摘要本工程位于苏州工业园区南施街与旺墩路交叉口西北角，西侧及北侧均为河道，地处苏州工业园区金融区。基坑面积约为16000m2，周长约为520m。基坑东侧地下室外边线距离用地红线5.2～10.2m，红线外侧为南施街；南侧地下室外边线距离用地红线5.7～6.4m，红线外侧即为旺墩路；西侧地下室外边线距离用地红线5.2～9.1m，红线外侧为中央河；北侧地下室外边线距离用地红线5.1m，红线外侧为中央河。拟建建筑物由1幢22层（局部15层）主楼（设有3层地下室）、和主楼北侧的4～5层裙房（3层地下室）及与其相通的外扩3层外扩纯地下室组成。49802

结合本工程地质、环境、挖深等诸多因素确定安全可靠的支护方案；为基坑土方开挖和地下室施工创造一个安全干燥的施工环境；考虑到邻近坑边有建筑和道路（下设有水、电、气等管线），为确保安全，以“变形”控制设计。本着“安全可靠、经济合理、技术可行、施工方便”原则，整个基坑采用一排钻孔灌注桩作挡土结构， 钢支撑作为支撑结构体系。基坑四周采用深层搅拌桩作止水帷幕。基坑内采用喷射井点降水+集水坑排水。

本设计中包括支护体系选型、围护结构的强度的计算、变形计算、场地内外土体稳定性计算、渗透计算、降水计算，电算校核，施工组织设计。其中施工组织设计包括降、排水的具体施工方法、土方开挖方案及具体施工方法、基坑工程施工中应该注意的一些问题及应急措施等。

毕业论文关键词：深基坑；支护结构；挡土结构；钢支撑；钻孔灌注

Abstract

The project is located in Suzhou Industrial Park Nanshi Street and Wangdun Road intersection northwest corner, where the west side and the north side are both river. What’s more, here is the financial district of the Suzhou Industrial Park. The foundation pit area is approximately 16000 square meters, circumference is about 520 meters. Basement is in the east side of the foundation pit, with a outside line approximately 5.2 to 10.2 meters far from the red line. Outside the red line is Nanshi Street. The outside line of the southern basement is about 5.7 to 6.4 meters far from the red line, out of which is Wangdun Road. The outside line of the western basement is about 5.2 to 9.1 meters far from the red line, out of which is Center River. The outside line of the northern basement is 5.1 meters far from the red line, out of which is Center River. The planned object is consist of a 22-story (partly 15-story )main building with three-story basement , a 4 or 5 story podium and a three-story basement linked to it.

Considering of the geologic environment, excavation depth of the foundation pit, to create an safe and dry surroundings for the earth work and basement, we carry out the design in control of displacement deformation, in order to keep  main traffic roads and buildings safe and to protect pipelines of water, electricity and coal gas below the surface well. According with fundamental technical standard, approaching safe reliability, the economical-reasonable and convenient construction and guaranteeing project time limit,we use nondisplacement piles as retaining structure, anchor rod bracing and inclined steel pipe bracing as bracing structures.Around the foundation pit, we use deep churning piles as detaining water pile construct enclosed cut off trench. With the purpose of dewatering, we use sump and well point.

The design of the support system includes selection, building envelope calculation of the strength and deformation calculation, the stability of the soil inside and outside the computing fileld, seepage calcuiation,precipitation,computer cherck ,construction design. Construction design includes the reduction, the specific construction of the drainage method, earth excavation and concrete construction method plan, foundation excavation should pay attention to some of the problems and emergency measures.