摘要
广州市西江引水工程场区地貌主体属于珠江三角洲冲击平原，在场区西部多分布剥蚀残丘。场区地势开阔低平，较为平坦，在剥蚀残丘地段地面起伏较大。场区多为农田、果园、鱼塘，部分地段分布有工业及民用建筑，交通十分便利。管道埋深多为6〜9米,部分管底所在底层为冲击砂层，冲击砂层为场区主要含水层，含水量大，且大部分具有承压水，在基坑设计中必须考虑止水。
本基坑重要性等级根据基坑深度和重要性为二级，为确保土方开挖、周边建筑物和市政设施的安全，需采取临时性支护。基坑支护采用的七种不同的支护方式，主要为钢板桩加直径609的钢管内支撑，也可设置钻孔灌注桩加钢支撑，不同地段设置不同道数的支撑，检修阀井基坑支护宽度为17.8m,一般地段基坑支护的宽度为11.8米。止水采用水泥搅拌桩做止水帷幕。钢板桩在基坑支护中具有墙身强度高、刚度大，材料可以回收利用，施工速度快等优点，因此在基坑支护中得到了广泛应用。
本设计详细对基坑支护进行了说明和计算，内容包括工程概况描述、基坑支护方案选择、支护结构设计与计算、基坑稳定性验算、基坑止水降水设计、施工组织设计、基坑施工监测。
关键词：西江引水工程；深基坑支护设计；钢板桩加内支撑；钻孔灌注桩加内支撑、水泥搅拌桩；止水帷幕。
ABSTRACT
Guangzhou xijiang diversion project area landscape subject in the pearl river delta plain,belong to impact in western area more than high residual distribution erosion.District is flat,open terrain,match residual mound district and denudation ground.Ground for farmland,orchard,fish,some areas are industrial distribution and civil construction,the traffic is very convenient.Pipe buried depth for more than 6〜9 meters,part of the place of shock tube sand layer,the impact of sand layer for main aquifers,baita mountains,and most content confined water foundation pit is,must be considered in the design of water.
The foundation pit excavation depth and significance to the importance for the second,to ensure the turkmen excavation,surrounding buildings and urban infrastructure,take temporary support.Excavation of the supporting by seven different ways,mainly for the steel tube diameter pile and 609,also can set the cast-in-place steel strut,different area with different number of support and maintenance valve shaft for foundation pit supporting width,17.8 m width of foundation excavation areas for 11.8 meters.The water using cement mixing pile as waterproof curtain.Steel sheet pile in foundation pit in wall body,high intensity,stiffness can be recycled materials,construction speed etc,and therefore in the foundation has been widely applied.
The design of foundation pit supporting details and calculation explains,including general description,excavation scheme selection,design and calculation of retaining structure and foundation pit excavation stability checking and stop water rainfall in design,construction and foundation pit construction organization and design.
Keywords:West river diversion project,Design of deep foundation pit supporting,Steel sheet pile with interior support,Bored piles with interior support,cement mixing pile,Waterproof curtain.
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