堆石骨料对混凝土层面剪切性能影响的试验研究

Experimental study of the influence of rocks on the interlayer shear behavior of rock-filled concrete

堆石混凝土层间界面上露出的块石棱角与周围自密实混凝土的相互作用决定了堆石混凝土的层间抗剪性能。该文设计并完成了24个堆石混凝土施工缝小型直剪试验,通过在施工缝上布置不同抗剪堆石骨料,研究了堆石骨料露出高度、数量和强度以及竖向荷载对堆石混凝土施工缝抗剪性能的影响。试验结果表明堆石骨料对堆石混凝土施工缝抗剪性能有显著影响。试验出现了2种典型的破坏模式:堆石骨料周围混凝土的挤压塑性破坏和堆石骨料直接剪切破坏。堆石骨料露出高度、数量和强度以及竖向荷载的变化会引起施工缝的抗剪性能和破坏模式变化。参考普通混凝土裂缝剪力传递理论,提出了堆石混凝土层间界面抗剪承载力公式,该方法考虑了外露堆石的几何特征,能够体现出不同的破坏模式。利用试验结果对所提出的公式进行验证,验证结果表明所提出的方法能够有效评估堆石混凝土的层间抗剪性能,为今后堆石混凝土层间抗剪能力的设计提供了有益的参考。

The shear resistance of rock-filled concrete(RFC)interlayers depends on the interaction between the exposed rock corners and the surrounding self-compacting concrete(SCC).This study uses 24 small direct shear tests of RFC joints to analyze the effects of the aggregate strength,exposure height and number,and normal pressure on the shear behavior of RFC joints.The results show that the aggregate significantly influences the RFC joint shear strength.Two typical failure modes are observed with compressive plastic failure of the SCC and direct shear failure of the shear rocks.The exposed height,number and strength of the aggregate as well as the normal pressure all affect the shear capacity and failure mode.Shear stress transfer theory of concrete cracks is used to develop a design method that considers the two failure modes for the RFC interlayer shear capacity.The method is verified by the test results and provides a design method for RFC interlayer shear predictions.