不同载荷边界条件下的地铁站深基坑变形特性研究袁庆利摘要：为更好地实现不同载荷边界条件下的基坑变形预测和控制，以天津市某地鐵站深基坑为研究对象，研究超载、卸载条件下基坑变形特征。通过对现场监测数据的分析，推导基坑北侧和南侧的变形规律，并将分析结果与无超载、卸载条件的普通基坑进行水平位移、地表沉降、土体蠕变等方面的对比，最后，根据超载与卸载产生主动土压力对水平位移的影响，制定了基坑变形控制措施。结果表明：1）载荷边界条件对基坑支护结构和地层的变形影响明显;2）北侧基坑围护结构的水平位移和地表沉降均远大于南侧，北侧变形常超过变形报警值，南侧则相反;3）北侧土层水平蠕变最大速率和竖向蠕变最大速率均大于基坑南侧，普通基坑水平蠕变的最大速率介于两者之间，表明控制边界载荷有利于控制土层变形速率;4）基坑北侧的主动土压力明显高于基坑南侧，由于卸荷作用，基坑南侧地连墙底部产生被动土压力，使基坑侧壁向迎土侧移动;5）合理安排开挖进度，加强支承刚度，减少地表超载，是控制荷载边界条件和基坑变形的有力措施。研究可为城区复杂荷载边界作用下的基坑监测、施工的优化提供依据。关键词：地基基础工程;荷载边界条件;深基坑;变形特性;天津地铁：TU476文献标识码：ADOI：10.7535/hbgykj.2021yx03008Abstract：Inordertopredictandcontrolthedeformationofsubwayfoundationpitunderdifferentloadboundaryconditions，thedeformationcharacteristicsoffoundationpitwerestudiedinacaseofTian激nmetrounderoverloadingandunloadingconditions.Basedontheanalysisoffieldmonitoringdata，thedeformationlawsofthefoundationpitwerededucedinthenorthandsouthsides，thentheresultswerecomparedwiththeordinaryfoundationpitwithoutoverloadingandunloadingconditionsintheaspectsofhorizontaldisplacement，settlementandsoilcreep.Finally，accordingtotheinfluenceoftheactiveearthpressuregeneratedbyoverloadandunloadonthehorizontaldisplacement，thedeformationcontrolmeasureswereformulated.Theresultsshowthat：1）thedeformationofsupportingstructureandstratumoffoundationpitisobviouslyinfluencedbytheloadboundaryconditions;2）thehorizontaldisplacementandsettlementoftheretainingstructureinthenorthsidearemuchlargerthanthoseinthesouthside，andthedeformationoftenexceedsthealarmvalueinthenorthside，whilethatinthesouthsideisonthecontrary;3）themaximumratesofsoilhorizontalcreepandverticalcreepinthenorthsidearehigherthanthoseofthesouthside，betweenwhichisthemaximumrateofsoilhorizontalcreepofordinaryfoundationpit，indicatingthatthecontrolofboundaryloadisgoodforcontrollingthesoildeformationrate;4）theactiveearthpressureonthenorthsideissignificantlyhigherthanthatonthesouthside.Thepassiveearthpressureisgeneratedatthebottomofthediaphragmwallonthesouthsideduetotheunloadingeffect，whichmakesthediaphragmwallmovetowardsthesoilside;5）reasonablearrangementofexcavationschedule，strengtheningofsupportstiffnessandreductionofsurfaceoverloadareeffectivemeasurestocontrolloadboundaryconditionsandfoundationpitdeformation.Theresearchresultprovidessomereferenceforfoundationpitmonitoringandconstructionoptimizationundercomplexloadboundaryinurbanarea.Keywords：groundfoundationengineering;loadboundaryconditions;deepfoundationpit;deformationcharacteristics;Tian激nMetro地铁深基坑的建设会受到周边环境的影响，特别是在城区密集建筑物以及市政设施的影响下，地铁的深基坑开挖具有高风险和高难度的特点，对基坑建设本身和周边建（构）筑物、周边交通、居民行人等都具有潜在的安全隐患[1-2]。因此，基坑现场监控测量是保证地铁深基坑安全开挖的重要前提[3-4]。国内外学者对深基坑展开了大量的监测和研究工作，总结出了一些研究成果[5-6]。在基坑边缘超载方...