层间堆石放置角度对堆石混凝土抗剪强度影响研究

Study on The Influence of Interlayer Rockfill Angle on The Shear Strength of Rock-filled Concrete

为研究层间堆石对堆石混凝土施工缝抗剪性能的影响机制,开展了在不同堆石放置角度下堆石混凝土试件的直剪实验,分析了施工缝抗剪强度和剪切裂隙的发展规律,并与数值计算结果进行对比阐述层间堆石提供的抗剪作用。研究结果表明:堆石混凝土中单个层间堆石的存在可使施工缝的平均抗剪强度较自密实混凝土提高43.55%。但是随着层间堆石放置角度增大,单个堆石和多个堆石受剪时施工缝的抗剪强度均呈逐渐降低的趋势。在单个层间堆石45°放置时,堆石与自密实混凝土的界面过渡区的破坏最为严重,层间堆石的存在对施工缝的抗剪强度增幅效果消失,其抗剪强度低于不含施工缝的自密实混凝土的约4.57%。据研究结果建议:在分层浇筑时,将层间堆石与施工缝接触的平面垂直于施工缝放置,从而实现堆石材料的更有效受剪。

To investigate the influence mechanism of interlayer rockfill on the shear performance of rock-filled concrete construction joints,direct shear tests under different interlayer rockfill placement angles were carried out.The shear strength of construction joints and the development law of shear cracks were analyzed,and compared with the results of numerical calculation to explain the shear effect provided by interlayer rockfill.The results showed that compared with self-compacting concrete,the existence of single interlayer rockfill in rock-filled concrete significantly increased the shear strength of construction joints by 43.55%.However,as the placement angle of the interlayer rockfill increased,the shear strength of the construction joints in shear for both single and multiple rocks showed a gradual decrease.When a single angle of interlayer rockfill was 45°,the interface transition zone between rockfill and self-consolidating concrete was the most serious in shear failure,and the effect of interlayer rockfill on the increase of shear strength of construction joints disappeared,the shear strength was about 4.57%lower than that of self-compacting concrete without construction joints.According to the research results,it was suggested that the plane of contact between the interlayer rockfill and the construction joint should be placed perpendicular to the construction joint during layered pouring,so as to achieve more effective shear of rockfill materials.