Study On Optimization Research Of Prestressed Anchor Cable Composite Soil Nailing Wall For Deep Foundation Pit

The retaining technique of the prestressed anchor cable composite soil nailing wall has been more and more mature in theory and engineering application.The applicability of the deep foundation pit has also been improved with various technologies.Faced with severe problems of the engineering accidents that occurred in the past,at present,whether the construction methods of the foundation pit or the designs of retaining engineering for the foundation pit have effectively improved the safety of foundation pit.Based on the premise of ensuring the safety of the foundation pit,this thesis optimizes the retaining structure of the prestressed anchor cable composite soil nailing wall.The main purpose of this thesis is to increase the cable spacing,firstly,an anchor cable with expandable capsule replaced the conventional prestressed anchor cable,and at the same time,in order to increase the degree of overall optimization,the influence in prestress of the anchor cable and the size of the waist beam was analyzed.Combining with the practical engineering,and using FLAC3 D software,mainly making some works in the following several aspects:(1)Taking a deep foundation pit engineering in Zhengzhou as the subject investigated,according to the reconnaissance report and the design of the deep foundation pit engineering,numerical simulation was performed using the finite difference software FLAC3 D,analyzed the horizontal displacement of soil mass,the vertical displacement of soil mass,soil stress and the axial force of soil nailing and anchor cable.(2)The support structure model was established by using the anchor cable with capsule instead of the normal one.The analysis of the anchor cable with capsule of the composite soilnailing wall for deep foundation pit was carried out to obtain the variations of the stress,displacement and internal force of the supporting structures.The results were compared with the result of the conventional anchor cable and the anchor cable with capsule had higher stability than conventional anchor cable.(3)Based on the anchor cable with capsule,to increase the spacing between anchor cables,then to analyze the displacement and internal force of this deep foundation pit.at the same time,to calculate the safety factor of the foundation pit for the stability after optimization.In order to better optimize the retaining structure,the prestress of the anchor cable and the size of the waist beam are selected to simulate the interaction between the and retaining structures and the displacement of the soil mass.The optimal parameters are selected and to optimize the combination.