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充填沥青对可缩性井壁接头力学特性影响分析

Analysis of the influence of bitumen filling on the mechanical characteristics of collapsible wall joints

  • 摘要: 为了研究充填沥青对可缩性井壁接头力学特性的影响,采用模型试验和数值计算相结合的方式,以淮北矿业集团临涣煤矿中央风井设立的可缩性井壁接头为工程背景,对未填充(K组)、充填沥青(T组)和充填沥青且将沥青注入管堵塞(TD组)等3种工况下可缩性井壁接头模型的力学特性进行试验,并建立流固耦合有限元模型进行数值模拟研究。研究结果表明,3种工况条件下可缩性井壁接头模型试验中,相较于K组的平均极限承载力,T组和TD组的平均极限承载力分别增长了12.81%和21.51%,同时验证了数值计算模型是可行的;数值计算分析表明T组和TD组比K组的可缩性井壁接头竖向极限承载力分别增长了11.04%和25.84%,其竖向极限承载力增长率与模型试验结果基本一致;进一步研究发现,随着竖向载荷逐步递增,K组的内、外立板竖向应力基本呈线性增加并趋于稳定值,TD组的内、外立板竖向应力变化趋势与K组的基本一致;T组的内、外立板竖向应力未呈现稳定递增,而是越靠近溢流口的位置,板的竖向应力−竖向载荷曲线的斜率越小,同一位置的竖向应力−竖向载荷曲线斜率变化规律受沥青流动速率的影响。同时,竖向载荷越大沥青流动速率越快,这使得对井壁竖向承载力的影响也逐渐加剧;沥青动力黏度的增加导致流动性和壁面剪切力减弱,减轻了对井壁内外立板的扰动和调压作用。

     

    Abstract: In order to study the impact of bitumen filling on the mechanical characteristics of collapsible shaft lining joints, a combination of model testing and numerical calculations was employed. The study focused on the vertical plate retractable shaft wall joint located in the central air shaft of Linhuan Coal Mine of Huaibei Mining Group. The mechanical properties of the compressible wall joint model were tested under three different conditions: unfilled (Group K), filled with asphalt (Group T), and filled with asphalt with a blocked injection pipe (Group TD). Additionally, a fluid-structrue coupling finite element model was established for numerical simulation. The results indicate that, compared to the average ultimate bearing capacity of Group K, the average ultimate bearing capacity of Group T and Group TD increased by 12.81% and 21.51% respectively. The numerical calculation model was found to be feasible. The numerical analysis reveals that the vertical ultimate bearing capacity of Group T and Group TD is 11.04% and 25.84% higher than that of Group K, showing a consistent growth rate with the model test results. Further investigation demonstrates that as the vertical load gradually increases, the vertical stress on the inner and outer vertical plates of Group K increases linearly and eventually stabilizes. The vertical stress of the inner and outer vertical plates in group T did not increase steadily, but the slope of the vertical stress-vertical load curve of the vertical plates was smaller the closer they were to the asphalt overflow, and the slope of the vertical stress-vertical load curve at the same position was affected by the asphalt flow vortexes. Simultaneously, the higher the vertical load, the faster the asphalt flow speed, which makes the influence on the vertical bearing capacity of the shaft wall gradually increase. The increase in dynamic viscosity of asphalt results in a reduction of fluidity and wall shear force, thereby decreasing disturbance and pressure regulation on the vertical plate inside and outside the shaft wall.

     

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