A joint test device for internal and external forces of a shield tunnel segment and its manufacturing and embedding method

Abstract

The invention relates to a device for jointly testing an internal force and an external force of a shield tunnel duct piece. The device comprises a steel bar strain gauge, a soil pressure sensor, a water stop steel plate and a cable protection box and a connecting screw, wherein one end of the steel bar strain gauge is connected with a steel bar strain gauge cable and is connected with a duct piece steel bar cage through a galvanized wire binding method, the steel bar strain gauge cable penetrates through the cable protection box, the cable protection box is connected with the water stop steelplate through the connecting screw, an adjusting nut and a washer are arranged between the connecting screw and the cable protection box, a corresponding number of wiring holes are distributed in thebottom surface of the cable protection box, the top face of the cable protection box is provided with a cable protection box cover, the bottom of the cable protection box is provided with protectivesponge. The device has the advantages that the steel bar strain gauge of the device is connected with the duct piece steel bar cage through the galvanized wire binding method, accordingly the processes of steel bar cage cutting and welding of the steel bar strain gauge to a connecting rod are omitted, the embedding time of a duct piece prefabrication factory is greatly shortened, and the influenceon the production of the duct piece prefabrication factory is smaller.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering testing, and in particular relates to a manufacturing and embedding method of a combined test device for the internal force of a shield tunnel segment and the external soil pressure of the segment. Background technique [0002] The shield method is the most common construction method for tunnel construction. Its working mechanism is that the cutter head of the shield machine is cut, the screw conveyor is unearthed, the hydraulic jack is pushed, and the segment assembly system is used to continuously assemble the standard prefabricated reinforced concrete segments. In order to form a lining tunnel structure system, each ring of the lining tunnel is connected by several segments through bolts, and the segments of each ring and adjacent rings are also connected by bolts, so that the entire tunnel is densely covered with segments and pipes. Sheet bolt connection points. Due to the existence of...

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Problems solved by technology

[0008] 2. The sensor thread cannot be soaked in water for a long time, otherwise the sensor will be invalid after water seeps into the sensor.

[0013] 1. There are three problems in the post-embedding method of the sensor that are difficult to solve: First, the embedding process is complicated, and the embedding time is too long, and the pre-embedded protective steel plate is prone to difficulty in dismantling the steel plate or damage to the installation chassis of the earth pressure sensor after dismantling, resulting in The earth pressure sensor cannot be placed in the segment. Such a long-term and complicated embedding method is not allowed by the segment production unit; second, the sensor post-embedment method needs to pass the cable through the segment, so it must be installed in the tube. The threaded pipe is reserved in advance, and the existence of the pipe is easy to make the segment leak; the third is that the sensor wire end cannot be buried in the segment, and the exposed wire end will cause the sensor to fail due to water immersion during the maintenance stage of the segment pool

[0014] 2. Although the invention of the monitoring rod can solve the above-mentioned three problems encountered by the sensor back-burying method, because it uses a strain gauge-type miniature earth pressure sensor, the test accuracy is affected by many factors such as temperature and cable length. Results are less reliable than vibrating wire sensors

In addition, piercing grouting holes on segments to embed sensors has strict requirements on the stratum. If it is implemented in strata with high water permeability, water seepage accidents may occur after the grouting holes are pierced, posing a serious threat to the operational safety of the tunnel.

[0015] 3. The sensor pre-embedding method can avoid the water immersion of the thread end and the water leakage of the segment, but this method has two disadvantages: first, the method requires welding to pre-embed the earth pressure sensor or the steel bar gauge in the steel cage, and the welding of the steel bar stress gauge It is also necessary to cut off the main reinforcement, and such embedding will take a long time; the second is that the earth pressure sensor buried by this method needs to expose the surface of the segment, and the surface of the segment must be smoothed for the needs of hoisting the segment, so that it must be After smoothing, it is very difficult to chisel off the concrete on the surface of the earth pressure sensor, and the earth pressure sensor is easily damaged

[0016] 4. The test items of the existing sensor embedding device are relatively single, and it is impossible to carry out risk assessment on the condition of the segment

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