近接基坑开挖影响下既有地铁附属结构联合支护体系优化分析  

Optimization of Combined Support Systems for Existing Subway Ancillary Structures Affected by Adjacent Excavation

作　　者：陶畅 彭丽云 刘兵科 陈涵宇 TAO Chang;PENG Liyun;LIU Bingke;CHEN Hanyu(College of Civil Engineering and Transportation,Beijing University of Architecture,Beijing 100044;Beijing Construction Civil Engineering Co.,Ltd.,Beijing 100015)

机构地区：[1]北京建筑大学土木与交通工程学院,北京100044 [2]北京建工土木工程有限公司,北京100015

出　　处：《都市快轨交通》2024年第6期106-114,共9页Urban Rapid Rail Transit

基　　金：国家自然科学基金(42172299)。

摘　　要：针对既有地铁附属结构在临近深基坑一侧,支护结构施作难的问题,提出“护坡桩+对拉锚杆+斜拉锚索”配合注浆联合支护体系。采用Midas软件建模,从对拉锚杆间距与直径、斜拉锚索锚固段长度与道数4个方面设计单因素优化方案,并通过工程实例验证方案的合理性。研究结果表明:桩顶最大水平位移随对拉锚杆间距的减小而减小,随对拉锚杆直径、斜拉锚索锚固段长度与道数的减小而增大;护坡桩桩顶水平、竖向位移的模拟结果与监测结果趋势吻合,竖向位移呈抛物线型,水平位移呈弓型;基坑在施工过程中,地铁附属结构的变形控制较好,远低于近接深基坑桩顶位移;基坑顶部沉降位移呈波动上升趋势,深层水平位移在不同开挖阶段的变形趋势均为中间大两端小,且随着开挖深度的增加,地铁附属结构的最大水平变形位置沿井壁逐渐向下移动。This paper proposes a combined support system comprising retaining piles,tensioned anchor rods,and inclined anchor cables with grouting to solve the problems associated with constructing supporting structures for deep excavations near obstacles on one side.The study utilized Midas software for modeling,and single-factor optimization analysis schemes were designed considering four aspects:spacing and diameter of tensioned anchor rods and number and length of segments for inclined tensioned anchor cables.The rationality of this scheme was validated using engineering examples.The results showed a match between the simulated trends of the horizontal and vertical displacements of the slope-protection pile tops and the monitoring results.The vertical displacement exhibited a parabolic trend,and the horizontal displacement exhibited an arched shape.The maximum horizontal displacement of the pile tops decreased as the spacing of the tensioned anchor rods decreased and increased as their diameters and the number and length of segments of inclined tensioned anchor cables decreased.During construction,the deformation of subway ancillary structures was well-controlled and significantly less than that of the adjacent deep excavation.The top settlement showed a fluctuating upward trend,whereas the deep horizontal displacement had a middle-high and end-low pattern at different excavation stages.As the excavation depth increased,the subway structures'maximum horizontal deformation shifted downward along theshaftwall.

关 键 词：城市轨道交通 联合支护体系 地铁附属结构 支护优化 数值计算 

分 类 号：TU745.3[建筑科学—建筑技术科学]