A Study Of Characters Of The Piles-Net Composite Foundation On Oversized Deep Soft Soil Located On Sloping Base

In the construction of the high speed railway in China, pile-net composite structure is widely applied foundation treatment. Oversized deep soft soil distributes widely in the east of China, and bearing bed with different angles which is called sloping base in this paper. The mechanism of the oversized deep railway foundation located on sloping base which is reinforced by pile-net composite structure, and the reinforcement measures are paid high attention to.In this paper, based on the analysis of the standards of different countries and the existing achievements, the computing theory of pile-net composite foundation is researched. From the researching, stipulation about soil arch of standard named DBGEO can get the computational accuracy. Appling differential equation of thin film, the computing theory about sub-grade reaction of the soil between piles is researched. And computing theory of the settlement of pile-net composite foundation is also researched.Based on the site survey of high speed railway in the east of China, the typical section of high speed railway is studied by geotechnical centrifuge model test for researching of deformation and failure mechanism of pile-net composite foundation. From the test results, deformation of piles and the failure of geo-grid occur in the pile-net composite structure, and the horizontal displacement and differential settlement in the vertical direction occur in embankment.Applying the geotechnical centrifuge model test, the reinforcement effect of inclined piles applied for reinforcing the existing pile-net composite foundation on oversized deep soft soil located on sloping base is researched. From the test results, for being reinforced by inclined piles, the deformation of piles and the failure of geo-grid can be controlled. And the displacement in the vertical and horizontal direction decrease. From the result, without influencing the operation of railway, the existing railroad bed can be reinforced by inclined piles, and good reinforcement effect could be gain.