ANALYSIS OF EXPANDED RADIUS AND INTERNAL EXPANDING PRESSURE OF CYLINDRICAL HOLE
JIA Shanghua1，2，ZHAO Chunfeng1，2，ZHAO Cheng1，2
(1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；2. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China)
Abstract：The expansion of cylindrical hole in sand was analyzed based on the yielding criterion of spatially mobilized plane(SMP). A theoretical relationship among the initial radius a0，the expanded radius a and the expanding pressure p of the cylindrical hole was derived employing the boundary conditions of plastic zone and the volumetric variation of soil around the cylindrical hole. The limit pressure of expansion pu and the stress and displacement fields in the elastoplastic zone were obtained with the theoretical relationship. A theoretical relationship among the radius of the plastic zone rp and the expanding pressure and initial radius a0 was derived under the plane strain condition. The limit bearing capacity of a pile in granular material was deduced by using the stress field formula. Finally，an example was presented to illustrate the variations of the stress and displacement fields，the radius of plastic zone a0 and the expanding pressure p.
2015, Vol. 34 
