现场堆石体振动碾压的颗粒流模拟及验证

Simulation and verification of particle flow of vibration rolling compaction of field rockfill

围绕现场堆石体振动碾压的颗粒流模拟及验证展开研究。首先,基于振动碾的双自由度集中质量模型,建立了对应的等效颗粒流模拟方法,然后考虑到现场堆石体由于'骨料分离'而产生的分层特性,建立了反映分层特性的堆石体颗粒流模型。其次,基于相对密实度一致性原则推导建立了二维、三维沉降变形的定量关系。最后,基于建立的数值模型对典型的工程案例进行验证模拟,并从沉降率、堆石料破碎、级配和孔隙率演化规律等多个角度进行论证分析。研究结果表明,数值试验较为真实地反映了实际工程中堆石体在振动碾压条件下的宏细观动力响应特征,验证了数值试验方法的可行性与合理性。相关研究有利于加深对于堆石体振动碾压细观机理的认识与理解,也为进一步研究现场堆石体振动碾压后的力学性质奠定了模型基础。

Numerical simulations based on the PFC2D are conducted to investigate the vibration rolling compaction(VRC) of prototype rockfill. At first, an equivalent numerical model for vibrating roller is developed based on the analytical 2-degree-of freedom lumped mass model, in which interaction between drum and frame is considered carefully. Secondly, a practical modelling procedure for prototype rockfill is proposed;so that the segregation behavior of rockfill grains can be replicated truthfully. Thirdly, based on the principal of relative degree of density, settlement relationship between 2D and 3D sample is derived in an analytical way. Finally, a practical case in real project is replicated by the proposed discrete model;and simulation results are compared to the observed data in site, such as settlement, breakage ratio, grading curve and porosity. The research results show that the proposed numerical model can replicate the macro and meso-behavior of prototype rockfill during VRC progress in a reasonable way, proving the feasibility and correctness. Related researchments can help to understand the mesoscopic mechanism of dynamic response of prototype rockfill under VRC load, and lay the foundation of investigating the mechanical behavior of compacted prototype rockfill in future.