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为了研究土体超固结特性、拉压模量及拉压泊松比差异等因素对球孔扩张的影响,将球孔扩张周围的土体分为弹性区和塑性区,在弹性区采用小变形理论,在塑性区采用大变形理论和修正剑桥模型,推导出考虑以上因素的塑性区半径、临塑扩孔压力以及极限扩孔压力的理论解答。研究结果表明:塑性区半径随着超固结比β的增大而逐渐减小,临界扩孔压力以及极限扩孔压力随超固结比β的增大而呈非线性增大;拉压泊松比v-/v+越小,临界扩孔压力越大,塑性区开展半径越小;临界扩孔压力随着拉压模量比E-/E+的增大而不断减小,塑性区半径随E-/E+的增大而不断增大;考虑以上因素能更加经济、合理地指导工程设计。
In order to study the influence of soil overconsolidation properties, tensile and compressive modulus and tension-compression Poisson’s ratio on ball-hole expansion, the soil around the ball-hole expansion is divided into elastic region and plastic region. In the elastic region, small Deformation theory, large deformation theory and modified Cambridge model are adopted in plastic zone to deduce the theoretical solution of plastic zone radius, plastic expansion and contraction pressure and ultimate expansion pressure considering these factors. The results show that the radius of plastic zone decreases with the increase of overconsolidation ratio β, and the critical expanding pressure and limiting expanding pressure increase nonlinearly with the increase of overconsolidation ratio β. The smaller the ratio of v- / v + is, the larger the critical expansion pressure is, and the smaller the radius of plastic zone is. The critical expansion of pore pressure decreases with the increase of tensile / compression modulus (E / E +). The radius of plastic zone E- / E + increase and continue to increase; consider the above factors can be more economical and reasonable guidance engineering design.