【摘要】 针对超大深基坑支护方案选择问题，以洛阳龙门站综合交通枢纽北广场工程为依托，建立超大深基坑支护方案指标评价体系，采用层次分析法和熵权法计算指标组合权重，利用模糊综合评价法选出合理的支护形式.运用Midas-GTS NX建立有限元模型，结合数值模拟和现场监测，分析在该支护形式下，基坑施工过程中土体和支护结构的变形规律.研究结果表明：通过计算确定基坑北侧、东侧和西侧采用放坡+土钉墙支护、南侧采用灌注桩+预应力锚索支护的方案.周边地表沉降分布规律符合沉降槽曲线，基坑西侧最大沉降发生在距坑边9 m位置，最大沉降量为18.32 mm,基坑南侧最大沉降发生在距坑边7 m位置，最大沉降量为15.82 mm,影响范围较基坑西侧减少9 m.基坑边坡水平位移和竖向位移最大值均发生在坡脚处.灌注桩水平位移随桩深呈先增大后减小趋势，桩身最大水平位移为15 mm,发生在桩长约10 m处.桩体产生向上位移，隆起量最终稳定在13.42 mm.现场监测结果均未超过控制值，基坑支护方案选取合理.更多还原

【Abstract】 Aiming at the selection of super deep foundation pit support scheme and its deformation law, based on the North Square Project of Luoyang Longmen Station Comprehensive Transportation Hub, an index evaluation system for super deep foundation pit support scheme was established. The weight of the index combination was calculated by the analytic hierarchy process and the entropy weight method, and the reasonable support form was selected by the fuzzy comprehensive evaluation method. By building finite element model with Midas-GTS NX, combined with numerical simulation and on-site monitoring, the deformation laws of soil and supporting structures during foundation pit construction were analyzed under this support form. The research results show that: the north, east and west sides of the foundation pit are supported by grading and soil nail wall, and the south side of the foundation pit is supported by cast-in-place piles and prestressed anchor cables. The distribution law of the surrounding surface settlement conforms to the settlement tank curve. The maximum settlement on the west side of the foundation pit occurs at a position 9 m away from the pit edge, and the maximum settlement is 18.32 mm. The maximum settlement on the south side of the foundation pit occurs at a position 7 m away from the pit edge, with a maximum settlement of 15.82 mm, and the affected area is 9 m less than that on the west side of the foundation pit. The maximum horizontal displacement and vertical displacement of the foundation pit slope both occur at the toe of the slope. The horizontal displacement of the cast-in-place pile increases first and then decreases with the depth of the pile. The maximum horizontal displacement of the pile body is 15 mm, which occurs at a pile length of about 10 m. The pile body is displaced upward, and the uplift is finally stabilized at 13.42 mm. The on-site monitoring results did not exceed the control value, and the selection of the foundation pit support scheme was reasonable.更多还原