箱涵回填偏移分析及纠偏实施技术

Analysis and Correction of the Deviation of Box Culverts Being Refilled

位于敞开段或基坑内的箱涵如果没有限位措施在覆盖或回填时极易产生偏移。深圳地铁桥隧相接处明挖箱涵回填过程中由于箱体外侧土体的土压力不够,在中间土体的挤压下造成两线箱体分别外移。加固的措施主要是通过用钢筋混凝土梁把两线箱体的底板连接,在箱体顶部加设素混凝土梁进行支撑以防止箱体向内倾覆,通过把两线箱体连为一个整体,以平衡中间回填土的挤压力,同时增加两线箱体外侧填土宽度,以增加外侧土压力。建议在施工过程中注意监控量测,以及时掌握箱体偏移情况调整回填方案。

Box culverts,if located in the open sections or in the foundation pits,are extremely liable to deviation,when they are being covered or backfilled without proper positioning measures taken.A good case in point is the respective outward moving of the two lines of open-cut box culverts,under the pressure of the mid earth body,at the intersection between the tunnel and the bridge of the Shenzhen Subway during the backfilling process because the pressure of the outside earth of the box culverts is not great enough.Reinforcing measures include connecting the bottom plates of the two lines of box culverts with reinforced concrete beams,providing plain concrete beams at the top of the box bodies to support them so as to prevent them from inward upsetting.Through integrating the two lines of box culverts into a whole body,the pressure from the backfill in the middle could be balanced,with the width of the outside fill enlarged to increase the outside earth pressure.It is highly advisable that much attention be paid to the survey and monitoring work during construction so as to keep abreast of the deviation of the box culvert and facilitate the timely readjustment of the backfill plan.