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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。
In order to study the strength and deformation characteristics of cement-soil under site construction process, the unconfined compressive strength and triaxial tests of cement mixing pile core samples were carried out. The effects of cement content and confining pressure on the strength of cement-soil core, Deformation characteristics of the impact of law. The results show that with the increase of cement content, the strength of cement-soil core samples increases obviously, the deformation modulus increases significantly, but the damage strain becomes smaller and the brittleness increases. When the cement content is more than 18% With the increase of confining pressure, the strength increases, the strain increases, the brittleness decreases, and the stress-strain curve may change. Under different confining pressures, the soil-cement-like triaxial The test first for the body shrinkage, after the change of body bulge, dilatancy occurs more than the strain of the strain strain is slightly smaller, is caused by the particle shear in the wrong plane, to a certain extent after the particle movement to shear strength peaked ; Cement soil structure yield stress is relatively large, under the action of confining pressure, its cemented structure is not damaged, the strength of the envelope to meet the molar - Coulomb linear strength law; according to the strength and deformation characteristics of cement soil, stress - strain full curve sub-elastic, Plasticity, softening three stages, Popovics model can be used to simulate it, and the experimental results are in good agreement.