Double-side-wall composite cross method construction method for large-span tunnel under complex geological condition

Abstract

The invention provides a double-side-wall composite cross method construction method for a large-span tunnel under the complex geological condition. The double-side-wall composite cross method construction method is used for solving the technical problems that during construction of a soft rock large-span tunnel, arch crown settlement is not easy to control and a support structure is prone to deforming, optimizing structural force, improving construction convenience and determining construction safety. According to the double-side-wall composite cross method construction method, pilot tunnelson the two sides are constructed firstly, and primary support side wall foundations are constructed in the pilot tunnels to serve as a bearing foundation of an upper primary support system, so that the problems that during construction of the soft rock large-span tunnel, arch crown settlement is not easy to control and the support structure is prone to deforming are solved; bases only serve as thebearing foundation of primary support, under the premise that the stability of the arch wall primary support system is guaranteed, an arch wall secondary lining can still be constructed through an integral formwork trolley, the technique is simple and convenient, the integrity of the secondary lining is guaranteed, the waterproof effect is good, and the construction quality is controllable; and the pilot tunnels on the two sides adopt the excavated section of an arc-shaped arch crown, compared with conventional pilot tunnels constructed through a double-side-wall heading method, the structureforce is more excellent, construction is convenient, and the construction quality of the support system is easy to ensure.

Description

technical field [0001] The invention relates to tunnels, in particular to a construction method of double side walls of large-span tunnels under complex geological conditions by a composite crossing method. Background technique [0002] At present, my country is in a period of rapid development of railway construction. The "four vertical and four horizontal" railways in China have basically taken shape. Restricted by factors such as requirements, line plane curve radius, disaster prevention and rescue, etc., most tunnels are equipped with long-span tunnel sections. [0003] The existing relatively mature tunnel excavation methods mainly include: full-section method, step method, step division method, upper and lower pilot pit method, middle partition method, intersecting middle partition method and double side wall pilot tunnel method, etc. For long-span tunnels that pass through faults and whose formation lithology is dominated by soft rocks such as mudstone and argillaceou...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a construction method of double-side wall compound crossing method for large-span tunnels under complex geological conditions, so as to overcome the unsuitable control of vault settlement and easy deformation of supporting structures in the construction of large-span tunnels in soft rock. Difficulties, optimize structural stress, improve construction convenience and ensure construction safety

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