盾构隧道施工对既有桩基沉降及管片受力的影响分析

在城市轨道交通建设中,盾构法施工以其特有的技术优势得到推广使用。而盾构掘进过程中近距离下穿(侧穿)建筑物时会引起其周围土层应力、应变、位移等性质的改变,对既有建构筑物产生影响,尤其是在建(构)筑物受土体应力变化影响比较敏感的情况下,更容易产生破坏,危及建筑物的安全。本文根据某市轨道交通一号线工程地质情况,利用MADIS模拟盾构掘进过程,分析盾构掘进过程中土层的应力和位移变化对车站站房桩基础及盾构管片的应力变化的影响,总结盾构掘进过程中站房桩基础及不同工况下盾构管片的应力变化规律,以便采取相关措施减少盾构掘进过程对既有建(构)筑物基础的影响。

STUDY ON THE IMPACT OF THE STRESS OF BOTH THE EXISTING PILE FOUNDATION AND SEGMENT BY SHIELD TUNNEL CONSTRUCTION

In urban rail transit construction, shield construction method is widely used by its unique technology advantage. Shield tun- neling under （beside） buildings can cause the change of the stress, strain and displacement of the surrounding soil, impact on both the building （structure）. Especially the building （structure） is relatively sensitive to changes in soil stress effects, it is more prone to damage, and endanger the safety of the building. Based on a city Rail Transit Line engineering geological conditions, the shield tunne- ling process is simulated using MADIS, the effect on the station building pile foundation and the lining segments by the change of soil stress and displacement is analyzed. The variable regularity of station house pile foundation and tunnel segments during shield tunneling under different working conditions is summarized, related measures have been taken to reduce the impact on the existing building dur- ing tunneling.