基于CPTU确定软黏土超固结比的理论改进方法

发布时间：2018-06-28 14:55

本文选题：土力学 + 孔压静力触探　；参考：《岩石力学与工程学报》2017年06期

【摘要】：利用孔压静力触探(piezocone penetration test,CPTU)试验结果确定超固结比(over consolidation ration,OCR)不仅能避免传统室内试验方法中土样扰动的问题,还能得到地层剖面上连续的OCR值。将静力触探锥头的挤土模式看作是球形孔的扩张,锥面上的正应力和剪应力分别假定为极限扩孔压力和锥土接触摩擦力;基于修正剑桥模型中圆孔扩张的近似闭合解,提出了利用CPTU测试结果确定OCR的理论改进方法。分别选取轻超固结和重超固结场地的CPTU试验结果,对提出方法的可靠性进行验证。结果表明,在综合考虑锥面粗糙度以及贯入速率等因素的影响后,预测得到的OCR值较已有理论方法更接近实测结果。最后在连云港海相黏土中对该理论改进方法进行应用,计算表明该土层处于欠固结~轻超固结状态。
[Abstract]:By using the pore pressure static sounding (piezocone penetration test results, it is determined that the overconsolidation ratio (over consolidation) can not only avoid the disturbance of soil samples in the traditional indoor test methods, but also obtain the continuous values of (piezocone penetration values in the formation profile. The squeezing model of the static penetration cone is regarded as the expansion of the spherical hole, and the normal stress and shear stress on the cone are assumed to be the ultimate reaming pressure and the contact friction force of the cone and soil, respectively, based on the approximate closed solution of the expansion of the circular hole in the modified Cambridge model. An improved method for determining OCR by CPTU test results is proposed. CPTU test results of light and heavy overconsolidation sites were selected to verify the reliability of the proposed method. The results show that the predicted OCR values are closer to the measured results than the theoretical methods after considering the influence of cone roughness and penetration rate. Finally, the improved method is applied to the marine clay of Lianyungang. The calculation shows that the soil layer is in the state of underconsolidation to light overconsolidation.
【作者单位】：长安大学建筑工程学院;同济大学地下建筑与工程系;
【基金】：国家自然科学基金资助项目(41272288) 中央高校基本科研业务费专项基金(310828171002)~~
【分类号】：TU43

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