本文对盾构隧道施工引起地层沉降的数值模拟进行了研究。文章采用三维数值模拟软件FLAC<'3D>如对盾构推进过程进行了模拟，并结合上海地铁2号线工程实测数据重点对开挖后30天内的地层沉降尤其是地表沉降规律进行了分析研究。主要研究内容包括：地表沉降与历时之间的关系、地层沉降随深度分布规律、隧道横截面地层沉降分布与沉降槽扩展规律、隧道纵向沉降分布规律。本文模拟所得地表沉降曲线与实测曲线较为吻合。文章认为，盾构施工中，壁后注浆浆液经历凝胶一固结过程，期间其抗压强度及其它力学性质在不断变化，必然对地层沉降产生影响。本文引入等代层的概念，以单液缓凝型浆液抗压强度试验数据及经验取值为主要依据，设置多组浆液强度变化值，采用多次数值模拟的方法，分析研究了浆液各时期强度对地层沉降尤其是地表沉降的影响。

The distubance of soil oaused by shield tunnel construction results in the∞il movement，Inaiuiy the g∞mld settlement,which is ogle ofthe problem hi#y concerned in the design andconstruction process ofshield tunneling． Shield tunneling is simulated by a finite difference code FLAC”．Then,the characteristic of ground settlement especially surface settlement in 30 days following the excavatioll at test site is studied on the basis ofthe combination ofthe measured data ofShangHai No．2 Subway Line and the result of numerical analysis．It generally analyzes the relation bctwccn s眦'face settlement and time,the characteristic of ground settlement with respect to the dep血加 characteristic ofground settlement on Imcrui section ofthe tunnel and the lateral extension of settlement as well as ground settlement oll longitudinal sectioll ofthe tunnel．Furthermore,the eLLrve ofsurface settlemem as aresult ofsimulating is close to the measured CUlNe． On the construction ofthe shield tunneling,the process from gelatination to consolidation for material of backfill grouting influences the ground settlement．The concept of equivalent circuIar zone is supposed by this thesis and compressive strength values in defferem times of aprocess ofslurry consolidating arg set as agroup andused in simulation with the help oftest data and empirical value of compressive strength of single fluid slurry in additional with delayed coagulant．In this way,a serial ofdata groups are took account ofby the&哪times of simulations to study the influence by soil settlement especially ground settlment of grouting slurry mainly the early stage compressive saength and final one． The two key results ofthis thesis are： First,the ground settlement in 30 days following the g“艘馏￡锄is differential in accord with the time． Second,the early stage compressive strength of the backfill grouting slurry influences the final surface settlement in 30 days foUwing the excavation effectively．On the other hand，the final stage compressive sUength is negligible． The results of this thesis may have some reference value to design and construction of shield tunneling．