Study On The Surrounding Rock Pressure Of Large-Diameter Shield Tunnels

The determination of the surrounding rock pressure of the shield tunnel is an important basis for the comparison and selection of construction plans and structural design,and only by clarifying its size and change situation and clarifying the influence of shield tunnel boring on the surrounding rock pressure can we better provide reference for tunnel construction.Relying on the Yellow Crane Tower tunnel project of the southern extension of Wuhan Heping Avenue(Zhongshan Road ～Zhangzhidong Road),this paper develops a surrounding rock pressure monitoring device based on fiber grating sensor,selects typical sections for monitoring and testing in the on-site construction section,and adopts the method of combining on-site monitoring test with numerical simulation calculation and theoretical analysis to study the variation law of surrounding rock pressure of large-diameter shield tunnel with shield tunneling construction.The main tasks are:(1)Based on optical fiber sensing technology,the surrounding rock pressure monitoring device was designed and developed,the indoor calibration experiment of the monitoring device was designed,and the strain characteristics of the monitoring device were analyzed.In the on-site construction section,typical sections were selected,monitoring devices were laid and installed,and the surrounding rock pressure was monitored on site,and the variation law of surrounding rock pressure of largediameter shield tunnel with shield boring construction was discussed through the study of the measured data.(2)According to the engineering investigation report,the stratigraphy of Wuhan Yellow Crane Tower Tunnel was generalized,and the three-dimensional model of the Yellow Crane Tower Tunnel was simulated and calculated by using the limited difference software FLAC3 D,the stratigraphic displacement,vertical surrounding rock stress and lining radial pressure of the Yellow Crane Tower Tunnel were analyzed,and the numerical calculation results of the surrounding rock pressure were compared and analyzed with the on-site monitoring data.(3)On the basis of the theory of surrounding rock pressure calculation by scholars at home and abroad,combined with the on-site monitoring data of Wuhan Yellow Crane Tower Tunnel Project,the overlying rock and soil mass of the tunnel are assumed,and the surrounding rock pressure calculation formula suitable for largediameter shield tunnels is derived based on the limit balance theory,and the surrounding rock pressure calculation results are compared and analyzed with the existing commonly used theoretical formulas and on-site monitoring data to verify the correctness and applicability of the formula.Figure [55] Table [4] Reference [83]...