研究目的:高铁旁基坑开挖日益增多，在软土地区极易导致高铁沉降，严重影响安全运营。目前软土地 区高铁旁基坑支护设计及监测技术尚不成熟，设计经验及监测数据极度缺乏。本文依托软土地区某紧邻高铁 的基坑实例,对其设计及监测进行研究。
研究结论:（1)提出高铁侧支护应按变形控制、对支护加强的方案实施，可减小路基沉降;（2)软土地区基 坑开挖后高铁沉降时间长，呈蠕变特性，每层土开挖后沉降速率先大后小，最终沉降值很大；（3)同一位置路 肩、接触网立柱、铁轨沉降基本一致，基坑中部沉降速率及沉降量较大，两侧及远离基坑处沉降较小；（4)坡脚 沉降比路肩、接触网立柱、铁轨沉降小；（5)周边基坑同时开挖及降水，导致两基坑交界处高铁沉降较大； (6)本基坑开挖与降水影响高铁距离约5倍基坑深度;（7)本基坑设计和监测经验可供高铁旁基坑设计、施工 借鉴。

Research purposes: The foundation pits which are adjacent to high speed railway are increasing, causing settlement easily in soft soil area which affects safe operation seriously. At present support design and monitoring technology of foundation pit adjacent to high speed railway in soft soil area is immature. Design experience and monitoring data is extremely deficient. The paper relying on the example of foundation pit adjacent to high speed railway in soft soil area researched the support design and monitoring.
Research conclusions :( 1) Suggestion of strengthening support according to deformation was put forward，which reduced roadbed settlement. (2) Settlement time of high speed railway after foundation pit excavation in soft soil area was long and it had creep characteristics. After each layer soil excavation，settlement rate was from the larger to the smaller and the final settlement value was very large. (3 ) In the same location settlement of shoulder, catenary column and track was basically same. Settlement rate and value in the central part of foundation pit was larger than both sides and the part far away from foundation pit. (4) Settlement at toe of slope was smaller than shoulder, catenary column and track. (5)The settlement of junctional zone between foundation pits was larger, caused by simultaneous excavation and dewatering.(6 ) The effect distance caused by excavation and dewatering was about five times of foundation pit depth. (7 ) Experience of design and monitoring can be referred to for foundation pits design adjacent to high speed railway.