磨料水射流多维参数对混凝土致裂性能影响特征

Effects of multi-dimensional parameters of abrasive water jet on cracking concrete

为提升磨料水射流(AWJ)技术在灾后混凝土结构应急中破拆中的应用水平,研究磨料水射流冲击破碎混凝土情况。首先,基于光滑粒子(SPH)法与有限元法(FEM)耦合的方法,构建磨料水射流冲击混凝土模型,然后通过改变磨料粒径、物性及磨料体积分数等参数,探究其对磨料水射流冲击破碎混凝土的影响机制。研究结果表明:粒径为0.2 mm的磨料水射流对混凝土基体产生的损伤最大,粒径为0.1 mm磨料水射流工况中基体破裂点距顶面最近,粒径为0.4 mm磨料水射流产生裂纹数量最多且容易导致基体破裂;石榴石磨料水射流对混凝土裂纹轴向扩展有利,精钢砂磨料水射流对混凝土裂纹径向扩展有利;磨料水射流对混凝土裂纹径向扩展影响为:磨料低积分数10%最大20%次之,15%最小,磨料对混凝土裂纹轴向扩展影响为磨料体积分数20%最大,10%次之,15%最小。

In order to improve application of AWJ technology in emergency demolition of post disaster concrete structures,breakage impact of concrete under AWJ was investigated.Firstly,a model of concrete impacted by AWJ was constructed based on coupled SPH and FEM.Then,its impact mechanism on broken concrete with AWJ was explored by changing abrasive particles’diameters,physical properties and abrasive volume fraction.The results indicate that AWJ with a diameter of 0.2 mm causes largest damage to concrete matrix,rupture point of matrix caused by AWJ with a diameter of 0.1 mm is closest to top surface of concrete,and AWJ with a diameter of 0.4 mm tends to cause matrix cracking and accounts for most cracks.It also reveals that garnet abrasive water jet is beneficial to axial propagation of concrete cracks while emery abrasive water jet is beneficial to their radial propagation.Influence of concentration on radial propagation of concrete cracks is as volume fraction of 10%>volume fraction of 20%>volume fraction of 15%,and that on their axial propagation is volume fraction of 20%>volume fraction of 10%>volume fraction of 15%.