Sensitivity Analysis Of The Influence Of Main Factors On The Deformation Of Internally Supported Excavation

As the depth of the excavation continues to increase and the surrounding environment becomes more and more complex,the design of f excavation is shifting from a design idea of stability control to a design idea of deformation control.In this paper,firstly,two typical excavations with internal support were monitored on site.On this basis,the PLAXIS model was established and the reliability of the model was verified.Then the deformation of the excavation was divided into three major aspects(soil,enclosure system,cement-soil reinforcement)for analysis,and the following work was doneBased on the soil hardening model(HS)in PLAXIS 3D,the effects of several parameters of soil on the lateral displacement of the retaining wall of the excavation and the settlement of the soil outside the pit are analyzed.The sensitivity of the 6 parameters is rankedThe influence of the elastic modulus,thickness and embedded depth of the retaining wall on the deformation and force of the excavation is analyzed.It is found that the thickness of the retaining wall has the most obvious influence on the deformation of the excavationThe distribution of internal supports in the vertical direction has been optimized to make the deformation and stress of the excavation more reasonable.A comparative analysis of the cement-soil reinforcement in the active area and the passive area of the excavation is carried out,and it is concluded that the reinforcement effect in the passive area is much better than the reinforcement effect in the active area And during the reinforcement of the passive zone,although the deformation is greatly restrained,the bending moment in the opposite direction and continuously increasing appears below the excavation surface of the foundation pit.It shows that from the perspective of stress,the wider and deeper the passive zone reinforcement is not,the more advantageous it is.It is necessary to strengthen the reinforcement of the embedded section of the retaining wallThe above calculation results are relativized,making the sensitivity of each parameter more intuitive and more comparable.