本文以西安某深基坑支护工程为依托，在黄土地区首次采用高压旋喷扩大头预应力锚索与SMW工法桩联合应用的基坑支护方案。根据现场监测数据，分析了基坑周边深层土体水平位移、周边地表沉降及支护结构的内力等变化规律；对深基坑开挖施工及支护全过程进行了二维数值模拟分析，并与现场实测数据进行对比，验证了数值模拟计算结果的合理性。利用有限元分析软件，通过改变支护结构的相关参数，研究了支护桩桩径、嵌固深度、预应力锚索等对SMW工法桩与预应力锚索联合支护结构变形及受力的影响规律，为本地区类似深基坑设计及施工提供参考。研究结果表明：坑周深层土体水平位移随深度变化曲线近似呈“弓形”，最大位移值发生在约基坑的1/2开挖深度处，位于1.5倍坑深以下的土体水平位移近似为零。相邻两道锚索施工时，下道锚索张拉锁定，会导致紧邻的上道锚索的拉力降低，锚索拉力减小值约为3%～10%，但对其它更远层锚索拉力影响甚微。监测结果显示本工程锚索拉力均远小于设计值，说明基坑设计偏于保守，设计方案存在优化空间。通过对深基坑开挖施工及支护全过程的有限元模拟计算，分析了七种不同工况下支护结构的受力及变形特征，得出基坑土体水平位移随深度变化规律与监测结果一致，但数值较实测值偏大。加大支护桩嵌固深度可有效的减小支护结构的变形；但嵌固深度达1倍基坑开挖深度时，对减小支护结构变形的影响不大，建议类似的工程支护桩的嵌固深度取0.8H为宜。锚索的加入可以明显改善联合支护结构的受力状态，增加锚索预应力能有效的减少开挖面以上支护结构的变形，提高基坑的整体稳定性。

On the basis of a building project of deep foundation pit supporting engineering in Xi'an，it first adopted the scheme of deep foundation pit by uniting high pressure jet expanding prestressed anchor cable with SMW pile construction method in Loess area。According to the tracking of monitoring data for analysis，discussed the tendency of supporting structure deformation with the rule of the week of pit deep horizontal below of soil、settlement around of the ground and internal force of retaining structure。The paper established two-dimensional finite element model simulation of deep foundation pit excavation and support the whole process，it compared with the monitored data measured，found that the result from finite element software consistent well with the measured data。Making use of the finite element method，the paper analyses the influence of different parameter，different diameter of supporting piles， different embedded depth of supporting piles，different strut axial forces to the deformation of prestressing anchor cable with SMW wall。It provides a reference basis for deep foundation pit design and construction of similar sites in this region。 The results showed that：week of pit deep horizontal displacement of soil with depth change curve is approximately "bow"，The maximum displacement occurs in the pit of about 1/2 the depth of excavation，the horizontal displacement of soil approximate to zero located at 1.5 times。 When the cable construction of two adjacent anchor，with the moment of anchor cable tension lock，it cause on road next to the anchor cable tension suddenly drops，reducing value of cable stress is about 3% ～10%，but it has little influence on the other farther layer，The monitoring analysis shows that the engineering anchor cable tension is far less than the design value， indicates pit design is conservative，there is a space-optimized design。The paper established finite element model simulation of deep foundation pit excavation and support the whole process，it analysis Seven different conditions of reinforces the palisade structured and summarized with deformation law of deep foundation pit。Draw the horizontal below of soil belong to change over depth with displacement of foundation pit wall and the monitoring results are consistent，but larger than the value of the measured value。Increasing the embedded depth of supporting piles can effectively reduce the deformation of supporting structure，but the embedded depth reachs 1H，it has a little effect on the deformation of the supporting structure，suggested a similar projects supporting piles capacity of appropriate to take with 0.8H。Prestressing anchor cable can obviously improve the stress of combination structure，increasing prestress can reduce the deformation of retaining structure effectively above the excavation surface，the foundation pit with overall stability will be improved。