【摘要】 北京地铁朝阳站坑中坑基坑呈现坑内施工空间有限、基坑深度不一等特点，常规的换撑方案使得各工序间相互干扰造成施工工期不满足要求。本文从简化深基坑换撑施工工序角度出发，基于“支架代撑法”理念，提出了满堂支架和钢斜撑的组合支护方案。采用数值模拟的方法对原换撑方案(钢倒撑)、侧墙代替换撑方案和满堂支架组合方案进行了研究，并通过现场监测验证了本论文方案的可行性。结果表明：(1)满堂支架组合换撑方案减少了施工步序，节省施工预算，保证施工过程中结构安全，并成功应用于异形坑中坑基坑主体结构施工中；(2)满堂支架方案较原换撑方案相比，地连墙变形最大值仅增加9%,仅施作侧墙方案较满堂支架方案水平变形增加35%;(3)已建侧墙和架体连接部位的约束作用使得架体整体变形较小，脚手架的内力表现为中间大，两边小的变化趋势。更多还原

【Abstract】 The pit-in-pit foundation of Beijing High Speed Railway Chaoyang Station presents the characteristics of limited construction space and varying depths of the pit, and the conventional solution of dismantling and replacing bracing makes the processes interfere with each other causing the construction period to be unsatisfactory. From the perspective of simplifying the construction process of deep foundation pit support replacement, based on the concept of ‘support replacement method’, a combined support scheme of full support and steel oblique support was proposed. Numerical simulations were used to study the original bracing replacement scheme(steel inverted bracing), the sidewall replacement bracing scheme and the full hall bracing combination scheme, and the feasibility of this thesis scheme was verified through on-site monitoring. The following conclusions were reached:(1) the full hall bracing scheme reduces the construction steps, saves the construction budget, ensures structural safety during construction and is successfully applied to the construction of foundation pit demolition and replacement bracing in shaped pits;(2) the maximum deformation of the ground connection wall increases by only 9% compared with the original demolition and replacement bracing scheme for the full hall bracing scheme, while the horizontal deformation increases by 35% compared with the full hall bracing scheme for the sidewall only scheme;(3) The constraint effect of the built side wall and the connection part of the frame body makes the overall deformation of the frame body small, and the internal force of the scaffold shows a trend of large in the middle and small on both sides.更多还原