Abstract: In view of the problem that the adjacent road construction would affect the displacement characteristics of the pier top of the existing pier by changing the contact stress distribution of the pile-soil interface of the pile foundation of the existing pier, an in-service pier of Chongqing Rail Transit Line 3 was taken as the engineering background, and a three-dimensional numerical model describing the foundation-base-pier interaction in the process of critical road construction was established by using the large-scale general finite element software ABAQUS. Based on the proposed model, the influence of road excavation, paving and operation on the horizontal and vertical displacement of pier top were studied. The research results show that: after subgrade excavation, with the increase of excavation depth (H), the horizontal displacement of pier top will continue to increase and the vertical settlement of pier top will continue to decrease. With the increase of the distance (L) from the road to the pier edge, the horizontal displacement of pier top will continue to decrease; however, the vertical settlement of pier top will continue to increase. Compared with subgrade excavation, the horizontal displacement of pier top caused by road paving tends to decrease, but the vertical displacement tends to increase. In the later operation of newly-built road, the horizontal displacement of bridge pier top caused by traffic load is relatively small, while the vertical settlement is significantly larger than that caused by road construction. In the obtained curve of horizontal displacement of pier top changing with excavation depth, the turning point of pier top horizontal displacement from close to the road to far away from the road varies during road construction. In the subgrade excavation, when the excavation depth is about 1.8 m, the horizontal displacement direction of pier top changes. In road paving, when the excavation depth is about 2.6 m, the horizontal displacement direction of pier top changes. In the later operation, when the excavation depth is about 3.1 m, the horizontal displacement direction of pier top changes.

Key words: highway engineering; excavation; paving; operation; pier top displacement

摘要： 针对临近道路施工会通过改变在役桥墩桩基础桩-土界面的接触应力分布从而影响在役桥墩的墩顶位移特征这一问题，以重庆轨道交通3号线某在役桥墩为工程背景，利用有限元软件ABAQUS建立了描述临界道路建设过程中地基-基础-桥墩相互作用的三维数值模型，基于此模型分别研究了道路开挖、铺筑及运营对墩顶水平、竖向位移的影响。研究结果表明：路基开挖后，随着开挖深度（H）增加，墩顶水平位移会不断增大，墩顶竖直沉降则会不断减小，随着道路至桥墩边缘距离（L）的增加，墩顶水平位移不断减小，竖直沉降反而不断增大；道路铺筑后引起的桥墩顶部水平位移较路基开挖有减小趋势，竖向位移却有增大趋势；新建道路在后期运营中，交通荷载引起的桥墩顶部水平位移相对较小，而竖直沉降较道路施工引起的位移明显增大；在得出的墩顶水平位移随开挖深度的变化曲线中，墩顶水平位移从靠近道路到远离道路的转折点在道路施工中有所变化；在路基开挖中，当开挖深度约为1.8 m时，墩顶水平位移方向发生变化；在道路铺筑中，当开挖深度约为2.6 m时，墩顶水平位移方向发生变化；在后期运营中，当开挖深度约为3.1 m时，墩顶水平位移方向发生变化。

关键词: 道路工程；开挖；铺筑；运营；墩顶位移