摘要该工程位于中部平原地区，地势相对较为平坦，除上层杂填土外，下层为成层粉土、淤泥质土及粘性土，周边有城市道路和已建居民楼和综合性办公楼。地下水较为丰富，其中粉土层和淤泥质土层透水性较好，所以必须采取竖向止水。结合周边环境并参考以往施工案例，本设计采用了两种支护结构形式，首先是基坑南北两侧距离用地红线较远，故采用桩锚支护，即单排桩+单层锚钉支护；东西两侧由于场地的局限性，采用双排桩支护。止水帷幕采用深层搅拌水泥土法，深层搅拌水泥土桩在相邻两支护桩的中间，与支护桩相互衔接200mm形成密封止水桩墙，既起到止水的作用，又增强支护桩的支护能力。本设计基坑重要性等级根据基坑开挖深度和重要性定为二级，各段基坑支护设计都本着安全、经济、合理的原则严格按照相关规范的要求进行。本设计对基坑支护做了详细的计算和说明，主要内容包括：工程概况的描述、基坑支护方案的对比与确定、基坑降水方式的确定、基坑涌水量计算、基坑降水平面图设计、止水帷幕的设计与计算、基坑支护结构设计与计算（包括支护桩长的计算、桩身最大弯矩的计算、锚钉支锚力的计算、锚钉长度的计算以及支护桩配筋计算）、基坑稳定性验算、基坑施工监测等。其中大部分计算过程通过手算完成，基坑稳定性验算部分借助理正深基坑软件完成。关键词：深基坑；桩锚支护；基坑稳定性；止水帷幕；基坑降水IAbstractTheprojectislocatedinthemiddleofplainsareas.Theterrainisrelativelyflat.Exceptfortheuppermiscellaneousfill,thelowermostlylayeredsilt,siltysoilandclaysoil.Thefoundationpitsurroundedbyurbanroadsandbuildingsthathavebeenbuilt.Theareaisrichingroundwaterandthewaterpermeabilityofsiltandmuckysoilisbetter.Soitisnecessarytousetheverticalwaterproofcurtain.Thedesignusestwoformsofsupportstructurecombinedwiththesurroundingenvironmentandwithreferencetootherconstructioncases.Thenorthandsouthsidesofthefoundationpitisfarawayfromtheredline.SothePile-anchorSupportisusedthatissinglerowpilesingletaganchorsupport;Duetothelimitationsofspace,doublerowpilessupportisusedoneastandwestsides.Eementdeepmixingmethodisusedtodevelopwaterproofcurtain.Itplaysaroleinwaterstop,butalsoenhancethesupportcapabilityofsupportpileswhenthedeepmixingcementpileslinkinthemiddleoftwoadjacentsoldierpiles200mmwhichformingasealedsealwaterstop.Accordingtoexcavationpitdepthandimportancethelevelofimportanceofthedesignisasecondary.Eachsegmentoftheexcavationdesignarestrictaccordancewiththerequirementsoftherelevantnormsdevelopinasafe,economicalandreasonableprinciple.Thedesignmadeadetailedcalculationandexplanationaboutthefoundationpit,themaincontentsinclude:adescriptionoftheprojectoverview,schemecomparisonandselectionoftheFoundationPitSupport,determiningofFoundationPitDewateringMethods,calculationoffoundationinflow,thedesignofFoundationPitprecipitationplanview,designandcalculationofwaterproofcurtain,thedesignandcalculationsofFoundationPitsupportstructure(includingthelongthcalculationofsupportingpiles,thecalculationofmaximumbendingmoment,thecalculationtaganchortensionandcalculationofthelengthoftaganchorandthereinforcementcalculationForsupportingpiles),thecheckingforfoundationstability,FoundationPitconstructionmonitoring.Keyword：DeepFoundation；Pile-anchorSupport；stabilityofFoundationPit；WaterstopCurtain；foundationpitdewateringII目录摘要........................................................................................................................IAbstract....................................................................................................................II第1章绪论........................................
