（1 同济大学土木工程学院 上海 200092； 2 宁波市建筑设计研究院 315010）
【提要】 针对某三层地下停车库基坑支护结构，进行了围护桩的支撑道数、支撑位置、围护桩的桩型、嵌固深度以及土层参数取值等五方面的优化设计，比较了有、无对撑支撑方式的两种支撑结构。计算表明，多种基坑支护方案的比较不仅节省工程造价，而且能提高基坑支护工程抗风险的能力。采用边坡加支护桩和内支撑基坑支护方案对开挖深度超过10m的基坑，可设两道支撑，支撑位置应尽量往下压，同时应控制基坑水平向的位移量。内支撑平面布局应综合考虑各种因素，尽量选用无对撑支撑方式。
【关键词】 基坑支护 停车库 排桩 嵌固深度
Analysis on Supporting Structure for a Underground Parking Foundation Pit/Wu Zhehua1,2, Xu Yang2, He Libo2, Xu Guoping2, Chen Yiyi1，Song Zhenqi2(1 Department of Civil Engineering,Tongji University,Shanghai 200092,China; 2 Ningbo Architectural Design & Research Institute, Ningbo  315010,China)
Abstract:Based on designing project of a threefloor underground parking, the optimization  design is discussed including the rows and situation  of  braces,the
 type  of pile,the embedded depth of pile and the value of c，φ of soil. Bracing system w
ith or without opposite braces is compared. For saving cost of construction and raising ability of antirisk,analysis and comparison of the multiple schemes are needed. The combination
 of slope and piles in row within bracing system is desirable to build foundation pit with  10m depth excavation. Two bracings and lower site of bracing would be more effective. Horizontal displacement of pit should be controlled.Bracing system around pit is preferred.
Keywords:foundation pit; supporting structure; parking; piles in row; embedded depth