高铁高架桥近距离穿越在建软土深基坑施工技术

Construction Technology of Soft Soil Deep Foundation Pit under Construction for High-Speed Railway Viaduct Short Distance Crossing

摘要: 由于软土有易触变性、高压缩性、强度低等特征，软土深基坑施工变形控制难度大；高铁高架桥桥基与在建车站基坑围护结构距离只有0.6 m，施工易造成相互影响。论文提出一种高铁高架桥近距离穿越在建软土深基坑施工技术，在超深地下连续墙施工位置的外围施工三轴搅拌桩，以加固围护结构，维护基坑稳定；桥基施工前，在桥基地层范围施工高压旋喷桩进行加固，以减小桥基施工对基坑的影响；高铁桥基在临近基坑施工至坑底并完成封底后进行施工，以减小桥基施工引起的基坑变形。

Abstract: Soft soil has the characteristics of thixotropy, high compressibility and low strength, so it is diffi-cult to control the deformation of foundation pit construction. The distance between the bridge foundation of the high-speed railway viaduct and the foundation pit retaining structure of the station under construction is only 0.6 m, so the construction is easy to cause mutual influence. A kind of construction technology of high-speed railway viaduct passing through soft soil deep foundation pit in short distance under construction is proposed, in order to reinforce the retaining structure and maintain the stability of foundation pit, the triaxial mixing pile is constructed in the periphery of the construction position of ultra-deep underground continuous wall. In order to reduce the influence of bridge foundation construction on foundation pit, high pressure rotary jet grouting pile is constructed in the range of bridge foundation stratum for reinforcement before bridge foundation construction. In order to reduce the foundation pit deformation caused by bridge foundation construction, the construction of high-speed railway bridge foundation is carried out after the construction of foundation pit to the bottom and the completion of bottom sealing.