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通过对原状软土进行平面变形蠕变实验,研究平面变形条件下主应力比对超固结软土蠕变特征的影响。研究表明,平面变形条件下,以广义剪应力定义超固结剪应力比OCR_q,包含了前期固结应力数量和主应力比特征,能全面地反映软土的超固结特性,相对于超固结球应力比OCR__p能更直接反映超固结软土平面蠕变变形的特征;平面变形超固结软土的蠕变系数与超固结剪应力比OCR_q具有一一对应的关系,OCR_q越大对应的蠕变系数越小。OCR_q相同时前期固结过程主应力比小的土体具有较大的蠕变系数。在不同主应力比下构成的超固结应力历史,使得平面变形超固结软土相对于正常固结状态具有较小的广义剪应力,一定条件下主应力比越小广义剪应力越大,对应的超固结状态下土体具有较大的长期蠕变变形。
The effect of principal stress ratio on the creep characteristics of overconsolidated soft soil under plane deformation was studied by plane deformation and creep tests on undisturbed soft soil. The results show that under the condition of plane deformation, the over-shear stress ratio OCR_q is defined by generalized shear stress, which contains the characteristics of pre-consolidation stress and principal stress ratio, which can fully reflect the over-consolidation characteristics of soft soil. The coccoon stress more directly reflects the characteristics of plane creep deformation of overconsolidated soft soil than that of OCR__p. The creep coefficient of overconsolidated soft clay has a one-to-one correspondence with OCR_q, and the larger OCR_q The corresponding creep coefficient is smaller. When OCR_q is the same, the soil with the lower principal stress ratio has larger creep coefficient. The history of overconsolidation stress formed under different principal stress ratios makes the over-consolidated soft soil with plane deformation have a smaller generalized shear stress than the normal consolidation state. Under certain conditions, the smaller the principal stress ratio, the larger the generalized shear stress, The corresponding super-consolidated soil has larger long-term creep deformation.