天河区间施工组织设计工程测量技术.doc

摘 要 本工程既有地面标高为19.02m～22.87m，规划地面标高为28m，根据本工程周边环境、地质条件、工程造价和施工场地，本设计基坑开挖深度约11.6～6.6m，对于盾构井及后续约20m基坑区段采用钻孔桩+内支撑围护型式，其余基坑段采用放坡开挖。根据基坑功能，结合地质及周边环境，依据湖北省基坑工程技术规程规定，采用钻孔桩支护段基坑重要性等级为一级，支护结构最大水平位移≤30mm，地面最大沉降≤30mm；放坡段基坑安全等级为二～三级。 盾构井及后续20m左右明挖段基坑支护采用?800@1000mm钻孔灌注排桩。盾构井设一道钢筋砼支撑（宽x高：0.8x1.0m）与一道?609、壁厚t＝16mm钢支撑。桩顶设1.0*1.0m冠梁，第二道撑采用双拼56a工字钢钢腰梁。后续20m明挖段设两道?609、壁厚t＝16mm钢支撑，水平间距4m，沿基坑纵向放坡线设置斜向冠梁。围护结构内侧采用?8@200X200钢筋网喷砼防护。主体结构形式为中间设中隔墙单层双跨箱型框架结构。 放坡开挖段+内支撑支护外，其余区段均采用放坡开挖。基坑钻孔桩围护与放坡开挖重叠段，先进行放坡开挖再施作冠梁，盾构井后续的斜坡段及平直段冠梁应一次性浇筑，保证整体性。基坑放坡开挖段，边坡采用两级放坡，DK2+120.100～DK2+190.000基坑段一、二级放坡坡度均为1:1.5；DK2+190.000～DK2+305.416基坑段一级放坡坡度为1:2，二级放坡坡度为1:1.5。一、二级坡中间设3m宽放坡平台，基坑放坡坡面采用100mm厚C25喷砼,内设?8@200x200钢筋网，并采用L=1.5m，沿坡面纵横间距均为1.2m的?16短筋固定坡面。坡面必须随挖随护，及时进行，以防止土体的软化、风化。结构形式为不连接的单层箱型框架结构。 关键词： 盾构 区间 钻孔桩 Abstract Existing ground elevation of the project for the 19.02m~22.87m, planning, ground elevation is 28m, according to the surrounding environment and geological conditions of the project, construction cost and construction sites, the design of Foundation pit excavation depth of about 11.6~6.6m, shield and subsequent 20m of the well Foundation pit support within the sector with bored pile + fender style, put rest pit excavation. Foundation pit of under features, combined with the geology and environment, established pursuant to the technical specifications for Foundation pit project in Hubei Province, retaining importance level for the level of Foundation pit with bored piles, maximum horizontal displacement of supporting structure of ≤ 30mm, ground Max settlement 30mm; slope excavation safety levels for two ~ three. Shield and subsequent 20m ? mined excavation pit used bored piles of 800@1000mm. Shield made up of reinforced concrete support (width x high: 0.8x1.0M) in conjunction with ? 609, t=16mm wall thickness steel supports. Set top 1.0*1.0M top beam, brace use the second road double 56A beams steel back beam. Follow-up 20m mined excavation located two ? 609 and wall thickness of t=16mm steel su