堆石混凝土抗压强度影响因素细观分析

Meso-scale analysis of influence factors on compressive strength of rock-filled concrete using particle-based discrete element method

为了研究影响堆石混凝土强度的因素,本文建立了堆石混凝土的二维颗粒离散元模型,分析块石分布形态、自密实混凝土强度、以及块石和自密实混凝土的胶结强度等因素对堆石混凝土强度的影响。细观数值计算结果表明,块石的分布形态对堆石混凝土强度有重要影响,当块石在受力方向能够独立承受荷载作用时,堆石混凝土试件的抗压强度较高,反之,强度较低。胶结面强度对堆石混凝土的强度也有一定影响,随着胶结面强度的增加,其抗压强度有所增加。自密实混凝土强度显著影响堆石混凝土单轴抗压强度,自密实混凝土强度越高,堆石混凝土的强度越大,但当自密实混凝土强度增加一定值后,堆石混凝土抗压强度趋于定值,而主要由胶结面强度和块石分布形态确定。

Rock-filled concrete（RFC） is an emerging casting technology for large-scale concrete construction and it has been used in many projects in hydraulic engineering. In this work, we have developed a two-dimensional particle-based discrete element model of RFC and investigated three influence factors on RFC strength, i.e. arrangement pattern of rock aggregates, strength of self-compacting concrete（SCC）, and strength of interface between SCC and rocks. The numerical results show that the packing pattern of rock aggregates significantly affects RFC strength. Higher compressive strength is shown in cases where the applied load is carried by rock aggregates than those cases where the load is supported by both constituents. RFC strength becomes higher with increasing strength of interfaces or SCC. However, the compressive strength of RFC may approach its maximum value when the strength of SCC increases up to a certain value, and it is subsequently determined by the arrangement pattern of rock aggregates and the strength of interfaces.