A Design Method of Primary Support of Tunnel Based on Safety Factor Method

Abstract

The invention discloses a tunnel initial support design method based on a safety factor method, and belongs to the field of tunnel engineering. By calculating surrounding rock pressure of shotcrete-bolt support, and combining a design function of a shotcrete-bolt support structure (i.e., a main bearing body or a temporary support), tunnel characteristics, construction quality, engineering importance and other factors, a total safety factor of the shotcrete-bolt support structure is determined, and a safety factor of a combined arch structure composed of a spray layer, a bolt and surrounding rock is also determined; and then the total safety factor of the shotcrete-bolt support structure is assigned to the corresponding spray layers and the corresponding bolts, thereby calculating the parameters of the spray layers and the bolts, and completing parameter design of the tunnel initial support structure. The tunnel initial support design method based on the safety factor method can providea reasonable and effective method for component selection and quantitative design of the tunnel initial support structure, avoids blindness and randomness of a traditional design method, steps are simple and convenient, implementation is convenient, and the promotion prospects are broad.

Description

technical field [0001] The invention belongs to the field of tunnel engineering, and in particular relates to a tunnel primary support design method based on a safety coefficient method. Background technique [0002] With the continuous development of road traffic and rail traffic in our country, tunnel engineering technology is becoming more and more mature, and various types of tunnels are being used more and more. According to the different construction methods of tunnel engineering, the existing tunnel engineering construction methods usually include open cut method, shield method, mining method, immersed tube method, etc. Among them, the mining method is a relatively traditional and widely used tunnel engineering construction method. method. [0003] For the tunnel engineering constructed by the mining method, the initial support of the tunnel refers to the timely support to control the deformation of the surrounding rock and prevent the collapse after the excavation o...

AI Technical Summary

Problems solved by technology

Among them, the stratum structure method can theoretically be applied to the analysis of various tunnel shapes and spray-bolt support structures under various geological conditions, but it is inconvenient to use, it is difficult to select stratum calculation parameters and stress release rates, and it is difficult to select bolts. Accurate simulation and other defects, the application is greatly restricted; the characteristic curve method is also difficult to apply in actual tunnel engineering due to the problems of calculation parameter selection and support construction time; It is a commonly used method in design, which is widely used in relevant codes and general drawings, but when the shape of the tunnel section or the span is greatly different, the parameters of the designed support structure will be far from the actual situation, and the obtained The reliability of structural parameters is low, which cannot fully meet the application of tunnel engineering, and affects the safety and stability of tunnel engineering

Although in some existing specifications related to tunnel engineering (such as "TB10108-2002 Technical Specifications for Shotcrete Construction Method of Railway Tunnels", "GB50086-2001 Technical Specifications for Bolt Sprayed Concrete Support", "JTG / D70-2010 Design Rules for Highway Tunnels ") and manuals (such as "Technical Manual for Railway Engineering Tunnel Design") put forward some setting regulations and construction requirements for shotcrete, anchor rods, steel mesh, and steel frames, but did not propose specific determination methods for each parameter, often just Given a large selection range, due to the lack of quantitative calculation methods and a clear concept of safety factor in the initial support, the determination of the support structure parameters is subject to increase, and the accuracy of the relevant parameters cannot be fully guaranteed, which makes the tunnel engineering Security and stability are greatly affected

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