压入式沉井与反力桩对地表沉降的耦合影响研究

Coupling effects of pressed caisson and uplift piles on surface settlement

利用压入式连续沉井群建造轨交地下车站是一种新型预制装配建造模式,但相较传统的明挖式基坑车站修建方式,目前尚缺乏对沉井压入过程环境影响的研究。为此,本研究以实际工程案例为背景,通过数值模拟,结合现有实测拟合沉降曲线,对比调查了沉井外侧反力桩的存在与否对地表沉降剖面的影响规律;进一步调查了桩间距对于地表沉降的调控作用;并基于抗拔承载力等效原则,同时探究了桩间距和桩径对周边土体沉降的影响。进而形成了桩外侧和桩间土体沉降剖面的修正归一化曲线,为压入式连续沉井群地下车站在高密度城市中心的实施提供参考支撑。

Constructing underground railway stations using the pressed continuous caisson group is a new type of prefabricated assembly construction mode.However,compared to the traditional open-pit excavation method of station construction,there is currently a lack of research on the environmental impact of the caisson pushing process.Therefore,taking the actual projects as a background,this study conducted numerical simulations and combined existing measured data to fit subsidence profile curves.The influences of the presence or absence of the reactive piles outside the caissons on the surface settlement profile are investigated.Further investigations are done on the regulation effects of pile spacing on the surface settlement.Based on the principle of the equivalent anti-pulling bearing capacity,the influences of pile spacing and pile diameter on the settlement of the surrounding soil are also explored.Consequently,a modified normalization curve for the settlement profile of the soil outside and between piles is formed,and it may provide reference support for the implementation of the underground stations with pressed continuous caisson group in densely populated urban centers.