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对掺加不同比例碎石的粗粒土进行了大型三轴试验,得到了颗粒级配对粗粒土强度和变形特性的影响规律.在素土中掺加不同比例的碎石可以明显改善土体的颗粒级配组成;素土和改良土的应力应变关系表现为加工硬化型,随着粗粒含量的增加,同一轴向应变对应的偏应力增大,围压增加也会导致偏应力增大;偏应力与轴向应变表现为明显的双曲线关系,初始切线模量和极限应力随着P5含量和围压σ3的增加而增大;P5含量的增加有助于提高土样内摩擦角φ和黏聚力C,而含泥量增加会导致内摩擦角φ和黏聚力C减小;低围压时粗粒含量较多的土样表现出明显的剪胀,较高围压时产生的体积应变较大;径向应变ε3与轴向应变ε1表现为明显的抛物线关系,通过改进的邓肯-张的E-ν模型得到初始泊松比μi受围压和颗粒级配的双重影响.
Large-scale triaxial tests were carried out on coarse grained soil with different proportions of gravel, and the effect of particle grading on the strength and deformation characteristics of coarse grained gravel was obtained. Adding different proportions of gravel in plain soils can obviously improve soil . The stress-strain relationship between plain soil and modified soil is hardenable. With the increase of coarse content, the deviatoric stress corresponding to the same axial strain increases, and the increase of confining pressure will also lead to the increase of deviatoric stress ; The relationship between deviatoric stress and axial strain is obviously hyperbolic. The initial tangent modulus and ultimate stress increase with the increase of P5 content and confining pressure σ3. The increase of P5 content helps to increase the soil friction angle φ And cohesion C, and the increase of mud content will lead to the decrease of internal friction angle φ and cohesion C; the soil samples with more coarse content at low confining pressure show obvious dilatancy and higher confining pressure The volumetric strain is larger; the radial strain ε3 and the axial strain ε1 show a clear parabolic relationship. The initial Poisson’s ratio μi is affected by both the confining pressure and particle size through the improved Duncan-Chang’s E-ν model.