed. The results of simulation testing are agreeble with the onsite instrumentation for the actual engineering piles on job site. This investigation provides references for pile design and construction of Zhaojiali bridge located in the karst region. This paper developed the design theory and method for pile design and construction located in special engineering geological conditions such as the karst region.