膨胀岩对南宁地铁1号线车站结构的影响研究

The influence of expansive rock on station structure of Nanning metro line 1

通过数值计算和模型试验,分别对膨胀岩分布区地铁车站受膨胀力作用,其结构的内力及变形规律进行研究。首先利用有限元分析软件ANSYS,对膨胀岩分布区地铁车站不利工况的受力进行分析。根据数值模拟结果,以1∶20的相似比进行模型试验研究,通过改变膨胀岩土体的含水率以实现膨胀力荷载的施加,进而得到地铁车站结构受力情况,并将其反演结果与数值计算结果进行对比分析。研究结果表明,随着含水量的增加,膨胀力逐步增大,在膨胀土接近饱和时,膨胀力达到45.5 kPa;膨胀力对底板跨中影响最大,弯矩值为18.6 N·m;模型试验反演结果与数值模拟结果较为接近,比值分别为115.1%、99.3%、94.1%;在相同条件下,底板局部受膨胀力作用时,内力变化最大。

Through numerical calculation and model test,the inner force and deformation law of the structure of the metro station in the area where the expansive rock is distributed are studied.Firstly,the finite element analysis software ANSYS was used to analyze the stress and deformation of the subway station under adverse conditions in the area where the expansive rock was distributed.According to the numerical simulation results,the model test was carried out with a ratio of 1:20.By changing the moisture content of the expansive rock and soil mass to achieve the application of the expansion force,the stress and deformation values of the subway station structure were obtained,and the inversion results were compared with the numerical calculation results.The test results showed that the expansion force gradually increased with the increase of water content.When the expansion soil was close to saturation,the expansion force reached 45.5 kPa.The expansion force has the greatest influence on the midspan of floor,and the bending moment is 18.6 N·m.The results of model test inversion are close to the results of numerical simulation,and the ratios are 115.1%,99.3%,94.1%.Under the same conditions,when the floor is partially subjected to expansion force,the internal force changes the most.