采空区密闭墙中微胶囊粒径对其囊壁强度的影响

针对采空区密闭墙裂隙修复滞后的问题,提出了采用微胶囊在密闭墙裂隙演化过程的初始阶段(启裂时段)开启裂隙修复的方法。该方法是利用裂隙尖端应力作用,撕破微胶囊囊壁,使包裹在囊壁内的修复剂流出,充填裂隙,在发生固化反应后完成裂隙修复。在密闭墙裂隙修复过程中,微胶囊粒径影响其囊壁强度,直接关系修复效果。为了研究微胶囊粒径对其囊壁强度的影响规律,通过正交试验制备了8种不同粒径同种壁厚的微胶囊,采用SEM扫描电镜进行粒径及壁厚表征,利用纳米压痕技术测定囊壁强度,得出囊壁强度随粒径的增大逐渐减小的二次函数关系。

Effect of particle size of microcapsules on strength of capsule wall in airtight wall of goaf

Aiming at the problem of delayed repair of cracks in the airtight wall of the goaf, a method to initiate crack repair using microcapsules in the initial stage of crack evolution of the airtight wall(cracking period) is proposed. This method makes use of the stress at the crack tip. The microcapsule wall is torn to allow the repair agent wrapped in the wall of the capsule to flow out and fill the gap. After the curing reaction, crack repair is completed. During the crack repair process of the airtight wall, the particle size of the microcapsule affects the strength of the capsule wall and directly affects the repair effect. In order to study the influence of particle size on the strength of microcapsules, eight kinds of microcapsules with different particle diameters and the same wall thickness were prepared by orthogonal experiments. The particle size and wall thickness were characterized by SEM,and the strength of the capsule wall was measured using nanoindentation technology. The quadratic function relationship that the strength of the capsule wall decreases with the increase of the particle size is obtained.