In order to investigate the lateral deformation of the flexible supporting structure of composite soil nailing wall with soil nailing plus prestressed anchoring rod,the soil mass was simplified into a model with infinite and continuously distributed soil springs when the stiffness of anti-lateral shift of the soil mass proper and the decrease of soil spring stiffness with the plastic development of the soil mass were taken into consideration.Based on the assumption that the earth pressure caused by pit excavation would be shared by soil,soil nail and prestressed anchoring rod according to their stiffness and the prestress would act on the soil mass in the form of external load,a computation method for the lateral displacement of the soil under its share of earth pressure load,prestress and ground overload in the flexible supporting structure was obtained.The numerical simulation of an engineering example was carried out with finite difference software FLAC3d and its result was compared with that obtained with the computation method presented.The result shows that the lateral deformation of the soil nailing wall obtained with foregoing two methods will basically be consistent with each other,illustrating that this method presented can be used to calculate the lateral deformation of the foundation pit with flexible supporting structure.%为了研究土钉加预应力锚杆复合土钉墙柔性支护结构的侧向变形,通过考虑柔性支护结构中土体自身的抗侧移刚度,将土体简化为无数个连续分布的土弹簧模型,并考虑土弹簧刚度随土体的塑性发展而折减.基于基坑开挖产生的土压力由土体、土钉和预应力锚杆按刚度大小共同分担的假定,以及预应力以外荷载的形式作用到土体的假定,得到柔性支护结构中土体在自身所分担的土压力荷载、预应力和地面超载的共同作用下侧移变形的计算方法.采用有限差分软件 FLAC3 d对某一工程实例进行数值模拟,并与采用该方法计算所得结果进行对比,结果显示两种途径所得变形基本一致,表明该方法可以计算柔性支护结构的基坑侧向变形.
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