水泥土芯样强度变形特性及本构关系试验研究

发布时间：2018-05-02 20:43

本文选题：水泥搅拌桩 + 强度变形特性　；参考：《岩土力学》2015年12期

【摘要】：为了研究现场施工工艺下水泥土的强度及变形特性,对水泥搅拌桩钻孔芯样进行了无侧限抗压强度试验与三轴试验,分析了水泥掺量与围压对水泥土芯样强度、变形特性的影响规律。结果表明:随着水泥掺量的提高,水泥土芯样的强度明显增强,变形模量显著增大,但其破坏应变变小,脆性增大;水泥掺量超过18%的水泥土芯样其应力-应变关系表现为软化型,随着围压的提高,其强度增强,破坏应变增大,脆性降低,且应力-应变关系曲线有可能发生转型;不同围压下的水泥土芯样三轴试验先为体缩,后变化为体胀,发生剪胀的应变较破坏应变略小,是由剪切面上颗粒错动引起的,在颗粒错动达到一定程度后抗剪强度才发挥到峰值;水泥土的结构屈服应力比较大,在围压的作用下其胶结结构未发生破损,强度包线满足摩尔-库仑线性强度规律;根据水泥土的强度变形特征,应力-应变全曲线分弹性、塑性、软化3个阶段,可采用Popovics模型对其进行模拟,与试验结果较为吻合。
[Abstract]:In order to study the strength and deformation characteristics of cemented soil in site construction process, the unconfined compressive strength test and triaxial test were carried out on the core sample of cement mixing pile, and the strength of cement core sample with cement content and confining pressure was analyzed. The influence of deformation characteristics. The results show that with the increase of cement content, the strength and deformation modulus of the core of cement-soil increase obviously, but the failure strain becomes smaller and the brittleness increases. The stress-strain relationship of cement-soil core samples with more than 18% cement content is softened. With the increase of confining pressure, the strength increases, the failure strain increases, the brittleness decreases, and the stress-strain relationship curve may be transformed. Under different confining pressures, the triaxial tests of cement-soil core samples are firstly bulk shrinkage, then body dilatation. The strain of shear dilatation is slightly smaller than that of failure strain, which is caused by the dislocation of particles on the shear surface. The shear strength reaches the peak value after the grain dislocation reaches a certain degree, the yield stress of the structure of cement soil is relatively large, the cemented structure is not damaged under the action of confining pressure, and the strength envelope line satisfies the linear strength law of Mohr-Coulomb. According to the strength and deformation characteristics of cement-soil, the stress-strain curve is divided into three stages: elastic, plastic and softening. The Popovics model can be used to simulate it, which is in good agreement with the experimental results.
【作者单位】：武汉大学土木建筑工程学院;长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家自然科学基金(No.51378403,No.51309028)资助~~
【分类号】：TU411

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