沿空留巷巷旁改性混凝土充填体的力学特性试验研究  

Experimental Study on Mechanical Properties of Modified Concrete Filling Body for Roadside Support of Gob-Side Entry Retaining

作　　者：杨卓 张东峰[1] 张小强[1] YANG Zhuo;ZHANG Dongfeng;ZHANG Xiaoqiang(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024

出　　处：《矿业研究与开发》2022年第6期134-140,共7页Mining Research and Development

基　　金：国家自然科学基金面上项目(51974194,52104097);山西省基础研究计划项目(20210302123147)。

摘　　要：普通混凝土作为沿空留巷巷旁支护充填体时,存在塑性变形能力小,难以协调变形,不能适应高地应力下巷道大变形量变形导致留巷复用困难等问题。针对普通混凝土材料性能的局限性,在用粉煤灰替代15%水泥增加混凝土试件强度的基础上,引入乙烯-醋酸乙烯酯聚合物(Ethylene Vinyl Acetate polymer, EVA)对混凝土材料进行改性试验,采用0.03 mm/s和0.01 mm/s两种不同的加载速率进行加载,测试不同EVA掺量的混凝土单轴抗压强度。试验表明:EVA的加入提高了混凝土的塑性变形能力和让压性能,且让压性在一定范围内随着EVA掺量的增加而增加,在EVA掺量达到15%时效果最佳,而在20%时呈下降趋势。通过力学特性分析得出,EVA对混凝土让压性的影响是通过抑制混凝土抗压时裂缝的扩展实现的,并通过声发射技术对试验进行检测,得出声发射能量与应力-应变曲线的变化趋势一致。When ordinary concrete is used as a filling material for roadside support of gob-side entry retaining, there are some shortcomings such as weak plastic deformation ability and difficulty in coordinating the deformation, which cannot adapt to the large deformation of roadway under high ground stress, resulting in the difficulty of roadway reuse. In view of the limitations of the ordinary concrete material, on the basis of replacing 15% cement with fly ash to increase the strength of concrete specimens, ethylene vinyl acetate polymer(EVA) was introduced to modify the concrete material. The uniaxial compressive strength of concrete with different EVA contents was tested by using 0.03 mm/s and 0.01 mm/s loading rates. The test results show that the addition of EVA improves the plastic deformation ability and compressive strength of concrete, and the compressive strength increases with the increase of EVA content in a certain range. The effect is the best when the EVA content reaches 15%, and shows a downward trend at 20% of EVA content. Through the analysis of mechanical properties, it is concluded that the influence of EVA on the compressive properties of concrete is realized by inhibiting the expansion of cracks in concrete under compression. The test is measured by acoustic emission technology, and obtained that the change trend of acoustic emission energy is consistent with stress-strain curve.

关 键 词：巷旁支护 高延性混凝土 EVA 声发射 破坏形态 

分 类 号：TD322[矿业工程—矿井建设]