Analysis Of Prestressed Bolt In Soil Nail Wall Supporting Structure

A flexible support structure,composed of prestressed anchor and soil nails,utilizes soil nails as its primary support element.The prestressed anchor rod combined with reinforcement reinforcement.It is widely used by its low cost,simple technology,and convenient construction.However,the prestressed anchor rod is an active force component,and the soil nails are passive stress components.How to control the deformation of the foundation pit by adjusting the support structure is still in a "semi-theoretical and semi-experience" state,and its design method is still immature.The influence of prestressed anchor on the nail nail support structure needs to be further discussed and analyzed.Starting from the actual engineering project,this article uses numerical simulation software to analyze the prestressed anchor rod on the deformed law and stability of the foundation pit in the nail support structure.The main research content includes:(1)Summarize the mechanism,deformation characteristics and destruction method of composite the wall of the plain layer,grouting,soil injection,nailing,prestressed anchor rod,prestressed anchoring rod,and composite the way of composite the soil nail wall.(2)Taking the cure project of Crystal Cabaraki Pit in Xi’an as the case,the excavation of foundation pit to support was performed for deformation monitoring,and Midas GTS NX was used Anchor composite soil nail support structure performed simulation analysis.Results indicate that the side of the foundation pit,beneath the two support structures,is "drum" due to the deformed foundation.The prestressed anchoring pole composite earth nail wall has a significant restraint on the deformation of the foundation pit.The maximum,The apex of the prestressed anchor rod lies at the junction of the anchor and the free sections.The axis force’s free section is the same and equivalent to the maximum axis.Deep increase and faster.(3)Using Midas GTS NX software simulation simulation analysis has the effects of prestressed anchor and their parameters and design positions on the structure of soil nail support.The simulation results show that:The prestressed anchor rod can decrease the axis of the soil nails from 13.39% to 50.64%,with the highest axis position being nearer to the slope,thus significantly diminishing the soil body of the active area and the effect of the foundation pit safety factor reaching 8.26%.The impact of prestressed and horizontal layout pitch has a greater impact on the stability of the foundation pit.The former is positive and the latter is negative.When the prestical anchor rod enters the corner and the slope corner is presented,the foundation pit displacement restrictions are the best.The depth and anchoring section reaches 1: 0.62,and the stability of the foundation pit after the free section reaches 1: 0.54 is no longer significant,When the ratio of anchor section to free segment reaches 1:0.88,it is the optimal length combination ratio.When the prestressed anchor rod is set to the upper part of the foundation pit,the surface deformation can be effectively controlled.When the lower part of the foundation pit is set,the foundation pit safety factor is the highest,different setting positions affect the safety factor by up to 4.26%.(4)Based on Terzaghi,the soil arch effect is proposed,the effect of the soil arch effect generated by the prestressed anchor rod,derived the soil arch curve equation that affects the effect of prestressed impact,and the functional relationship image of the arched height and the friction angle.The arch height rises with a decrease in the friction angle,and the distance between it is positively correlated with the distance between the anchor rod,which is inversely linked to the prestressed value.The soil arch’s stress was lessened,thus diminishing its effect.