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采用静止土压力系数K0描述土体初始应力各向异性程度,建立了压力控制边界条件的柱孔扩张数值模型,分析压力为边界条件的圆柱孔扩张特性。计算结果表明,初始应力条件各向异性时,柱孔周围的土体的径向位移是不相等的,扩张后的柱孔呈椭圆形,初始应力各向异性是柱孔非对称扩张的内在原因;塑性区的分布具有明显的方向性,塑性区最大半径位于柱孔周围初始大主应力方向上;在相同的扩张压力下,随不排水抗剪强度增加,土体的塑性区减小,且土体初始应力各向异性造成的土体塑性区分布各向异性程度也随之减小;在相同的扩张压力下,柱孔初始应力越大,其塑性区范围越大,且土体初始应力各向异性造成的土体塑性区分布的各向异性程度也越大。
The static earth pressure coefficient K0 is used to describe the initial stress anisotropy of the soil. A numerical model of pore expansion under pressure control boundary conditions is established, and the expansion behavior of cylindrical pores under pressure as the boundary condition is analyzed. The calculated results show that the radial displacements of the soil around the column hole are not equal when the initial stress conditions are anisotropic, and the expanded columnar hole is elliptical. The initial stress anisotropy is the intrinsic reason for the asymmetric expansion of the column hole ; The distribution of plastic zone has obvious directionality and the maximum radius of plastic zone lies in the direction of initial principal principal stress around column hole. Under the same expansion pressure, the plastic zone of soil decreases with the increase of undrained shear strength The anisotropy of soil plasticity distribution caused by the initial stress anisotropy of soil also decreases. Under the same expansion pressure, the larger the initial stress of column hole, the larger the plastic zone, and the initial stress of soil Anisotropy caused by soil anisotropy distribution of the greater the plastic zone.