Construction method of crushed rock tunnel undercrossing steep slope high bridge pier

Abstract

The invention provides a construction method of a crushed rock tunnel undercrossing steep slope high bridge pier. Sedimentation and offset of a pier at the tunnel high bridge pier section are effectively controlled, and the safe reliability of the crushed rock tunnel undercrossing steep slope high bridge pier is enhanced. The construction method comprises the following steps: (1) constructing an earth surface anchor cable near a bridge pier slope; (2) constructing a small pilot tunnel advance support far away from the bridge pier side, excavating a small pilot tunnel far away from the bridge pier side, constructing preliminary support and temporary support in the pilot tunnel on the side, and pouring a low wall on the side; (3) constructing advance support in a longitudinal first section range; (4) constructing a small pilot tunnel advance support near the bridge pier side in the longitudinal first section range, excavating a small pilot pier near the bridge pier side, constructing preliminary support and temporary support in the pilot tunnel on the side, and pouring a low wall on the side; (5) excavating middle core soil in an upper step, a middle step and a lower step, and excavating and constructing a temporary inverted arch in the upper step; (6) constructing an arch secondary lining timely in the longitudinal first section range; (7) sequentially constructing a longitudinal second section according to the step (3) to the step (6); (8) sequentially constructing a longitudinal third section according to the step (3) to the step (6) and completing tunnel undercrossing high bridge pier section construction.

Description

technical field [0001] The invention relates to tunnel engineering, in particular to a construction method for a broken rock tunnel passing under a high bridge pier on a steep slope. Background technique [0002] As my country's railway construction gradually advances to the southwestern mountainous area, there will be more and more cases of constructing railway tunnels next to existing buildings (structures). Among them, the construction of railway tunnels next to existing viaduct piers is a relatively common situation. The safety of broken rock tunnels buried shallowly and passing under large piers at close range has been paid more and more attention by relevant scholars, designers and construction personnel. Conventional tunnels pass under bridge pile foundations, generally using pile group foundations, the pile foundation load is small, and measures such as grouting reinforcement, pile foundation underpinning, and changing construction methods are often used. Few double...

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Problems solved by technology

[0003] At present, there are many studies on the settlement and safety control of urban subway shield tunnels passing through urban high-rise buildings and ordinary bridge pile foundations. The cross-sectional area of ​​high-speed railway tunnels is 1 to 2 times larger than that of urban subways, and the load of high-rise bridge piers in mountainous areas is also higher than that of urban high-rise buildings. The building load is heavy, so the risk of high-speed railway tunnels passing through high piers is relatively high. However, there are few studies on the schemes of broken rock tunnels passing through complex terrain and high piers in mountainous areas, especially the lack of independent research on tunnels passing under complex steep slope terrain and large piers. Research on Construction Method of Pile Foundation

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