研究目的:沉降控制是湿陷性黄土区高速铁路建设中的技术难题。本文以郑西客运专线湿陷性黄土路基试验工程为依托，通过开展沉降变形观测、大型浸水试验、路基沉降预测，对高速铁路技术条件下水泥土挤密桩地基的沉降变形特性、湿陷性消除效果、沉降控制效果等进行了研究。
研究结论:挤密桩最大处理深度一般不超过 15 m。本试验场地采用 15 m 挤密桩处理，恒载预压 6 个月路基的剩余沉降量便已满足铺设无砟轨道对路基工后沉降的控制要求，浸水后该地基加固层仅出现了极少量的沉降，加固层的黄土湿陷性已完全消除。在湿陷性黄土厚度小于 15 m 的场地，采用挤密桩处理地基是一种有效的沉降控制方法。
Research purposes: Settlement control is a key technical problem in construction of high － speed railway in collapsible loess region ． Based on the tests to the subgrade of the passenger delicate line from Zhengzhou to Xi＇an in collapsible loess region，the study was done on the settlement deformation characteristics，the collapsibility elimination effect and settlement control effect of the cement － soil compact pile foundation of the high － speed railway by conducting the observation of the settlement deformation，the large － sized submerging test and prediction of the subgrade settlement．
Research conclusions: The maximum reinforcement depth of compaction piles should not exceed 15m． The compact pile with the depth of 15m was used for the test subgrade． The surplus settlement volume of the subgrade that had been loaded by dead load for six months could meet the control requirement of the post － construction settlement for the ballastless track，and only a little settlement occurred to the reinforced layer of the foundation after submerging． And the collapsibility of the loess in the reinforced layer was eliminated fully． In the area with the thickness of the collapsible loess less than 15m，the compact pile is an effective way to reinforce the foundation for the settlement control．
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