Shallow-tunnel advance-core-soil extrusion displacement monitoring system and method

Abstract

The invention discloses a shallow-tunnel advance-core-soil extrusion displacement monitoring system which comprises a ground monitoring system and an extrusion displacement monitoring device. The ground monitoring system includes a total-station type electronic distance meter and a reference point system, the reference point system is arranged in the direction of the tunnel axis, and the reference point system in use is located in an undisturbed-by-construction area in front of the tunnel face or a ground deformation stabilized area in the rear of the tunnel face. The shallow-tunnel advance-core-soil extrusion displacement monitoring system is low in cost and simple in operation, all operations are performed in the tunnel, and tunnel deformation can be effectively foreknown to have tunnel stability anticipated all-dimensionally in advance.

Description

technical field [0001] The invention belongs to the technical field of tunnel deformation monitoring devices or equipment, and in particular relates to a monitoring system and method for extrusion displacement monitoring of advanced core soil in shallow buried tunnels. Background technique [0002] During the excavation of the tunnel, the advanced core soil has already begun to deform before the tunnel face passes through, which is mainly manifested as the extrusion deformation of the advanced core soil toward the tunnel face and the pre-convergence deformation of the inner contour toward the inside. The research shows that the deformation of the advanced core soil in front of the tunnel face can not only evaluate the stability of the cavern, but also predict the deformation response of the surrounding rock in front of the tunnel face in advance. Xinyi method emphasizes the importance of advanced core soil stability in tunnel excavation, and advocates the monitoring of extru...

AI Technical Summary

Problems solved by technology

Xinyi method emphasizes the importance of advanced core soil stability in tunnel excavation, and advocates the monitoring of extrusion displacement by inserting a sliding micrometer in front of the tunnel face. Simply put, each measuring point of the sliding micrometer The extrusion displacement of the measuring point is determined relative to the change of the distance from the fixed end in front, but the disadvantages of this method are: (1) When the sliding micrometer measuring tube is installed, the advanced core soil near the face of the installation position is due to the previous The excavation and unloading action has already produced part of the extrusion displacement, so the extrusion displacement measured by this part of the advanced core soil is only a part of the real displacement; (2) The innermost end of the measuring tube is assumed to be stationary during the measurement process , but due to the limitation of the drilling length, the installation length of the sliding micrometer is generally only within 30m, and the influence range of tunnel excavation in front of the tunnel face is roughly 1.5 times the hole diameter, so the tunnel face advances to a certain The distance from the "fixed end" of the post-measurement tube, which is assumed to have no displacement, has actually begun to generate horizontal displacement. At this time, the extrusion displacement calculated by other measuring rings is actually only a part of the real displacement; it can be seen from this that this The effective measurement length of the sliding micrometer is limited in this way, if you want to avoid it, you can only solve this problem by continuously overlapping the measuring tube

The sliding micrometer is a high-precision instrument, and the measuring tube is expensive, and it is difficult to avoid damage to the measuring tube regardless of the construction method. In addition, the installation and reading of the instrument in this way need to be carried out at the face of the tunnel, and the inside of the hole is complicated. The construction environment is difficult to avoid interference with the measurement work. In summary, it is not practical to use the sliding micrometer to monitor the pre-convergence displacement of the advanced core soil.

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