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基于统一强度理论,考虑渗流、各向异性、剪胀特性以及中主应力等因素的综合影响,推导了柱孔扩张问题弹塑性解答。结果表明,富水条件下的扩孔问题中考虑渗流体积力的影响是非常有必要的,不考虑渗流影响的扩孔压力比实际工程偏小;渗流体积力越大,塑性区半径越小。另外,传统的扩孔解答假定土体为各向同性初始应力状态高估了极限扩孔压力,也低估了扩孔过程中圆孔周边的塑性区范围,造成工程安全等级偏低。该结果为海底圆形隧道以及渗流条件下地下水平构筑物施工弹塑性分析提供了理论依据,对工程设计具有一定参考价值。
Based on the unified strength theory, considering the combined effects of seepage, anisotropy, dilatancy characteristics and intermediate principal stress, the elastic-plastic solution of cylindrical cavity expansion is deduced. The results show that it is very necessary to consider the influence of seepage volume force in the problem of reaming under water-rich conditions. The expansion pressure irrespective of seepage effect is smaller than the actual project. The larger the seepage volume force, the smaller the radius of plastic zone. In addition, the conventional hole expansion solution assumes that the soil overestimates the ultimate expansion pressure for the isotropic initial stress state, and underestimates the plastic zone around the circular hole in the reaming process, resulting in a lower level of engineering safety. The results provide a theoretical basis for the elasto-plastic analysis of the construction of circular submarine tunnels and underground horizontal structures under seepage conditions, and have certain reference value for engineering design.