高流态注浆材料膨胀及蠕变特性试验研究

Experimental study on expansion and creep characteristics of highflow sealed grouting material

为探究高流态注浆材料膨胀规律以及注浆后煤体蠕变力学特性和孔隙结构,设计新非线性黏塑性元件结构,并据此构建蠕变力学模型。首先,制备高流态注浆材料并将其注入至煤体中,以模拟钻孔周围煤体注浆情况;然后,采用压汞试验和单轴分级加载蠕变试验方法,测试注浆后煤体孔隙结构以及不同应力水平下注浆煤体蠕变性能,进而获取注浆煤体在不同蠕变阶段的应变变化规律。最后基于蠕变试验结果,设计新非线性黏塑性元件,并将其引入到鲍埃丁-汤姆逊模型,反演获得蠕变模型相关参数,揭示注浆后煤体的蠕变失稳破坏规律。研究结果表明:高流态注浆材料膨胀率相比普通水泥材料提高92%,能够有效解决水泥基注浆材料固化后收缩的问题;当高流态注浆材料注入煤体后,煤体失稳破坏临界荷载为15.3 MPa,在一定程度上提高了煤体稳定性。

In order to investigate the expansion law of high flow grouting material and the creep mechanical properties and pore structure of coal after grouting,a new nonlinear viscoplastic element was created and a creep mechanical model was constructed.Firstly,the high flow grouting material was prepared and injected into the coal body to simulate the coal body grouting around the borehole.Secondly,mercury injection experiment and uniaxial fractional loading creep test were used to test the pore structure of the coal after grouting and the creep performance of the coal under different stress levels,and the strain variation law of the coal at different creep stages was obtained.Finally,based on the creep test results,a new nonlinear viscoplastic element was constructed and introduced into the Boedin-Thomson model.Finally,the relevant parameters of the creep model were obtained by inversion,the reliability of the model was verified,and the creep instability failure law of the coal after grouting was obtained.The results show that the expansion rate of high flow grouting material is 92%higher than that of ordinary cement material,which effectively improves the shrinkage problem of cement-based grouting material after curing.After the high flow grouting material is injected into the coal body,the critical load of instability failure of the coal body is 15.3 MPa,which improves the stability of the coal body to some extent.