关键词: 水泥搅拌桩, 强度变形特性, 无侧限抗压强度试验, 三轴试验, Popovics模型

Abstract: Consolidation drained triaxial compressive tests and unconfined compression strength tests were carried out on cement-mixed pile core samples to study the strength and deformation properties of the cemented soil on-site construction process. The effects of confining pressure and cement content on strength and properties of cement-mixed pile core samples are investigated. It is observed that with increasing the cement content, the strength, deformation modulus and the fragility of the cemented soil core samples obviously increase, but the failure strain decreases; when the cement ratio is more than 18%，the stress-strain relationships of the samples show softening; and with increasing cell pressure, the strength and destruction strain increase, the friability decreases, and the stress-strain curves may transform in the form. The behaviors of the samples all firstly exhibit a volumetric shrinkage and then a dilatancy under different confining pressures. in the consolidation drained triaxial compressive tests. And the dilatation-induced strain is slightly smaller than the failure strain. The dilatancy is caused by moving of particles. Only the particles moving reach a certain extent，the shear strength can develop up to a peak. Because the cemented soil has larger structural yielding stress, its cementation structure is not damaged under confining pressures, and its strength envelope meets Mohr-Coulomb linear rule. According to the strength and deformation properties of cemented soil, its complete stress-strain curve can be divided into three stages of elastic, plastic, softening. Popovics model is used to simulate the stress-strain relationship of cemented soil core sample, which shows that the calculated results agree well with the experimental results.

Key words: cement-mixed pile, strength and deformation properties, unconfined compression strength test, triaxial compressive test, Popovics model