Method for reasonably earthing and setting cross river-sea shield tunnel

Abstract

The embodiment of the invention provides a method for reasonably earthing and setting a cross river-sea shield tunnel. The method comprises the following steps: acquiring tunnel design and a construction parameter and determining physical and mechanical parameters of an earthing layer and a water layer on the tunnel; calculating a muddy water support pressure upper limit value capable of guaranteeing shield tunneling safety under different earthing thicknesses; calculating a muddy water support pressure lower limit value capable of guaranteeing shield tunneling safety under different earthingthicknesses; calculating a shield muddy water support pressure allowable difference value capable of guaranteeing tunneling safety under different earthing thicknesses; determining the maximal fluctuation range of shield muddy water support pressure in the tunneling process; enabling the maximal fluctuation range of the shield muddy water support pressure to be equal to the shield muddy water support pressure allowable difference value under a certain earthing thickness to acquire the minimal earthing thickness and considering safety coefficient to acquire earthing thickness. According to themethod, the rationality of the earthing thickness of the cross river-sea shield tunnel is guaranteed, and cleavage and instable failure of the tunneling face of the cross river-sea shield tunnel are avoided.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a method for setting reasonable covering soil of shield tunnels across rivers and seas based on excavation safety. Background technique [0002] With the development of traffic in coastal cities along the river, in order to alleviate the pressure of urban traffic, it has become a trend to build large-section tunnels across rivers and seas. Soft soil tunnels across rivers and seas are often constructed using mud-water balance shields. Due to the constraints of line alignment, stratum conditions and project cost, it is generally required that the covering soil thickness should be as thin as possible, which is called the small covering soil interval. During the construction of shield tunnels in small soil-covered sections, shield excavation is faced with many challenges such as high water pressure, interaction between soft and hard strata, changeable underwater topograp...

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Problems solved by technology

[0003] In the existing technology, measures such as reinforcement or increasing the thickness of the covering soil are generally adopted for the special small covering soil section, and measures such as deepening the originating and arriving shafts of the shield tunnel are also adopted when restricted by special conditions, which increases the project cost and construction difficulty

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