黄土地区新建铁路路基狭窄场地地基加固处理研究

依托黄土地区某新建铁路填方路基与黄土峁间需设置变电所的基础工程，结合场地空间狭窄条件和黄土湿陷性特征，采用排桩挡墙收坡及旋喷桩加固墙前地基，保证路基边坡稳定性和承载力要求，并通过桩顶位移和地基承载力测试评价其治理效果。结果表明：桩顶水平位移主要经历快速增长和保持稳定两个阶段，且墙前土开挖越深，桩顶水平位移越大；3个测点的最大桩顶水平位移分别为19.7、20.8、20.2 mm，均小于控制值；墙前地基采用旋喷桩加固，呈正方形布置，直径0.6 m，间距1.2 m，桩深10.0 m，复合地基承载力和边坡稳定性满足设计要求。

Study on the Foundation Reinforcement Treatment of Narrow Site of New Railway Subgrade in Loessland

Relying on the foundation engineering of a substation between a newly built railway filling subgrade and the loess hillock in the loessland, combined with the narrow conditions of the site space and the collapsibility of the loess, the authors adopt the row piles to retain wall and close slopes, use jet grouting pile to reinforce foundation before the wall so as to ensure the stability and bearing capacity of the roadbed slope, and evaluate the treatment effect by pile top displacement and foundation bearing capacity test. The results show that the horizontal displacement of the pile top mainly undergoes two stages: rapid growth and constant stability, and the deeper the excavation of the soil in front of the wall, the greater the horizontal displacement of the pile top. The maximum horizontal displacement of the pile top at the three measurement points is 19.7, 20.8, 20.2 mm respectively, which are less than the control values; the foundation in front of the wall is reinforced by jet grouting piles in a square manner with diameter of 0.6 m, spacing of 1.2 m, and pile depth of 10.0 m, and the composite foundation bearing capacity and slope stability meet the design requirements.