南百铁路钢管格栅膨胀土挡墙数值模拟研究

Numerical Simulation Study on Expansive Soil Retaining Wall with Steel Pipe Grid on Nanbai Railway

西南地区分布有大面积膨胀土,传统支护措施对膨胀土边坡的支护效果并不理想。针对这一问题,本文以南宁-昆明铁路增建二线工程百色地区膨胀土弃渣边坡为工程背景,提出一种刚柔结合的钢管格栅膨胀土挡墙,并采用FLAC 3D模拟技术研究验证了该支护措施的有效性及选取了合理的钢管间距。研究表明:(1)钢管格栅膨胀土挡墙在膨胀土边坡含水率变化时,能够有效限制膨胀土边坡的变形;(2)相较于传统土工格栅挡墙,钢管的加入加强了钢管格栅膨胀土挡墙的整体刚度,能够协调墙体不同高度的变形及位移,保证墙体的稳定性;(3)贯入土体的钢管增加了挡墙整体的抗滑和抗弯能力,减少其在水平方向的变形和位移,防止土体中含水率过大时发生塌滑;(4)该新型支护措施应采用梅花式布管。该研究可为类似研究和工程提供参考依据。

Large areas of expansive soil are widely distributed in Southwest China. The traditional support measures cannot support the expansive soil slope effectively. In order to solve this problem, based on the expansive soil waste slope in Baise area of second railway line of Nanning-Kunming Railway, this paper puts forward a rigid-flexible retaining wall with steel pipe grid, uses FLAC 3D simulation technology to verify the effectiveness of the support measure and select a reasonable distance between steel pipes. The study results show that:(1) the expansive soil retaining wall with steel pipe grid can effectively restrict the deformation of expansive soil slope when the moisture content of expansive soil slope changes;(2) compared with traditional geogrid retaining wall, steel pipe can reinforce the overall stiffness of expansive soil retaining wall with steel tube grid, coordinate the deformation and displacement of the wall body at different heights, and ensure the stability of the wall body;(3) the steel pipe penetrating into the soil can increase the overall anti-sliding and anti-bending capacity of the retaining wall, reduce its deformation and displacement in the horizontal direction, and prevents the collapse of the soil when the moisture content is too large;(4) The quincuncial pattern shall be adopted for steel pipe arrangement in the new support measure. This study can provide references for similar study and project.