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滨海风积砂因结构松散、自稳能力差、级配不良不易压实,被视为一种特殊土。水泥固化是常用的加固手段,而水泥剂量对风积砂力学性能的影响规律及细观作用机制目前尚不清楚。利用GDS土工三轴试验仪,对不同水泥剂量(0%,4%,6%)的水泥固化滨海风积砂进行不同有效围压(50,100,150 k Pa)下的CD试验。结合室内试验数据和水泥砂样显微照片,建立水泥固化滨海风积砂细观结构的颗粒流PFC2D模型,进行三轴试验的细观数值仿真分析。研究结果表明,水泥固化滨海风积砂应力–应变关系呈应变软化型,水泥剂量对滨海风积砂强度贡献明显,对体变影响相对较小。采用颗粒平行黏结方式的颗粒流数值仿真能有效反映水泥固化滨海风积砂的细观力学特性,水泥剂量对水泥固化滨海风积砂的黏结破坏数、配位数、位移场均有显著影响。
Coastal wind sand due to loose structure, poor self-stability, poor grading is not easy to compaction, is considered a special kind of soil. Cement curing is commonly used reinforcement methods, and the impact of cement dosage on the mechanical properties of aeolian sand and meso-mechanism of action is not yet clear. Using the GDS geotechnical triaxial tester, CD tests were conducted at different effective confining pressures (50, 100, 150 k Pa) for cement-bound coastal aeolian sand with different cement dosages (0%, 4%, 6%). Combined with indoor test data and cement sand micrographs, a particle flow PFC2D model of cement solidified coastal aeolian sand was established and the numerical simulation of triaxial test was carried out. The results show that the stress-strain relationship of cement-solidified coastal aeolian sand is strain-softened, and the contribution of cement content to the strength of coastal aeolian sand is obvious, and the influence on the volume change is relatively small. Particle flow numerical simulation with particle parallel bonding method can effectively reflect the meso - mechanical properties of cement - solidified coastal aeolian sand. The cement dosage has a significant effect on the number of cement damage, coordination number and displacement field of cement - solidified coastal aeolian sand.