End wall type tunnel portal overall anti-overturning design method

Abstract

The invention discloses an end wall type tunnel portal overall anti-overturning design method to improve the stability safety factor of a tunnel portal, ensure a design to be accurate and reliable, effectively reduce the end wall concrete masonry consumption and effectively reduce the engineering cost. The method comprises the following steps: (1) determining basic calculating data including stratigraphic characteristic parameters, building material parameters and a stability parameter K0; (2) determining the size of each part of the portal; (3) dividing unit grids to a whole wall body and a wall back soil body in contact with the wall body to form a plurality of wall body units and wall back soil body units; (4) calculating end wall soil pressure distribution; (5) calculating overturning resultant moment; (6) calculating stabilizing resultant moment; (7) performing anti-overturning checking calculation.

Description

technical field [0001] The invention relates to a tunnel door structure, in particular to an overall anti-overturning design method for an end wall type tunnel door. Background technique [0002] Tunnel door is a support structure built by masonry and decorated with architectural decoration at the entrance of the tunnel. It is connected with the tunnel lining and road cutting, and is the main component of the entire tunnel structure, as well as the symbol of the entrance and exit of the tunnel. The end-wall tunnel door is a type of tunnel door that is often used. It is widely used in the opening support and retaining of railways, highways, hydraulic tunnels and underground structures. In the past anti-overturning design of the end-wall tunnel door, domestic Usually, the end wall of the tunnel door is regarded as a retaining wall structure, and the design is approximated by the strip method. The analysis of the end wall is transformed into the analysis of the retaining wall ...

AI Technical Summary

Problems solved by technology

This conventional design method originated from the standard design of railway tunnel portals compiled in the 1950s in my country. It has great disadvantages both in theory and in engineering applications, and is obviously unreasonable and uneconomical.

Since the end wall of the portal is closely connected to the lining and embedded in the cutting slope, its stress condition is much better than that of the general retaining wall. However, the original design method uses a narrow strip to calculate the thickness of the end wall separately, without considering the end wall and the lining. The combined effect and various favorable factors, and the end wall is not considered as a whole structure, which is obviously unreasonable in theory

At the same time, through decades of engineering practice, it has been shown that the end wall of the portal built according to the original design method is rarely overturned and damaged, which shows that the actual safety of the previously designed portal is too high, and there is a large safety margin, which has caused masonry and other problems. Waste of building materials, poor social and economic benefits

With the development of social economy and technological progress, there are more and more applications of high-speed and long-span railway tunnels, and the performance of building materials has also been greatly improved. The tunnel diameter, door thickness and overall performance have been greatly improved From an economic and rational point of view, the original overturning design method of the portal is no longer suitable for the current technology and social and economic development, and it is necessary to make inventions and innovations in the design method

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