Shield construction method for three-line parallel under-passing trunk railway tunnel

Abstract

The invention discloses a shield construction method of digging three parallel tunnels under a trunk railway, which belongs to the field of tunnel construction technology. The construction method of the invention comprises the procedure that: the model analysis on each construction sequence and method is made by a three-dimensional finite element and the shield construction sequence is selected; to select the reinforcement project of the railway bed is selected according to the influence degree of the dynamic stress, the load-carrying structural model is adopted to calculate and decide the shield area reinforcing bars enhancement project under the dynamic load of the railway train; the construction parameters are selected according to the test results and the performance of the shield machine, the front earth pressure is reasonably set , the synchronizing mortar injection is enhanced, the forward digging speed and the axis deviation are strictly controlled, the secondary mortar injection is made, the foam or mud is filled by utilizing a pre-embedded injection hole; the strict monitoring measures to monitor the shield construction process is adopted so that the construction unit can adjust the construction parameters in time and guarantee the construction safety. The invention not only guarantees the construction quality and the construction safety of the project but also creates good economic benefit.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a shield construction method for tunnels with three parallel lines passing under a main railway line. Background technique [0002] Shield method tunnel construction is a construction method of underground excavation to construct tunnels under the ground. Due to the advantages of fast construction speed, stable tunnel quality, and less impact on the surrounding environment, shield method construction has gained rapid development since its inception. Development, has been widely used in urban subway, municipal, energy and other engineering fields. The shield construction process will cause changes in the internal stress of the soil, change the strength of the soil structure, and cause the ground to move within a certain range around the tunnel. When the construction tunnel passes through the railway, it will inevitably cause uplift, settlement, etc. Negative Effects. ...

AI Technical Summary

Problems solved by technology

Judging from the existing engineering examples, there are single-line or double-line shield tunnels passing through the railway, but there is no shield tunneling method in which the three-line small-space tunnels pass through the railway successively under the condition that the train speed is 140km / h.

The three-line tunnel is constructed in close proximity, no matter whether the three lines are constructed simultaneously or successively, there must be complex mutual influences, especially the construction of the tunnel first will be affected by the construction of the later tunnel, and the vibration of the train will also affect the stress redistribution of the tunnel and the stratum Displacement has a significant impact, which increases the difficulty of tunnel construction, and is a compound and close construction problem

On the other hand, in the process of shield tunneling in which the three-line tunnel crosses the railway successively, there are multiple disturbances and superimposed effects on the stratum, which can easily cause the settlement of the surface and the main railway line to exceed the limit. In the case where the railway operation is not allowed to be interrupted Under the current situation, the shield construction of the three-line tunnel passing through the railway in succession poses serious hazards to the high-speed operating trains.

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