Testing device and testing method for relation between restraint stress and extrusion deformation of tunnel face

Abstract

Provided are a testing device and a testing method for a relation between a restraint stress and an extrusion deformation of a tunnel face. A cylindrical pressure chamber is formed by means of a side wall, a top cover and a pedestal in a sealing embedded manner. An oil cylinder is fixed in a groove arranged in a central part of an upper surface of the pedestal. A piston which is in the oil cylinder stretches upwardly into the pressure chamber. An exhaust valve is disposed closed to the side wall on the top cover. An air cylinder barrel, which is smaller than the oil cylinder in diameter, is sealedly embedded on an air cylinder groove arranged in the central part of a bottom surface of the top cover. The air cylinder groove is provided with a vent hole which stretches out through the top cover. A piston in the air cylinder is connected to a displacement measuring rod. An upper end of the displacement measuring rod stretches out from the top cover and is connected to a displacement dial gauge. A water inlet valve is disposed on a position of the pedestal, wherein the position is between an inner chamber of the pressure chamber and the oil cylinder. With the testing device, the relation between the restraint stress and the extrusion deformation of a tunnel face can be accurately tested under different conditions of surrounding rock, thereby providing reliable testing data for design and construction of a tunnel. On the premise of effectively ensuring stabilization of the tunnel face, construction cost is reduced and construction speed is increased.

Description

technical field [0001] The invention relates to a test device and a test method for the relationship between constraint pressure and extrusion deformation of tunnel face. Background technique [0002] In the process of tunnel construction, especially in the excavation of weak surrounding rock, the rear of the face (tunnel excavation face) is empty, while the front is squeezed by the surrounding rock, losing balance, and the face of the face will be convex backward. Extruded deformation. When the extrusion deformation is too large (greater than the empirical control value of 7cm), it will lead to the destruction of the surrounding rock in front, the collapse of the tunnel face, and the instability of the tunnel, which will affect the construction process and even cause accidents. In order to ensure the rapid and safe construction of the tunnel, it is necessary to ensure the stability of the tunnel face. Usually, the constraint pressure on the tunnel face (rear) is increased ...

AI Technical Summary

Problems solved by technology

In the current tunnel construction, the relationship between the extrusion deformation of the tunnel face and the surrounding rock and the restraining pressure imposed by it is estimated by experience, that is, the number and length of the bolts, the amount of grouting, and the area of ​​the core soil. Based on experience, the constraint pressure is either too large, which increases unnecessary construction costs and reduces the construction speed; or the constraint pressure is too small, which cannot effectively ensure the stability of the tunnel face, and the safety of tunnel construction cannot be guaranteed.

Images