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通过室内三轴试验研究美国中部密西西比河流域低塑性粉土的液化重固结后剪切强度。研究成果表明,正常固结低塑性粉土液化后不排水剪切强度Su随重固结度的增加而提高,而且呈现类固结现象。类似于未受震动的情况,液化完全重固结后不排水剪切强度比Su,OC/Su,NC与固结比OCR呈幂指数关系,只是幂指数相对于未受震动情况稍大。随着OCR的增加,完全重固结引起的不排水剪切强度变化?Su,recon先提高后降低,当OCR=3.42时,?Su,recon达到最大值。液化完全重固结后不排水剪切行为不具有准稳态现象,随着轴应变增加,应力逐渐增加直至达到临界状态。另外,液化完全重固结后不排水剪切应力-应变曲线可被有效固结应力?′c归一化。最终提出了计算液化完全重固结后低塑性粉土不排水剪切强度的计算公式。
Through the laboratory triaxial tests, the shear strength after liquefaction and heavy consolidation of low plastic silt in the Mississippi River basin in the central United States was studied. The research results show that the undrained shear strength, Su, increases with the increase of the degree of consolidation, and shows the phenomenon of quasi-consolidation. Similar to the unshaken case, the undrained shear strength ratio Su, OC / Su, NC and consolidation ratio OCR showed a power exponential relationship after liquefaction was completely re-consolidated, except that the power exponent was slightly larger than that without vibration. With the increase of OCR, the undrained shear strength caused by complete re-consolidation changes? Su, recon first increased and then decreased, when OCR = 3.42,? Su, recon reached the maximum. The unconsolidated shear behavior after complete re-consolidation of liquefaction does not have the quasi-steady state phenomenon. As the axial strain increases, the stress gradually increases until it reaches the critical state. In addition, the undrained shear stress-strain curve after liquefaction is completely re-consolidated can be normalized by the effective consolidation stress. Finally, the formula for calculating the undrained shear strength of low plasticity silt after liquefaction is completely re-consolidated is proposed.